Electronics > Beginners
Lab power supply and noise immunity
(1/1)
den:
Hello everyone.
Short background first. We have here a test lab (equipped with sensors) which is located in a container like this: https://goo.gl/images/ZYWPxb . Over the container there is a ventilation AC motor. Driver for the motor (for controlling RPM) is inside the cell. There are two PSUs, one is some kind of PC supply with several volatge outputs, and one generic SMPS. Nothing is isolated. And as mentioned - we have different sensors there: pressure, temperature (thermocouples and thermistors), flow etc. The sensor signals are acquired by a computer. There are also mains sockets inside the lab, and also luminescent lights.
Now, one problem we definetely have is noise in sensor lines from ventilation motor driver. Understandable why it is there, but I have no idea what to do with that. We also have noise when some other equipment swithes on, like CNC, which is nearby. Here I do not get why we see it - I thought the lab is kind of inside a faraday cage.
So these are two direct questions - how to solve these problems?
But I would like also to understand general stuff, like:
- how lab mains earthing/grounding should be done? Is it important, or maybe not really?
- Can bad grounding (rel. high impedance) create noise in sensor signal? I assume yes.
- Sould PSUs in the lab be isolated or not?
- If they are isolated - how can I read sensor voltages, if my computer (which does acquisition) is plugged into mains?
- What are best pactices to sensor wiring, especially if I conatcntly have to connect additional stuff?
- What are other very important points to take into account, which I am missing?
Thanks in advance,
Den
Navigation
[0] Message Index
Go to full version