Hello everyone, I am currently working on establishing communication between ControlLogix PLCs and Delta V DCS through EtherNet/IP. A VIM2 card has been set up to support EtherNet/IP devices. According to Mynah's knowledge base, the VIM2 is capable of Class 1 (I/O) connections with ControlLogix PLCs, using the 1756-ENBT format. Each ENBT corresponds to a VIM dataset, specifically designed for simplex VIM architecture. I have successfully configured 3 PLCs with the DCS, although they were never simultaneously connected due to plant maintenance. Upon restart and simultaneous connection of all 3 PLCs, communication errors with the DCS occurred. Troubleshooting revealed seamless communication with the DCS when only one ControlLogix PLC is connected, but issues arise when multiple PLCs are connected simultaneously. Troubleshooting efforts are ongoing, and communication is restored only when all but one PLC is connected, and the cable is reinserted. I have verified the network for duplicate IP addresses but found none. Is there something I may be overlooking? My experience with the Delta V DCS is limited. Thank you.
Are you currently employed by Emerson or are you the end user of their systems? Emerson's support contracts can be costly and comprehensive; do you have one in place? In my past experience, I found that a Mynah VIM set to default update rates could overload the communication capacity of a 1756-ENBT with Class 3 tag reads and writes. The "inter-scan delay" feature of the Mynah did not function properly, causing constant requests and limiting control. However, it has been 15 years since I last worked with them, so improvements may have been made by now. How are the Class 1 connections configured exactly? Do the Mynah VIM2's appear as Generic Modules in the ControlLogix I/O tree, or as I/O modules with a 1756-ENBT acting as an adapter? Are you using traditional 1756-ENBTs or newer models like the 1756-EN2T or -EN3T? If you have three PLCs attempting to establish connections with a DCS as an "adapter"/"target", does the VIM2 differentiate them based on the source IP address or through other means like the CIP Slot Number? Monitor the I/O connection status in Studio 5000 and check for any error codes using GSV instructions. If possible, set up a mirror port on a managed switch and use Wireshark to capture data, as this could provide valuable insights.
It sounds like you've done some extensive troubleshooting already. Based on your description, I wonder if the issue might be related to network hardware limitations or bandwidth overloading. Are your switches capable of handling the simultaneous traffic from all three PLCs? Or could it be that with all three PLCs communicating simultaneously, the total amount of data surpasses the DCS or your network equipment's handling capacity? It might be beneficial to monitor your network traffic and check the load on your DCS during the simultaneous connection phase. On another note, if limitations of your VIM2 card are a potential problem, if possible, you might look into expanding the resources or even evaluating other methods of interfacing your PLCs with the Delta V system.
Hey there! It sounds like you've already done a good deal of troubleshooting. One thing that comes to mind is that even though there are no duplicated IP addresses, there might be some latency or timing issues when all 3 PLCs are trying to connect simultaneously. This might be potentially due to oversubscription of bandwidth when all PLCs are trying to send data simultaneously, causing the Delta V DCS to be overwhelmed. Have you also considered checking each PLC's packet interval? Adjusting it could potentially solve the issue. It's also worth looking into the Ethernet switch capabilities to ensure it can handle the necessary data flow. Keep us posted!
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Answer: Answer: The issue could be related to network configurations, data traffic conflicts, or potential limitations in the setup that may affect communication stability. Troubleshooting efforts should focus on identifying and resolving these potential causes.
Answer: Answer: To ensure smooth communication, it is important to verify network settings, check for any data transmission conflicts, and confirm that the configurations of both the PLCs and the DCS are compatible and correctly set up for EtherNet/IP communication.
Answer: Answer: Troubleshooting steps may involve checking for IP address conflicts, reviewing network configurations, testing communication stability with individual PLC connections, and investigating any potential hardware or software limitations that could impact simultaneous connections between multiple devices.
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