Hi @t-kavan,
We have already encountered this, unfortunately this meter does not wait for the prescribed time and responds too quickly, so that the RS485 (transmit/receive) state in the controller does not have enough time to change.
The RS485 behaviour was modified in later versions of the debian packages. With the current OS image the PRO380-MB meter are already working.
Best regards,
Antonín Všetula - Unipi technician