liminfoKeyence Error Code Reference
Keyence PLC & vision system error code reference with causes and solutions
About Keyence Error Code Reference
The Keyence Error Code Reference is a searchable database covering 55+ error codes for the Keyence KV-series PLC (KV-8000, KV-7500, KV-7300), IV/CV vision inspection systems, SR barcode readers, and SL-V safety controllers. Each entry provides the error code identifier, a plain-language description, root-cause analysis, and numbered resolution steps that maintenance technicians and automation engineers can follow on the factory floor.
Error categories span KV PLC system faults (ERR 01-15), CPU and program errors (ERR 20-29), EtherNet/IP and Modbus/TCP communication diagnostics (ERR 50-59), vision system camera and inspection failures (IV-E/CV-E/SR-E codes), safety controller alarms (SF-E codes), and I/O expansion module faults (ERR 30-36). Coverage includes watchdog timer errors, memory faults, IP conflicts, barcode read failures, light curtain misalignment, and analog input range issues.
All lookups run entirely in your browser with zero data sent to any server. The interface supports category filtering, keyword search across all error codes, and dark mode for use in dimly lit production environments. It works on desktop, tablet, and mobile devices without any download or account.
Key Features
- Searchable database of 55+ Keyence error codes with root-cause analysis and resolution steps
- Covers KV-8000/7500/7300 PLC system errors, CPU faults, and program execution errors (ERR 01-29)
- EtherNet/IP, Modbus/TCP, socket, SNTP, FTP, and SMTP communication diagnostics (ERR 50-59)
- IV/CV vision system camera errors, inspection NG diagnostics, and SR barcode reader faults
- Safety controller alarms including light curtain, muting, emergency stop, and CIP Safety errors (SF-E codes)
- I/O expansion module faults for analog input/output, high-speed counter, positioning, and serial units
- Category-based filtering across six groups: PLC System, CPU & Program, Communication, Vision, Safety, and I/O
- 100% client-side processing with dark mode support — no sign-up, no download, completely free
Frequently Asked Questions
What does Keyence KV PLC ERR 01 (watchdog timer error) mean?
ERR 01 on a Keyence KV PLC indicates the CPU watchdog timer triggered because the program scan cycle exceeded the configured time limit. Typical causes include infinite loops in ladder logic, excessive subroutine nesting, or heavy EtherNet/IP communication loads. Open the KV STUDIO scan time monitor to identify the bottleneck section, optimize the program by removing unnecessary loops, and consider increasing the watchdog timer value in the system settings if justified.
How do I troubleshoot Keyence EtherNet/IP communication errors (ERR 50-59)?
EtherNet/IP errors on Keyence KV PLCs range from physical link-down (ERR 50) to IP conflicts (ERR 51) and scanner timeouts (ERR 52). Start by checking the LINK LED on the CPU, verifying the Ethernet cable (Cat5e or higher), and running a ping test. In KV STUDIO, confirm the RPI (Requested Packet Interval), Assembly Instance sizes, and EDS file registration. For Modbus/TCP (ERR 55), verify port 502, Unit ID, and register address mapping.
How do I resolve Keyence IV vision system camera errors (IV-E001)?
IV-E001 indicates the IV series camera lost communication with the controller. Check the Ethernet cable connection between camera and controller, verify PoE switch output, and inspect the camera power LED. If the LED is off, the issue is power-related. Try a different Ethernet port or cable. If the problem persists, test with a replacement camera to isolate a hardware fault.
What causes Keyence safety controller SF-E001 (redundancy mismatch)?
SF-E001 occurs when the dual-channel safety inputs (CH1 and CH2) do not match within the configured discrepancy time. This typically means an emergency stop button or safety sensor has a wiring error, or one channel of a dual-channel sensor has failed. Use a multimeter to check both channel signals at the safety input terminals, inspect NC/NO wiring against the wiring diagram, and verify the discrepancy time setting.
How do I fix Keyence KV PLC analog input range exceeded (ERR 31)?
ERR 31 on a KV-AD analog input module means the measured value exceeded the configured range (e.g., 4-20mA or 0-10V). Measure the sensor output directly with a multimeter. In KV STUDIO, verify the input mode setting (current vs. voltage) matches the sensor type, and check the wiring method (2-wire vs. 4-wire for 4-20mA). Replace or recalibrate the sensor if its output is abnormal, and adjust the input filter for noise.
How do I reset a Keyence KV PLC error and resume operation?
To reset a KV PLC error: 1) Read the error code from the CPU front-panel LED or KV STUDIO error log. 2) Resolve the root cause (hardware inspection, wiring fix, program correction). 3) Toggle the CPU mode switch from STOP to RUN, or use KV STUDIO to switch modes. 4) For persistent hardware errors, power-cycle the PLC after physical repair. Battery warnings (ERR 12) require replacing the CR2032 battery with power ON and resetting the alarm in KV STUDIO.
What SR barcode reader errors does this reference cover?
This reference covers three SR series barcode reader error codes: SR-E001 (read failure due to poor print quality, wrong distance/angle, or ambient light), SR-E002 (communication error from RS-232 or Ethernet cable faults or parameter mismatch), and SR-E003 (settings corruption or incomplete transfer). Use AutoID Network Navigator for configuration, and the AutoTune function for automatic read optimization.
Is this Keyence error code reference free to use?
Yes, the Keyence Error Code Reference is completely free with no usage limits, no account registration, and no software download required. All processing runs locally in your browser, so no data is ever transmitted to a server. It is part of liminfo.com's collection of free online engineering and industrial automation tools.