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All about Keithley DMM7510. Bugs and features, recipes, advice, notes.
MegaVolt:
--- Quote from: JxR on May 17, 2020, 11:15:07 am ---Both the DMM7510 and DMM6500 should be able to use a PT1000 RTD. Change 3/4-Wire RTD to "User" and set RTD Zero to 1000.
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Thank you! I missed that moment.
--- Quote from: essele on May 17, 2020, 12:15:10 pm ---I've just posted a couple of bugs around the temp measurement stuff in the Tek forum, so I though I'd add them here for completeness.
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Thank you!
--- Quote ---(a) Using a thermistor, with 1.7.0e the display reads in kilo degrees ... not very helpful! It was fine in the older firmware.
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Yes it is not convenient :(
--- Quote ---(b) Using a PT1000 (not sure that's relevant), with 1.7.0e the display reads "-DispNan-" ... graphing is fine, so the value is actually read ok. Haven't tried this in the older firmware.
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This is strange. I connected a 1 kΩ resistor and got the measurements.
--- Quote ---I've also found quite a few display issues, but in the scheme of things they seem less important. I must say my first impressions (after only 2 days) is that the hardware seems great, the capabilities (esp the triggering stuff) are superb, but the firmware quality is awful!
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Unfortunately, a number of modes work either with an error or with noise that can hardly be called Gaussian. It seems that tested only some ranges that are really great.
MegaVolt:
--- Quote from: Kleinstein on May 16, 2020, 09:38:56 pm ---It is probably the values to show. They seem to use the same number of total digits. So one more digit resolution once below 10 V. For the average the higher resolution may actually make some limited sense.
The peak to peak and StdDev values still have some digits well in the noise / fantasy. It is not a big deal, but ideally there should not be much more digits than actually real. If at the edge one more digit can be good - so the average could get one more digit, while the peak to peak and StdDev case should get less.
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Yes, I understand. I was uncomfortable getting an extra digit by switching the display. I'd love to have all the numbers on any display.
MegaVolt:
Ohhhhhhhh !!! I found curious documents. True, they are in Russian.
1. This is a test procedure for the device.
2. Description of the type of measuring instrument.
These documents describe the conditions under which the device is accepted in the state registry of Russia. And the presence of these documents means acceptance by the state as a metrological device. Those. these are the parameters that an independent metrology laboratory checks and guarantees.
MegaVolt:
Nameplate describing noise quality with shorted inputs in DigiV mode:
essele:
--- Quote from: MegaVolt on May 17, 2020, 03:43:30 pm ---
--- Quote ---(b) Using a PT1000 (not sure that's relevant), with 1.7.0e the display reads "-DispNan-" ... graphing is fine, so the value is actually read ok. Haven't tried this in the older firmware.
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This is strange. I connected a 1 kΩ resistor and got the measurements.
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That's bizarre ... I've just attached a 1k resistor, using 4W resistance mode it's fine .. I switched to temperature and 4RTD and it said '-DispNAN-', then I went through some of the other transducer devices and it's started working ... very weird.
Just tried a reset and still it appears to be working, although it said "PT100" but was reading a correct value ... so I don't think "reset" actually reset the zero value. That seems like another bug. (This is reproducible -- it's nice to know reset isn't actually a reset!)
Power cycled, and it then seems to be working fine ... PT100 shows "overflow", and then setting the zero value to 1000 works ok.
So I think there's some sequence of events that I went through (I had been using a thermistor before) that got it into this confused state. I've tried going back over some similar steps but can't reproduce it.
Further -- the "zero" setting actually persists if you go from 4RTD to Thermistor and then back to 4RTD even though it says "PT100", so they are not properly resetting values. If you manually select "PT100" then it's ok.
Horrible.
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