Sinamics V20 Inverter NOT STARTING pumps

Hi there,

We have 3 V20 inverters driving 4 KW pumps each controlled by PLC via MODBUS. In Auto, the pumps will be started/stopped one by one based on header pressure. Attached are parameters list. When "Auto" is selected in PLC, index 2 is selected in the drive

1. In Auto, the inverters receive the frequency set point from PLC but not starting

2. There is P0705 parameter shown in the drive, but it is not mentioned in V20 inverter manual.

Thanks in Advance for any help/direction to the experts in this group.

Best regards,.. Venkat