The Guardmaster 440C-CR30-22BBB configurable safety relay signals a fault with the FAULT indicator on its front, and reports a fault code (fault type + fault code, in hex) in Connected Components Workbench (CCW), in Studio 5000 or over Modbus. This article explains how to read the fault, what the common codes mean and how to clear them in the right order, based on Rockwell Automation user manual 440C-UM001I (November 2022).
Two kinds of fault: recoverable and nonrecoverable
This is the first thing to establish (440C-UM001I, chapter 16, pp.133–134):
| FAULT indicator | Fault kind | How it clears |
|---|---|---|
| Flashing red (2 Hz) | Recoverable, an application fault: channel discrepancy, cross loop, reset button held, muting fault, sequence fault… | Remove the cause, then cycle the inputs involved. Only the outputs tied to the faulted input switch off; other outputs keep working |
| Steady red | Nonrecoverable, a fault of the device itself or its hardware | Correct the cause, then cycle power so the relay re-runs its internal tests. If the damage is permanent, the relay stays in the safe state after power-up |
The other indicators on the relay (Table 21, p. 125): RUN off is Program mode, steady green is Run mode, and flashing green means running with a configuration that has not been verified. COM green means communication over the serial port or USB. What the IN/OUT indicators show is set by the programmer in CCW ("LED Configuration"), so check the configuration before you read meaning into them (p. 124).
Rockwell lists possible root causes of nonrecoverable faults as transient EMC disturbance, high-voltage or high-current spikes, interruptions of the supply voltage, and transient overloads on the safety outputs, such as high inrush current (p. 134).
Where to read the fault code
- CCW (USB, online): in the Logic Editor the faulted block turns red. Hover over the block to see the fault message, or right-click it and choose "Show Fault". For a recoverable fault, Device Details only says "Fault: Recoverable". For a nonrecoverable fault it shows the type and status. "Faults" in the Safety Tree lists recent nonrecoverable faults and lets you Export them to a .csv file (pp.134–136).
- Studio 5000 (through the EtherNet/IP plug-in): the tags
MajorFault,MinorFault,MajorFaultType,MajorFaultCode,MinorFaultType,MinorFaultInstance(number of the faulted block, 01…24) andMinorFaultCode(Appendix F, pp.177–178). - Modbus (HMI or Micro800): coils 000265…000272 for each hardware fault group, fault bits per SMF block, and fault log holding registers 000849…000860 (Table 23, p. 136).
Common fault codes
A fault code has two parts: type (group) and code. Minor (recoverable) faults have type 10H (safety monitoring function, SMF) or 40H (safety output function, SOF). Major faults have type 01H hardware, 02H safety input, 04H safety output, 08H power, 10H communication, 20H configuration, 40H time monitoring, 80H plug-in.
| Type / Code | Meaning | Check / action |
|---|---|---|
| 10H / 01H (minor) | Pulse test failure: a channel is shorted to 24 V or to another channel | Input wiring, cross shorts between channels |
| 10H / 02H (minor) | Reset held on: the reset input did not return to OFF within 3 seconds | Stuck reset button or a wire shorted to 24 V |
| 10H / 05H, 06H (minor) | Mode selector: no position selected, or several positions at once | Changeover between positions must be within 250 ms. Cycle through the valid modes to clear |
| 10H / 07H (minor) | Hazardous motion: hazard feedback went OFF while the unlock command was ON | Guard-locking logic. Press the Lock Request input to clear |
| 10H / 08H (minor) | Channel fault / contact bounce: one channel went to the safe state and back while the other did not change | Switch mechanism, contact bounce, slow-closing gate. Set both inputs LO until the filter time expires, then bring them HI again (p. 47) |
| 10H / 20H (minor) | Discrepancy: the two channels did not reach the same state within the configured discrepancy time | Wiring, mechanical offset between the two channels. Set both LO, then bring both HI within the discrepancy time (pp.47–48) |
| 10H / 04H, 10H, 40H, 80H (minor) | Muting faults: mute time exceeded, too long between sensors, wrong sensor or light-curtain sequence | Obstructions, sensor alignment, application timings. Codes such as 14H, 44H… are combinations of these faults |
| 40H / 01H (minor) | Retrigger: the enabling input went OFF→ON while the output delay was running | Application logic and wiring |
| 02H / 01…18 (major) | Safety input pulse test failure. Code = faulted terminal number + 1 | Wiring of that terminal, shorts to 24 V or to another channel |
| 04H / 01…10, 11…20 (major) | Safety output: plausibility failure (01…10) or pulse test failure (11…20), for terminals 12…21 | Output wiring shorted to 24 V or to another channel, output load |
| 08H / 01…03 (major) | Power fault: over/under voltage, main transistor test failure, under-voltage reset | The 24 V supply to the relay |
| 20H / 05, 21 (major) | Plug-in in slot 2 / slot 1 differs from the configuration | Actual plug-in against the project, then download the configuration again |
| 06 / 07 (major) | Configuration not verified and the 24-hour run limit has passed | Verify the configuration in CCW (p. 33) |
| 40H / 20, 21 (major) | Memory module restore or backup failed | Memory module seated in slot 1, repeat the operation |
| 01H / … (major) | Internal hardware fault: RAM, ROM, watchdog, firmware… | Cycle power, check noise reduction and surge suppression. If it persists, contact Rockwell |
Source: Tables 47 and 48 (Appendix F, pp.179–182), chapter 4 (p. 33), chapter 7 (pp.47–48). The full list with corrective actions is in the "CR30 FaultCode" attachment to Knowledgebase QA41400 and in Appendix F of 440C-UM001I.
Order of checks
- Look at the FAULT indicator: flashing or steady red, to know whether the fault is recoverable.
- Read the code in CCW, Studio 5000 or the HMI, and record type, code and instance (which block) before clearing it.
- Input faults: check each channel's wiring, shorts to 24 V, cross shorts between channels, misaligned or bouncing gate switches, E-stop contacts.
- Output faults: check the output wiring and the load (contactors, coils). Rockwell notes that any output fault, internal or external, always needs a power cycle to find out whether it is recoverable (Appendix A, p. 159).
- Configuration or plug-in faults: compare the fitted plug-ins with the project and check the verification status.
Clearing the fault in the right order
- Recoverable faults: after fixing the cause, cycle the inputs involved. The manual's example (pp.137–138): once a cross fault has been removed, the E-stop block and the gate block stay red. You press and release the E-stop, open and close the gate, and the system then waits for the Reset button.
- Nonrecoverable faults: fix the cause, then cycle power to the relay.
- Clearing a fault can let the machine run again. Before resetting, make sure nobody is inside the hazard zone, guards are closed, and the site's lockout and permit-to-work rules are followed.
- Do not lengthen the discrepancy or input filter time, and do not bypass an input just to make a fault go away. That changes the safety function; it does not fix the fault.
Every safety function must be validated again by the responsible engineer after any change to wiring, devices or configuration.
When it is hardware
If the FAULT indicator is still steady red after a power cycle, after the wiring has been corrected and after the supply and noise measures have been checked, the relay may have permanent hardware damage. It will hold itself in the safe state (p. 134). At that point contact Rockwell technical support and plan a replacement.
What to record before calling for support
- FAULT flashing or steady, and the RUN state.
- Type, code, instance, and the .csv exported from "Faults" in CCW.
- Relay firmware and CCW versions, plug-in catalog numbers fitted.
- Verification ID and the CCW project.
- When it happens: at power-up, when a gate opens, on reset, or when a large motor starts.
Need an engineer to check it on site: request support.
Frequently asked questions
What does a flashing red FAULT indicator on a 440C-CR30 relay mean?
A flashing red FAULT indicator (2 Hz) signals a recoverable fault, an application fault such as channel discrepancy, cross loop, reset button held, muting fault or sequence fault. Remove the cause, then cycle the inputs involved; only the outputs tied to the faulted input switch off (440C-UM001I, pp. 133–134).
How do I clear a steady red FAULT on a Guardmaster 440C-CR30?
Steady red is a nonrecoverable fault of the device itself or its hardware: correct the cause, then cycle power so the relay re-runs its internal tests. If it is still steady red after the wiring, the supply and the noise measures have been checked, the relay may have permanent hardware damage and holds itself in the safe state (p. 134); contact Rockwell technical support at that point.
What is fault 10H / 20H on a 440C safety relay?
It is a discrepancy fault: the two channels did not reach the same state within the configured discrepancy time. Check the wiring and any mechanical offset between the two channels, then set both LO and bring both HI within the discrepancy time (pp. 47–48). Do not lengthen the discrepancy time just to make the fault go away, because that changes the safety function.
Where do I read 440C-CR30 fault codes in Studio 5000?
Through the EtherNet/IP plug-in, the codes are in the tags MajorFault, MinorFault, MajorFaultType, MajorFaultCode, MinorFaultType, MinorFaultInstance and MinorFaultCode (Appendix F, pp. 177–178). In CCW, "Faults" in the Safety Tree lists recent nonrecoverable faults and lets you export them to a .csv file.
Why does a 440C relay report fault 06 / 07?
Code 06 / 07 (major) means the configuration has not been verified and the 24-hour run limit has passed. A flashing green RUN indicator shows the relay is running with an unverified configuration; the fix is to verify the configuration in CCW (p. 33).
Sources
- Rockwell Automation, 440C-UM001I-EN-P, Guardmaster Configurable Safety Relay User Manual, 11/2022 — p. 33, 47–48, 123–125, 133–138, 159, 177–182
- Rockwell Automation Knowledgebase QA41400 (public), 440C-CR30-22BBB Fault Code List, published 14 December 2024
Read 25 October 2026. This article paraphrases the sources and does not quote them; read the original documents before designing or working on a system. Links open the latest edition in Rockwell's literature library; page numbers refer to the edition cited.