Lab equipment questions

billinrosehill  wrote:

Nobody wants to wait 30 minutes to take a measurement.

And almost nobody does. The warm-up time is the time required to ensure the calibration is valid. Which does not mean the measurements are useless or wildly inaccurate. Sure, the measurements could be slightly off, but not enough it would matter in most cases. How you probe your circuit vastly affects the accuracy of the measurement more compared to the warm-up state of the DMM.

The more important reason to for the warm-up period is because the measurements are not traceable until the temperature is stabilized. In other words, if you were going through a test plan for a device then you would wait for all the equipment to warm up. If you're debugging something or making a quick measurement (how DMMs are used 99% of the time), then there is no reason to wait.

I Am still learning about my bench multimeter. Is the third prong on the mains plug sufficient for safety? Is the ground screw for noise reduction? If I need to ground with the screw, what do I connect to? I have attempted to get information with google, but I can’t find the right query. Also, what is the best way to ask questions like this. Do I need to start a thread each time?

A new thread is usually preferred for each unrelated question. It makes it easier to focus the answers on it. (Also it helps for indexing and searching when someone else looks for the same information.)

In general, yes the mains plug is sufficient for safety. According to your multimeter's manual (Page 3, LO terminal), the terminals float above earth ground with 500V of isolation. So the chassis screw is just for the chassis. The only time I can think to use that is if you're measuring a floating DUT and you want to give it a path to earth ground.

Here is a good reference for grounding:

https://www.keysight.com/us/en/assets/7018-01897/technical-overviews/5989-9200.pdf

Thanks again. The article is very helpful. I read the “manual “ for the multimeter, but I couldn’t  understand it. I haven’t studied long enough. I hope these questions are not annoying.

Test Equipment manuals are (usually) excellent at explaining how functions work. They are lousy at explaining how to use them.

Test Equipment manuals are (usually) excellent at explaining how functions work. They are lousy at explaining how to use them.

The XDM2041 is a rather advanced device. For learning, a simple and cheaper DMM would make the learning curve less steep.