ModBus connection in AC800F
In my plant AC800F controller used as DCS and must be connect to safeguarding system through Modbus.My question is that how many data can be supported in modbus card like (Serial Module FI 820F)?and also for these transfered data the license is needed(count as IO)?
also in my plant we use 3 DCS based on plant section and each one uses AC800F.for connection between these DCS via softwrare link,what things need/to do?
So far I know there is no limit on number of data to be communicated but there are selection on transmission rate and number of slaves/subscribers. So max 32 subscribers including one master can be communicated. Note on FI 820F there are two serial channels and each channel can act as master or slave.
Yes, you need license for these transferred data. modbus variable count as license I/O.
Regarding second question, If each AC 800F controller from 3 DCS are under same project then you can link or share/transact values via global variables... Just export those variables which ever you want to share between these three controllers. But if these three controllers are in three different projects then you can use ethernet send/recieve block where you can communicate values over ethernet no license is required. Else you can use modbus where license is required.
Again suggested to get connect with your local ABB sales/service representative...
Hope that helps...
if you add more data you will notice how the data update is delayed, if your process have not problem with that.
another consideration is to try to use this modbus link to transfer information that are not critical