Zeal Posted March 5 Share Posted March 5 Hello Sir/Madam, The SCADA project has 4 PLC's connected on Modbus TCP communication protocol. However, if any device is switched off the project file runs too slow. Is there a need that all 4 devices must be power on. Is there any suggestion that if no device is connected or any one or more device are connected the SCADA doesn't run slow. A trial of device bypass using sequence has not much success as the project file is closed on its own without any error. Is it possible that there is a log of the file being shutdown?. Quote Link to comment Share on other sites More sharing options...
AzeoTech Posted March 5 Share Posted March 5 If you have multiple PLC's that are on different IP addresses and not on a single RS485 chain, you can simply give all the channels of each PLC a different Timing/Offset combination. This will cause DAQFactory to query them simultaneously, and timeouts caused by one PLC being offline won't affect the others. So, for example, PLC1 might have its channels on Timing 1, Offset 0, while PLC2 might have Timing 1, Offset 0.25, and PLC3 might have Timing 1, Offset 0.5. As for device bypass, it is likely that you created circular logic and blew the stack. I'd have to see your document to truly tell. Quote Link to comment Share on other sites More sharing options...
Zeal Posted March 6 Author Share Posted March 6 Thank you for the response. So, After giving the channels of each PLC a different Timing/Offset combination will solve the issue of lagging of data if any one more PLC is not powered up?. I will share the document for sure by the end of week. Quote Link to comment Share on other sites More sharing options...
AzeoTech Posted March 6 Share Posted March 6 Yes, by giving each set of channels for a single PLC different Timing/Offset combinations it will poll each PLC in a separate thread and so won't interfere with each other. Quote Link to comment Share on other sites More sharing options...
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