Greetings everyone! I am facing an issue with my ControlLogix PLC that is connected to 6 1794-ASB Flex I/O racks. Everything was functioning smoothly until a month ago when communication was lost on rack 16 or 6, and all efforts to restore it have been in vain. Despite trying a replacement module and switching with a known functioning one, the problem persists with a persistent yellow triangle in Studio 5000. The dip switch settings have been tampered with, complicating the restoration process. I will be sharing the configuration settings from Studio in hopes of receiving guidance. Despite seeking help from Rockwell and an experienced individual in the field, the issue remains unresolved, causing frustration. It appears to be related to a rack size matter as indicated in the images, but interpreting standard, compact, and other addressing options according to Rockwell's instructions is proving to be challenging. Assistance in resolving this issue would be greatly appreciated.
It is possible that the issue lies with a small capacitor or varistor inside a DH+ splitter box connected to the PLC. If you are experiencing similar issues, it may be worth checking these components. I recall facing this issue myself and after contacting Rockwell for advice, we replaced the faulty component and communication was restored immediately. This simple fix made the investment in Tech Connect well worth it, as our system was up and running smoothly again.
After facing challenges with a flex IO communication issue between controllogix and EthernetIP, it was revealed that the problem stemmed from a faulty card or backplane module within the system. Initially, the focus was on the 1794-AENT card not communicating, but it was later discovered that there was an issue in the rack causing the 1794-AENT to misinterpret the rack size. To quickly restore production, a full swap out was performed as it was more efficient than troubleshooting through trial and error.
It appears there is a discrepancy in your project between the stated 3/4 rack and the actual 1/2 rack module being displayed. This suggests a potential issue with the connection between bases or a faulty base, possibly between modules 2&3 or 3&4. It is worth noting that dip switches may vary across different series (A through at least E) and there have been instances of incorrect documentation. It is recommended to verify the series you are using and consult the appropriate documentation, including any corrections for previous series. Additionally, consider updating to a newer CLX firmware, as using outdated firmware may cause issues with module connectivity. I recall a situation where converting a PLC5 to L72 CLX with multiple physical racks on a DHRIO module resulted in RIO not functioning properly until the latest V20 firmware was utilized. If you continue to encounter difficulties, updating to the latest firmware version may resolve the issue.
5618 noted that although the project specifies a 3/4 rack, the module appears to be a 1/2 rack. This discrepancy suggests a potential issue with the connection between bases or a faulty base, particularly between modules 2&3 or 3&4 (with the first module being zero). It is important to consider the possibility of dip switches changing across different series (A through E) and incorrect documentation. Verify the series of your equipment and cross-reference documentation for any necessary corrections. Additionally, ensure that you have updated to the latest CLX firmware, as outdated firmware could cause connectivity issues. It is worth noting that the user experienced difficulties with RIO functionality until updating to the latest V20 firmware. The system consists of 5 modules (0-4), and clarification on the rack size is needed. Furthermore, there is a mention of a blinking module active light that also needs to be addressed.
The project specifies that five modules will be 3/4 rack in size. However, the diagnostic for the communication module indicates that it may only detect 3 or 4 I/O modules, which are 1/2 rack in size.
It sounds like you've been through a lot trying to troubleshoot that issue! Since you've already replaced the module and checked the dip switches, I would recommend verifying the communication settings for that specific rack in Studio 5000, as sometimes it's just a matter of a small setting being overlooked. Also, double-check the physical connections and any potential cable issues, since intermittent problems can often be caused by faulty wiring. If you haven’t already, it might be worth resetting the configuration on that rack to default and then reapplying your settings, just to rule out any hidden corruption. Hang in there—sometimes these kinds of issues can be resolved with a fresh set of eyes or by stepping away for a bit and coming back to it!
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Answer: Answer: Several factors could be at play, such as faulty modules, incorrect dip switch settings, or issues related to rack size configuration.
Answer: Answer: Troubleshooting steps may include checking module replacements, verifying dip switch settings, and reviewing rack size configuration in Studio 5000.
Answer: Answer: Understanding and correctly setting the rack size in Studio 5000 is crucial for proper communication with Flex I/O racks. It involves selecting between standard, compact, and other addressing options as per Rockwell's instructions.
Answer: Answer: If standard troubleshooting methods like replacing modules and adjusting dip switch settings have not resolved the issue, seeking guidance from experienced professionals or contacting Rockwell's technical support may be necessary.
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