I am working on creating my own DIY ControlLogix power supply and have been experiencing some issues with certain modules not powering up properly. I am utilizing four separate power sources to supply the chassis with various voltages (1.2V, 3.3V, 5V, 24V). Currently, I have successfully powered up an L63/A, CNB/E, and IB16/E. I am able to connect online with the processor and use the controlnet without any issues. However, when I try to insert other cards such as L61/B, ENET, DHRIO/B, DNB/D, they either do not light up or display a solid red fault light. I have confirmed that these cards work by reinstalling the proper power supply, and I have also tried placing them in different slots within the chassis. I am unsure if there is a necessary communication link between the chassis and the power supply that is missing. There are four pins on the power supply whose functions I am unsure of. Any guidance or assistance on this matter would be greatly appreciated. Thank you.
How did you manage to discover the additional pins? It's fascinating!
I recently tested a 1756-PB72 using a multimeter. It is important to note that I have properly linked all the common terminals of the power sources. In the Allen Bradley power supply, all common terminals are grounded. Interestingly, my investigation revealed that four pins appear to be unconnected. I discovered that a voltage of 1.2V is essential for backplane communication. While the cards can operate without it, they may encounter communication issues. At this point, the purpose of the 3.3V remains unclear as there is no noticeable impact whether it is connected or not.
I identified the issue with my electronics setup: the 5v power supply experienced voltage sag when other modules were turned on. While my multimeter didn't detect this, my scope did. For future troubleshooting, I can verify that the provided wiring diagram is effective.
A user named ThinkPad successfully identified and resolved an issue with their 5v power supply experiencing voltage sag when other modules were powering up. Despite not being detectable with a multimeter, the issue was visible when using a scope. This serves as a valuable reference for others facing similar challenges. Well done, MacGyver! Welcome to the forum.
ThinkPad mentioned that they identified the issue with their 5V power supply, which experienced voltage sag when other modules were powering up. Despite not being able to detect this with a multimeter, it was visible using a scope. This information is valuable for anyone facing a similar problem, as it confirms the effectiveness of the wiring diagram. Thank you for sharing, this knowledge will definitely be beneficial for future troubleshooting.
It sounds like you've put a lot of effort into this project already. I'm wondering if the problem with certain cards could be due to differences in power requirements. Each type of card might need different power loads to function correctly. As to the four pins on the power supply, they could potentially be used for signaling or fault detection purposes. I would recommend checking the documentation or reaching out to the manufacturer for more clarity. In addition, if you have an oscilloscope, you might be able to diagnose whether there are any irregularities in the power delivery. Keep up the troubleshooting, don't get discouraged!
It sounds like you're dealing with a complex issue! While I can't provide a definitive answer, I can provide some speculative troubleshooting solutions. It's possible you might be experiencing an issue with load regulation or voltage alignment. Power supplies need to provide exact voltages to each module to function properly, and the tolerances can be pretty tight. Those unknown pins on your power supply could be the key - they may be there to provide a feedback loop, keeping the output voltage stable despite fluctuations in the load. I'd also recommend checking your power supply's total capacity, ensuring that it can meet the cumulative power demands of all the modules you're trying to power up. If possible, replicate a similar setup with a known working power supply and see if the same problem occurs.
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Answer: Answer: There could be several reasons for modules not powering up properly, such as incorrect power supply connections, faulty modules, or missing communication links between the chassis and power supply.
Answer: Answer: The solid red fault light on modules could indicate power supply issues, incorrect installation, or compatibility problems. It's important to check the power supply connections, module compatibility, and installation procedures.
Answer: Answer: To troubleshoot power supply module issues, you can verify the power supply connections, test the modules in a different setup to confirm functionality, check for any communication links missing between the chassis and power supply, and review the documentation for the power supply to understand the functions of the pins in question.
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