Electronics > Metrology

HMP4040 calibration and adjustment

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I have a HMP4040 sitting on my bench and it's a little bit off from its spec. I'm basically very happy with it because it's astonishingly precise and i got used to it being spot on. But now it's off and I would like to adjust it back to being perfect again. The manufacturer does not provide any GPIB commands or tools to do this. Does anyone of you know how to do a proper calibration and adjustment on these devices?


The only hint to some command can be found in the manual.


Hi branadic,

what you are referring to is the status bit of the calibration. I can poll it and it it set to 0 as expected. The manual says that these bits get set if the state of the related bit is "questionable".
I don't expect my calibration to be "broken". I just want to set the calibration factors to new values but I can't find any service manual containing the related commands or a proprietary tool to do the calibration with.

I attached some pictures of a quick teardown if anybody is interested.
To get into the device you have to unscrew 6 TORX10 screws on the back. One of them is hidden behind the "warranty void" sticker and another one hides behind the communication port.
Additionally you have to remove the two fand covers on the sides of the case. Then you can push the inner part forward to get it out of the housing.

The PCBs look nice, but sparingly labeled. Components are of good quality and known brands (Nichicon caps, EPCOS chokes) and a lot of ATMEL ATmega processors.

Hi guys,

i have >30 HMP4040 in my lab and every year we perform the calibration.
Actually we didn't found any of them out of spec in any of the measurement.

When a well known calibration company used a "wrong" calibration procedure, many units were declared out of spec
and the adjustment was "required". (when we found that the procedure was wrong, R&S declared them in spec).
They were not able to adjust them, they checked from Rhode&Schwarz (that acquired Hameg) the tool availability and is not sold to third party companies.
Adjustment is possible only at R&S.
We checked also with another calibration company if the tool was available and they confirmed it is not.

Thanks wildbill for your insight. I/we also operate >80 HMP series supplies therefore we would have been very interested in doing the services inhouse.
But if the required tools and information is not given to 3rd parties I can stop looking for a solution now.
But all in all the HMP40x0 series is a very nice tool and as I mentioned also very precise.
We only had 3 mishaps so far. One went up in flames over night  :-DD
And on the other 2 one of the output channels broke. But that was most likely our fault.


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