Computerlink Troubleshooting & Codes

This page summarizes TOYOPUC Computerlink response errors that users commonly see. It is not a complete manufacturer code table; use the JTEKT TOYOPUC manuals for formal definitions.

First Checks

• Confirm that Computerlink communication is enabled on the PLC side.
• Confirm the TCP/UDP port and network settings in the TOYOPUC setup page.
• Confirm that the application selected the exact canonical TOYOPUC profile.
• For write errors, check PLC run/write permission and protection settings before retrying.
• For relay access, configure the relay hops explicitly; relay topology is not auto-discovered.

Connection Checks

Symptom	First check
Connection timeout	Confirm the PLC host address and the configured Computerlink port. TCP examples use 1025.
TCP connection refused	Confirm Computerlink is enabled on the target PLC and the TCP port is open.
UDP requests do not return	Confirm the UDP port configured for the target PLC.
Intermittent timeouts	Increase timeout/retry settings, reuse a connection, and avoid reconnecting for every small request.

Addressing Checks

Symptom	First check
Profile rejected before communication	Use one exact canonical profile from the library's PLC Profiles page.
Unknown device area	Confirm that the selected profile supports that family.
Address out of range	Compare the selected profile with the shared Computerlink Device Ranges page.
Basic address rejected	Use P1-, P2-, or P3- for basic families such as D, M, X, Y, T, C, L, N, R, and S.
Dword read returns a bit	Use :D for dword access and .D only for bit 13 inside a word.

Write Checks

Symptom	First check
A write appears to change the wrong value	Stop and confirm that you are using a test address you control.
FR value does not survive power cycle	Stage the FR write and then commit it when persistence is intended.
Relay write or read does not reach the target PLC	Set the relay hop string explicitly.

Common PLC Codes

Code	Typical cause	First check
0x40	Address or address plus count is outside the CPU range. This is also the common result when FR is not exposed on the tested unit.	Check the selected profile, address range, and count.
0x24	Subcommand is not supported by the CPU or routed target.	Check whether the feature exists on that CPU; for example some targets reject A0.
0x23	Command code is not supported.	Check the selected helper and profile.
0x31	Write or function call is prohibited while the sequence is running.	Check PLC run/write settings before retrying.
0x34	Access is prohibited by configuration.	Check PLC communication and protection settings.
0x41	Word or byte count is outside the permitted range.	Split the request or reduce the count.
0x52	Timer/counter set-value and current-value command type do not match.	Check whether the helper targets a preset or current value.
0x66, 0x70, 0x72	Relay link module did not answer or could not execute the request.	Check relay hops and the target PLC path.
0x73	Relay command collision on the same link module; retry is appropriate.	Retry after a short delay or reduce concurrent relay access.
0x11	CPU module hardware failure.	Check the PLC CPU status before continuing.