This chapter of the GE Fanuc SNP Communications Reference provides solutions to possible problems with the SOI-120 and SOI-260 and their use with the GE Fanuc SNP communications protocol. Typically, any problems that occur involve communications between the SOI-120 or SOI-260 and the PLC. The communications software used to communicate with the PLC has passed critical compliance tests, usually eliminating the software as a possible source of a problem. The only other possible sources are the cabling and the communication port parameters involved (baud rate, etc.). The communication parameters must be identical for both the SOI-120 or SOI-260 and the PLC. The cabling and the communications port parameters are always the first things to check. You can check the communications port parameters either from the SOI or from the SOI-SPS programming software. If the cabling and communications parameters are correct, put the SOI- 120 or SOI-260 in Self-Test mode to rule out any non-functioning features of the SOI.
The below screens appear on the SOI to indicate a problem:
Attempting to communicate to PLC. Action: None. Normal display when initiating communications with the PLC.
PLC ERR MJ/MN:0000
Communications not established with the PLC. This is displayed after attempting to establish communications with the PLC and fails after three (3) tries). (Refer to footnote for further details.) Action: Check cabling and communications parameters to verify that the PLC matches those of the SOI-200. Perform the Self-Test function if the Comm port is suspected.
COMM ERROR MJ/MN:0000
Press Any Key
Communication to the PLC was lost after three attempts. Action:
Check SOI-to-PLC cabling. Check PLC operating conditions.
The SOI reports the Major/Minor errors codes as received from the GE SNP PLC. If the major and minor error codes are nonzero the error code is defined by the GE SNP. Otherwise, if zero, the SOI did not detect a response from the PLC.
GE Fanuc PLC
GE Fanuc PLC