hardware pv cannot be written on the registry

Hi All,

I  supplied to customer an ABB CM50 process controllers with Modbus capability. The customer will hook these up to their Lookout software v6.2. In the event of hooking up, the process controllers can communicate but once they configure the PV, SET Points and the Outputs, it cannot be written in the registry except for bits, such as the A/M switch and the ON-OFF switch. What seems to be the problem?

any solution is much appreciated.

thanks and regards guys