Integration _ Gericke Feeder with DeltaV


I need to integrate a Gericke feeder (slave) and the DeltaV system (Master). Gericke feeder has an Easydos controller with serial port and in the DeltaV system I have a serial card. I connected the serial card of the DeltaV with the serial port of the Easydos, but the yellow led is off.

Please let me know what is the correct procedure to connect the Gericke feeder with the DeltaV.