Troubleshooting/diagnostics

1. Check the hardware and software requirements described in this documentation (TwinCAT version, CE image version etc.);
2. Compare the interoperability check list of control station and controlled station;
3. Check the IO configuration and mapping of PLC variables in TwinCAT System Manager (configuration of serial interface, baudrate, parity, stoppbits settings). Compare them to the parameters set in the communication partner;
4. Check whether the FB_IEC870_5_101TProtocol() function block issues an error code. The documentation for the error codes can be found here: Overview of error codes;
5. Check the protocol parameters that are transferred to the function block (link address, link address octet size, FRAMELength  etc.). Compare them to the parameters set in the communication partner;
6. Check the configured address lengths (instance of ST_IEC870_5_101TBuffer, TX/RX data buffer): ASDU address octet size, information object address octet size, cause of transfer octet size, max ASDU size. Compare them to the parameters set in the communication partner;
7. Check the configured data points (type, information object address etc.);
8. Check if the other communication partner issues an error code;
9. Activate the debug output during connection establishment and/or of ASDU data. Open the TwinCAT System Manager and activate the LogView window. Analyze/check the debug output strings;