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Technical support / Re:Modbus TCP Slave problem
« on: April 23, 2013, 01:10:31 PM »
Sorry for the late reply BC, got tied up in some other details. My problem ended up originating from another system (other contractor) using the same IP and port as we were using. Once we changed the port number communication has been great. We're still a bit doubtfull, so I'm going to add code similar to what the REBOOT would have done.
I will increment the value of a DM field every second. When the SCADA connects it will read the counter, then zero the counter. Nice routine communication means the counter should get zeroed more than once a second. If there is an outage then the counter will keep increasing.
If the PLC DM field reaches one minute it will "make note" and could also REBOOT if that's what you need.
I will also add code to my SCADA that will "make note" if the DM value is greater than 15 seconds.
I havn't written the code yet, but that will be the strategy. If there is a more elegant solution I'd like to learn about it because I think this bit of code is a valuable addition and it will find it's way into future projects as well.
I will increment the value of a DM field every second. When the SCADA connects it will read the counter, then zero the counter. Nice routine communication means the counter should get zeroed more than once a second. If there is an outage then the counter will keep increasing.
If the PLC DM field reaches one minute it will "make note" and could also REBOOT if that's what you need.
I will also add code to my SCADA that will "make note" if the DM value is greater than 15 seconds.
I havn't written the code yet, but that will be the strategy. If there is a more elegant solution I'd like to learn about it because I think this bit of code is a valuable addition and it will find it's way into future projects as well.