Electronics > Metrology

Advantest R6581 8.5 digit DMM mini teardown/repair

<< < (159/181) > >>

leighcorrigall:
I also quickly have translated section 3, page 19, number 5. I am guessing that the resistance measurement current may also be related. I really wish that the calibration steps made note of these settings before I sent the instrument in for calibration. :-\

Original text:

(5) 抵抗測定電流の選択

抵抗の測定電流は、HI-POWERまたはLOW-POWERに選択できます。それぞれの電流 値は、[表3-8]を参照して下さい。HI-POWERはLOW-POWERに比べて確度良く測定ができますが、比測定抵抗での消費電力が大きいため、測温抵抗体など自己発熱の影響を受けやすい素子の抵抗を測定する場合は、LOW-POWERが有効です。

Google Translation:

(5) Selecting the resistance measurement current

The measurement current of the resistor can be selected from HI-POWER or LOW-POWER. Refer to [table 3-8, page ] for each current value. HI-POWER can measure more accurately than LOW-POWER, but since it consumes a large amount of power in the ratio measurement resistor when measuring the resistance of a device that is easily affected by self-heating, such as a resistance temperature detector, LOW-POWER is enabled.

Kleinstein:
For the highest Ohms ranges the may not be much choice in the test current. They just need the lowerst test current for the highest ohms.

The high ohms ranges may not work with a short integration time (e.g.  < 10 PLC) if the Az mode is selected. One may even get better readings in the non AZ case with high Ohms (10 M or more). The non AZ modes adds a little offset error, but less "leakage" / no charge injection form AZ switching, that can look like leakage with a high resistance source, especially if the is additional cable capacitance.

The high Ohms measurements are relatively sensitive to leakage currents, e.g. from a dirty board. The ACAL procedure does not fully compensate for this (there can be slightely different leakage paths). So it is possibility that a meter may acurally fail on the high ohms range. One may habe to live with a larger tolerance for these ranges.  I remember other reports on problems with high ohms.

A similar porblem with high ohms is also on the calibrator side - switching and the cables may add errors. So the calibrator / cal lab could in principle also be the problem. Chances are one would need manually connected precision resistors, not a calibrator like FLuke 57xx. The high ohms part may not be used very often.

leighcorrigall:

--- Quote from: Kleinstein on August 23, 2021, 06:11:35 pm ---
...

A similar porblem with high ohms is also on the calibrator side - switching and the cables may add errors. So the calibrator / cal lab could in principle also be the problem. Chances are one would need manually connected precision resistors, not a calibrator like FLuke 57xx. The high ohms part may not be used very often.

--- End quote ---

Hi Kleinstein,

Thank you for the quick response and comments! I'll try and ask them about the settings they used before they go at it again tomorrow. All I know so far is the attached report. According to the document, they are using precision resistors for the high-ohm ranges.

EDIT: OOT is an abbreviation for 'Out of Tolerance' from the second last page.

Regards.

Mickle T.:
1) External calibration (as well as internal one) doesn't use any of the user-defined settings in the DMM.
2) The main problem with R6581T is a "T" symbol :) R6581T - is a technological multimeter. It used only for ADVANTEST T2000 IC/SoC/ASIC test system, but not in metrology laboratories. R6581T don't have any official specs or manuals.

leighcorrigall:

--- Quote from: Mickle T. on August 23, 2021, 08:45:31 pm ---1) External calibration (as well as internal one) doesn't use any of the user-defined settings in the DMM.
2) The main problem with R6581T is a "T" symbol :) R6581T - is a technological multimeter. It used only for ADVANTEST T2000 IC/SoC/ASIC test system, but not in metrology laboratories. R6581T don't have any official specs or manuals.

--- End quote ---

Interesting, Mickle. Perhaps, the Advantest is working as it should.

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version