EPLAN P8 — Device Designation (-) Reference Guide
| Based on IEC 81346 | IEC 61346 | ISO 10628 | ISA-5.1 | Expert conventions across electrical, automation, instrumentation, IT, and mechanical disciplines |
34 sections covering every device type across all disciplines:
Foundation:
- Full IEC 81346 primary letter table (A–Y) with two-letter combinations and typical devices
- IEC vs ISA vs common practice cross-reference table — so you know which standard applies when
Power & Protection:
- LV breakers (
QF, MCB, MCCB, ACB, RCBO) with descriptive suffixes for every feeder type - MV switching (
QB, QD, QS, QE, FU) + VCB-specific (CLOSING_COIL, TRIP_COIL1/2, ANTI_PUMP_K, SPRING_CHARGED, draw-out interlock switches) - Protection relays — all types (
F_OC, F_EF, F_DIFF, F_DIST, F_REF, F_BUCHH, F_WTI, F_ARC) - CTs, VTs, power analysers, energy meters, phase monitors
Motor Control:
- Contactors — every type (
KM_MAIN, KM_STAR, KM_DELTA, KM_FWD, KM_REV, KM_VFD, KM_BP, KM_NORM, KM_ALT) - Relays, timers (
KT_SD, KT_ON, KT_OFF, KT_RETRANS, KT_FLASH) - VFDs, soft starters, braking resistors
Instrumentation (both worlds):
- IEC
BT, BP, BF, BL, BA sensor codes - Full ISA-5.1 tag system — first letter table, last letter table, and every common tag (
FT101, PT201, TT301, LT401, AT501) with H/L/HH/LL safety suffix convention
PLC & Safety:
- Every PLC module type (
CPU_A/B, PM, IM, DI01, DO01, AI01, RTD01, CM_PN, CM_PB, SYNC_MOD) - Safety relays and devices (
F3_ESTOP, F3_GUARD, F3_LIGHT, RFID_SAFE, AREA_SCAN, LIGHT_CRT) - SIS modules (
CPU_S_A/B/C, DI_S01, DO_S01)
Complete worked examples — DOL starter, star-delta, PLC panel, DCS instrumentation loop, MV feeder panel, SIL2 safety shutdown loop (all six showing full =FUNCTION+LOCATION-DEVICE tags)
Table of Contents
- Fundamentals
- IEC 81346 Device Reference Designation — Letter Codes
- Power Devices — Breakers, Isolators, Switches
- Protection & Measuring Devices
- Contactors, Relays & Timers
- Transformers & Power Conversion
- Drives, Starters & Motor Control
- Motors, Actuators & Prime Movers
- Power Supplies & Energy Storage
- Terminals, Connectors & Cabling
- Sensors & Detectors (Digital / Binary)
- Instrumentation — Analog Measurement
- Instrumentation — ISA Tag Naming (P&ID)
- Control & Signal Conditioning Devices
- Indication & Signalling Devices
- Operator Interface Devices (Buttons, Switches, Selectors)
- PLC & Controller Modules
- Safety Devices & Safety Relays
- Communications & Network Devices
- HMI, Computers & IT Hardware
- Heating, Cooling & Environmental
- Pneumatic & Hydraulic Devices
- Mechanical & Structural Components
- Cables, Conduits & Routing
- Panel Building Hardware
- MV Switchgear Specific Devices
- Battery & DC System Devices
- Fire, Gas & Safety Detectors
- Building Services Devices
- Numbering Conventions & Suffixes
- Full Tag Examples — Complete Projects
- Cross-Reference: IEC 81346 vs ISA-5.1 vs Common Practice
- Common Mistakes
- Expert Tips
Fundamentals
The Three Pillars of EPLAN Referencing (IEC 81346)
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| = Function designation → WHAT it does
+ Location designation → WHERE it is
- Device designation → WHAT it is (the component itself)
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What Device Designation Represents
The - designation is the tag of the actual component — it uniquely identifies the physical device within its location and function context. It answers:
“Which specific component is this?”
Full Tag Syntax
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| =FUNCTION+LOCATION-DEVICE
=CTRL+CP1-CPU1 PLC CPU, in panel CP1, control function
=PWR+MCC1.M01-KM1 Contactor KM1, in MCC drawer M01, power function
=INST+FIELD-FT101 Flow transmitter FT101, in field, instrumentation
=SAFE+CP1.SAFE-F3_ESTOP Safety relay, in safety section of CP1
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Numbering Structure
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| [Letter Code] + [Number] Basic form
[Letter Code] + [Number] + [Suffix] Extended form
Examples:
-K1 Relay 1
-KM1 Main contactor 1
-KM_STAR Star contactor (named suffix)
-F1 Protection device 1
-F_OC_A Overcurrent relay, incomer A (descriptive suffix)
-QF1 Circuit breaker 1 (Q = switching, F = protection)
-PQ1 Power quality analyser 1
-FT101 Flow transmitter tag 101 (ISA style)
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When to Use Numbers vs Descriptive Suffixes
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| Numbers alone (recommended for simple panels):
-K1, -K2, -K3 Easy, sequential, no ambiguity
Descriptive suffixes (recommended for complex panels):
-KM_MAIN Immediately clear this is the main contactor
-KM_STAR Star contactor in star-delta
-KM_DELTA Delta contactor in star-delta
-K_WD Watchdog relay
-F_OC Overcurrent protection
ISA instrument tags (process / P&ID projects):
-FT101 Flow transmitter loop 101
-PT302 Pressure transmitter loop 302
-TIC401 Temperature indicating controller loop 401
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IEC 81346 Device Reference Designation — Letter Codes
The first letter(s) define the device type. IEC 81346 uses a two-level system.
Primary Letter — Device Kind
| Letter | Device Kind | Typical Devices | |——–|————|—————-| | B | Converts physical variable → signal | Sensors, transducers, encoders, detectors | | C | Stores energy or material | Capacitors, batteries, tanks, accumulators | | D | Processes / stores information | PLCs, computers, HMIs, recorders, displays | | E | Provides radiation or thermal energy | Heaters, lamps, UV emitters | | F | Protects against dangerous conditions | Fuses, breakers, protection relays, safety devices | | G | Generates / supplies electrical energy | Power supplies, batteries, generators, UPS | | H | Signals / indicates state or condition | Lamps, buzzers, horns, displays, annunciators | | K | Processes signals / controls / switches | Relays, timers, contactors, PLC outputs | | M | Provides mechanical energy | Motors, actuators, cylinders, pumps (motor part) | | N | Regulates / controls process variable | VFDs, PID controllers, regulators | | P | Measures / tests | Meters, analysers, instruments, gauges | | Q | Switches / varies electrical energy | Isolators, circuit breakers, disconnectors | | R | Restricts / stabilises energy or flow | Resistors, reactors, chokes, dampers | | S | Converts manual operation → signal | Push buttons, switches, selectors, keyboards | | T | Converts electrical quantities | Transformers, CT, VT, rectifiers, inverters | | U | Keeps objects in a defined position | Clamps, brakes, locks, holders | | V | Processes materials or products | Conveyors, mixers, reactors, valves (flow) | | W | Conducts / transmits / distributes | Cables, busbars, waveguides, antenna | | X | Connects / terminates | Terminal blocks, connectors, plugs, junction | | Y | Positions / guides | Positioners, guides, stepper actuators |
Common Two-Letter Combinations Used in Practice
| Code | Meaning | Example Device | |——|———|—————-| | BK | Encoder / speed sensor | Rotary encoder | | BP | Pressure sensor | Pressure switch | | BT | Temperature sensor | Thermocouple, PT100 | | BL | Level sensor | Float switch, level switch | | BF | Flow sensor | Flow switch | | BA | Analyser sensor | Gas analyser input | | BG | Position / limit switch | Proximity sensor, limit switch | | CM | Motor capacitor | Run / start capacitor | | DD | Data / logic processor | PLC, computer | | EH | Heating element | Trace heating, panel heater | | EL | Lighting element | Lamp, LED strip | | FA | Fuse (general) | Cartridge fuse | | FB | Overcurrent protective device | MCCB, MCB | | FC | Combined protective device | RCBO, motor circuit breaker | | FD | Residual current device | RCD, RCCB | | FU | HV fuse | HRC fuse, expulsion fuse | | GA | Battery | Lead-acid, Li-ion battery | | GB | Battery charger | Float charger, SMPS charger | | GS | Power supply (AC/DC) | SMPS, linear PSU | | GU | UPS | UPS system | | HA | Acoustic alarm | Buzzer, horn, siren | | HL | Indicator lamp | Pilot lamp, LED indicator | | HR | Digital display / readout | Digital panel meter | | KA | Auxiliary relay | General purpose relay | | KC | Contactor | Motor contactor | | KM | Main contactor | Main power contactor | | KT | Timer relay | On-delay, off-delay, star-delta timer | | KW | Watchdog relay | PLC watchdog output | | MA | Motor (asynchronous) | AC induction motor | | MB | Brake (motor) | Electro-mechanical brake | | MC | Motor (DC) | DC motor | | MS | Servo motor | Servo / stepper motor | | MT | Motor (special) | Torque motor, linear motor | | NA | VFD / frequency converter | Variable frequency drive | | NC | PID controller | Process controller | | NR | Regulator | Voltage regulator, pressure regulator | | PA | Ammeter | Current meter | | PB | Power analyser | Power quality analyser | | PC | Counter | Event counter, hour meter | | PF | Frequency meter | Hz meter | | PH | Phase sequence relay | Phase monitor relay | | PJ | Energy meter | kWh meter | | PQ | Power quality analyser | PQ meter with harmonics | | PV | Voltmeter | Voltage panel meter | | PW | Power meter | kW meter | | QA | Switch / disconnector | Load break switch, isolator | | QB | Circuit breaker (HV) | Vacuum/SF6 circuit breaker | | QD | Disconnector / isolator (HV) | Air-break disconnector | | QE | Earthing switch | Earth switch (MV/HV) | | QF | Circuit breaker (LV) | MCCB, MCB, ACB | | QM | Motor circuit breaker | Combined contactor + breaker | | QS | Load break switch | LBS, on-load switch | | RA | Resistor | Fixed resistor | | RB | Braking resistor | Dynamic brake resistor | | RL | Inductor / reactor | Line reactor, choke | | RR | Variable resistor | Rheostat, potentiometer | | SA | Selector switch | Multi-position rotary switch | | SB | Push button | Momentary push button | | SK | Key switch | Key-operated switch | | SL | Limit switch (manual) | Mechanical limit switch | | SS | Selector switch (maintained) | Mode selector, local/remote | | TA | Current transformer | Metering / protection CT | | TC | Thyristor / SCR | Power thyristor, soft starter | | TF | Filter transformer | Isolation transformer | | TM | Power transformer | Distribution transformer | | TV | Voltage transformer | Metering / protection VT/PT | | TY | Rectifier / converter | AC/DC converter | | VA | Valve (process) | Control valve, on/off valve | | VF | Fan | Cooling fan, ventilation fan | | VP | Pump | Process pump | | XB | Busbar | Busbar connection point | | XD | Distribution terminal | DIN rail terminal block | | XP | Plug / socket | Connector plug | | XS | Socket | Socket outlet | | XT | Terminal block | Screw/spring terminal | | YA | Solenoid actuator | Solenoid coil, solenoid valve | | YB | Brake | Electromechanical brake | | YV | Solenoid valve | Pneumatic / hydraulic solenoid valve | | ZA | Zener barrier | Intrinsic safety barrier | | ZI | Galvanic isolator | HART isolator, signal isolator | | ZF | EMC filter | Line filter, EMC filter |
Power Devices — Breakers, Isolators, Switches
LV Circuit Breakers & Isolators
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| -QF_MAIN Main incomer air circuit breaker (ACB) — mains level
-QF_INC Incomer MCCB (moulded case circuit breaker)
-QF1 .. -QFn Numbered outgoing circuit breakers / MCBs
-QF_MCC1 Feeder breaker to MCC1
-QF_DB1 Feeder breaker to DB1
-QF_UPS Feeder breaker to UPS
-QF_PLC MCB for PLC power
-QF_HMI MCB for HMI power
-QF_FIELD MCB for field device power
-QF_SAFE MCB for safety system power
-QF_HEAT MCB for panel heater
-QF_LIGHT MCB for panel lighting
-QF_24V MCB for 24VDC supply
-QS1 .. -QSn Load break switch / isolator (maintained open/close)
-QS_LOCAL Local isolator switch
-QS_MBP Maintenance bypass switch (UPS)
-QR1 Residual current circuit breaker (RCCB)
-RCBO1 RCBO (RCD + MCB combined)
-MCB_L1 MCB for lighting circuit 1
-MCB_P1 MCB for power circuit 1
-MCB_H1 MCB for HVAC circuit 1
-MCB_E1 MCB for emergency circuit
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HV / MV Switching Devices
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| -QB1 .. -QBn Vacuum / SF6 circuit breaker (HV/MV)
-QB_INC Incomer VCB
-QB_TIE Bus tie / bus section VCB
-QB_FDR1 Feeder VCB 1
-QB_TX1 Transformer feeder VCB
-QB_MTR1 MV motor feeder VCB
-QD1 .. -QDn Disconnector / isolator (air-break, HV)
-QD_LINE Line side disconnector
-QD_BUS Bus side disconnector
-QS1 .. -QSn Load break switch (MV — ring main, RMU)
-QS_RING_IN Ring incomer LBS
-QS_RING_OUT Ring outgoing LBS
-QS_TX TX feeder LBS
-QE1 .. -QEn Earthing switch (MV/HV)
-ES1 .. -ESn Earthing switch (alternative common naming)
-ES_LINE Line earth switch
-ES_BUS Busbar earth switch
-FU1 .. -FUn HRC fuse (MV transformer feeder)
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Manual Isolation & Changeover
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| -QS_MAINS Mains isolation switch
-QS_GEN Generator isolation switch
-QS_ATS ATS changeover switch (manual)
-QS_NORM Normal supply isolator
-QS_ALT Alternative supply isolator
-COS1 Changeover switch (manual 2-position)
-MTS1 Manual transfer switch
-ISOL1 Panel isolation switch (lockable)
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Protection & Measuring Devices
Protection Relays
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| -F1 .. -Fn General protection device (numbered)
-F_OC Overcurrent protection relay
-F_EF Earth fault protection relay
-F_DIFF Differential protection relay
-F_DIST Distance protection relay
-F_REF Restricted earth fault relay
-F_BUCHH Buchholz relay (oil transformer)
-F_WTI Winding temperature indicator / relay
-F_OTI Oil temperature indicator / relay
-F_PRD Pressure relief device / relay
-F_OSL Oil surge relay / gas relay
-F_UV Undervoltage relay
-F_OV Overvoltage relay
-F_PHASE Phase sequence / phase loss relay
-F_MOTOR Motor protection relay (multifunction)
-F_THERM Thermal overload relay (standalone)
-F_SAFE Safety relay (non-SIL general purpose)
-F_BUSBAR Busbar protection relay
-F_ARC Arc flash detection relay
-F_FREQ Under/over frequency relay
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Measurement & Metering
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| -CT1 .. -CTn Current transformer (protection / metering)
-CT_INC Incomer CT
-CT_FDR1 Feeder CT 1
-VT1 .. -VTn Voltage transformer / potential transformer
-VT_BUS Busbar VT
-VT_METER Metering VT
-PA1 Ammeter (panel-mount)
-PV1 Voltmeter (panel-mount)
-PW1 Wattmeter / power meter
-PF1 Power factor meter
-PQ1 .. -PQn Power quality analyser (full PQ with harmonics)
-PQ_MAIN Main incomer power quality analyser
-PQ_FDR1 Feeder 1 power quality analyser
-KWH1 .. -KWHn Energy meter / kWh meter
-KWH_MAIN Main energy meter
-KWH_LIGHT Lighting sub-meter
-KWH_POWER Power sub-meter
-FREQ1 Frequency meter
-PH1 Phase sequence indicator
-PC1 Hour meter / event counter
-PLC_METR1 Power line carrier meter
-THD1 Total harmonic distortion analyser
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| -KM1 .. -KMn Main contactor (general numbered)
-KM_MAIN Main power contactor (DOL starter)
-KM_STAR Star contactor (star-delta starter)
-KM_DELTA Delta contactor (star-delta starter)
-KM_FWD Forward contactor (reversing starter)
-KM_REV Reverse contactor (reversing starter)
-KM_VFD VFD output contactor
-KM_BP Bypass contactor (VFD bypass)
-KM_RUN Run bypass contactor (soft starter inline type)
-KM_NORM Normal supply contactor (ATS)
-KM_ALT Alternative supply contactor (ATS)
-KM_COOL Cooling fan contactor (transformer)
-KM_AUX Auxiliary contactor (signal/interlock duty)
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Auxiliary & Interposing Relays
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| -K1 .. -Kn General relay (numbered)
-KA1 .. -KAn Auxiliary relay (IEC 81346 style)
-K_START Start permissive relay
-K_STOP Stop command relay
-K_RUN Running confirm relay
-K_TRIP Trip / fault relay
-K_FAULT General fault relay
-K_ALARM General alarm relay
-K_READY Ready / healthy relay
-K_REMOTE Remote command relay
-K_LOCAL Local command relay
-K_ATS ATS changeover relay
-K_INC_A Incomer A auxiliary relay
-K_TIE Bus tie interlock relay
-K_WD Watchdog relay (PLC healthy)
-K_INTERLOCK Interlock relay (general)
-K_PERMISSIVE Permissive relay
-K_INHIBIT Inhibit relay
-K_LATCH Latching relay
-KP1 Pulse relay
-KR1 Reed relay
-KM_AUX1 Auxiliary contact block (add-on)
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Timers
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| -KT1 .. -KTn Timer relay (general numbered)
-KT_SD Star-delta changeover timer
-KT_ON On-delay timer
-KT_OFF Off-delay timer
-KT_RETRANS Retransfer delay timer (ATS)
-KT_TRANS Transfer delay timer (ATS)
-KT_START Start delay timer
-KT_RESTART Auto-restart delay timer
-KT_FLASH Flasher / pulse timer
-KT_WD Watchdog timer
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| -TM1 .. -TMn Power transformer (general)
-TM_MAIN Main power transformer
-TX1 .. -TXn Transformer (alternative common tag)
-T1 .. -Tn Transformer (simple projects)
-T_CTRL Control transformer (230V to 24VAC)
-T_ISO Isolation transformer
-T_AUTO Autotransformer
-TF1 Filter / EMC transformer
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| -CT1 .. -CTn Current transformer
-VT1 .. -VTn Voltage transformer (potential transformer)
-TA1 Current transformer (IEC 81346 two-letter)
-TV1 Voltage transformer (IEC 81346 two-letter)
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Power Conversion
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| -TY1 Rectifier / AC-DC converter
-INV1 Inverter (DC-AC)
-CONV1 Converter (general)
-TC1 Thyristor controller / soft starter power stack
-CHRG1 Battery charger
-GB1 Battery charger (IEC 81346 style)
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Reactors & Filters
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| -RL1 .. -RLn Line reactor / choke (VFD, harmonic)
-L1 Inductor (simple notation)
-EMC1 .. -EMCn EMC line filter
-ZF1 EMC filter (IEC 81346 style)
-THF1 Tuned harmonic filter
-HF1 High-frequency filter
-C1 .. -Cn Capacitor (power factor / filter)
-CM1 Motor run capacitor
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Drives, Starters & Motor Control
Variable Frequency Drives (VFDs)
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| -VFD1 .. -VFDn VFD unit (general numbered)
-VFD_X VFD for X-axis
-VFD_Y VFD for Y-axis
-VFD_Z VFD for Z-axis
-VFD_SP VFD for spindle
-VFD_P1 VFD for pump 1
-VFD_FAN1 VFD for fan 1
-NA1 .. -NAn VFD / frequency converter (IEC 81346 two-letter)
-INV_MAIN Main drive inverter
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Soft Starters
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| -SS1 .. -SSn Soft starter unit (general numbered)
-SS_P1 Soft starter for pump 1
-TC1 .. -TCn Thyristor controller / soft starter (IEC 81346)
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Motor Protection & Starter Components
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| -F_THERM1 Thermal overload relay
-F_MOTOR1 Motor protection relay (multifunction — Siemens 3RU, ABB EF, Sprecher)
-QM1 Motor circuit breaker (combined QF + thermal protection)
-KM_MAIN Main contactor
-KM_AUX Auxiliary contact block
-PTC1 PTC thermistor trip relay (winding temperature)
-NTC1 NTC temperature monitoring relay
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Braking
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| -RB1 .. -RBn Braking resistor (dynamic brake for VFD)
-BR1 Brake resistor (alternative notation)
-YB1 Electromechanical brake (motor-mounted)
-MB1 Brake (IEC 81346 two-letter)
-BC1 Brake controller / rectifier
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Motors, Actuators & Prime Movers
Motors
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| -M1 .. -Mn Motor (general numbered — most common)
-MA1 .. -MAn AC induction motor (IEC 81346 two-letter)
-MC1 DC motor
-MS1 Servo motor
-MT1 Torque motor / special motor
-P1 .. -Pn Pump motor (process / P&ID convention — see ISA section)
-FAN1 .. -FANn Fan motor (common in HVAC)
-COMP1 Compressor motor
-CONV1 Conveyor drive motor
-SP1 Spindle motor
-AG1 Agitator motor
-MIX1 Mixer motor
-BLW1 Blower motor
-PUMP1 Pump motor (descriptive)
-HYD_MTR1 Hydraulic power unit motor
-EXT1 Extruder motor
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Actuators & Valves
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| -YA1 .. -YAn Solenoid actuator / solenoid valve coil
-YV1 .. -YVn Solenoid valve (pneumatic / hydraulic)
-YV_FWD Forward solenoid valve
-YV_REV Reverse solenoid valve
-YV_CLAMP Clamp solenoid valve
-YV_UNCLAMP Unclamp solenoid valve
-VA1 Control valve (process — motorised)
-VA_CTRL1 Control valve positioner
-MOV1 Motor-operated valve
-AOV1 Air-operated valve / pneumatic valve
-HOV1 Hand-operated valve (if monitored)
-POS1 Valve positioner
-ACT1 Linear actuator (electric)
-ACT_SERVO1 Servo actuator
-CYL1 .. -CYLn Hydraulic / pneumatic cylinder
-GRAB1 Gripper actuator
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Mechanical Drives
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| -GB1 Gearbox (monitored — speed feedback)
-CLUTCH1 Clutch (electric)
-BRAKE1 Mechanical brake (release coil)
-COUPLING1 Flexible coupling (if instrumented)
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Power Supplies & Energy Storage
Power Supplies
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| -PS1 .. -PSn Power supply unit (general numbered)
-PS_A Power supply A (redundant pair)
-PS_B Power supply B (redundant pair)
-GS1 SMPS / switch-mode power supply (IEC 81346)
-SMPS1 Switch-mode power supply
-PSU1 Power supply unit
-PS_PLC PLC power supply (system power module)
-PS_IO I/O power supply
-PS_LOOP1 Loop power supply (4-20mA instrument loops)
-PS_SAFE Safety system power supply (isolated)
-PM1 Power module (PLC-integrated, e.g. Siemens PM)
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UPS & Buffering
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| -UPS1 .. -UPSn UPS unit
-GU1 UPS (IEC 81346 two-letter)
-UPS_BUF1 24VDC UPS buffer module (DIN rail, e.g. SITOP UPS1600)
-BATT_BUF1 Battery buffer module
-BATT_MGT1 Battery management module
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Batteries & Capacitors
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| -GA1 .. -GAn Battery / battery bank
-BATT1 Battery (common industrial notation)
-C1 .. -Cn Capacitor (power / filter)
-CAP1 Supercapacitor module
-CB1 Capacitor bank (PFC step)
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Terminals, Connectors & Cabling
Terminal Blocks
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| -X1 .. -Xn Terminal block / terminal strip (general — most common)
-XT1 Terminal block (IEC 81346 two-letter)
-X_DI1 Digital input terminal group
-X_DO1 Digital output terminal group
-X_AI1 Analog input terminal group
-X_AO1 Analog output terminal group
-X_RTD1 RTD input terminal group
-X_SAFE1 Safety circuit terminal group
-X_PWR1 Power terminal group
-X_COMM1 Communications terminal group
-X_EARTH Earth / PE terminal bar
-X_SCREEN Cable screen / shield terminal
-XD1 DIN rail terminal (IEC 81346)
-PE1 Protective earth terminal bar
-N1 Neutral terminal bar
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Connectors & Plugs
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| -XP1 .. -XPn Plug / male connector
-XS1 .. -XSn Socket / female connector
-XP_PWR Power connector plug
-XP_COMM Communications connector (M12, RJ45 on device)
-XP_HMI HMI connection plug
-XP_USB USB connector
-XP_SD SD card / memory card
-XB1 Busbar connector (IEC 81346)
-JB1 Junction block (multi-pin)
-MC1 Multi-pin connector (general)
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Cable & Wiring References
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| -W1 .. -Wn Cable / wire (IEC 81346 — W = conducting)
-WC1 Control cable
-WP1 Power cable
-WS1 Signal cable
-WF1 Fibre optic cable
-WN1 Network cable (Cat6, etc.)
-CAB1 Cable (common industrial notation)
-PIGTAIL1 Fibre pigtail
-JUMPER1 Jumper wire / patch lead
-LOOM1 Wire loom / harness
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Sensors & Detectors (Digital / Binary)
Position & Presence
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| -B1 .. -Bn Sensor / detector (general — most common simple notation)
-BG1 .. -BGn Position / limit sensor (IEC 81346)
-SL1 .. -SLn Mechanical limit switch
-SQ1 .. -SQn Proximity / position switch (common European notation)
-BQ1 Proximity switch (IEC 81346)
-PROX1 Inductive proximity sensor
-PROX_EXT1 Extended range proximity sensor
-CAP1 Capacitive proximity sensor
-ULTRA1 Ultrasonic proximity sensor
-PHOTO1 Photoelectric sensor
-REFLX1 Retro-reflective photosensor
-THR_BEAM1 Through-beam sensor
-LASER1 Laser distance / presence sensor
-COLOUR1 Colour sensor
-RFID1 RFID reader
-LS1 Level switch (discrete — float or electrode)
-FS1 Flow switch (discrete — paddle or thermal)
-PS_SW1 Pressure switch (discrete)
-TS_SW1 Temperature switch (discrete — bimetal or capillary)
-VS1 Vibration switch
-TILT1 Tilt switch
-SLIP1 Slip detection sensor
-ROPE_SW1 Rope / cable pull switch (conveyor safety)
-SKIRT1 Skirt monitoring switch
-BELT_ALIGN1 Belt alignment switch
-ZERO_SPD1 Zero speed switch
-OVERSPD1 Overspeed switch / detector
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Door, Guard & Safety Sensing
1
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6
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| -SL_DOOR1 Door limit switch
-SL_GUARD1 Guard door limit switch
-SL_HATCH1 Hatch / access panel switch
-MAG_SW1 Magnetic door switch
-RFID_GUARD1 RFID guard lock / interlock
-TPSW1 Trapped key switch
-HANDLE1 Handle switch
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Rotational & Motion
1
2
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6
7
| -BK1 .. -BKn Encoder (IEC 81346)
-ENC1 Rotary encoder (absolute or incremental)
-ENC_ABS1 Absolute encoder
-ENC_INC1 Incremental encoder
-RESOLVER1 Resolver feedback
-TACHO1 Tachometer (analogue speed feedback)
-SPEED1 Speed sensor (magnetic pickup)
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Instrumentation — Analog Measurement
Temperature
1
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5
6
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8
9
| -BT1 .. -BTn Temperature sensor (IEC 81346)
-TT1 .. -TTn Temperature transmitter (ISA style — 4-20mA output)
-TE1 .. -TEn Temperature element (thermocouple or RTD — ISA)
-RTD1 RTD sensor (PT100/PT1000 — direct)
-TC_THERMO1 Thermocouple element (K, J, T type)
-TW1 Thermowell (protective pocket for TE)
-TSTAT1 Thermostat (discrete control — see also SB / SS)
-WT1 Winding temperature sensor (transformer)
-OT1 Oil temperature sensor (transformer)
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Pressure
1
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3
4
5
6
| -BP1 .. -BPn Pressure sensor (IEC 81346)
-PT1 .. -PTn Pressure transmitter (ISA style)
-PE1 .. -PEn Pressure element (ISA)
-PDT1 Pressure differential transmitter
-PG1 Pressure gauge (local — no signal output)
-PSV1 Pressure safety valve (relief — not a sensor but appears on I/O)
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Flow
1
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4
5
6
7
8
9
10
11
| -BF1 .. -BFn Flow sensor (IEC 81346)
-FT1 .. -FTn Flow transmitter (ISA style)
-FE1 .. -FEn Flow element (orifice plate, venturi — ISA)
-FIT1 Flow indicating transmitter
-FC1 Flow controller
-FM1 Flow meter (volumetric, Coriolis, magnetic)
-MAG1 Magnetic flow meter
-CORI1 Coriolis flow meter
-ULTRA_F1 Ultrasonic flow meter
-VORTEX1 Vortex flow meter
-ROTA1 Rotameter / variable area flow meter
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Level
1
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6
7
8
9
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11
12
| -BL1 .. -BLn Level sensor (IEC 81346)
-LT1 .. -LTn Level transmitter (ISA style — continuous)
-LE1 .. -LEn Level element (ISA)
-LIT1 Level indicating transmitter
-LG1 Level gauge / sight glass (local)
-RADAR1 Radar level transmitter (guided wave or free space)
-ULTRA_L1 Ultrasonic level transmitter
-BUBBLER1 Bubbler level system
-DISPL1 Displacer level transmitter
-FLOAT1 Float-type level sensor
-HYDRO1 Hydrostatic level transmitter
-LOAD_CELL1 Load cell (for level by weight)
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Analytical
1
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3
4
5
6
7
8
9
10
11
12
13
14
15
16
| -BA1 .. -BAn Analyser sensor (IEC 81346)
-AT1 .. -ATn Analytical transmitter (ISA style)
-AE1 .. -AEn Analytical element (ISA)
-PH_METER1 pH analyser / transmitter
-COND1 Conductivity analyser
-DO2_1 Dissolved oxygen analyser
-TURB1 Turbidity analyser
-CL2_1 Chlorine residual analyser
-TOC1 Total organic carbon analyser
-GAS_IR1 Infrared gas analyser (CO2, CH4, etc.)
-GAS_CATA1 Catalytic gas detector (%LEL)
-GAS_EC1 Electrochemical gas detector (H2S, CO, O2, etc.)
-GAS_OP1 Open-path gas detector (IR beam)
-FLUE1 Flue gas analyser
-MOISTURE1 Moisture / humidity transmitter
-VISCOSITY1 Viscosity analyser
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Position & Displacement (Analog)
1
2
3
4
| -LVDT1 LVDT position transducer
-POT1 Potentiometer (position feedback)
-LINEAR_ENC1 Linear encoder
-DRAW_WIRE1 Draw-wire / cable extension transducer
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Force, Torque & Vibration
1
2
3
4
5
6
| -LOAD_CELL1 Load cell (force / weight)
-TORQUE1 Torque transducer
-STRAIN1 Strain gauge transmitter
-VIB_TX1 Vibration transmitter (4-20mA, proximity probe)
-ACCEL1 Accelerometer (vibration / shock)
-BEARING_TX1 Bearing temperature / vibration transmitter
|
Instrumentation — ISA Tag Naming (P&ID)
ISA-5.1 standard. First letter(s) = measured variable, last letter(s) = function/device type.
First Letter — Measured Variable
| Letter | Variable | |——–|———| | A | Analysis (composition) | | C | Conductivity | | D | Density | | F | Flow | | H | Hand (manual) | | I | Current (electrical) | | J | Power | | K | Time | | L | Level | | M | Moisture / humidity | | P | Pressure | | Q | Quantity / event | | R | Radiation | | S | Speed / frequency | | T | Temperature | | U | Multivariable | | V | Vibration / viscosity | | W | Weight / force | | X | Unclassified | | Y | Event / state (relay) | | Z | Position / dimension |
Last Letter(s) — Function / Device Type
| Letter(s) | Function | |———–|———| | E | Primary element (sensing element, no output) | | T | Transmitter (4-20mA / HART / FF output) | | I | Indicator (local display only) | | C | Controller | | R | Recorder | | S | Switch (discrete output) | | V | Control valve (final control element) | | IT | Indicating transmitter | | IC | Indicating controller | | IR | Indicating recorder | | ICV | Indicating control valve (with positioner) |
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19
20
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23
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31
32
33
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47
48
49
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58
59
60
61
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65
| --- Flow ---
-FE101 Flow element (orifice plate) loop 101
-FT101 Flow transmitter loop 101
-FIT101 Flow indicating transmitter
-FS101 Flow switch (discrete)
-FC101 Flow controller
-FCV101 Flow control valve
-FM101 Flow meter (totalisers)
--- Pressure ---
-PE201 Pressure element loop 201
-PT201 Pressure transmitter
-PIT201 Pressure indicating transmitter
-PS201 Pressure switch (discrete)
-PC201 Pressure controller
-PCV201 Pressure control valve
-PSV201 Pressure safety valve
-PDT201 Differential pressure transmitter
--- Temperature ---
-TE301 Temperature element (thermocouple/RTD)
-TT301 Temperature transmitter
-TIT301 Temperature indicating transmitter
-TS301 Temperature switch (discrete)
-TC301 Temperature controller
-TW301 Thermowell
--- Level ---
-LE401 Level element
-LT401 Level transmitter
-LIT401 Level indicating transmitter
-LS401 Level switch (discrete — high or low)
-LSH401 Level switch high
-LSL401 Level switch low
-LSHH401 Level switch high-high (SIL — safety trip)
-LSLL401 Level switch low-low (SIL — safety trip)
-LG401 Level gauge (local — no signal)
-LC401 Level controller
-LCV401 Level control valve
--- Analytical ---
-AE501 Analytical element
-AT501 Analytical transmitter
-AIT501 Analytical indicating transmitter
-AS501 Analytical switch
--- Vibration ---
-VT601 Vibration transmitter
-VS601 Vibration switch
-VIT601 Vibration indicating transmitter
--- Speed ---
-ST701 Speed transmitter
-SS701 Speed switch (discrete — zero speed / overspeed)
-SE701 Speed element (magnetic pickup)
--- Position / Valve Status ---
-ZT801 Position transmitter (valve)
-ZS801 Position switch (limit switch — valve open/closed)
-ZSO801 Position switch — open
-ZSC801 Position switch — closed
--- Multifunction transmitters ---
-UT901 Multivariable transmitter
-TDT1001 Temperature differential transmitter
|
Control & Signal Conditioning Devices
Isolators & Signal Conditioners
1
2
3
4
5
6
7
8
9
10
11
12
| -Z1 .. -Zn Zener barrier / isolator (general)
-ZA1 .. -ZAn Zener barrier (intrinsic safety — IEC 81346)
-ZI1 .. -ZIn Galvanic isolator (IEC 81346)
-ISO1 Galvanic isolator (common notation)
-HART_ISO1 HART-transparent galvanic isolator
-SC1 Signal conditioner (4-20mA repeater / splitter)
-SC_SPLIT1 Signal splitter (1 in → 2 out)
-SC_CONV1 Signal converter (0-10V → 4-20mA, etc.)
-SC_LIMIT1 Signal limiter / trip amplifier
-SC_ALARM1 Alarm trip amplifier
-MTL1 MTL Zener barrier (by brand — common usage)
-P&F1 Pepperl+Fuchs isolator (by brand — common usage)
|
Loop & Power Conditioning
1
2
3
4
5
| -PS_LOOP1 Loop power supply (for 4-20mA sensors)
-SPLITTER1 Power / signal splitter
-REPEATER1 Signal repeater (RS485, etc.)
-CONVERTER1 Protocol converter
-MODEM1 Modem (RS232/485 to TCP/IP, etc.)
|
Indication & Signalling Devices
Indicator Lamps
1
2
3
4
5
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7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
| -HL1 .. -HLn Indicator lamp / pilot light (general — most common)
-HL_POWER Power on / system healthy (green)
-HL_RUN Running / active (green)
-HL_STOP Stopped / off (white or blue)
-HL_FAULT Fault / alarm (red)
-HL_WARN Warning (amber / yellow)
-HL_READY Ready (green or white)
-HL_TRIP Trip / protection operated (red)
-HL_CLOSED Breaker/contactor closed (red — IEC convention)
-HL_OPEN Breaker/contactor open (green — IEC convention)
-HL_REMOTE Remote mode active (blue or white)
-HL_LOCAL Local mode active (amber)
-HL_AUTO Auto mode active (green)
-HL_MANUAL Manual mode active (amber)
-HL_ESTOP E-stop active (red)
-HL_SAFE Safe / guard active (amber)
-HL_COMM Communications fault (red)
-HL_BATT Battery / UPS on battery (amber)
-HL_NORM Normal supply (green)
-HL_ALT Alternative supply (amber)
-HL_STAR Star mode (star-delta — amber)
-HL_DELTA Delta mode (star-delta — green)
|
Audible & Visual Alarms
1
2
3
4
5
6
7
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9
10
11
12
13
14
| -HA1 .. -HAn Audible alarm — buzzer / horn (IEC 81346)
-HORN1 Alarm horn / siren
-BUZZ1 Buzzer
-SIREN1 Siren (multi-tone)
-BELL1 Bell
-BEAC1 Beacon / revolving light
-STACK_LIGHT1 Stack light / signal tower (combined)
-HL_STACK_G Stack light — green section
-HL_STACK_A Stack light — amber section
-HL_STACK_R Stack light — red section
-HL_STACK_B Stack light — blue section
-ANNUNC1 Annunciator panel / window annunciator
-DISPLAY1 Digital display / alphanumeric readout
-HR1 Panel meter / digital readout (IEC 81346)
|
1
2
3
4
5
6
7
8
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10
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12
13
14
15
16
17
| -SB1 .. -SBn Push button (general — most common)
-SB_START Start push button (green)
-SB_STOP Stop push button (red)
-SB_RESET Fault reset push button (blue or black)
-SB_ACK Alarm acknowledge push button
-SB_JOG Jog / inch push button (black)
-SB_FWD Forward push button
-SB_REV Reverse push button
-SB_UP Up push button
-SB_DOWN Down push button
-SB_OPEN Open push button (valve / door)
-SB_CLOSE Close push button (valve / door)
-SB_TEST Test push button (lamp test)
-SB_LAMP_TEST Lamp test push button
-SB_ESTOP Emergency stop (mushroom head, latching red)
-SB_SAFE_RESET Safety reset push button
-SB_ENABLE Enable / enable-for-jog push button
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Selector & Maintained Switches
1
2
3
4
5
6
7
8
9
| -SS1 .. -SSn Selector switch (general maintained — most common)
-SS_LOCAL Local / Remote / Off selector
-SS_MODE Mode selector (Auto / Manual / Maintenance)
-SS_SPEED Speed selector (Low / Medium / High)
-SA1 Rotary selector switch (IEC 81346)
-SS_3POS 3-position selector (Left / Off / Right)
-SS_HAND_OFF_AUTO Hand / Off / Auto selector (HOA — common in process)
-SS_VFD_BP VFD / Bypass selector
-SS_DIR Direction selector (Forward / Off / Reverse)
|
Key Switches
1
2
3
4
5
6
| -SK1 .. -SKn Key switch (general)
-SK_MAINT Maintenance mode key switch
-SK_BYPASS Safety bypass key switch
-SK_ENABLE Enable key switch
-SK_MASTER_RESET Master reset key switch
-TPKS1 Trapped key switch (safety interlock system)
|
Potentiometers & Analogue Operator Devices
1
2
3
| -RR1 Potentiometer / rheostat (speed setpoint)
-SPEED_POT1 Speed reference potentiometer
-SETPOINT1 Analogue setpoint adjuster
|
1
2
3
| -JOYSTICK1 Joystick (multi-axis)
-THUMBWHEEL1 Thumbwheel switch (BCD input)
-FOOT_SW1 Foot switch / foot pedal
|
PLC & Controller Modules
CPU & System Modules
1
2
3
4
5
6
7
8
9
10
| -CPU1 .. -CPUn PLC CPU module
-CPU_A CPU A (primary — redundant system)
-CPU_B CPU B (standby — redundant system)
-PM1 Power module (PLC-integrated supply)
-IM1 Interface module (rack-to-rack expansion)
-IM_SEND1 IM send module (left rack)
-IM_RECV1 IM receive module (right/remote rack)
-SYNC_MOD Synchronisation module (redundant CPU)
-RACK1 Rack / backplane (if tagged separately)
-BM1 Backplane module
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I/O Modules
1
2
3
4
5
6
7
8
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12
13
14
15
| -DI01 .. -DIn Digital input module (numbered)
-DO01 .. -DOn Digital output module
-AI01 .. -AIn Analog input module (4-20mA / 0-10V)
-AO01 .. -AOn Analog output module
-RTD01 RTD / thermocouple input module
-CNT01 Counter / high-speed input module
-ENC01 Encoder interface module
-IO_LINK01 IO-Link master module
-PWM01 PWM output module
-DI_SAFE01 Safety digital input module
-DO_SAFE01 Safety digital output module
-AI_SAFE01 Safety analog input module
-HART_MUX1 HART multiplexer module
-FF_H1_01 Foundation Fieldbus H1 card
-DP_SLAVE1 PROFIBUS DP slave module (IM for ET200)
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Communications Modules
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| -CM_PN1 PROFINET communications module
-CM_PB1 PROFIBUS DP master module
-CM_DP1 PROFIBUS DP (alternative)
-CM_485_1 RS485 / Modbus RTU module
-CM_232_1 RS232 serial module
-CM_ETH1 Ethernet module (TCP/IP)
-CM_IEC104_1 IEC 60870-5-104 comms module
-CM_DNP3_1 DNP3 comms module
-CM_MQTT1 MQTT / IoT gateway module
-CM_IOLINK1 IO-Link master communications
-CM_ASI1 AS-Interface master
-CM_CAN1 CANopen master module
-CM_MODBUS1 Modbus TCP/RTU module
-NIC1 Network interface card (PC/server)
-GPS_SYNC1 GPS time synchronisation module
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Safety PLC Modules
1
2
3
4
5
6
7
8
| -CPU_S1 Safety CPU (SIL-rated)
-CPU_S_A Safety CPU A (redundant)
-CPU_S_B Safety CPU B (redundant)
-CPU_S_C Safety CPU C (TMR)
-DI_S01 Safety DI module
-DO_S01 Safety DO module
-AI_S01 Safety AI module
-DIAG_MOD1 Diagnostic module (SIS health monitoring)
|
Safety Devices & Safety Relays
Safety Relays & Controllers
1
2
3
4
5
6
7
8
9
10
| -F3_ESTOP Safety relay — E-stop category (e.g. PILZ PNOZ X, Siemens 3SK)
-F3_GUARD Safety relay — guard door monitoring
-F3_LIGHT Safety relay — light curtain / area scanner
-F3_TWO_HAND Safety relay — two-hand control
-F3_ENABLE Safety relay — enabling device
-F3_MAT Safety relay — safety mat / pressure mat
-F3_MUTE Safety relay — muting function
-SAFE_CTRL1 Safety controller (e.g. PILZ PNOZmulti, B&R SafeLogic)
-F_SAFE_PLC Safety PLC integrated module
-SIM1 Safety integrity monitor module
|
Safety Sensors & Detection
1
2
3
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5
6
7
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14
15
| -SB_ESTOP Emergency stop push button (latching, twist-to-release)
-SB_ESTOP_ROPE Rope pull / cable pull e-stop switch
-SL_GUARD1 Guard door interlock switch (solenoid lock type)
-MAG_SAFE1 Magnetic safety switch (non-contact guard)
-TPSW1 Trapped key switch (key exchange system)
-RFID_SAFE1 RFID safety switch (coded — IEC 60947-5-3 type 4)
-LIGHT_CRT1 Light curtain (safety — Type 4 AOPD)
-AREA_SCAN1 Safety area scanner (laser — SICK, LEUZE, Keyence)
-SAFETY_MAT1 Safety pressure mat / floor mat
-SAFE_EDGE1 Safety edge / bumper (robot perimeter)
-TWO_HAND1 Two-hand control device
-ENABLE_DEV1 Enabling device (3-position switch — pendant)
-SAFE_DOOR1 Safety door interlock (EUCHNER, Schmersal)
-SAFE_HINGE1 Safety hinge switch
-INTERLOCK1 Mechanical / trapped key interlock
|
Communications & Network Devices
Ethernet & Industrial Network
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
| -SW_CORE_OT Core OT Ethernet switch (managed Layer 2/3)
-SW_DIST_OT1 Distribution OT switch
-SW_PN1 PROFINET switch (DIN rail — Scalance, Moxa, etc.)
-SW_EIP1 EtherNet/IP switch
-SW_MGMT1 Management network switch (out-of-band)
-SW_CORE_IT Core IT switch
-RTR_WAN1 WAN router
-RTR_4G1 4G / LTE router (cellular)
-FW_OT_IT1 OT/IT firewall / industrial firewall
-FW_CORP1 Corporate perimeter firewall
-AP_INDUS1 Industrial WiFi access point
-FC_FIBER1 Fibre / copper media converter
-FDP1 Fibre distribution panel
-PATCH_ETH1 Ethernet patch panel
-HUB1 Network hub (legacy — avoid in new designs)
|
Serial & Fieldbus
1
2
3
4
5
6
7
| -CM_485_1 RS485 module / repeater
-CONV_485_TCP1 RS485 to Modbus TCP converter
-DP_COUPLER1 PROFIBUS DP Y-coupler / repeater
-FF_COUPLER1 Foundation Fieldbus H1 coupler / power conditioner
-ASI_MOD1 AS-Interface module / slice
-IOLINK_HUB1 IO-Link hub
-HART_MOD1 HART modem / interface
|
Telemetry & WAN
1
2
3
4
5
6
7
8
9
10
11
| -MODEM_4G1 4G LTE modem
-MODEM_3G1 3G UMTS modem (legacy)
-RADIO_UHF1 UHF radio modem (licensed)
-RADIO_900M1 900MHz licence-exempt radio
-SAT_MODEM1 Satellite modem (VSAT, Ku-band)
-FIBER_MOD1 Fibre optic modem
-MW_IDU1 Microwave indoor unit
-ANT_4G1 4G antenna
-ANT_RADIO1 Radio antenna (Yagi, omni)
-ANT_GPS1 GPS antenna
-LIGHTNING_ARR1 Antenna lightning arrester
|
Time & Synchronisation
1
2
3
4
| -NTP_SRV1 GPS-disciplined NTP server
-GPS_RCV1 GPS receiver module
-PTP_GM1 IEEE 1588 PTP grandmaster clock
-TIME_CODE1 IRIG-B time code receiver (substation)
|
HMI, Computers & IT Hardware
HMI & Operator Terminals
1
2
3
4
5
6
7
8
9
10
11
12
13
14
| -TP1 HMI touchpanel (Siemens TP, comfort series)
-TP_700 Siemens TP700 / KTP700 (by model — common)
-OP1 Operator panel (button-based, no touch)
-KTP1 Key touchpanel (combined keys + touch)
-MP1 Multi-panel HMI
-PC_HMI1 HMI PC / industrial PC with SCADA client
-PC_IPC1 Industrial PC (panel PC, DIN rail PC)
-THIN1 Thin client / zero client
-WS_HMI1 HMI workstation (office-type PC)
-WS_ENG1 Engineering workstation
-WS_SCADA1 SCADA operator workstation
-MON1 .. -MONn Monitor / display
-TOUCH_MON1 Touchscreen monitor
-VIDEO_WALL1 Video wall processor
|
Servers
1
2
3
4
5
6
7
8
9
10
11
12
13
| -SRV1 .. -SRVn Server (general)
-SRV_SCADA1 SCADA primary server
-SRV_SCADA_STB SCADA standby server
-SRV_HIST1 Historian server
-SRV_OPC1 OPC server (DA / UA)
-SRV_APP1 Application server
-SRV_ENG1 Engineering / development server
-SRV_DR1 Disaster recovery server
-SRV_WEB1 Web server
-SRV_BACKUP1 Backup server
-ESXI1 VMware ESXi host
-HYPER_V1 Microsoft Hyper-V host
-VM1 .. -VMn Virtual machine (if tagged individually)
|
Storage & Peripherals
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
| -NAS1 Network attached storage
-SAN1 SAN storage array
-HDD1 Hard disk drive (if tagged)
-TAPE_LIB1 Tape library
-KVM_SW1 KVM switch
-KVM_TX1 KVM extender — transmitter (server end)
-KVM_RX1 KVM extender — receiver (desk / console end)
-IPKVM1 IP KVM aggregator / console server
-SCS1 Serial console server
-USB_HUB1 USB hub
-PRINTER1 Alarm printer / label printer
-SCANNER1 Barcode scanner / document scanner
-UPS_RACK1 Rack-mount UPS
-PDU_A1 Rack PDU A side
-PDU_B1 Rack PDU B side
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Cybersecurity Appliances
1
2
3
4
5
6
| -DATA_DIODE1 Data diode (unidirectional security gateway)
-FW_OT_IT1 OT/IT boundary firewall appliance
-IDS_SENSOR1 OT intrusion detection sensor
-PAM_APPLN1 Privileged access management appliance
-SRV_SIEM1 SIEM server
-SRV_JUMP1 Jump server / bastion host
|
Heating, Cooling & Environmental
Panel Heating & Thermostat
1
2
3
4
5
| -HTR1 .. -HTRn Anti-condensation heater / panel heater
-EH1 Heating element (IEC 81346)
-THERM1 Thermostat (for panel heater control)
-HYGROSTAT1 Hygrostat (humidity-based heater control)
-PTC_HTR1 PTC self-regulating heater
|
Panel Cooling & Ventilation
1
2
3
4
5
6
| -FAN1 .. -FANn Panel cooling fan (filter fan unit)
-VF1 Ventilation fan (IEC 81346)
-FFU1 Filter fan unit (complete assembly)
-HEAT_EXC1 Heat exchanger / air conditioner (panel-mount)
-VORTEX1 Vortex cooler (pneumatic, Ex areas)
-AC_UNIT1 Panel air conditioning unit
|
Environmental Sensors
1
2
3
4
| -THERM_PANEL1 Panel internal thermostat / temperature monitor
-HUMID1 Humidity sensor (internal)
-FLAME_DET1 Flame detector (cabinet fire protection)
-SMOKE_DET1 Smoke detector (inside cabinet)
|
Pneumatic & Hydraulic Devices
Valves
1
2
3
4
5
6
7
8
9
10
11
12
13
| -YV1 .. -YVn Solenoid valve (pneumatic / hydraulic)
-YV_FWD Forward solenoid valve
-YV_REV Reverse solenoid valve
-YV_CLAMP Clamp solenoid
-YV_UNCLAMP Unclamp solenoid
-YV_BRAKE Brake release solenoid
-YV_VENT Vent solenoid valve
-YV_SAFETY Safety / dump solenoid valve
-VA_CTRL1 Motorised control valve (process)
-VA_ON_OFF1 Motorised on/off valve
-VA_ISOL1 Motorised isolation valve
-PV1 Proportional valve (hydraulic)
-SERVO_V1 Servo valve (hydraulic)
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Actuators & Cylinders
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| -CYL1 .. -CYLn Pneumatic / hydraulic cylinder
-CYL_EXT1 Cylinder extend solenoid
-CYL_RET1 Cylinder retract solenoid
-ACT_LIN1 Linear actuator (electric)
-ACT_ROT1 Rotary actuator
-POSITIONER1 Valve positioner (electropneumatic — 4-20mA input)
-EP_POSITIONER1 EP positioner (electro-pneumatic)
-TRANSDUCER_IP1 I/P transducer (current to pneumatic)
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Pneumatic Control
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| -AIR_REG1 Pressure regulator (instrument air)
-FRL1 Filter-regulator-lubricator unit
-MFLD1 Pneumatic manifold
-CHECK_V1 Check valve (if monitored)
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Mechanical & Structural Components
Machine Hardware (tagged when wired)
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| -ENC_DOOR1 Enclosure door (if interlocked)
-LOCK1 Solenoid lock (door or guard)
-LIMIT_MECH1 Mechanical limit switch (cam-operated)
-HOME_SW1 Home position switch
-BUFFER1 Mechanical buffer / end stop (if wired)
-SCALE1 Linear scale (glass or magnetic)
-RULER1 Ruler / measuring tape sensor
-LEVEL_SITE1 Spirit level sensor (machine levelling)
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Cables, Conduits & Routing
IEC 81346 uses -W prefix for cables / conductors. In practice many engineers use project-specific cable numbering.
Cable Numbering Conventions
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| --- IEC 81346 style ---
-W1 .. -Wn Cable (general)
-WC1 Control cable
-WP1 Power cable
-WS1 Signal cable (instrument)
-WF1 Fibre optic cable
-WN1 Network cable
--- Project number style (most common in practice) ---
-CAB001 .. -CABnnn Sequential cable number
-CC001 Control cable 001
-PC001 Power cable 001
-SC001 Signal cable 001
-FC001 Fibre cable 001
-NC001 Network cable 001
--- Area / route coded style ---
-CAB_A_001 Cable in area A, number 001
-CAB_MCC1_M01 Cable from MCC1 to motor M01
--- Trunkings & Conduits ---
-TRNK1 Cable trunking run 1
-CNDUIT1 Conduit run 1
-TRAY1 Cable tray run 1
-DUCT1 Underground cable duct
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Panel Building Hardware
Panel Structure Components
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| -DIN1 .. -DINn DIN rail (mounting rail)
-DUCT1 .. -DUCTn Cable duct / wireway
-GLAND1 Cable gland (if individually tagged)
-GLAND_PG16_1 PG16 cable gland
-GLAND_M20_1 M20 metric cable gland
-GLAND_EX1 Ex-rated cable gland
-EARTH_BAR1 Earth busbar / earth rail
-PE_BAR PE (protective earth) terminal bar
-N_BAR Neutral terminal bar
-LOCK_OFF1 Lockout hasp / lockout device
-DOOR_LOCK1 Panel door lock
-WINDOW1 Viewing window (if referenced)
-LABEL1 Panel / device label (if in BOM)
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Surge Protection
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| -SPD1 .. -SPDn Surge protection device (SPD / lightning arrester)
-SPD_AC1 AC surge arrester (Type 1, 2, or 3)
-SPD_DC1 DC surge arrester
-SPD_DATA1 Data line surge arrester (RS485, analogue)
-SPD_ETH1 Ethernet surge arrester
-MOV1 Metal oxide varistor
-TVS1 Transient voltage suppressor
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MV Switchgear Specific Devices
Devices specific to MV switchgear not covered in earlier sections
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| -QB1 Vacuum / SF6 circuit breaker
-QD1 Air-break disconnector / pantograph
-QS1 Load break switch (ring main)
-QE1 / -ES1 Earthing switch
-FU1 HRC fuse (MV TX feeder)
-CT1 Current transformer (protection / metering)
-VT1 Voltage transformer (metering / synch)
-CLOSING_COIL1 Closing coil (VCB)
-TRIP_COIL1 Trip coil 1 (VCB — main)
-TRIP_COIL2 Trip coil 2 (VCB — backup)
-ANTI_PUMP_K1 Anti-pump relay
-MOT_OP1 Motor operator (VCB / LBS motorised operation)
-POSITION_IND1 Position indicator (mechanical — open/close)
-SPRING_CHARGED1 Spring charged indicator / switch
-DRAW_OUT_LOCK1 Draw-out position interlock
-TEST_POS1 Test position switch (draw-out equipment)
-INSERT_POS1 Inserted / service position switch
-EARTH_POS1 Earthed position switch
-ARC_DETECT1 Arc flash detector (fibre / light)
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Battery & DC System Devices
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| -BATT1 .. -BATTn Battery cell / battery string
-BATT_BANK1 Battery bank (complete assembly)
-CELL_MON1 Battery cell monitoring module
-BMS1 Battery management system module
-CHRG_A Charger A (float / boost)
-CHRG_B Charger B (standby)
-FLOAT_CHRG1 Float charger
-BOOST_CHRG1 Boost / equalise charger
-DC_QF1 DC MCB (for DC distribution feeders)
-DC_FUSE1 DC fuse (blade or cartridge)
-DIODE1 Isolation diode (parallel charger coupling)
-SHUNT1 Current shunt (for DC current measurement)
-BATT_MON1 Battery monitor / impedance tester
-LOW_V_DISC1 Low voltage disconnect relay
-HI_V_DISC1 Overvoltage disconnect relay
-EARTH_FAULT_MON1 DC earth fault monitor (Bender, etc.)
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Fire, Gas & Safety Detectors
Fire Detection
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| -SD1 .. -SDn Smoke detector (general)
-SMOKE_ION1 Ionisation smoke detector
-SMOKE_OPT1 Optical smoke detector
-HEAT_DET1 Heat detector (rate-of-rise or fixed temperature)
-FLAME_IR1 IR flame detector
-FLAME_UV1 UV flame detector
-FLAME_UV_IR1 UV/IR combined flame detector
-MULTI_DET1 Multi-criteria detector (heat + smoke)
-VESDA1 VESDA / aspirating smoke detector (sampling point)
-BEAM_DET1 Beam smoke detector (projected)
-CALL_POINT1 Manual call point / break glass
-SIRN_FIRE1 Fire alarm sounder / siren
-STRB_FIRE1 Fire alarm strobe
-SOUNDER_BASE1 Detector sounder base
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Gas Detection
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| -GD_GAS1 Gas detector (general)
-GD_CATA1 Catalytic bead gas detector (%LEL — combustible)
-GD_IR_FIXED1 Fixed infrared gas detector (CH4, CO2, etc.)
-GD_OP1 Open-path gas detector (IR beam — area coverage)
-GD_H2S1 H2S toxic gas detector (electrochemical)
-GD_CO1 CO toxic gas detector
-GD_O2_DEF1 Oxygen deficiency detector
-GD_O2_ENR1 Oxygen enrichment detector
-GD_CL2_1 Chlorine gas detector
-GD_NH3_1 Ammonia gas detector
-GD_SONIC1 Acoustic gas leak detector (ultrasonic)
-GD_CTRL1 Gas detection controller / addressable module
-BEACON_GAS1 Warning beacon (gas detection alarm)
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Life Safety
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| -SPRINKLER1 Sprinkler flow switch (if wired to I/O)
-SUPPRS_VALVE1 Suppression system valve (FM200, CO2)
-HAND_HELD_EXT1 Portable extinguisher monitor
-PULL_STN1 Pull station (Halon / clean agent release)
-ABORT_SW1 Abort switch (suppression system)
-SOUNDER_VAC1 Evacuation sounder
-STRB_EVAC1 Evacuation strobe
-PA_SPKR1 PA / EVAC loudspeaker
-INTERCOM1 Intercom station (safety / emergency)
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Building Services Devices
Access Control & Security
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| -CARD_RDR1 Card reader (access control)
-KEYPAD1 PIN keypad
-INTERCOM_DR1 Door intercom
-MAG_LOCK1 Magnetic door lock
-ELEC_STRIKE1 Electric door strike
-EXIT_BTN1 Exit button (green — door release)
-PIR1 PIR motion sensor (security / building)
-CCTV_CAM1 CCTV camera
-CCTV_DOM1 CCTV dome camera
-CCTV_PTZ1 CCTV PTZ camera
-VIDEO_REC1 Video recorder / NVR
-SIREN_SEC1 Security siren / intruder alarm sounder
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Lighting
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| -EL1 .. -ELn Luminaire / light fitting (IEC 81346)
-LIGHT1 Light fitting
-EMERG_LIGHT1 Emergency light fitting (maintained)
-EMERG_SIGN1 Emergency exit sign
-EMERG_CENTRAL1 Central battery emergency lighting system
-DALI_CTRL1 DALI lighting controller
-DALI_BUS1 DALI bus coupler / power supply
-DIM1 Dimmer module
-SENS_LIGHT1 Daylight sensor / photocell
-MOTION_LIGHT1 Motion-activated lighting switch
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Numbering Conventions & Suffixes
Sequential Numbering (most common)
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| -K1, -K2, -K3, -K4 Simple sequential — good for small panels
-KM1, -KM2, -KM3 Sequential by type — good for MCCs
-DI01, -DI02, -DI03 Zero-padded — essential for sorted reports
-FT101, -FT102, -FT103 ISA loop-based — process industry
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Alphabetical Suffixes (for duplicates / phases)
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| -CT_A, -CT_B, -CT_C Phase A, B, C CTs
-CPU_A, -CPU_B Redundant pair A/B
-PS_A, -PS_B Redundant power supplies
-QF_INC_A, -QF_INC_B Dual incomer A and B
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Descriptive Suffixes (for clarity in complex panels)
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| -KM_MAIN Immediately identifies main contactor
-KM_STAR Identifies star contactor clearly
-F_OC_A Overcurrent relay incomer A
-HL_RUN Run indicator (no ambiguity)
-SB_ESTOP E-stop button (safety critical — must be obvious)
-SW_PN_A1 Switch for PROFINET in area A1
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ISA Loop Number Convention
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| -FT101 First two letters = variable + device type, three digits = loop number
-FT101A Suffix letter = multiple devices in same loop (transmitter A)
-FT101B Second transmitter in same loop (e.g. 2oo3 voting)
-FT101C Third transmitter in loop (TMR / 2oo3)
-LS401H Level switch high (H suffix = high trip)
-LS401L Level switch low (L suffix = low trip)
-LS401HH Level switch high-high (HH = safety trip)
-LS401LL Level switch low-low (LL = safety trip)
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Panel / Location Coded Prefixes (alternative style)
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| -CP1_K1 Relay in panel CP1 — location embedded in device tag
(Not recommended in EPLAN — this is what the + location is for)
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Full Tag Examples — Complete Projects
Example 1 — DOL Motor Starter in MCC
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| =PWR.INC+MCC1.INC-QF_INC Main incomer MCCB
=METER+MCC1.INC-CT_INC Incomer CT
=METER+MCC1.INC-PQ1 Power analyser
=MOTOR.DOL+MCC1.M01-QF1 Motor M01 feeder MCCB
=MOTOR.DOL+MCC1.M01-F_MOTOR1 Motor protection relay
=MOTOR.DOL+MCC1.M01-KM_MAIN Main contactor
=CTRL+MCC1.M01-SS_LOCAL Local/remote selector
=CTRL+MCC1.M01-SB_START Start push button
=CTRL+MCC1.M01-SB_STOP Stop push button
=CTRL+MCC1.M01-HL_RUN Run indicator lamp
=CTRL+MCC1.M01-HL_TRIP Trip indicator lamp
=CTRL+MCC1.M01-X1 Terminal block (field wiring)
=MOTOR+FIELD-M1 Motor (in field)
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Example 2 — Star-Delta Starter
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| =MOTOR.STAR_D+MCC1.M02-QF1 Feeder MCCB
=MOTOR.STAR_D+MCC1.M02-F_MOTOR2 Motor protection relay
=MOTOR.STAR_D+MCC1.M02-KM_MAIN Line contactor
=MOTOR.STAR_D+MCC1.M02-KM_STAR Star contactor
=MOTOR.STAR_D+MCC1.M02-KM_DELTA Delta contactor
=MOTOR.STAR_D+MCC1.M02-KT_SD Star-delta timer
=CTRL+MCC1.M02-SB_START Start button
=CTRL+MCC1.M02-SB_STOP Stop button
=CTRL+MCC1.M02-HL_STAR Star mode indicator
=CTRL+MCC1.M02-HL_DELTA Delta mode indicator
=CTRL+MCC1.M02-HL_TRIP Trip indicator
=MOTOR+FIELD-M2 Motor (in field)
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Example 3 — PLC Control Panel
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| =PWR.CTRL+CP1.POWER-QF_MAINS Mains incoming MCB
=PWR.24V+CP1.POWER-PS1 24VDC SMPS primary
=PWR.24V+CP1.POWER-PS2 24VDC SMPS redundant
=PWR.UPS+CP1.POWER-UPS_BUF1 24VDC UPS buffer module
=PWR.24V+CP1.DIST_24V-FT1 PLC fused terminal block
=PWR.24V+CP1.DIST_24V-FT2 I/O fused terminal block
=PWR.24V+CP1.DIST_24V-FT3 Field sensor fused terminal
=CTRL.PLC+CP1.PLC-CPU1 PLC CPU
=CTRL.IO+CP1.IO-DI01 Digital input module 01
=CTRL.IO+CP1.IO-DO01 Digital output module 01
=CTRL.IO+CP1.IO-AI01 Analog input module 01
=CTRL.COMM+CP1.COMM-CM_PN1 PROFINET module
=CTRL.SAFE+CP1.SAFE-F3_ESTOP E-stop safety relay
=CTRL.SAFE+CP1.SAFE-F3_GUARD Guard door safety relay
=CTRL+CP1.RELAY-K_WD Watchdog relay
=CTRL.HMI+CP1.DOOR.HMI-TP_700 HMI touchpanel
=SAFE.ESTOP+CP1.DOOR.OP-SB_ESTOP E-stop push button
=CTRL+CP1.DOOR.OP-SS_MODE Mode selector
=CTRL+CP1.DOOR.OP-SB_RESET Reset button
=CTRL+CP1.DOOR.OP-HL_POWER Power indicator
=CTRL+CP1.DOOR.OP-HL_RUN Run indicator
=CTRL+CP1.DOOR.OP-HL_FAULT Fault indicator
=CTRL+CP1.TERM.DI-X_DI1 DI terminal block
=CTRL+CP1.TERM.AI-X_AI1 AI terminal block
=CTRL+CP1.TERM.SAFE-X_SAFE1 Safety terminal block
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Example 4 — Process Instrumentation Loop (Flow)
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| =INST+FIELD-FE101 Flow element (orifice plate)
=INST+FIELD-FT101 Flow transmitter (HART 4-20mA)
=INST+INST_CAB_01.BARRIER.AI-Z_FT101 Zener barrier for FT101
=INST+MARSH_CAB_A.AI-X_AI_FT101 Marshalling terminal block
=DCS.IO+DCS_CAB1.IO_RACK_A-AI01 DCS AI card (receives FT101 signal)
=DCS+CTRL_RM.DESK1.PC_HMI1-WS_DCS1 DCS HMI workstation
=PWR+MCC1.M01-KM_MAIN Pump contactor (flow control output)
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Example 5 — MV Switchgear Feeder Panel
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| =MV.FDR+MV_SW1.FDR_1-QB1 Feeder VCB
=MV.FDR+MV_SW1.FDR_1-QD1 Line disconnector
=MV.FDR+MV_SW1.FDR_1-QE1 Earth switch
=MV.FDR+MV_SW1.FDR_1-CT1 Protection CT phase A
=MV.FDR+MV_SW1.FDR_1-CT2 Protection CT phase B
=MV.FDR+MV_SW1.FDR_1-CT3 Protection CT phase C
=PROT.OC+MV_SW1.FDR_1-F_OC1 Overcurrent relay (e.g. REF615, SEL-751)
=PROT.EF+MV_SW1.FDR_1-F_EF1 Earth fault relay
=METER+MV_SW1.FDR_1-PQ1 Power quality analyser
=CTRL+MV_SW1.FDR_1-CLOSING_COIL1 VCB closing coil
=CTRL+MV_SW1.FDR_1-TRIP_COIL1 VCB trip coil 1
=CTRL+MV_SW1.FDR_1-TRIP_COIL2 VCB trip coil 2 (backup)
=CTRL+MV_SW1.FDR_1-ANTI_PUMP_K1 Anti-pump relay
=CTRL+MV_SW1.FDR_1-HL_CLOSED Breaker closed indicator (red)
=CTRL+MV_SW1.FDR_1-HL_OPEN Breaker open indicator (green)
=CTRL+MV_SW1.FDR_1-SB_CLOSE Close push button
=CTRL+MV_SW1.FDR_1-SB_OPEN Open push button
=CTRL+MV_SW1.FDR_1-SS_LOCAL Local/remote selector
=CTRL+MV_SW1.FDR_1-X1 Control wiring terminal strip
=DC+MV_SW1.FDR_1-QF_DC1 DC MCB for trip circuit
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Example 6 — Safety PLC SIL2 Shutdown Loop
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| --- Field sensing ---
=SIS.IO+FIELD-PT201A Pressure transmitter A (SIL2 — 2oo3)
=SIS.IO+FIELD-PT201B Pressure transmitter B
=SIS.IO+FIELD-PT201C Pressure transmitter C
--- Marshalling ---
=SIS.IO+MARSH_CAB_B.DI_SAFE-X_PT201 Safety PT terminal (2oo3 wiring)
=SIS.IO+MARSH_CAB_B.BARRIER_S-Z_PT201A Safety barrier for PT201A
--- SIS Logic Solver ---
=SIS.IO+SIS_CAB1.IO_A-DI_S01_A Safety DI module (1oo2D architecture)
=SIS.IO+SIS_CAB1.IO_B-DI_S01_B Safety DI module B
=SIS.LOGIC+SIS_CAB1.LOGIC_A-CPU_S_A SIS logic solver A
=SIS.LOGIC+SIS_CAB1.LOGIC_B-CPU_S_B SIS logic solver B
=SIS.POWER+SIS_CAB1.POWER_A-PS_S_A SIS power supply A
=SIS.POWER+SIS_CAB1.POWER_B-PS_S_B SIS power supply B
--- Final Element ---
=SIS.IO+SIS_CAB1.IO_A-DO_S01_A Safety DO module A
=ESD.L2+FIELD-SDV201 Shutdown valve (solenoid — de-energise to close)
=ESD.L2+FIELD-YV_SDV201 Solenoid valve coil on SDV201
=ESD.L2+FIELD-ZS_SDV201_O Position switch — open
=ESD.L2+FIELD-ZS_SDV201_C Position switch — closed
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Cross-Reference: IEC 81346 vs ISA-5.1 vs Common Practice
| Device | IEC 81346 | ISA-5.1 | Common Practice |
|---|
| Circuit breaker (LV) | QF | — | QF, CB, MCB, MCCB |
| Circuit breaker (MV) | QB | — | QB, VCB, ACB |
| Contactor | KC / KM | — | KM, K |
| Fuse | FA | — | FU, F, FA |
| Motor | MA | — | M, MA |
| Solenoid valve | YV / YA | — | YV, SV, VA |
| Relay (aux) | KA | — | K, KA, CR |
| Timer | KT | — | KT, TR, T |
| Indicator lamp | HL | — | HL, PL, IL |
| Push button | SB | — | SB, PB, BS |
| Selector switch | SS / SA | — | SS, CS, SA |
| Transformer | TM / T | — | T, TR, TM |
| CT | TA | — | CT, TA |
| VT | TV | — | VT, PT, TV |
| Power supply | GS | — | PS, GS, PSU |
| UPS | GU | — | UPS, GU |
| Terminal block | XT / X | — | X, XT, TB |
| Flow transmitter | BF | FT | FT (process), BF (IEC) |
| Pressure transmitter | BP | PT | PT (process), BP (IEC) |
| Temperature transmitter | BT | TT | TT (process), BT (IEC) |
| Level transmitter | BL | LT | LT (process), BL (IEC) |
| Control valve | VA | CV / FCV | FCV, PCV, LCV (ISA) |
| VFD | NA | — | VFD, VSD, NA |
| Safety relay | KF | — | F3, KF, SR |
| Zener barrier | ZA | — | ZA, ZB, MTL |
| Encoder | BK | — | ENC, BK, EC |
Common Mistakes
| ❌ Wrong | ✅ Correct | Reason |
|---|
-PANEL_A | +PANEL_A | Panel is a location, not a device |
-CONTROL_SYSTEM | =CTRL | Control system is a function, not a device |
-M_01 (inconsistent spacing) | -M01 | Spaces / inconsistency breaks EPLAN sort order |
-K1, -k1, -K_1 for same relay type | Pick one style — -K1 | Inconsistent capitalisation and separators = different devices |
-FT101 without context | =INST+FIELD-FT101 | Always needs = and + to be complete |
Using name only: -MAIN_CONTACTOR | -KM_MAIN | No type letter = can’t filter by device type in reports |
Same tag in two locations: +CP1-K1 and +MCC1-K1 | Both valid if function differs | Duplicate tags across different =+ combinations are OK — EPLAN uses full path |
-1K (number before letter) | -K1 | IEC 81346 requires letter code first |
-QF001 and -QF01 in same project | -QF01 throughout | Mixed zero-padding breaks alphabetical sort in reports |
-PT_HIGH_PRESSURE_TRANSMITTER_LOOP_201 | -PT201 | Too long — truncated in reports, hard to read on diagrams |
| Omitting device tag entirely | Always assign - tag | Blank device tag = invisible in BOM and terminal reports |
Using -WIRE1 for every wire | Reserve -W for cables, not individual wires | EPLAN handles internal wiring differently from cables |
Expert Tips
1. Always use a letter code — never just a number
-K1 not -1. The letter is what lets EPLAN and IEC reports group, filter, and sort by device type. Reports like parts lists, terminal diagrams, and cable schedules all depend on it.
2. Zero-pad your numbers from the start
-DI01 not -DI1. When you have -DI01 through -DI12, they sort correctly. -DI1 through -DI12 sorts as 1, 10, 11, 12, 2, 3… which makes every report painful.
3. Choose IEC 81346 codes OR ISA codes — not both
Process plant? Use ISA (-FT101, -PT201). Machine or panel? Use IEC (-KM1, -QF1). The worst projects mix both. Decide at project kick-off.
4. Descriptive suffixes add value in complex panels
-KM_MAIN, -KM_STAR, -KM_DELTA is better than -KM1, -KM2, -KM3 in a star-delta starter. The person wiring the cabinet shouldn’t need to look up which -KM2 is.
5. ISA loop numbers carry meaning — use them consistently
-FT101 means flow transmitter, loop 101. The loop number should match your P&ID. Don’t start loops at 1 — use area-coded numbers (100-series = area 1, 200-series = area 2) for large plants.
6. Use letter suffixes for redundant devices in the same loop
-FT101A, -FT101B, -FT101C for three transmitters in a 2oo3 SIL voting loop. This is the ISA convention and immediately tells the instrument engineer the devices belong to the same loop.
7. High-high / low-low convention for safety trips
-LSH401 = level switch high, -LSHH401 = level switch high-high (safety). The H/L/HH/LL suffixes are recognised across industries. Use them for anything connected to an SIS/ESD.
8. Terminal blocks get -X1, -X2 etc. — not -T1 or -TB1
EPLAN specifically uses -X prefix for terminal blocks in its terminal diagram generation engine. Using other letters means your terminal reports may not auto-populate correctly.
9. Never embed location into the device tag
-CP1_K1 is wrong — the panel CP1 information belongs in +CP1. The device tag should just be -K1. The full reference =CTRL+CP1-K1 already carries the location.
10. Document your device tag convention in a legend page
Create a EAC (explanatory documents) page at the front of the project listing all device tag abbreviations used. Future engineers, clients, and maintenance teams will spend hours less confused.
Based on IEC 81346 | IEC 61346 | ISA-5.1 | ISA-20 | IEC 60617 | IEC 61131 | IEC 61511 | IEC 62271 | IEC 61439 | IEC 61850 Expert conventions compiled from electrical, automation, instrumentation, process, power, safety, and IT engineering disciplines
