Which documents I need for communication between DCS and Subsystems with Modbus? I must do this communication with documents... Which Documents I need? How to start?
I am not sure what documents you might need. You may not "need" any. As a practical matter a listing of the data to collect with the pertinent information for each point is something you will need to have, but it might not need to be in any special written form.
If you're talking about the documents needed to get the project working, then the tasks are to
- setup the communications channel (RS-485, RS-232, ethernet, serial server, phone modem, whatever)
- access the data register locations on the slave(s)/server(s)
- deal with any data retrieved from the slave
To do those tasks, one typically needs
- the slave's Modbus map,
- communications port information for both slave and master
- working knowledge of programming/configuring the master
- working knowledge of the programming/configuration of the system to deal with data distribution
The slave's documentation typically includes a register map and comm link data. The documentation is sometimes available on the web, on occasion only after an adventure.
I'm told that a DCS master's documentation is usually available to registered DCS users, but I don't live in that world, so I can't say. DCS documentation is rarely, if ever, publicly available.
If you're talking about what documentation is needed for a client, then
- a couple sentences on what gets read or written where and why
- a spreadsheet in Excel with tags, register numbers, word formats
- screen shots of communications setup dialogue boxes
- com network diagram for all components, including serial wiring if used can help the guy who has to modify or troubleshoot it down the road.
