I am facing an unusual issue with the performance of our PanelView Plus 7 units, which are connected to a ControlLogix via an EN2T module. While they usually work fine, there are instances when reconnecting a PVP to the Stratix 2000 16-port switch results in it not functioning properly. The error message displayed on the PVP is "CIP FWDOPEN rejected" or "CIP FWD OPEN failed." Upon checking the EN2T webpage, I noticed that the "CIP Bad field/other rejects" counters were at 90, which I believe may be causing the CIP FWD OPEN failures. Your assistance in resolving this issue would be greatly appreciated. Please refer to the attached screenshot of the counters. It is important to note that the TCP and CIP connections have not been maxed out and are well below the allowable limits. The IO packet rate is only 1400 pps and the HMI\MSG PPS is between 6 to 9, both of which are below the limits. However, I suspect that the issue lies with the "Bad field/other rejects" shown in the image.
Before proceeding, it is crucial to verify that the device is negotiating 100mbps at full duplex. If not, try reconnecting the ethernet cable to the en2t port. Consider using a tester to ensure proper connectivity. Furthermore, it is advisable to explore Rockwell's product compatibility and download center for relevant information. Look into the firmware version of your panel views and review the release notes and download options. Keep an eye out for any notifications regarding a necessary firmware update for your en2t or, in rare cases, a potential hardware revision.
When troubleshooting network connectivity, ensure that the device is negotiating at 100mbps full duplex. Try reseating the ethernet cable for the EN2T module and use a tester if available. Refer to Rockwell's product compatibility and download center for further assistance. Verify the firmware version of your panel views and review the release notes for any relevant information. It is possible that your EN2T module may require a firmware update or even a new hardware revision. After conducting various troubleshooting steps, a Wireshark analysis revealed issues with "Invalid Attribute values" responses from the EN2T modules when attempting to establish connections with PVP or ME applications. The error message "CIP Connection open failed" was consistently observed on the HMI diagnostics. This issue persisted regardless of whether the HMI application was running on PVP or PC. Check out the Wireshark snippet below for a visual representation of the problem encountered.
It sounds like you've done quite a bit of troubleshooting already, which is helpful. In your case, the "CIP FWD OPEN rejected" error message generally signifies an issue with the connection between devices. Also, the high "CIP Bad field/other rejects" counters indicate an occurrence of communications errors, possibly due to misconfiguration or network issues. Although you mentioned that your TCP and CIP connections are under permissible limits, it'd still be beneficial to check whether your firmware is updated. Outdated firmware can often bring about unforeseen problems. If everything checks out, you may want to look into your network settings or connections. Perhaps even consider the quality of your Ethernet cables, as sometimes physical damage can cause intermittent issues.
It appears the issue could be related to a mismatch between the requested and supported communication parameters on the end device, hence the "Bad field/other rejects." Essentially, it could be possible that the requests sent by your PVP 7 unit(s) are not matching the specifications supported by your ControlLogix via an EN2T module. This could be due to incorrect setup or a software glitch. If you haven’t tried already, you could consider resetting the systems involved, updating software/firmware, or additionally evaluate the device and connection configuration. It may also be worth involving tech support if these attempts don't yield any positive results.
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Answer: - The "CIP FWDOPEN rejected" or "CIP FWD OPEN failed" error messages may be caused by high counts of "CIP Bad field/other rejects" on the EN2T module, as indicated in the attached screenshot.
Answer: - To resolve the issue of high "CIP Bad field/other rejects" counters on the EN2T module, troubleshooting steps such as checking for network configuration errors, ensuring proper cabling, and verifying device compatibility can be helpful.
Answer: - Adjusting network settings, reviewing switch configurations, and ensuring proper network communication protocols can help prevent the occurrence of "CIP FWDOPEN rejected" or "CIP FWD OPEN failed" errors on the PanelView Plus 7 units connected to ControlLogix via the EN2T module.
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