The modbus RTU communication from the ICP 7188 and the Caterpillar SCM module stops communicating after the genset hand off auto switch has been placed not in auto.
Caterpillar SCM Module
When the Caterpillar genset hand of auto switch is placed not in auto for monthly genset tests or to manually run the generator the SCM module on the generator senses this state change and sends a "wait" command on the modbus network that the ICP 7188's modbus driver can not handle.
There are two resolutions to this problem depending on what version of the modbus driver running in the ICP 7188.
- If the modbus driver dated 2-16-2001 is being used in the ICP, the only resolution will be to power cycle the ICP after the genset has been placed in "not in auto". This will re-initiate the communication on the modbus network. This modbus driver version does not have the capabilities to handle the 'wait" message from the SCM module.
- Upgrade to the final modbus build for the ICP 7188 dated 3-4-2005. This driver has the ability to receive the "wait" command from the SCM module on the modbus network.
To upgrade the ICP 7188 to the final modbus build, simply place the ICP7040.exe, SP7040.def, and SP7040.exe files from the attached.zip file in the linkterm directory, and redownload the ICP.
NOTE: The ICP7188 is no longer officially supported by Schneider Electric as the gateway device for I/Net integration efforts. The Xenta 913 is the official replacement for the ICP 7188 when doing third party integration to an I/Net system.