Pilz PNOZ Error Codes

FEED BACK LOOP: External error at the feedback loop inputs

What it means: The feedback loop (the N/C auxiliary contacts of the external contactors switched by a safety output, wired back to an input) reported a state that does not match the output. Pilz states that on outputs with advanced fault detection a feedback loop error puts the system in a safe state and shuts down all outputs.^[1]

Device response: Safe state, all outputs off on outputs with advanced fault detection; restart with the rotary knob (3 to 8 s) after the fix

Likely causes

• Contactor contact welded or mechanically stuck, so its N/C auxiliary contact does not close
• Broken wire, loose terminal or wrong input in the feedback loop
• Contactor wiring does not match the circuit diagram in the PNOZmulti Configurator project

First checks, in this order

1. Check that each external contactor drops out fully when the output switches off; replace a contactor with welded contacts.
2. Check the feedback loop wiring and terminals against the circuit diagram in the PNOZmulti Configurator.
3. Never bridge the feedback loop to get the machine running.
4. After the fix, press the rotary knob for 3 to 8 seconds to restart, then test the safety function.

FAULTY TEST PULSE: Error caused by test pulses

What it means: An input wired to a test pulse output (T0 to T3) did not see the test pulse it expects. The test pulses are how the base unit detects shorts between inputs (cross-shorts).^[1]

Likely causes

• Short across contacts between two input channels (cross-short)
• Input cable shorted to +24 V or 0 V
• Input wired to a different test pulse output than the project expects
• Damaged sensor cable

First checks, in this order

1. Put the system in a stop state and use the Force Test Pulse menu on the display to switch the test pulse outputs by hand and find the faulty line.
2. Check the cables of both channels for a short between them, or to 24 V or 0 V.
3. Check that each input uses the test pulse output shown in the Configurator circuit diagram.
4. Restart with the rotary knob (3 to 8 s) after the fix and test the safety function.

PARTIALLY OPERATED: Function element was or is partially operated

What it means: Only one channel of a dual-channel safety device (for example an E-STOP or a safety gate) opened, or the two channels did not switch together. Pilz lists this as an input error that does not put the base unit in a safe state: RUN stays on and IFAULT flashes.^[1]

Likely causes

• E-STOP pressed or gate opened only partly, so just one contact opened
• Misaligned or worn safety switch
• One contact or one channel wire faulty

First checks, in this order

1. Operate the safety device fully so both channels open, then close it again.
2. Check the switch alignment and both contact channels.
3. Check the wiring of both channels.
4. The message is stored, not shown automatically: call it up on the display with the rotary knob.

FAULTY OUTPUT: External error on the output

What it means: The base unit has found an external fault on a safety output, for example a short across contacts. In the LED table this kind of error shows as OFAULT lit with RUN off, a safe condition.^[1]

Device response: Safe condition; restart with the rotary knob (3 to 8 s) after the fix

Likely causes

• Short between two outputs
• Output cable shorted to +24 V or 0 V
• Fault in the load or its wiring

First checks, in this order

1. Check the output wiring for shorts to other outputs, to 24 V and to 0 V.
2. Check the connected load and its wiring.
3. Restart with the rotary knob (3 to 8 s) after the fix and test the safety function.

CHIP CARD ?: Chip card is not inserted, blank or unreadable

What it means: The base unit cannot read a project from the chip card. The LED table lists a missing chip card as an external error that leads to a safe condition (FAULT lit, RUN off).^[1]

Likely causes

• Chip card missing
• Blank card, or a card without the current project
• Dirty, scratched or bent card, so the contacts do not touch

First checks, in this order

1. Switch the unit off before inserting or exchanging the chip card.
2. Insert the chip card that holds the current project; keep the contact surface clean and undamaged and do not bend the card.
3. Switch on, check the project name, CRC and date on the display, then hold the rotary knob for 3 to 8 seconds to load it.
4. Test the safety devices after the card is exchanged.

FAULTY PROJECT: The chip card or device memory contains a project that is faulty or incompatible

What it means: The project stored on the chip card or in the base unit cannot be run, because it is damaged or does not fit this device.^[1]

Likely causes

• Project made for a different device or firmware version
• Corrupted project data on the chip card or in the device memory

First checks, in this order

1. Check the device type and firmware version in the Device Info menu.
2. Load a correct project from the PNOZmulti Configurator over USB, or from a chip card with the right project.
3. Test the safety devices after the project download.

NO PROJECT: No project in the device memory (e.g. after a factory reset)

What it means: The base unit holds no project, so it cannot switch any safety outputs on.^[1]

Likely causes

• Factory reset or Project RESET was carried out
• Replacement base unit not yet loaded

First checks, in this order

1. Load the project from the chip card (hold the rotary knob for 3 to 8 seconds) or over USB with the PNOZmulti Configurator.
2. Check the project name and CRC on the display.
3. Test the safety devices after the project download.

LOAD SUPPLY: Error in the supply voltage for the semiconductor outputs

What it means: The separate 24 V DC supply for the semiconductor outputs is missing or out of tolerance. Pilz states this supply must always be present, even when the semiconductor outputs are not used.^[1]

Likely causes

• 24 V not connected to the semiconductor output supply terminals (24 V and 0V)
• External fuse or circuit breaker F2 tripped
• Power supply overloaded or voltage outside 24 V DC -20 %/+25 %

First checks, in this order

1. Measure the voltage at the semiconductor output supply terminals.
2. Check the external fuse protection F2 (10 A circuit breaker, characteristic B/C).
3. Connect this supply even if no semiconductor outputs are used.

SUPPLY LOW: Supply voltage is below the tolerance level

What it means: The control system supply on A1/A2 is below the allowed range (24 V DC -20 %, about 19.2 V).^[1]

Likely causes

• Weak or overloaded 24 V power supply
• Voltage drop on long or thin supply cables
• Loose A1 or A2 terminal

First checks, in this order

1. Measure the voltage between A1 (+24 V DC) and A2 (0 V); you can also read it in the Operating Info menu.
2. Check that the power supply delivers 1.6 A continuous and 3 A inrush for the base unit.
3. Check the external fuse protection F1 (6 A circuit breaker, characteristic B).

SUPPLY HIGH: Supply voltage exceeds the tolerance level

What it means: The control system supply on A1/A2 is above the allowed range (24 V DC +25 %, about 30 V).^[1]

Likely causes

• Power supply set too high or faulty
• Wrong supply connected to A1/A2

First checks, in this order

1. Measure the voltage between A1 and A2, or read it in the Operating Info menu.
2. Adjust or replace the 24 V DC power supply.

CONFIGURATION: Hardware registry does not match the configuration

What it means: The expansion modules the base unit finds do not match the hardware set up in the project.^[1]

Likely causes

• Expansion module missing, of a different type, or in a different slot than in the PNOZmulti Configurator
• Jumper between modules missing or not seated
• Terminator missing on an open interface

First checks, in this order

1. Compare the modules on the rail and their order with the project; the Device Info menu lists each module by position.
2. Check the jumpers between the units and the terminators on the unconnected interfaces.
3. Only connect or disconnect modules and terminators with the supply switched off.

FAULTY DEVICE: Internal error on the base unit

What it means: The base unit has detected an internal fault.^[1]

Likely causes

• Internal hardware fault in the base unit
• Severe interference or overvoltage

First checks, in this order

1. Switch the supply off and on again.
2. If it comes back, read the error stack (display or PNOZmulti Configurator) and give the entries to Pilz technical support.
3. Return a faulty unit to Pilz.

RUN off, DIAG flashing: The existing user program has been deleted

What it means: The project has been erased from the base unit (Project RESET or factory reset), so the safety outputs stay off until a project is loaded. After a factory reset the display shows FACTORY RESET DONE while DIAG flashes.^[1]

Likely causes

• Project deleted in the Project RESET menu
• Factory reset carried out on the device or from the Configurator

First checks, in this order

1. Load the project from the chip card or over USB with the PNOZmulti Configurator.
2. Test the safety devices after the project download.

RUN off, FAULT on: External error on the base unit, leading to a safe condition, e.g. chip card not inserted

What it means: An external fault on the base unit itself has put the system in a safe condition.^[1]

Likely causes

• Chip card not inserted or unreadable
• Other external error on the base unit

First checks, in this order

1. Read the short text on the display.
2. Check that a chip card with the current project is inserted (switch off first).
3. Restart with the rotary knob (3 to 8 s) after the fix.

RUN off, OFAULT on: External error on the base unit outputs, e.g. short across the contacts, leading to a safe condition

What it means: An external fault on the base unit outputs has put the system in a safe condition.^[1]

Likely causes

• Short across contacts between outputs
• Output shorted to 24 V or 0 V
• Feedback loop or load wiring fault

First checks, in this order

1. Read the short text on the display (for example FAULTY OUTPUT or FEED BACK LOOP).
2. Check the output and feedback loop wiring for shorts.
3. Restart with the rotary knob (3 to 8 s) after the fix and test the safety function.

RUN on, OFAULT flashing: External error on the base unit outputs, which does not lead to a safe condition, e.g. feedback input defective

What it means: An external output problem was found, but the system keeps running.^[1]

Likely causes

• Feedback input defective
• Wiring fault on an output or feedback loop

First checks, in this order

1. Call up the stored message on the display with the rotary knob.
2. Check the feedback loop contacts and wiring of the outputs involved.

RUN on, IFAULT flashing: External error on the base unit inputs, which does not lead to a safe condition, e.g. partially operated

What it means: An external input problem was found, for example a partly operated dual-channel device, but the system keeps running.^[1]

Likely causes

• Safety device operated on one channel only
• Misaligned safety switch or a faulty channel

First checks, in this order

1. Call up the stored message on the display with the rotary knob.
2. Operate the safety device fully and close it again.
3. Check both input channels and their wiring.

RUN off, DIAG and FAULT flashing: Internal error on the base unit

What it means: The base unit has found an internal fault and stopped.^[1]

Likely causes

• Internal hardware fault in the base unit

First checks, in this order

1. Switch the supply off and on again.
2. If it comes back, read the error stack and contact Pilz technical support; return a faulty unit to Pilz.

RUN off, DIAG and IFAULT flashing: Internal error on the base unit (inputs)

What it means: The base unit has found an internal fault in its input section and stopped.^[1]

Likely causes

• Internal fault in the input circuitry of the base unit

First checks, in this order

1. Switch the supply off and on again.
2. If it comes back, read the error stack and contact Pilz technical support; return a faulty unit to Pilz.

RUN off, DIAG and OFAULT flashing: Internal error on the base unit (outputs)

What it means: The base unit has found an internal fault in its output section and stopped.^[1]

Likely causes

• Internal fault in the output circuitry of the base unit

First checks, in this order

1. Switch the supply off and on again.
2. If it comes back, read the error stack and contact Pilz technical support; return a faulty unit to Pilz.

DIAG on: Base unit in a STOP condition

What it means: Status rather than a fault: the base unit is stopped, so the safety outputs are off.^[1]

Likely causes

• System stopped, for example for a project download or for commissioning work

First checks, in this order

1. Check the display and the Configurator for the reason for the stop.
2. Restart the system once the work is finished and test the safety functions.

DIAG flashing: The fieldbus module has not been recognised, or the base unit was identified by the PNOZmulti Configurator via the Ethernet interface, or an existing fieldbus connection was interrupted

What it means: A communication status: the fieldbus module is not recognised or its connection dropped, or the Configurator is sending its identify signal to this unit.^[1]

Likely causes

• Fieldbus module not recognised
• Fieldbus connection interrupted
• Identify function used in the PNOZmulti Configurator

First checks, in this order

1. Check the fieldbus module seating, cable and network.
2. Check whether someone is using the identify function in the Configurator.

FAULT on: Plug terminator not connected

What it means: The FAULT LED is lit steadily on its own: the plug terminator on the side of the unit is missing, so the unit will not start.^[3][4][6]

Also on: PNOZ s5 (same LED table)

Device response: Unit off; reset by switching the supply off and on

Likely causes

• Plug terminator not inserted at the side of the unit
• Terminator left out after a contact expansion module was removed

First checks, in this order

1. Insert the plug terminator at the side of the unit.
2. Switch the supply voltage off and then on again.

FAULT flashing: Internal error, unit defective

What it means: The FAULT LED flashes on its own: the unit has found an internal fault.^[3][4]

Also on: PNOZ s5 (same LED table)

Device response: Unit off; power cycle, replace the unit if it stays

Likely causes

• Internal fault in the safety relay

First checks, in this order

1. Switch the supply voltage off and then on again.
2. If the LED still flashes, replace the unit.

All LEDs off: Short across contacts/earth fault; unit switched off

What it means: Every LED is dark, POWER included: a short across contacts or an earth fault has made the unit switch itself off.^[3][4]

Also on: PNOZ s5 (same LED table)

Device response: Unit switched off; remove the cause and switch the supply off for 1 minute

Likely causes

• Short across contacts in the input circuit (cross-short between channels)
• Earth fault in the input, start or feedback circuit
• Supply missing (check this first)

First checks, in this order

1. Find and remove the short across contacts or earth fault in the input, start and feedback wiring.
2. Switch the supply voltage off for 1 minute, then on again.

IN1, IN2 flashing alternately, FAULT on: Connection error (possibly: cable resistance in the input circuit is too high) or short detected between S12 and S22

What it means: The input channels cannot be read cleanly: either the input circuit cable is too long or too thin, or the two channels are shorted together.^[3][4]

Also on: PNOZ s5 (same LED table)

Device response: Unit off; power cycle after the fix

Likely causes

• Cable resistance in the input circuit too high (cable too long or cross-section too small)
• Short between S12 and S22
• Loose terminal in the input circuit

First checks, in this order

1. Check the input wiring and terminals.
2. Check the input circuit cable length against the maximum overall cable resistance in the technical details.
3. Find and remove any short between S12 and S22.
4. Switch the supply voltage off and then on again.

IN1 flashing, FAULT on: Power-up blocked due to short-term interruption at S12; channels in the input circuit not opened simultaneously

What it means: Channel 1 (S12) opened briefly without channel 2, so the relay blocks the restart until both channels have been opened together.^[3][4]

Also on: PNOZ s5 (same LED table)

Device response: Restart blocked; reset by opening both channels together and closing them again

Likely causes

• E-STOP or gate switch operated only partly
• Bouncing or loose contact in channel 1
• Misaligned safety switch

First checks, in this order

1. Open S11-S12 and S21-S22 at the same time (operate the E-STOP or open the gate fully), then close them again.
2. Check channel 1 contacts, wiring and switch alignment.

IN2 flashing, FAULT on: Power-up blocked due to short-term interruption at S22; channels in the input circuit not opened simultaneously

What it means: Channel 2 (S22) opened briefly without channel 1, so the relay blocks the restart until both channels have been opened together.^[3][4]

Also on: PNOZ s5 (same LED table)

Device response: Restart blocked; reset by opening both channels together and closing them again

Likely causes

• E-STOP or gate switch operated only partly
• Bouncing or loose contact in channel 2
• Misaligned safety switch

First checks, in this order

1. Open S11-S12 and S21-S22 at the same time, then close them again.
2. Check channel 2 contacts, wiring and switch alignment.

IN1 and IN2 flashing together, FAULT on: Power-up blocked due to short-term interruption at S12 and S22; channels in the input circuit not opened simultaneously

What it means: Both channels had short interruptions that did not happen together, so the relay blocks the restart.^[3][4]

Also on: PNOZ s5 (same LED table)

Device response: Restart blocked; reset by opening both channels together and closing them again

Likely causes

• Safety device operated slowly or only partly
• Bouncing contacts in the input circuit

First checks, in this order

1. Open S11-S12 and S21-S22 at the same time, then close them again.
2. Check both input channels and the safety switch.

START flashing, FAULT on: Position of rotary switch is not permitted or rotary switch was adjusted during operation

What it means: The rotary switch on the front is between positions or was turned while the unit was running.^[3][4]

Also on: PNOZ s5 (same LED table)

Device response: Unit off; power cycle after setting the switch

Likely causes

• Rotary switch not locked into a position
• Setting changed while the supply was on

First checks, in this order

1. Switch the supply off, set the rotary switch until it clicks into a permitted position, then switch on again.
2. Fit the adhesive seal over the rotary switch so it cannot be changed.

All LEDs on (POWER, IN1, IN2, OUT, START, FAULT): The operating mode selector switch "mode" is in its start position (vertical position)

What it means: The unit has not been given an operating mode: the mode selector is still in its vertical start position.^[3][4]

Also on: PNOZ s5 (same LED table)

Likely causes

• New unit installed without setting the mode switch
• Mode switch turned back to the start position

First checks, in this order

1. Switch off the supply voltage.
2. Set the required operating mode (automatic, monitored start, start-up test, with or without cross-short detection) on the mode switch; check that it clicks into place.
3. Switch on and test the safety function.

POWER flashing: Supply voltage too low

What it means: The supply is below what the unit needs. This is the one PNOZsigma error that does not light the FAULT LED.^[3][4]

Also on: PNOZ s5 (same LED table)

Likely causes

• Weak or overloaded power supply
• Voltage drop on the supply cables
• Supply outside the tolerance of -15 %/+10 %

First checks, in this order

1. Measure the supply voltage at the unit.
2. Raise the supply voltage if needed (24 V DC units: about 20.4 V to 26.4 V).

Welded contacts (unit will not restart): Contact malfunctions

What it means: If the safety contacts have welded, the unit cannot be reactivated after the input circuit has opened.^[3][4]

Also on: PNOZ s5 (same text; on the s5 the delayed contacts may also open before the delay time ends after an error)

Likely causes

• Contacts welded by overload or short circuit in the load circuit
• Missing or oversized contact fuse

First checks, in this order

1. Check the load circuit for a short or overload.
2. Check the contact fuse protection against the technical details; Pilz recommends a fuse ahead of the output contacts to prevent welding.
3. Treat the unit as faulty and replace it; test the safety function after replacement.

RUN off, OFAULT on: External error on the base unit outputs, e.g. short across the contacts, leading to a safe condition

What it means: An external fault on the base unit outputs has put the PNOZmulti in a safe condition.^[2]

Also on: PNOZ m1p ETH (same manual)

Likely causes

• Short across contacts between outputs
• Output shorted to 24 V or 0 V

First checks, in this order

1. Check the output wiring for shorts.
2. Read the error stack with the PNOZmulti Configurator.
3. Restart the base unit after the fix and test the safety function.

Input LED flashing, RUN off, IFAULT on: External error leading to a safe condition, e.g. short across the contacts or error at safety mat input

What it means: An external input fault has put the PNOZmulti in a safe condition; the flashing input LED shows which input.^[2]

Also on: PNOZ m1p ETH (same manual)

Likely causes

• Short across contacts between input channels
• Fault at a safety mat input
• Input cable shorted to 24 V or 0 V

First checks, in this order

1. Check the wiring of the input whose LED flashes, including its test pulse line.
2. Check the safety mat and its cable if one is connected.
3. Restart the base unit after the fix and test the safety function.

RUN on, IFAULT flashing: External error on the base unit inputs, which does not lead to a safe condition, e.g. partially operated

What it means: An input problem such as a partly operated dual-channel device; the system keeps running.^[2]

Also on: PNOZ m1p ETH (same manual)

Likely causes

• Safety device operated on one channel only
• Misaligned safety switch or a faulty channel

First checks, in this order

1. Operate the safety device fully and close it again.
2. Check both input channels and their wiring.
3. Read the error stack with the PNOZmulti Configurator.

RUN on, OFAULT flashing: External error on the base unit outputs, which does not lead to a safe condition, e.g. feedback input defective

What it means: An output problem such as a defective feedback input; the system keeps running.^[2]

Also on: PNOZ m1p ETH (same manual)

Likely causes

• Feedback input defective
• Feedback loop contact or wiring fault

First checks, in this order

1. Check the feedback loop contacts of the contactors and their wiring.
2. Read the error stack with the PNOZmulti Configurator.

RUN off, FAULT on: External error on the base unit, leading to a safe condition, e.g. terminator not connected

What it means: An external fault on the base unit itself has put the system in a safe condition.^[2]

Also on: PNOZ m1p ETH (same manual)

Likely causes

• Terminator not connected
• Chip card or other external error on the base unit

First checks, in this order

1. Switch off and check that the terminator is connected.
2. Read the error stack with the PNOZmulti Configurator.
3. Switch on again and test the safety function.

RUN off, DIAG flashing: The existing user program has been deleted

What it means: The project memory of the base unit has been cleared (general reset), so the outputs stay off until a project is loaded.^[2]

Also on: PNOZ m1p ETH (same manual)

Likely causes

• General reset done with the OA0-I19 jumper to load a new chip card project

First checks, in this order

1. Switch off, remove the OA0-I19 jumper, insert the chip card with the current project and switch on.
2. Or load the project with the PNOZmulti Configurator.
3. Test the safety functions after the download.

RUN off, DIAG and FAULT flashing: Internal error on the base unit

What it means: The base unit has found an internal fault and stopped.^[2]

Also on: PNOZ m1p ETH (same manual)

Likely causes

• Internal hardware fault in the base unit

First checks, in this order

1. Switch the supply off and on again.
2. If it comes back, read the error stack and contact Pilz technical support.

RUN off, DIAG and IFAULT flashing: Internal error on the base unit

What it means: The base unit has found an internal fault (shown with IFAULT, the input section) and stopped.^[2]

Also on: PNOZ m1p ETH (same manual)

Likely causes

• Internal fault in the base unit

First checks, in this order

1. Switch the supply off and on again.
2. If it comes back, read the error stack and contact Pilz technical support.

RUN off, DIAG and OFAULT flashing: Internal error on the base unit

What it means: The base unit has found an internal fault (shown with OFAULT, the output section) and stopped.^[2]

Also on: PNOZ m1p ETH (same manual)

Likely causes

• Internal fault in the base unit

First checks, in this order

1. Switch the supply off and on again.
2. If it comes back, read the error stack and contact Pilz technical support.

RUN off, expansion module FAULT on, IN/OUT flashing: External error, leading to a safe condition, e.g. short across the contacts

What it means: An external fault on an expansion module has put the system in a safe condition; the flashing IN/OUT LED on the module shows the input or output involved.^[2]

Also on: PNOZ m1p ETH (same manual)

Likely causes

• Short across contacts on the expansion module wiring
• Input or output cable shorted to 24 V or 0 V

First checks, in this order

1. Check the wiring of the module input or output whose LED flashes.
2. Read the error stack with the PNOZmulti Configurator.
3. Restart after the fix and test the safety function.

RUN off, expansion module FAULT on: External error on the output

What it means: An external fault on an expansion module output has put the system in a safe condition.^[2]

Also on: PNOZ m1p ETH (same manual)

Likely causes

• Short or wiring fault on an expansion module output
• Load fault

First checks, in this order

1. Check the output wiring and the load on that expansion module.
2. Read the error stack with the PNOZmulti Configurator.

RUN off, DIAG flashing, expansion module FAULT flashing: Internal error on the expansion module

What it means: An expansion module has found an internal fault and the system stopped.^[2]

Also on: PNOZ m1p ETH (same manual)

Likely causes

• Internal fault in the expansion module
• Module jumper or connection problem

First checks, in this order

1. Switch the supply off, check the jumper and terminator, and switch on again.
2. If it comes back, read the error stack and contact Pilz technical support.

RUN on, expansion module FAULT flashing: External error on the inputs, which does not lead to a safe condition, e.g. partially operated; feedback input defective

What it means: An input problem on an expansion module (for example a partly operated device or a defective feedback input); the system keeps running.^[2]

Also on: PNOZ m1p ETH (same manual)

Likely causes

• Safety device on the module operated on one channel only
• Feedback input defective

First checks, in this order

1. Operate the safety device fully and close it again.
2. Check the module input and feedback wiring.
3. Read the error stack with the PNOZmulti Configurator.

RUN off, DIAG on: Base unit in a STOP condition

What it means: Status rather than a fault: the base unit is stopped, so the safety outputs are off.^[2]

Also on: PNOZ m1p ETH (same manual)

Likely causes

• System stopped, for example for a project download

First checks, in this order

1. Check in the PNOZmulti Configurator why the system is stopped.
2. Start the system again once the work is finished and test the safety functions.

DIAG flashing: The fieldbus module has not been recognised, or the base unit has been identified via the PNOZmulti Configurator

What it means: A communication status: the fieldbus module is not recognised, or the Configurator is sending its identify signal to this unit.^[2]

Also on: PNOZ m1p ETH (same manual)

Likely causes

• Fieldbus module not recognised
• Identify function used in the PNOZmulti Configurator

First checks, in this order

1. Check the fieldbus module seating and its connection to the base unit.
2. Check whether someone is using the identify function in the Configurator.

RUN on, IFAULT on, CI flashing: Error on cascading input; unit remains in a RUN condition

What it means: The cascading input that links this PNOZmulti to another PNOZmulti or PNOZelog unit has an error; the unit keeps running.^[2]

Also on: PNOZ m1p ETH (same manual)

Likely causes

• Wiring fault on the cascading input
• Upstream unit in the cascade not supplying a valid signal

First checks, in this order

1. Check the cascading wiring between the units.
2. Check the state of the upstream unit.
3. Read the error stack with the PNOZmulti Configurator.

RUN on, OFAULT on, CO flashing: Error on cascading output; unit remains in a RUN condition

What it means: The cascading output to the next PNOZmulti or PNOZelog unit has an error; the unit keeps running.^[2]

Also on: PNOZ m1p ETH (same manual)

Likely causes

• Short or wiring fault on the cascading output
• Downstream wiring fault

First checks, in this order

1. Check the cascading output wiring for shorts.
2. Read the error stack with the PNOZmulti Configurator.

Earth fault: Earth fault: The supply voltage fails and the safety contacts open

What it means: An earth fault in the start or input circuit makes the supply voltage fail, and the safety contacts open.^[5]

Device response: Safety contacts open; remove the cause and switch the supply off for about 1 minute

Likely causes

• Damaged cable insulation in the input or start circuit
• Input or start wire touching earth or the machine frame

First checks, in this order

1. Find and repair the earth fault in the input and start wiring.
2. Switch the supply voltage off for about 1 minute, then on again; the unit is then ready for operation.
3. Test the safety function.

Short across contacts (fuse tripped): Shorts across contacts in the input circuit

What it means: In dual-channel operation with cross-short detection, a short between the input channels trips the unit's internal fuse and the output contacts open. With cable runs near the maximum length, the trip can take up to 2 minutes.^[5]

Device response: Output contacts open; remove the short and switch the supply off for about 1 minute

Likely causes

• Short between the two input channels (for example S22 and S32)
• Pinched or damaged two-channel cable

First checks, in this order

1. Find and remove the short between the input channels.
2. Switch the supply voltage off for about 1 minute to reset the fuse.
3. Test the safety function.

POWER LED off: LED "POWER" does not light: Short circuit or no supply voltage

What it means: The POWER LED stays dark, so the relay has no working supply.^[5]

Likely causes

• Short circuit (for example in the input or start circuit)
• No supply voltage at the unit

First checks, in this order

1. Measure the supply voltage at the supply terminals.
2. Check the wiring for a short circuit or earth fault.
3. After a short or earth fault, switch the supply off for about 1 minute before switching on.

Welded contacts (unit will not restart): Contact malfunctions

What it means: If the safety contacts have welded, the relay cannot be reactivated after the input circuit has opened.^[5]

Likely causes

• Contacts welded by overload or short circuit in the load circuit
• Missing or oversized contact fuse

First checks, in this order

1. Check the load circuit for a short or overload.
2. Check the contact fuse protection; Pilz recommends a fuse ahead of the output contacts to prevent welding (values in the technical details).
3. Treat the unit as faulty and replace it; test the safety function after replacement.

OPERATING MODE SWITCH SELECTOR: Error on the operating mode selector switch function element

What it means: The mode selector switch element in the project reports an invalid state.^[1]

Likely causes

• Selector switch between positions or faulty
• Wiring fault on the selector inputs
• Selector wiring does not match the project

First checks, in this order

1. Turn the selector fully into one position.
2. Check the selector switch and its input wiring against the Configurator circuit diagram.
3. Restart with the rotary knob (3 to 8 s) after the fix.

OUTPUT WITH ADVANCED FAULT DETECTION: External error on the output with advanced fault detection

What it means: A fault was found on a semiconductor output used in advanced fault detection mode (where two loads may share one output). Pilz requires a connected feedback loop and excluded shorts across contacts and external power sources for this mode.^[1]

Likely causes

• Short across contacts or external voltage on the output cable
• Feedback loop of that output faulty or not connected
• Load or contactor fault

First checks, in this order

1. Check the output and feedback loop wiring; Pilz suggests separate multicore cables to exclude shorts and external voltages.
2. Check the connected contactors.
3. Restart with the rotary knob (3 to 8 s) after the fix and test the safety function.

TEMPERATURE: Operating temperature is outside the permitted range

What it means: The base unit is running too hot or too cold.^[1]

Likely causes

• Cabinet ambient outside 0 to 60 °C (55 °C without forced convection)
• Mounting distances to other heat-producing devices too small
• Cabinet cooling failed

First checks, in this order

1. Read the unit temperature in the Operating Info menu.
2. Check the cabinet temperature and the mounting distances; add air conditioning if needed.

PRESSURE SENSITIVE MAT: Error on the input of a pressure-sensitive mat

What it means: The input used for a pressure-sensitive safety mat reports a fault.^[1]

Likely causes

• Damaged safety mat or mat cable
• Wiring fault between the mat and its inputs or test pulse outputs

First checks, in this order

1. Check the mat and its cable for damage.
2. Check the mat wiring against the Configurator circuit diagram (Pilz describes safety mat wiring in the PNOZmulti Special Applications document).
3. Restart after the fix and test the safety function.

ERROR: Error that cannot be assigned

What it means: The base unit has an error it cannot put in any other category.^[1]

Likely causes

• Unclassified internal or external error

First checks, in this order

1. Read the error stack entries (EC, EN and PA values) on the display or with the PNOZmulti Configurator.
2. Switch the supply off and on.
3. Give the error stack entries to Pilz technical support if it comes back.

NEW PROJECT: New project detected on the chip card

What it means: The chip card holds a project that differs from the one in the device memory.^[1]

Likely causes

• Chip card with a newer or different project inserted

First checks, in this order

1. Check the project name, CRC and date shown on the display.
2. To use it, accept the new project in the Project menu (ACCEPT NEW, login required in the User login menu).
3. Test the safety devices after the new project is loaded.

PROJECT NOT RESET: The project was not deleted

What it means: A request to delete the project from the base unit memory did not complete.^[1]

Likely causes

• Delete project action not confirmed or interrupted
• No user login for the Project RESET menu

First checks, in this order

1. Log in through the User login menu and repeat Project RESET.
2. Make sure the system is in a stop state.

NUMERIC FAULT: A violation of the numeric value range was identified on an analogue module

What it means: A calculated value on an analogue expansion module went outside its numeric range.^[1]

Likely causes

• Analogue value outside the range the project expects
• Scaling or math settings in the project not matched to the sensor

First checks, in this order

1. Measure the sensor signal at the analogue input.
2. Check the analogue element settings in the PNOZmulti Configurator project.

ANALOG INPUTSIGNAL FAULTY: A violation of the workspace was identified on an analogue current input on an analogue module

What it means: The current on an analogue input left the working range set for it.^[1]

Likely causes

• Sensor signal outside the configured working range
• Broken sensor cable or sensor fault

First checks, in this order

1. Measure the current at the analogue input.
2. Check the sensor, its supply and its cable.
3. Check the range settings in the Configurator project.

ANALOG MEASUREMENT ERROR: A measurement error was identified on an analogue current input on an analogue module

What it means: The analogue module could not measure an input current correctly.^[1]

Likely causes

• Sensor or cable fault
• Interference on the analogue cable
• Faulty analogue module

First checks, in this order

1. Check the sensor and its cable, including shielding.
2. Measure the input current.
3. Contact Pilz support if the module itself is suspected.

MEASURING RANGE VIOLATION: A violation of the measuring range was identified on an analogue current input on an analogue module

What it means: The current on an analogue input is outside the measuring range of the module.^[1]

Likely causes

• Sensor current too high or too low
• Short or break in the sensor cable

First checks, in this order

1. Measure the current at the analogue input.
2. Check the sensor and its wiring for a short or break.