Greetings, I am a new member of this forum and would appreciate any guidance on my issue. I am encountering difficulties while trying to operate an Eaton MMX VFD with a combination of Analog 4-20ma output and Digital output from a Horner XL7. Although I can successfully start the VFD/pump using the Digital output to control a relay, my 4-20ma signal drops to 0ma as soon as I initiate the VFD. This issue persists despite the signal reading correctly when the VFD is not in operation. I suspect a grounding issue may be causing this anomaly, but I have been unable to resolve it thus far. All VFD parameters have been verified to be correct. Interestingly, the setup functions as expected when I manually source the 4-20ma signal using a meter. Any assistance on this matter would be highly valued and appreciated. Thank you.
Adding more information can greatly assist in configuring the XL7 analog for either current or voltage by utilizing the built-in configuration through cScape software. Can you provide details on how the VFD is wired and set up? Also, how is the XL7 wired and configured for optimal performance?
Hello and welcome to the forum! I've come across similar issues in the past. It does sound like a grounding issue as you mentioned. However, another possibility could be a conflict between your digital and analog signals. VFDs can sometimes be a bit tricky when it comes to mixed signals. It's worth checking if this is causing a short, or if there's an error when you initiate the VFD. Also, you may like to analyze the shielding and segregation of your 4-20ma line, as oftentimes, electrical noise from other parts of the system can affect the analog output. Good luck, hope you resolve the issue soon!
Welcome to the forum! It's indeed possible that it could be a grounding issue, or possibly some interaction between the digital and analog signals. First, I’d suggest isolating the system - try operating the VFD independently from the 4-20ma signal and vice versa, to see if one is impacting the other. Second, cross check your wiring if it's following the recommended practice by Horner for this specific case. If these measures don't solve the problem, consider looking into external factors such as power supply stability or even electromagnetic interference which may interrupt the analog signal. Hope this helps!
Hey there! It sounds like you're dealing with a tricky issue. Since the 4-20 mA signal works when you source it manually but drops when the VFD is running, it definitely could be a grounding problem or possibly interference from the VFD. First, double-check that your ground points are solid and that there’s no potential difference causing issues. You might also want to isolate the control signal wiring from the power wiring to reduce any noise interference. Some users have had success using twisted pairs for the analog signals too. Have you considered using a differential input on the VFD? That could help mitigate any grounding issues. Hope this helps!
Hi there! It sounds like you’ve done quite a bit of troubleshooting already. The issue might indeed be related to grounding, especially since you mentioned that the 4-20mA signal drops when the VFD is powered up. Make sure that your VFD and the control device share a common ground to avoid voltage differences that could affect the signal. Also, try to isolate the control wiring from power lines, as electrical noise from the VFD can interfere with the signal. If possible, test the setup with a different analog output to see if that changes anything. Good luck, and I hope you get it sorted out soon!
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Answer: - The 4-20ma signal dropping to 0ma when starting the VFD could indicate a grounding issue causing the anomaly. It is essential to investigate and address any grounding issues to ensure proper signal transmission.
Answer: - To troubleshoot the control signal issue, you can start by verifying all VFD parameters for correctness. Additionally, checking for proper grounding connections and ensuring the compatibility of the analog and digital outputs with the VFD can help identify and resolve the problem.
Answer: - The setup functioning as expected when manually sourcing the 4-20ma signal using a meter suggests that the issue may lie within the automation system's configuration or signal transmission between the Horner XL7 PLC and the Eaton MMX VFD. Further investigation into the communication protocols and signal pathways may be necessary to pinpoint the root cause.
Answer: - Some steps that can be taken to address the dropping 4-20ma signal issue include checking and improving the grounding connections, ensuring the correct
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