EPLAN P8 — Function Designation (=) Reference Guide
| Based on IEC 81346 | Expert conventions from machine building, process, energy, and infrastructure industries |
Table of Contents
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 (component tag)
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Structure Syntax
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| =FUNCTION+LOCATION-DEVICE
Examples:
=CTRL+MCC1-Q1 Contactor Q1, in MCC1, performing control function
=PWR+PANEL_A-F1 Fuse F1, in Panel A, in power distribution
=SAFE+DB1-K1 Relay K1, in distribution board 1, safety function
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Hierarchy Separator
Use . to add sub-levels:
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| =CTRL.PLC PLC sub-function within control
=PWR.UPS UPS sub-function within power
=DRIVE.AXIS1 Axis 1 sub-function within drive system
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IEC 81346 Standard Letter Codes
Used on large infrastructure, energy, and authority-submitted projects. Required by many European utilities and EPC contractors.
| Code | Function Class | Typical Use |
|---|
=A | Processing / converting energy (non-electrical to electrical) | Generators, PV inverters, fuel cells |
=B | Converting physical variable to signal | Sensors, transducers, encoders |
=C | Storing energy or material | Capacitors, tanks, batteries, accumulators |
=D | Processing or storing information | PLCs, computers, HMIs, recorders |
=E | Providing radiation or thermal energy | Heaters, lamps, UV sources |
=F | Protecting against dangerous conditions | Fuses, circuit breakers, safety relays |
=G | Providing electrical energy from a primary source | Batteries, UPS, power supplies |
=H | Signalling or indicating | Indicator lights, alarms, buzzers, displays |
=K | Processing signals or information for control | Relays, timers, logic modules |
=M | Providing mechanical energy (prime movers) | Motors, actuators, cylinders |
=N | Regulating or controlling a process variable | PID controllers, regulators, VFDs |
=P | Measuring or testing | Meters, analyzers, test equipment |
=Q | Switching or varying electrical circuits | Contactors, switches, isolators |
=R | Restricting or stabilising movement or flow | Resistors, throttle valves, dampers |
=S | Converting manual action to signals | Push buttons, selector switches, keyboards |
=T | Converting electrical quantities | Transformers, converters, transducers |
=U | Keeping objects in defined position | Clamps, brakes, locks |
=V | Processing materials or products | Mixers, reactors, conveyors |
=W | Conducting, transmitting or distributing energy/signals | Cables, busbars, waveguides |
=X | Connecting or terminating | Terminal blocks, connectors, junction boxes |
=Y | Positioning or guiding | Positioners, guides, actuators |
IEC 81346 Example Set — Pump Station
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| =A01 Generator / energy conversion
=B01 Flow sensors
=B02 Pressure sensors
=B03 Level sensors
=C01 Battery bank / energy storage
=D01 PLC main controller
=D02 HMI panel
=F01 Motor protection
=F02 Short circuit protection
=G01 24VDC SMPS power supply
=H01 Alarm and indication
=K01 Control relays
=M01 Pump motor 1
=M02 Pump motor 2
=M03 Agitator motor
=N01 VFD for pump 1
=N02 VFD for pump 2
=P01 Flow measurement
=P02 Energy meter
=Q01 Main incoming isolator
=Q02 MCC feeders
=T01 Power transformer
=X01 Terminal junction boxes
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Machine Building
Convention: Short descriptive English tags, 3–6 characters. Most common in European and Australian machine builders.
General Machine
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| =CTRL Main machine control system
=CTRL.PLC PLC and I/O subsystem
=CTRL.HMI Operator interface
=CTRL.SAFE Safety logic (within control)
=PWR Power distribution
=PWR.MAIN Main incoming power
=PWR.UPS Uninterruptible power supply
=PWR.24V 24VDC control power rail
=PWR.48V 48VDC power rail
=DRIVE Drive and motion system
=DRIVE.X X-axis servo
=DRIVE.Y Y-axis servo
=DRIVE.Z Z-axis servo
=DRIVE.SP Spindle drive
=DRIVE.CONV Conveyor drive
=SAFE Safety system
=SAFE.ESTOP Emergency stop circuit
=SAFE.GUARD Guard door monitoring
=SAFE.LIGHT Light curtain system
=SAFE.TWO Two-hand control
=SENS Sensing and detection
=SENS.POS Position sensing
=SENS.PROX Proximity detection
=SENS.TEMP Temperature sensing
=SENS.PRESS Pressure sensing
=ACT Actuators
=ACT.PNEU Pneumatic actuators
=ACT.HYD Hydraulic actuators
=ACT.SERVO Servo actuators
=IO I/O expansion
=IO.DI Digital input modules
=IO.DO Digital output modules
=IO.AI Analog input modules
=IO.AO Analog output modules
=COMM Communications
=COMM.PNET PROFINET network
=COMM.PBUS PROFIBUS network
=COMM.ETH Ethernet network
=COMM.IO IO-Link system
=LIGHT Machine lighting
=HEAT Enclosure heating
=FAN Enclosure cooling / fans
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CNC Machine Specific
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| =CNC CNC controller system
=CNC.AXIS Axis control
=CNC.SPIN Spindle control
=CNC.TOOL Tool changer
=CNC.COOL Coolant system
=CNC.CHIP Chip conveyor
=CNC.PROBE Touch probe system
=CNC.MIST Mist extraction
=HYD Hydraulic system
=HYD.UNIT Hydraulic power unit
=HYD.CLAMP Hydraulic clamping
=PNEU Pneumatic system
=PNEU.UNIT Pneumatic supply unit
=PNEU.CLAMP Pneumatic clamping
=LUBE Lubrication system
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Robotic Cell
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| =ROB Robot system
=ROB.R1 Robot 1
=ROB.R2 Robot 2
=ROB.CTRL Robot controller
=ROB.TOOL End effector / tooling
=ROB.CONV Infeed/outfeed conveyor
=ROB.WELD Welding equipment
=ROB.GRIP Gripper system
=SAFE Cell safety system
=SAFE.FENCE Perimeter fence monitoring
=SAFE.SCAN Safety laser scanners
=SAFE.MUTE Safety muting
=VISION Vision system
=VISION.CAM Cameras
=VISION.CTRL Vision controller
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Panel Building & OEM
Convention: Often minimal or single-level. Focus on what is inside the panel.
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| = (blank — acceptable for single-panel projects)
=MAIN Main distribution
=CTRL Control section
=PWR Power section
=IO I/O section
=COMM Communications section
=METER Metering section
=AUX Auxiliary circuits
=LIGHT Lighting circuits
=HEAT Heating circuits
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MCC (Motor Control Centre) Panel
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| =MCC Motor control centre
=MCC.INC Incoming section
=MCC.BUS Busbar section
=MCC.FDR1 Feeder 1
=MCC.FDR2 Feeder 2
=MCC.SOFT Softstarter section
=MCC.VFD VFD section
=MCC.DIST Distribution section
=AUX Auxiliary control
=METER Power metering
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Distribution Board
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| =DB Distribution board
=DB.MAIN Main incomer
=DB.LT Lighting circuits
=DB.PWR Power socket circuits
=DB.HVAC HVAC circuits
=DB.EMERG Emergency circuits
=DB.EDB Essential distribution board
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Process & Chemical Industry
Convention: Functional areas aligned to P&ID. Numbers used to distinguish parallel trains or units.
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| =U10 Unit 10 — Raw material intake
=U20 Unit 20 — Pre-treatment
=U30 Unit 30 — Reaction
=U40 Unit 40 — Separation
=U50 Unit 50 — Purification
=U60 Unit 60 — Product storage
=U70 Unit 70 — Utilities
=U80 Unit 80 — Waste treatment
=U90 Unit 90 — Packaging and dispatch
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Within a Unit (e.g. Reaction Unit =U30)
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| =U30.HEAT Heating subsystem
=U30.MIX Mixing subsystem
=U30.PRESS Pressure control
=U30.VENT Venting system
=U30.SAFE Safety interlock system
=U30.SAMPLE Sampling system
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Utilities
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| =UTIL Utilities general
=UTIL.STEAM Steam system
=UTIL.CW Cooling water
=UTIL.CDA Compressed dry air
=UTIL.N2 Nitrogen system
=UTIL.ELEC Electrical utilities
=UTIL.INST Instrument air
=UTIL.WATER Process water
=UTIL.WASTE Waste collection
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DCS / Instrumentation Split
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| =DCS Distributed control system
=DCS.CTRL Controllers and I/O
=DCS.HIST Historian
=DCS.HMI Operator workstations
=ESD Emergency shutdown system
=F&G Fire and gas system
=INST Field instrumentation
=INST.FLOW Flow instruments
=INST.PRESS Pressure instruments
=INST.TEMP Temperature instruments
=INST.LEVEL Level instruments
=INST.ANAL Analysers
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Oil & Gas
Convention: Follows ISA / IEC 81346 hybrid. Functional groupings align to process units and safety systems.
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| =WELLHEAD Wellhead control
=MANIFOLD Manifold control
=SEP Separation train
=SEP.1ST First stage separator
=SEP.2ND Second stage separator
=SEP.3RD Third stage separator
=SEP.TEST Test separator
=COMPRESS Compression system
=COMPRESS.K1 Compressor train 1
=COMPRESS.K2 Compressor train 2
=COMPRESS.FLARE Flare knockout
=EXPORT Export system
=EXPORT.PUMP Export pumps
=EXPORT.METER Fiscal metering
=EXPORT.PIPE Pipeline interface
=UTIL Utilities
=UTIL.FUEL Fuel gas system
=UTIL.INST Instrument air
=UTIL.FIRE Firewater system
=UTIL.HVAC HVAC and pressurisation
=UTIL.POWER Power generation
=UTIL.UPS UPS system
=ESD Emergency shutdown system
=ESD.L1 ESD level 1 — process shutdown
=ESD.L2 ESD level 2 — process unit shutdown
=ESD.L3 ESD level 3 — emergency shutdown
=F&G Fire and gas detection
=F&G.FLAME Flame detectors
=F&G.GAS Gas detectors
=F&G.HEAT Heat detectors
=F&G.SMOKE Smoke detectors
=PSD Process safety devices (PSVs, BDVs)
=ICSS Integrated control and safety system
=ICSS.DCS DCS portion
=ICSS.SIS Safety instrumented system
=ICSS.F&G F&G controller
=TURRET Turret system (FPSO)
=MOORING Mooring system
=OFFL Offloading system
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Water & Wastewater Treatment
Convention: Process stages as function designations. Common in council, utility, and infrastructure projects.
Water Treatment Plant
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| =INTAKE Raw water intake
=INTAKE.SCREEN Intake screening
=INTAKE.PUMP Intake pumping
=COAG Coagulation dosing
=FLOC Flocculation
=CLARI Clarification / sedimentation
=FILT Filtration
=FILT.RAPID Rapid sand filtration
=FILT.SLOW Slow sand filtration
=FILT.MEMB Membrane filtration
=FILT.BW Filter backwash system
=DOSE Chemical dosing
=DOSE.CL2 Chlorine dosing
=DOSE.FLUOR Fluoride dosing
=DOSE.LIME Lime dosing
=DOSE.ACID Acid dosing
=STOR Clear water storage
=DIST Distribution pumping
=SLUDGE Sludge handling
=SLUDGE.THCK Sludge thickening
=SLUDGE.DISP Sludge disposal
=SCADA SCADA and telemetry
=SCADA.RTU Remote terminal units
=SCADA.COMM Communications network
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Wastewater Treatment Plant
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| =INFLOW Inlet works
=INFLOW.SCREEN Inlet screening
=INFLOW.GRIT Grit removal
=PRIM Primary treatment
=PRIM.SETT Primary settlement
=PRIM.SCUM Scum removal
=BIO Biological treatment
=BIO.ASP Activated sludge process
=BIO.MBR Membrane bioreactor
=BIO.AIRLIFT Aeration / air lift
=BIO.AIR Aeration blowers
=SEC Secondary settlement
=TER Tertiary treatment
=TER.UV UV disinfection
=TER.FILT Sand filtration
=RETURN Return activated sludge
=WASTE Waste activated sludge
=SLUDGE Sludge processing
=SLUDGE.THICK Sludge thickening
=SLUDGE.DIGEST Anaerobic digestion
=SLUDGE.DEWATER Sludge dewatering
=SLUDGE.INCINR Sludge incineration
=BIOGAS Biogas handling
=BIOGAS.STORE Biogas storage
=BIOGAS.GEN Gas to energy (CHP)
=ODOUR Odour control
=UTIL Site utilities
=SCADA SCADA system
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Power Distribution & Energy
Convention: Based on voltage levels, switchgear designations, and IEC standards. Used by utilities, EPC, and substation designers.
HV/MV Substation
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| =GEN Generation (if applicable)
=GEN.G1 Generator 1
=GEN.G2 Generator 2
=HV High voltage system (e.g. 132kV, 66kV)
=HV.BUS_A HV busbar A
=HV.BUS_B HV busbar B
=HV.INC1 HV incoming feeder 1
=HV.INC2 HV incoming feeder 2
=HV.TIE HV bus tie
=TX Transformer
=TX.T1 Transformer 1
=TX.T2 Transformer 2
=TX.COOL Transformer cooling
=TX.PROT Transformer protection
=MV Medium voltage system (e.g. 11kV, 6.6kV, 3.3kV)
=MV.BUS_A MV busbar A
=MV.BUS_B MV busbar B
=MV.TIE MV bus tie
=MV.FDR1 MV feeder 1
=MV.FDR2 MV feeder 2
=MV.MOTOR MV motor feeders
=LV Low voltage system (415V / 400V)
=LV.MDB Main distribution board
=LV.EMDB Essential MDB
=LV.UPS UPS system
=LV.DB1 Distribution board 1
=LV.DB2 Distribution board 2
=PROT Protection and metering
=PROT.DIFF Differential protection
=PROT.OVERCUR Overcurrent protection
=PROT.EARTH Earth fault protection
=PROT.DIST Distance protection
=PROT.BUSBAR Busbar protection
=SCADA Substation automation system (SAS)
=SCADA.RTU RTU / IED gateway
=SCADA.IED Individual IEDs (IEC 61850)
=SCADA.HMI Local HMI
=COMM Protection communications
=COMM.FIBER Fibre optic network
=COMM.PLC Power line carrier
=EARTH Earthing system
=LIGHTING Substation lighting
=BATT DC battery and charger system
=BATT.CHRG Battery charger
=BATT.BANK Battery bank
=BATT.DIST DC distribution board
=HVAC Control room HVAC
=FIRE Fire detection and suppression
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UPS System
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| =UPS UPS system
=UPS.RECT Rectifier
=UPS.INV Inverter
=UPS.BATT Battery bank
=UPS.BYPASS Static bypass
=UPS.MBP Manual maintenance bypass
=UPS.DIST UPS distribution board
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Building Automation (BAS/BMS)
Convention: System type + zone or floor number. Follows ASHRAE and building services standards.
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| =BMS Building management system (head end)
=BMS.SERVER BMS server
=BMS.CTRL System controllers
=BMS.FIELD Field controllers (DDC, BCU)
=HVAC HVAC systems
=HVAC.AHU1 Air handling unit 1
=HVAC.AHU2 Air handling unit 2
=HVAC.FCU Fan coil units
=HVAC.CHILLER Chiller plant
=HVAC.BOILER Boiler plant
=HVAC.PUMP Pumping systems
=HVAC.CT Cooling towers
=HVAC.VAV VAV boxes
=HVAC.ERV Energy recovery ventilation
=LIGHTING Lighting control
=LIGHTING.DALI DALI network
=LIGHTING.EMERG Emergency lighting
=ACCESS Access control
=CCTV CCTV system
=FIRE Fire detection
=LIFT Lift / elevator system
=POWER Power monitoring
=POWER.METER Smart metering
=POWER.PV Solar PV monitoring
=SECUR Security system
=CARPARK Car park management
=IRRIG Irrigation system
=WATER Water metering
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Automotive Manufacturing
Convention: Production line segments and process stations. Used by Tier 1 suppliers and OEMs.
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| =BODY Body shop
=BODY.STAMP Stamping press line
=BODY.WELD Welding line
=BODY.WELD.R1 Welding robot group 1
=BODY.WELD.R2 Welding robot group 2
=BODY.GEO Geometry station
=PAINT Paint shop
=PAINT.PREP Surface preparation
=PAINT.ED Electro-deposition primer
=PAINT.SEAL Sealing and underbody
=PAINT.BASE Basecoat
=PAINT.CLEAR Clearcoat
=PAINT.OVEN Paint ovens
=PAINT.CONV Conveyors
=TRIM Trim and final assembly
=TRIM.T1 Trim line 1
=TRIM.T2 Trim line 2
=TRIM.GLASS Glass installation
=TRIM.ELEC Electrical installation
=CHASSIS Chassis and drivetrain
=CHASSIS.ENG Engine installation
=CHASSIS.TRANS Transmission
=CHASSIS.AXL Axle and wheel
=FINAL Final quality and test
=FINAL.ALIGN Wheel alignment
=FINAL.TEST End of line test
=FINAL.AUDIT Quality audit
=CONV Material handling conveyors
=CONV.OVERHEAD Overhead conveyor
=CONV.SKID Skid conveyor
=CONV.AGV AGV system
=UTIL Plant utilities
=UTIL.COMPRESS Compressed air
=UTIL.WELD_GAS Welding gases
=UTIL.PAINT_AIR Paint supply air
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Food & Beverage
Convention: Process stages from intake to packaging. Often follows FSSC 22000 / GMP documentation structure.
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| =RECV Raw material receiving
=RECV.WEIGH Weighing and intake
=RECV.STORE Raw material storage
=CLEAN CIP / SIP cleaning system
=CLEAN.CIP1 CIP circuit 1
=CLEAN.CIP2 CIP circuit 2
=CLEAN.SIP Steam-in-place
=PREP Ingredient preparation
=PREP.SIFT Sifting and screening
=PREP.BLEND Dry blending
=PREP.HYDRATE Hydration / mixing
=COOK Cooking process
=COOK.BATCH Batch cookers
=COOK.CONT Continuous cooker
=COOK.STEAM Steam injection
=COOL Cooling process
=COOL.PLATE Plate heat exchanger
=COOL.FLASH Flash cooling
=COOL.CHILL Chill tunnel
=FILL Filling and packaging
=FILL.DOSING Dosing system
=FILL.FILL1 Filler line 1
=FILL.FILL2 Filler line 2
=FILL.SEAL Sealing
=FILL.LABEL Labelling
=PACK Secondary packaging
=PACK.CART Cartoning
=PACK.WRAP Shrink wrap
=PACK.PALLETISE Palletising
=REFRIG Refrigeration system
=REFRIG.COMP Compressor rack
=REFRIG.COLD Cold store
=REFRIG.FREEZE Freezer
=STEAM Steam generation
=STEAM.BOILER Boiler
=STEAM.DIST Steam distribution
=WASTE Waste management
=WASTE.EFFLUENT Effluent treatment
=UTIL Site utilities
=UTIL.CDA Compressed dry air
=UTIL.CO2 CO2 system
=UTIL.N2 Nitrogen system
=UTIL.WATER Water treatment
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Pharmaceutical & Cleanroom
Convention: Strict GMP documentation alignment. Function designations often mirror validation documents (URS/DQ/IQ/OQ/PQ).
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| =HVAC HVAC / cleanroom conditioning
=HVAC.AHU1 Air handling unit 1 (Grade A/B)
=HVAC.AHU2 Air handling unit 2 (Grade C/D)
=HVAC.HEPA HEPA filtration
=HVAC.LAF Laminar air flow units
=HVAC.PRESS Room pressurisation control
=HVAC.TEMP Temperature and humidity
=WFI Water for injection system
=WFI.STILL WFI still / distillation
=WFI.STORE WFI storage
=WFI.DIST WFI distribution loop
=PW Purified water system
=PW.RO Reverse osmosis
=PW.EDI Electrodeionisation
=PW.STORE PW storage
=PW.DIST PW distribution loop
=CIP Clean-in-place system
=SIP Steam-in-place system
=AUTOCLAVE Autoclave sterilisation
=FORM Formulation
=FORM.WEIGH Weighing isolator
=FORM.BLEND Blending
=FORM.GRANUL Granulation
=FORM.COAT Tablet coating
=FILL.VIAL Vial filling line
=FILL.AMPUL Ampoule filling
=FILL.SYRINGE Syringe filling
=LYOPHIL Lyophilisation (freeze drying)
=INSPECT Visual inspection
=PACK Packaging
=PACK.BLISTER Blister packing
=PACK.LABEL Labelling
=COLD Cold chain
=COLD.REFRIG Refrigerated storage
=COLD.FREEZE Frozen storage
=BMS Building management system
=ELOG Electronic batch record / MES interface
=SAFE Safety system
=SAFE.ESD Emergency shutdown
=SAFE.ALARM Alarm management system
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Renewable Energy — Solar PV
Convention: Based on string configuration and inverter groupings.
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| =PV Photovoltaic generation
=PV.STR_A String group A
=PV.STR_B String group B
=PV.STR_C String group C
=SCB String combiner boxes
=SCB.1 SCB 1
=SCB.2 SCB 2
=INV Inverter system
=INV.1 Inverter 1
=INV.2 Inverter 2
=INV.3 Inverter 3
=XFMR Step-up transformer(s)
=XFMR.T1 Transformer 1
=XFMR.T2 Transformer 2
=GRID Grid connection
=GRID.POC Point of connection
=GRID.METER Export metering
=GRID.PROT Grid protection relay
=BESS Battery energy storage system
=BESS.BATT Battery modules
=BESS.PCS Power conversion system
=BESS.BMS Battery management system
=BESS.HVAC BESS HVAC
=SCADA Plant SCADA / monitoring
=SCADA.MET Meteorological station
=SCADA.COMM SCADA communications
=CTRL Site plant controller
=FIRE Fire detection
=CCTV CCTV and security
=UTIL Site auxiliary power
=UTIL.TXAUX Auxiliary transformer
=UTIL.DB Auxiliary distribution board
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Renewable Energy — Wind
Convention: Turbine-based with site level groupings.
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| =WTG Wind turbine generator
=WTG.T01 Turbine 01
=WTG.T02 Turbine 02
=WTG.T03 Turbine 03
=WTG.NACELLE Nacelle systems
=WTG.TOWER Tower systems
=WTG.BLADE Blade pitch system
=WTG.YAW Yaw system
=WTG.GEAR Gearbox and drivetrain
=WTG.GEN Generator
=WTG.CONV Power converter
=ARRAY Array cable system
=ARRAY.C1 Array circuit 1
=ARRAY.C2 Array circuit 2
=OSS Offshore substation (offshore)
=OSS.MV MV switchgear
=OSS.HV HV switchgear
=OSS.TX Offshore transformer
=OSS.AUX Auxiliary systems
=ONSHORE Onshore substation
=ONSHORE.TX Onshore transformer
=ONSHORE.GRID Grid connection
=SCADA Wind farm SCADA
=SCADA.MET Metmast
=SCADA.COMM Comms network
=SAFE Safety and ice detection
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Marine & Shipbuilding
Convention: Follows IACS / classification society standards. Ship systems and compartments used.
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| =PROPUL Propulsion system
=PROPUL.ME1 Main engine 1
=PROPUL.ME2 Main engine 2
=PROPUL.GEAR Gearbox
=PROPUL.PROP Propeller / shaft
=PROPUL.BOW Bow thruster
=PROPUL.STERN Stern thruster
=ELECT Electrical power generation
=ELECT.DG1 Diesel generator 1
=ELECT.DG2 Diesel generator 2
=ELECT.DG3 Emergency generator
=ELECT.SW Main switchboard
=ELECT.ESW Emergency switchboard
=ELECT.DIST Distribution switchboards
=BRIDGE Bridge systems
=BRIDGE.NAV Navigation systems
=BRIDGE.COMM Communications
=BRIDGE.DP Dynamic positioning
=BRIDGE.AIS AIS / GMDSS
=CARGO Cargo systems
=CARGO.PUMP Cargo pumps
=CARGO.TANK Tank monitoring
=CARGO.INERT Inert gas system
=STAB Stability systems
=STAB.BALLAST Ballast system
=STAB.HEEL Heel correction
=FIRE Fire detection and suppression
=FIRE.CO2 CO2 flooding
=FIRE.SPRINK Sprinkler system
=BILGE Bilge system
=HVAC HVAC and ventilation
=SAFE Safety management system
=HULL Hull monitoring
=ENGINE_RM Engine room monitoring
=SCADA Integrated automation system (IAS)
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Rail & Transportation
Convention: Aligned to subsystem codes used in rail projects (EN 50128, EN 50129). RAMS-driven.
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| =TRAC Traction power system
=TRAC.OCS Overhead contact system
=TRAC.SS Traction substations
=TRAC.RETURN Return current system
=SIGNAL Signalling system
=SIGNAL.ATP Automatic train protection
=SIGNAL.ATO Automatic train operation
=SIGNAL.ATS Automatic train supervision
=SIGNAL.INTLK Interlocking
=COMMS Communications
=COMMS.RADIO Radio system
=COMMS.SCADA SCADA / TIMS
=COMMS.PA Passenger announcement
=COMMS.CCTV CCTV
=PLATFORM Platform systems
=PLATFORM.PSD Platform screen doors
=PLATFORM.LIFT Lifts and escalators
=PLATFORM.DISP Passenger displays
=DEPOT Depot systems
=DEPOT.WASH Train wash
=DEPOT.FUEL Fuelling / charging
=DEPOT.MAINT Maintenance equipment
=TUNNEL Tunnel systems
=TUNNEL.VENT Tunnel ventilation
=TUNNEL.FIRE Tunnel fire and life safety
=TUNNEL.DRAIN Drainage and pump sumps
=TRACK Track equipment
=TRACK.SWITCH Track switches and points
=TRACK.HEAT Track heating
=SAFE Safety and SIL systems
=POWER Auxiliary power
=POWER.LV Station LV distribution
=POWER.UPS UPS systems
=LIGHTING Station and tunnel lighting
=LIGHTING.EMERG Emergency lighting
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Data Centre & IT Infrastructure
Convention: Tier classification aligned. Follows TIA-942 / EN 50600.
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| =POWER Power distribution
=POWER.UTIL Utility incoming
=POWER.GENSET Generator sets
=POWER.ATS Automatic transfer switches
=POWER.UPS_A UPS system A
=POWER.UPS_B UPS system B
=POWER.PDU_A PDU A side
=POWER.PDU_B PDU B side
=POWER.RPP Remote power panels
=POWER.FLOOR Floor PDUs
=POWER.METER Power metering
=COOL Cooling system
=COOL.CHILLER Chiller plant
=COOL.CRAC Computer room air conditioners
=COOL.CRAH Computer room air handlers
=COOL.RDHx Row/rack cooling
=COOL.CT Cooling towers
=COOL.PUMP Chilled water pumps
=COOL.ECON Economiser / free cooling
=NETW Network infrastructure
=NETW.CORE Core switches
=NETW.DIST Distribution switches
=NETW.ACCESS Access layer
=NETW.OOB Out-of-band management
=NETW.FIBER Fibre backbone
=FIRE Fire detection and suppression
=FIRE.VESDA VESDA early warning
=FIRE.SUPPRS Suppression system (FM200, Novec)
=DCIM Data centre infrastructure management
=DCIM.ENV Environmental monitoring
=DCIM.POWER Power chain monitoring
=DCIM.ASSET Asset management
=ACCESS Physical access control
=CCTV CCTV system
=SAFE Safety and emergency
=SAFE.ESD Emergency power off (EPO)
=STRUCT Structured cabling
=STRUCT.MDA Main distribution area
=STRUCT.HDA Horizontal distribution area
=STRUCT.ZDA Zone distribution area
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Mining & Heavy Industry
Convention: Mining process stages and areas. Common in APAC and African mining projects.
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| =MINE Mining operation
=MINE.DRILL Drilling system
=MINE.BLAST Blast management
=MINE.HAUL Haul road and truck dispatch
=MINE.DWATER Dewatering
=CRUSH Crushing plant
=CRUSH.PRI Primary crusher
=CRUSH.SEC Secondary crusher
=CRUSH.TERT Tertiary crusher
=CRUSH.SCRN Screening
=GRIND Grinding circuit
=GRIND.SAG SAG mill
=GRIND.BALL Ball mill
=GRIND.CYCL Cyclones
=FLOAT Flotation circuit
=FLOAT.ROUGH Rougher cells
=FLOAT.CLEAN Cleaner cells
=FLOAT.SCAV Scavenger cells
=REAGENT Reagent dosing
=REAGENT.LIME Lime dosing
=REAGENT.COLL Collector
=REAGENT.FROTH Frother
=THICKEN Thickening
=THICKEN.CONC Concentrate thickener
=THICKEN.TAIL Tailings thickener
=FILTER Filtration
=FILTER.DISC Disc filter
=FILTER.PRESS Filter press
=CONVEYOR Conveyor systems
=CONVEYOR.C1 Conveyor 1
=CONVEYOR.C2 Conveyor 2
=CONVEYOR.OLC Overland conveyor
=WATER Water circuit
=WATER.FRESH Fresh water
=WATER.PROC Process water
=WATER.RECLAIM Reclaim water
=TAILS Tailings management
=TAILS.PIPE Tailings pipeline
=TAILS.DAM Tailings storage facility
=POWER Site power distribution
=POWER.GRID Grid connection / bulk supply
=POWER.SS1 Substation 1
=POWER.SS2 Substation 2
=COMM Site communications
=SAFE Safety systems
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HVAC Systems
Convention: Equipment type with zone or air handling unit number.
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| =AHU Air handling units
=AHU.AHU01 AHU 01
=AHU.AHU02 AHU 02
=AHU.AHU03 AHU 03 (fresh air)
=FCU Fan coil units
=FCU.L1 Level 1 FCUs
=FCU.L2 Level 2 FCUs
=VAV VAV system
=VAV.ZONE_A Zone A VAV
=VAV.ZONE_B Zone B VAV
=CHILLER Chiller plant
=CHILLER.CH1 Chiller 1
=CHILLER.CH2 Chiller 2
=CHILLER.CH3 Standby chiller
=BOILER Boiler plant
=BOILER.B1 Boiler 1
=BOILER.B2 Boiler 2
=PUMP Pumping systems
=PUMP.CHW Chilled water pumps
=PUMP.HW Heating water pumps
=PUMP.CW Condenser water pumps
=CT Cooling towers
=CT.CT1 Cooling tower 1
=CT.CT2 Cooling tower 2
=VENT Mechanical ventilation
=VENT.SUPPLY Supply air
=VENT.EXHAUST Exhaust air
=VENT.SMOKE Smoke exhaust
=VENT.CARPARK Carpark ventilation
=CTRL BMS / controls
=REFRIG Refrigerant system
=HEX Heat exchangers
=BMS Building management interface
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Safety & SIL Systems
Convention: Safety layers and safety functions. Aligned to IEC 61508 / IEC 61511.
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| =SIS Safety instrumented system (overall)
=SIS.SIL1 SIL 1 functions
=SIS.SIL2 SIL 2 functions
=SIS.SIL3 SIL 3 functions
=SIF Safety instrumented functions
=SIF.SF001 Safety function 001 (e.g. high pressure shutdown)
=SIF.SF002 Safety function 002 (e.g. high temperature shutdown)
=SIF.SF003 Safety function 003 (e.g. high level shutdown)
=ESD Emergency shutdown system
=ESD.L1 Process shutdown (PSD)
=ESD.L2 Emergency shutdown (ESD)
=ESD.L3 Abandon platform (APS — offshore)
=BPCS Basic process control system
=F&G Fire and gas system
=F&G.ZONE_A Fire zone A
=F&G.ZONE_B Fire zone B
=SAFE.ESTOP Emergency stop system
=SAFE.GUARD Guarding / access interlock
=SAFE.SAFE_IO Safety I/O modules
=SAFE.LOGIC Safety PLC / logic solver
=SAFE.VALVE Safety valves (SDV, BDV, XV)
=RELIEF Pressure relief system
=RELIEF.PSV Pressure safety valves
=RELIEF.FLARE Flare / vent system
=GROUNDING Earthing and bonding
=GROUNDING.LPS Lightning protection
=GROUNDING.STAT Static bonding
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Full Structure Examples
Example 1 — Water Pump Station (small project)
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| Full tag: =CTRL+DB1-K1
Meaning: Control relay K1, located in distribution board DB1, performing control function
Full tag: =PWR+MCC1-Q3
Meaning: Contactor Q3, in MCC1, power distribution function
Full tag: =SAFE+MCC1-F1
Meaning: Motor protection relay F1, in MCC1, safety function
Full tag: =INST+FIELD-FT101
Meaning: Flow transmitter FT101, in field, instrumentation function
Full tag: =SCADA+CTRL_ROOM-PLC1
Meaning: PLC1, in control room panel, SCADA function
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Example 2 — Manufacturing Cell (multi-level)
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| =CTRL.PLC+CP1-CPU PLC CPU in control panel CP1
=CTRL.IO+CP1-DI01 Digital input module in CP1
=DRIVE.X+CP1-VFD_X X-axis VFD in CP1
=SAFE.GUARD+CP1-F3_SAFE Safety relay for guarding in CP1
=CTRL.HMI+OP1-TP700 HMI touchpanel at operator station OP1
=ACT.PNEU+MACHINE-CYL1 Pneumatic cylinder 1 on machine
=SENS.POS+MACHINE-B1 Proximity sensor B1 on machine
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Example 3 — Substation (IEC 81346 strict)
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| =T1+PAN_1-F1 Transformer T1 protection, panel 1, fuse F1
=Q1.PROT+PAN_1-K21 Feeder Q1 overcurrent relay in panel 1
=G1+BATT_RM-G1 DC battery bank G1 in battery room
=D1+CTRL_RM-PLC RTU/PLC D1 in control room
=H1+PAN_1-HL1 Alarm indicator H1 in panel 1
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Common Mistakes
| ❌ Wrong | ✅ Correct | Reason |
|---|
=PANEL_A | +PANEL_A | Panel A is a location, not a function |
=MOTOR_1 | -M1 or +LOC-M1 | Motor 1 is a device, not a function |
=CABINET_3 | +CAB3 | Cabinet is a location |
=ELECTRICAL | =PWR or =CTRL | Too vague — what function? |
=PLANT | +PLANT | Plant is a location |
| Mixing conventions mid-project | Pick one and stick to it | Consistency is critical |
Over-nesting: =A.B.C.D.E | Max 2–3 levels | Deep nesting causes report issues |
Using spaces: =CTRL PWR | =CTRL.PWR | Spaces break EPLAN structure |
Starting with number: =1CTRL | =CTRL1 | Numbers must not lead in IEC 81346 |
Expert Tips
1. Agree with the client before starting
Ask: “How do you mentally divide your system?” Use their language.
2. Match your = structure to the P&ID or SLD
If the P&ID has units U10–U90, your EPLAN = should mirror that.
3. Keep it short
=CTRL is better than =MAIN_CONTROL_SYSTEM. Tags appear in reports — long names truncate.
4. Reserve =Z or =MISC for exceptions
Always have a catch-all so unclassified circuits have somewhere to go without breaking the structure.
5. Create a designation key page
Use page type EAC (Explanatory documents) to document what each = designation means. Future engineers will thank you.
6. Don’t create too many top-level designations
5–15 top-level = entries is ideal. More than 20 and the project becomes hard to navigate.
7. Consider report filtering from day one
Every = designation becomes a filter in EPLAN reports. Good designations = useful, filterable BOMs and connection lists.
8. Validate with a test page early
Create one page per = designation at the start. Check that your filter logic, page numbering, and report output all work as expected before building out the full project.
Based on IEC 81346 | IEC 61355 | IEC 61511 | ISA-5.1 | TIA-942 | EN 50600 | IACS Expert conventions compiled from machine building, process, energy, infrastructure, and maritime industries
