Applies To:
  • CitectSCADA

Some applications may need control of serial port control lines to raise and lower these.

Until now, this was not possible from cicode.

Some uses of the COMX driver via a third party equipment, need the COMX driver

to restart after faults.

New options have been added to the COMX driver.


When the -e option is added to the driver Special Options (in the Ports form) when COMWrite can be used

to change the output signal lines. The format is "~EIAXXXyXXXy".


INT hPort;
STRING buffer = "~EIARTS1";
INT number= 8
hPort = ComOpen("PORT1_BOARD1", 0);
ComWrite(hPort, buffer, number, 15)


sets RTS high

Full options for XXXy are :

SWF0 // Simulate XOFF received
SWF1 // Simulate XON received
RTS1 // Set RTS high
RTS0 // Set RTS low
DTR1 // Set DTR high
DTR0 // Set DTR low
BRK1 // Set the device break line
BRK0 // Clear the device break line


With some serial interfaces, line faults can cause the COMX read thread to shutdown. This meant the driver would

not recover after the fault. With the -nt option (no terminate), the thread is NOT shutdown. This allows the system to recover.


Do not terminate at startup if errors occur. Keep retrying to init the driver .

For this to work, the driver must to a COMReset in its InitUnit() code, or Cicode should be

doing this.

Covers NCRs 15527, 15528, 15806, 17482