Hello everyone, we are facing an issue with our CompactLogix PLC (L27ERM) as it can only handle up to 16 CIP connections. Since we are currently at 15 connections, we are considering replacing it with a ControlLogix PLC (L71 with EN2T). We have successfully migrated all the logic and connections to the new PLC while keeping the same IP address. However, we are experiencing random, intermittent communication losses which result in inconsistencies. The system runs smoothly for a while before devices in the EN2T I/O tree start flickering with caution signs. We use a couple of 1783-US16T's to connect the devices and the L71 PLC needs to communicate with a SLC 5/05 as well. Any suggestions on how to resolve these communication issues?
Capture a screenshot of your Input-Output (IO) tree, specifically focusing on the devices located under the EN2t. This will help us identify the Brand, Make, and Model of each device.
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If you are utilizing the continuous task, it may appear to be a potential overhead time slice problem.
The consistent task involves implementing the same logic setup in both the CMPTLGX and CTLGX, with only a change in processor and utilization of the EN2T instead of the onboard Ethernet. The rack solely consists of the processor and the EN2T card, with no additional I/O. The only modification to the logic involves adding a prefix in MSG paths to establish communication between the CTLGX and the SLC. The ultimate objective is to phase out the SLC in the future.
Do they rely on implicit connections? Check out the EN2T diagnostic log to troubleshoot. Disable all devices and gradually enable them one by one until the issue reoccurs. This method helps identify the root cause of the problem efficiently.
I'd recommend beginning with a thorough review of your network infrastructure: check both the physical connections and network traffic patterns. The ControlLogix PLC and EN2T have a lot more bandwidth and processing power, but they also put more pressure on your network than CompactLogix. The caution signs you've mentioned could be a result of network congestion or weak signal strength. To help manage bandwidth consumption, you might also want to place non-critical I/O on an isolated network. Additionally, regarding the communication with SLC 5/05, ensure that you're using appropriate data types and structured requests - avoid unconnected messaging as much as possible. Hope this helps!
It seems like you've done a good job migrating but the flickering could be due to unrecognized IP addresses due to switching over. Check that your IP configuration is correct across your EN2T I/O tree. Another suggestion would be to limit the number of CIP connections using the same network. As for the L71 communication with the SLC 5/05, ensure that your RSLogix500 processor is set up for the directed messages and that they aren't causing timing issues. Lastly, keep an eye on your network traffic using Wireshark or a similar tool to see if there are any anomalies. Best of luck!
Hey there, it seems like you've put in good work troubleshooting the issue so far. These intermittent communication losses could be due to a bottleneck somewhere on your network caused by an overload of traffic on the EN2T, or possibly an issue with your I/O tree configuration. You might want to try enabling Connection Monitoring on your EN2T to more effectively troubleshoot the path of your network traffic. Another suggestion would be to check the parameters in your I/O tree, especially RSLogix 5000, ensuring devices are added correctly and that their RPI (Requested Packet Interval) is appropriately configured. Also, check how your PLC is communicating with the SLC 5/05, making sure all protocols are fully compatible. Hope this helps!
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Answer: 1. What could be causing the random communication drops on the ControlLogix PLC post-migration from CompactLogix? - The random communication drops could be caused by various factors such as network configuration issues, compatibility issues between devices, or inadequate network bandwidth.
Answer: - The ControlLogix PLC (L71 with EN2T) can handle a significantly higher number of CIP connections compared to the CompactLogix PLC (L27ERM), but it is important to ensure that it is configured properly to handle the required connections.
Answer: - Troubleshooting steps may include checking network settings, verifying device compatibility, ensuring an adequate number of available CIP connections, and monitoring network traffic for any abnormalities that could be causing the communication losses.
Answer: - To ensure stable communication between the ControlLogix PLC (L71) and the SLC 5/05, it is important to verify compatibility, configure proper communication settings, and troubleshoot any issues that may arise during the communication process.
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