Applies To:
  • CitectSCADA 3.00 4.00

Question: I have a Westinghouse PLC 1500 with a 1799 Modbus emulation card. How can I use this with Citect? 

The 1799 Modbus emulation card must be set up with the Modbus Slave Emulation Communications package. This converts the Modbus messages into the Westinghouse format, and supports Modbus messages of up to 125 words (250 bytes). The only Modbus function code not supported by the emulation card is writing to multiple coils, function 15. If this function is needed, the MODBUS driver will need modifying to allow a new citect.ini variable to force writing of multiple coils one bit a time. Contact Citect Support for more information.

Also, refer to the Westinghouse NCMZ 1799 System Manual Appendix L for more information on the emulation card.