The PROG and USER serial ports implement the QEM proprietary communication protocol called BIN1.

The SERCOM and MODBUS devices can be used with all communication serial ports including PROG PORT. Use the following number settings during the device declaration to select the communication channel:

  0		PROG PORT
  1		USER PORT
  2		AUX1 PORT    (if available for this hardware)
  3		AUX2 PORT    (if available for this hardware)

When the SERCOM and MODBUS devices use the PROG PORT or USER PORT, they address the channel only if the communication status of the device is open (st_opencom = 1). When the channel of the device is closed (st_opencom = 0) in the serial, the BIN1 protocol returns active. To force the BIN1 protocol on the PROG port (thereby preventing the SERCOM device from occupying the channel) active the SW1 dip @dip@.

When using the MODBUS RTU protocol on serial port @ports@ with RS485 electric configuration, remember that when the serial port is transmitting, the controller maintains the channel (DE) active for a longer time than the “MODBUS RTU” specification. To this must be consider a minimum time of 5 milliseconds after which it is possible to receive a new message. Also the SERCOM device, when it ends a transmission, has the same time the channel is active (DE).