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8/9/2010 1:50 PM | |
Joined: 1/17/2007 Last visit: 10/15/2024 Posts: 1546 Rating: (537)
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The functions that are used are P_SND_RK (for sending data) and P_RCV_RK (for receiving data).
Absolutely it is. This is all covered by the modbus protocol. There are 4 data types: Holding registers and input registers are analogue data, and coils and discrete inputs are digital data.
As many as you want to, it is only limited by the modbus address space and the CPU memory size (which limits how large a DB can be programmed). There is one proviso: the modbus protocol driver for the CP341 has limits for the maximum packet size (see attched manuals). So if you want more data than this, you would have to spread it over multiple requests.
There is no other way of doing modbus on a 300 system as the CP340 does not support loadable drivers. The manuals you require depend and whether you are master or slave and also which modbus protocol you intend to use (ASCII or RTU). I expect that it will be RTU slave as that is the most common, but I have included all the manuals so all bases are covered. Here are the manuals: Modbus master RTU Modbus slave RTU Modbus master ASCII Modbus slave ASCII |
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