Applies To:
  • CitectSCADA 3.00

How can I use full duplex serial communications to an AB PLC?  

When using serial communications to AB PLCs, the Citect KE drivers (KE2, KE3, KE5, KE250, KE500) operate in half duplex mode Normally this is not a problem as the PLC is set to operate in half duplex mode also. However in some cases full duplex communications are needed, as for example to communicate to the Teledenken Softwires PLC5 emulator.

To achieve full duplex you must use the Interchange drivers (ABKT2, ABKT3, ABKT5, ABKT250). Normally these drivers use DH+ with the 1784KT board, however this is not essential and the drivers can be configured to use serial communications instead. They must use the PC's COM ports, and the Interchange software and the PLC must be set up to operate in full duplex mode.