EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: kwass on February 17, 2015, 11:21:46 pm
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In trying to find a way to defeat the auto power off function on my AM-570 multimeter I came across an interesting entry mode. Holding down the HOLD and the MAX/MIN button while turning on the meter will show all zeros on the display. Once you release these buttons the zeros will remain indicating that it's in some sort of special mode. At this point if you press the HOLD button the display will increment by 1 for each press then wrap around: e.g.: 0000 to 0009 back to 0000. Pressing the MAX/MIN button will increased the displayed value by 10 then wrap around: e.g.: 0010 - 0090 - 0000. So any value from 0000 to 0099 can be set, but not stored. Turning off the meter and turning it back on in this special mode resets it to 0000.
I don't think that this is some sort of calibration mode because I don't see any change in the meter's readings when I set different values. It might be some sort of self-test mode but it seems pretty lame if it is. I was hoping that it might allow for a way to defeat the auto-off function, but so far that's not the case either.
Any idea of what this is? Has anyone come across this on other meters that might use the same chip?