Subject: Troubleshooting Signal Issues with Schneider Electric PLCs at a Water Treatment Plant Hello everyone, I am currently assisting a Water Treatment Plant in diagnosing signal problems with their Schneider Electric PLCs. The setup involves an M580 PLC (referred to as PLC-A) which outputs a 0-10 VDC signal via a BMXAMO0410 analog output card (2-wire configuration). This output is directly connected to a BMXAMI0810 analog input card on a second PLC (PLC-B). In our configuration, the common wire of PLC-B is connected to terminal 2, while the positive wire is connected to terminal 3 of the BMXAMI0810. This wiring appears to be correctly aligned with channel 0 specifications for that input card. However, we are facing an issue where the input card is not accurately reading and scaling the voltage. The expected scaling from 0-10V should result in a range of 0-10,000 using user-defined scaling settings. Instead, the card is only scaling from 0-10V to just 0-163. To troubleshoot, the team has already replaced the input and output cards, yet the problem persists. Using a multimeter, we confirmed the presence of a 0-10 VDC signal at the PLC termination points. If anyone has encountered similar issues or has suggestions for resolving this problem, your input would be greatly appreciated! Thank you!
Is this a fresh installation, or was it previously operational? Have you ensured that the input card is set up for a 0-10V input type and configured with a scaling format of 0-10000? Additionally, did you attempt switching to a current signal, such as 4-20mA or 0-20mA, for both the input and output cards?
Are they utilizing screw terminals or push-type connectors? I've noticed that wire ferrules on push-type terminals sometimes fail to establish a proper connection. As Tarik mentioned, ensure that the channel is appropriately configured for 0-10V operation. If they have two Schneider PLCs, why not consider leveraging I/O scanning or messaging to facilitate data exchange instead of relying on costly hard-wired analog channels?
It sounds like you’ve done some solid groundwork with the troubleshooting so far! One thought that comes to mind is to double-check the settings on the analog input card itself. Sometimes the issue could stem from the configuration in the PLC software where the scaling or the input type isn’t set correctly. Since you’re expecting a scaling factor of 1000 (for 0-10V to 0-10,000), ensure that the scaling parameters in your programming application match that expectation. Additionally, verifying the grounding and isolation between the two PLCs may also help if there's any interference affecting the readings. Good luck!
It sounds like you've already done quite a bit of groundwork! One thing to check might be the configuration settings in the PLC-B's programming. Ensure that the input channel is set correctly to interpret the signal as a 0-10 VDC input and not some other range. Sometimes, scaling parameters can be inadvertently set to different units or ranges, which would explain why you're getting that unexpected result. If all else fails, looking into the grounding and shielding of your cables could help, as noise and interference in the signal could skew readings as well. Good luck, and I hope you get it sorted out soon!
✅ 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: 1. Verify the wiring connections between
Join hundreds of satisfied customers who have transformed their maintenance processes.
Sign up today and start optimizing your workflow.