The ControlLogix CPU is linked to Flex IO through ControlNet. The Flex IO setup includes 5 modules: IB10X, OB6/AIE8, BIE4XOE2, and BIR8IR8. The two BIR8IR8 modules experience excessive heat, causing all inputs to read at full scale, whether connected to a field or not. Despite the Module OK LED indicating normal operation with a solid green light, the issue persists. When connected to the CPU via RSLogix, no problems are detected in the IO tree. Replacing the faulty modules allows the system to resume operation. This is an older installation that has been running for years, with two other Flex IO drops set up similarly but not experiencing the same problems. Even when the faulty modules are tested in a separate rack, the same issues arise. Given the recurring nature of this problem, further investigation is needed to determine the root cause.
When troubleshooting issues with your system, it is important to verify the TB3 base wiring according to the manual 1794-IR8 and cross-reference it with the details provided in chapter 2. Additionally, be sure to address any "noise" coming from the 24V DC power supply to the modules. It is also worth checking for any AC interference on the field wiring to the RTDs. If the modules continue to exhibit the same behavior on both your test rig and field setup, it could indicate potential faults in the modules themselves. Be sure to thoroughly investigate and address points A and B mentioned above to ensure smooth operation.
When troubleshooting issues with your 1794-IR8 module, consider the following possibilities: 1. Verify that the TB3 base wiring is correct by referring to the manual and double-checking against the details in chapter 2. 2. Check for any "noise" on your 24V dc supply that may be affecting the modules. It is also important to inspect for possible AC interference on your field wiring to the RTDs. 3. If the modules continue to exhibit the same behavior in both the test rig and field setup, they may be faulty. This could be due to a combination of incorrect wiring and electrical interference. Additional details provided by DABA suggest that: 1. The wiring has not been changed and is part of an old installation that experiences intermittent failures. 2. Conducting a scope test on the DC supply may help identify any potential sources of noise. 3. Within a few months, there have been issues with 8 modules failing. 4. Temperature checks on faulty modules reveal significant differences when no inputs are connected versus with test resistors installed. Considering the ongoing challenges, it may be necessary to return the modules to Rockwell for further analysis.
Kellian mentioned that a ControlLogix CPU is connected to Flex IO via ControlNet. The Flex IO setup includes 5 modules: IB10XOB6, AIE8, BIE4XOE2, and BIR8IR8. However, the two IR8 modules tend to get very hot, causing all inputs to go to full scale, regardless of field connections. Despite the Module OK LED showing a solid green light (indicating normal functionality), the issue persists. When connected to the CPU through RSLogix, the IO tree shows no problems. Replacing the faulty modules temporarily resolves the issue, but it keeps recurring. This older installation has been in operation for years, with two other Flex IO drops configured similarly but not experiencing the same problem. Testing the faulted modules in a separate rack yields the same problematic results. It is crucial to identify and address the underlying cause of these recurring issues to ensure system stability and functionality. Dear Kellian, I am encountering the same issue you described with the Flex IR8 modules. Interestingly, allowing the IR8 modules to sit disconnected for a few hours seems to temporarily resolve the problem. One IR8 module that initially appeared faulty miraculously started working again after some time. If you have found a solution to this issue, please share it with me. Your insights would be greatly appreciated. Thank you. Mike Hanners Procter & Gamble PCI&S
From the symptoms you've described, it sounds like the BIR8IR8 modules might be the victims of a power surge or excessive environmental heat, which could be causing the internal components to overheat and malfunction. This can occur even if diagnostic tests do not indicate a problem. Other Flex IO in similar setups may not experience the same issues, simply because of slight variations in use, exposure, or environmental conditions. I would recommend checking the power supply for voltage spikes or inconsistencies, and also verify the temperature of the location where these modules are kept. These could provide clues as to why the modules are overheating.
It's interesting that the problem persistently occurs with only the BIR8IR8 modules. Since everything seems to be working fine in the IO tree and Module OK LED, and the issues persist even after moving the modules to a separate rack, this might be suggestive of an internal hardware issue in the BIR8IR8 modules rather than an overall system problem. It might also be worth checking that the modules are receiving the correct voltage. As a possibility, there might be a design or manufacturing flaw in these modules which makes them susceptible to overheating. It could also be an environmental issue, are these modules exposed to more heat or less ventilation than the others? Given this is an older installation, it could also be a lifecycle issue as electronics do degrade over time. Some sort of thermal analysis might help pinpoint the issue. An oscilloscope could be used to check the waveform of the power supply for any irregularities. Just a few thoughts to explore.
It sounds like you've tried most of the common troubleshooting steps, ruling out wiring and configuration errors. Despite the Module OK LED showing no anomaly, the repeating issue even in a mitigated environment like a separate rack indicates a potential hardware fault. I suggest checking the environment factors where the system operates, like temperature, humidity, and voltage spikes, which can all lead to premature failure of modules. Alternatively, consider the possibility of a compatibility issue. Though uncommon, some older installations may face issues with certain module batches due to changes in manufacturing processes or components. I'd also recommend using an infrared thermometer to monitor the overheating modules closely and gauge precisely how hot they are getting—it might help further understand what's causing the heat issue.
✅ Work Order Management
✅ Asset Tracking
✅ Preventive Maintenance
✅ Inspection Report
We have received your information. We will share Schedule Demo details on your Mail Id.
Answer: - The overheating issue with the BIR8IR8 modules can lead to all inputs reading at full scale, even when not connected to a field device. This issue persists despite the Module OK LED showing normal operation. Replacing the faulty modules has been found to resolve the problem temporarily.
Answer: - The root cause of the overheating issue in the BIR8IR8 modules, which are part of an older Flex IO setup in a ControlLogix system, needs further investigation. The fact that the problem occurs even when the faulty modules are tested in a separate rack suggests a recurring issue that requires detailed troubleshooting.
Answer: - Troubleshooting steps may involve checking the ControlNet connection between the CPU and Flex IO, verifying the module configuration in RSLogix, inspecting the wiring and field devices connected to the modules, and possibly examining the environmental conditions where the modules are installed. Further investigation is necessary to determine the exact cause of the overheating problem.
Join hundreds of satisfied customers who have transformed their maintenance processes.
Sign up today and start optimizing your workflow.