I have an installation with a very strange phenomenon.
Hardware is as follows:
ControlLogix rack with Prosoft MVI56 (modbus module)
Kingfisher PC-1 with MC-11 module (RS-232 serial card)
The Prosoft port 1 is connected to the MC-11. The MC-11 is setup as a slave with a Modbus S2 driver. The Prosoft has 5 read commands, reading 5 different blocks of data. Under normal circumstances the data is all valid.
The problem is really random. Occasionally, data being returned for a given command is not from the requested block, it happens to be from a block 110 registers before. ie requested starting address is 41700 but data returned is from address 41590. The offset is consistent but the timing is random. Sometimes once a day, sometimes several times!
We've updated the PC1 firmware (1.43d) and the MC11 is one firmware revision behind (C0156).
If you're wondering, we weren't able to use the PC1 port (DF1) as it is already connected to another PLC not part of our project. Kingfisher themselves are puzzled by this.
Hardware is as follows:
ControlLogix rack with Prosoft MVI56 (modbus module)
Kingfisher PC-1 with MC-11 module (RS-232 serial card)
The Prosoft port 1 is connected to the MC-11. The MC-11 is setup as a slave with a Modbus S2 driver. The Prosoft has 5 read commands, reading 5 different blocks of data. Under normal circumstances the data is all valid.
The problem is really random. Occasionally, data being returned for a given command is not from the requested block, it happens to be from a block 110 registers before. ie requested starting address is 41700 but data returned is from address 41590. The offset is consistent but the timing is random. Sometimes once a day, sometimes several times!
We've updated the PC1 firmware (1.43d) and the MC11 is one firmware revision behind (C0156).
If you're wondering, we weren't able to use the PC1 port (DF1) as it is already connected to another PLC not part of our project. Kingfisher themselves are puzzled by this.
