Question: Is it possible to start and stop the Grundfos smart pumps while in multi-pump control mode through the BACnet CIM card when in alternating mode?

Answer: In multi-pump function we do actually not use the same control mode and operating mode parameters as described when running by BMS, local or simple I/O.
In this function the master pump (the one which has established the multi-pumps system, by connecting to the slave) just creates the enabling on either pump1 (master or pump2 (slave)

This means that when the Master is for example running, the slave pump becomes “inactive” – so it doesn’t directly go into stopped operating mode.
When the slave is “inactive” it CAN NOT be started by the BMS system.
BUT when the pump is “active” it can however be stopped by the BMS communication. Shown below is the priority scheme can be used.

An important note is that the pump-system can be stopped and started from the master of the two pumps. So when sending a start signal to the system, this will have to be sent to the master as this will be sent to the slave also. The start/stop (or on/off) can also be made from the pump-panel or digital input – it does not have to be from a CIM command.