Micro830, Micro850 and Micro870 controllers (2080) show a fault first on the FAULT indicator: flashing red is a recoverable fault, steady red is a nonrecoverable fault that needs a power cycle. The actual error code (0xF0xx, 0xD011…) is read from the fault log in Connected Components Workbench (CCW). This article summarizes the indicator table, the common codes and the recovery sequence from Rockwell manual
What the status indicators mean
The Micro830 has 7 status indicators (p. 19); the Micro850 and Micro870 add Module status and Network status for EtherNet/IP (pp. 20–21). Meanings from the table on p. 314:
| Indicator | State | Meaning |
|---|---|---|
| Power | Off | No input power, or a power error |
| Run | Flashing green | Memory backup/restore in progress, not a fault |
| Fault | Flashing red | Recoverable fault |
| Fault | Steady red | Nonrecoverable fault, needs a power cycle |
| Module status | Flashing red | Minor fault (covers minor and major recoverable faults) |
| Module status | Steady red | Major fault (nonrecoverable) |
| Module / Network status | Flashing green and red | Power-on self-test (POST); how long it takes depends on the project size |
| Network status | Off | Not powered, or no IP address |
| Network status | Flashing green | IP address configured, but no Ethernet application connected |
| Network status | Steady red | Duplicate IP address on the network (only if duplicate IP detection, ACD, is enabled) |
In normal operation POWER and RUN are on (p. 314). On the RJ45 port, steady yellow means link and flashing green means activity (p. 23).
Reading the error code in CCW
The fault log is on the Diagnostics page in CCW. It holds brief information about the last fault and detailed information about the last 10 nonrecoverable faults (p. 315).
To save the fault log to a file (CCW version 9 or later, p. 320):
- Open CCW and connect to the controller.
- In "Project Organizer", right-click the controller and select "Diagnose > Fault". The "Fault Diagnostics" tab opens.
- Select "Get Fault Log" and save the .txt file.
After a nonrecoverable major fault, once power has been cycled, select "Core Dump Upload" on the same tab to save a .bin core dump (up to 8 KB) for Rockwell technical support. This needs firmware 22.011 and CCW 22.00 or later. Updating the controller firmware clears the core dump (p. 320), so retrieve it before any firmware update.
Common error codes
The codes below are selected from Table 126 (pp. 315–319). "Type": R = recoverable, NR = nonrecoverable, as the table gives it.
| Code | Type | Meaning | What to check |
|---|---|---|---|
| 0xF000 (p. 315) | R | Unexpected controller reset caused by a noisy environment or an internal hardware failure | Check wiring and noise. If system variable _SYSVA_USER_DATA_LOST is set, the program was recovered but user data was cleared; if not, the program was cleared |
| 0xF001 (p. 315) | R | Program cleared: power lost during a download or a memory module transfer, cable pulled during a download, or the RAM integrity test failed | Download again, or transfer with the memory module restore utility |
| 0xF002 (p. 315) | NR | Hardware watchdog tripped: program scan longer than 3 seconds | Cycle power, read the fault log; check _SYSVA_USER_DATA_LOST as for 0xF000 |
| 0xF003 (p. 315) | R | Memory module failed, poor connection, or not compatible with the controller firmware | Remove and reinsert the module; replace it; or upgrade the firmware to a compatible revision (see rok.auto/pcdc) |
| 0xF210 (p. 317) | R | Expansion I/O terminator missing | Power off, fit the terminator on the last expansion module, power on |
| 0xF230 (p. 317) | R | Too many expansion I/O modules | Power off, check there are no more than four modules, power on |
| 0xF27z / 0xF29z / 0xF2Az (p. 317) | R | Expansion module in slot z: communication fault / module fault / power failure | z = slot number (z = 0: slot cannot be identified). Check, then replace the module in slot z |
| 0xF2Bz (p. 317) | R | Expansion I/O configuration fault | Make the configuration in the program match the hardware; check or replace the module |
| 0xF300 / 0xF303 (p. 317) | R | Restore requested but the memory module is empty (F300) or not present (F303) | Check the module is fitted and holds a valid project |
| 0xF0Bz (p. 318) | R | Plug-in module configuration does not match the actual I/O (z = slot) | Correct the plug-in configuration in the program; check or replace the plug-in module |
| 0xF860 (p. 318) | R | Data overflow, for example a divide-by-zero in ladder, ST or FBD | Correct the program, build, download with CCW, go to Run |
| 0xF8A3 (p. 319) | R | Major fault because a Class 1 connection failed in Run mode | Find the Ethernet module with the faulted connection and fix it |
| 0xD00F (p. 319) | R | Hardware type selected in the configuration (for example embedded I/O) does not match the actual base | Select the correct hardware in the project |
| 0xD011 (p. 319) | R | Program scan time exceeded the watchdog timeout | See below |
Motion codes (0xF100…0xF15z), EII/HSC/STI codes (0xF830…0xF850) and the rest: see Table 126.
0xD011: watchdog timeout
Check whether the program is caught in a loop (p. 319). The case the manual gives: a FOR loop in Structured Text whose upper limit is the maximum value of the variable, such as a USINT with 255 or a UINT with 65535. One fix is a data type with a larger maximum value, then build, download and go to Run. Increase the watchdog in system variable _SYSVA_TCYWDG only if the program is designed to scan for longer than 3 seconds. STI/EII/HSC interrupts, communication and PTO motion also lengthen the scan; with a marginal watchdog setting they can cause 0xD011 (p. 128).
0xF8A3 and the EtherNet/IP network
In the Ethernet module configuration, the "Major fault on controller if connection faults while in Run mode" checkbox decides whether a lost connection in Run raises a major fault; the "Connection Fault" field shows the code as 0xYYYY (p. 139), listed in Table 51 from p. 151.
For network detail: in the controller configuration, select "Diagnose" then "Communication" (p. 322; the diagnostic parameters need firmware 21.011 or later). Rockwell recommends keeping "I/O Comms Utilization" below 60 %; the easiest way to lower it is to increase the RPI of the devices under Ethernet-Modules (p. 326).
Recovery and clearing the fault
From the controller error recovery model (p. 321):
- Power indicator off: check the wiring.
- Power on: check the Fault indicator (flashing red = recoverable, steady red = nonrecoverable).
- Nonrecoverable: cycle power; the controller then goes to a recoverable fault (p. 320).
- Diagnose in CCW and look the code up in the table on p. 315.
- Clear the fault, correct the cause, then test and verify the system.
On p. 320: optionally save the fault log, then clear the fault with CCW; if the program was lost, build and download it again; if the fault persists, send the fault log to Rockwell technical support.
Safety: clearing a fault, cycling power or switching to Run can restart the machine. Follow the plant's permit-to-work and lockout rules.
Before calling for support
Have ready (p. 327): controller type, series letter, revision letter, firmware (FRN) number and indicator status; add the fault log and core dump if available.
For ControlLogix/CompactLogix faults see Logix major fault codes; for the older line see MicroLogix 1500 fault codes. For an engineer on site: request support.
Frequently asked questions
What does a flashing red FAULT indicator mean on a Micro850?
It is a recoverable fault, which can be cleared without a power cycle (p. 315). Read the code in the fault log, correct the cause, then clear the fault with CCW.
How do I handle a steady red FAULT indicator on a Micro800?
It is a nonrecoverable fault, so cycle power first. Then save the fault log, clear the fault with CCW, and if the program was lost, build and download it again (p. 320).
Where is the Micro800 fault log in CCW?
Right-click the controller in "Project Organizer", select "Diagnose > Fault", then "Get Fault Log" to save a .txt file; this needs CCW version 9 or later (p. 320).
What is error 0xD011 on a Micro800?
The program scan time exceeded the watchdog timeout (p. 319). Check for loops, such as a FOR loop whose upper limit is the maximum value of the variable; increase _SYSVA_TCYWDG only if the program is designed to scan for longer than 3 seconds.
What are errors 0xF210 and 0xF230 on a Micro850?
0xF210 means the terminator is missing on the last expansion module; 0xF230 means too many expansion modules, the maximum being four (p. 317). Power off, fix the hardware, power on, then clear the fault.
Sources
- Rockwell Automation,
2080-UM002S-EN-E , Micro830, Micro850, and Micro870 Programmable Controllers User Manual, 04/2026 — Appendix D pp. 313–327 (indicators p. 314; Table 126 pp. 315–319; corrective actions, fault log, core dump p. 320; error recovery model p. 321; Ethernet Diagnostics pp. 322–326; calling for assistance p. 327); indicators by model pp. 19–21; RJ45 p. 23; watchdog p. 128; Module Properties p. 139; Table 51 from p. 151
Read 8 November 2026. This article paraphrases the sources and does not quote them; read the original documents before designing or working on a system.