HP 66332A Calibration Issues - Page 1
Forum section: electronics / general

author: Nanitamuscen
author_rank: Contributor
timestamp: October 18, 2022, 05:52:03 pm
content: I can’t figure out how to properly calibrate this power supply with option j02. I will attach the calibration procedure for blocks without this option and the description of the option itself in files.According to the description of the option, in parallel with the output, you need to connect a 25 uF 30 V capacitor in series and a 0.25 ohm resistor to ensure the stability of the output.But what stage of the calibration is carried out with the connected chain, and which without, I do not understand.Also, I do not understand the points with the calibration of the negative current, what parameters should be set on the auxiliary laboratory power supply.

author: alm
author_rank: Super Contributor
timestamp: October 19, 2022, 12:06:25 am
content: Quote from: Nanitamuscen on October 18, 2022, 05:52:03 pmThe way I read the instructions for the J02 option, you need to use the 25 uF cap in series with a 0.25 Ohm resistor across the output for all tests except the peak current calibration (which I can't find in the 66312A manual, but may have been in a different version?).Quote from: Nanitamuscen on October 18, 2022, 05:52:03 pmThe manual says: Set the negative supply to the full scale voltage rating of the UUT. I'd say the output current should be greater than the maximum current rating of the UUT. The manual doesn't say, but I'd expect it to prompt for the current reading from the DMM, otherwise what's the point of the DMM?

author: Nanitamuscen
author_rank: Contributor
timestamp: October 19, 2022, 06:42:32 am
content: Unfortunately, I have not found any other documentation on the calibration of this power supply. Therefore, I do not understand what the peak current calibration is.66332a differs little from 66312a, so you can look at the documentation for both units.What is UUT? How does the abbreviation stand for?The current will be quite small, because according to the documentation, a 1.1 kOhm resistor is connected in series. Or do I understand something wrong?

author: maat
author_rank: Regular Contributor
timestamp: October 19, 2022, 06:51:21 am
content: UUT =UnitUnderTest.Those devices have two current ranges. A low range and a high range. The low range ist calibrated using the 1.1k resistor and the high range using the 0.1 Ω shunt. The peak current calibration is (in your case) done at 5 A. So you need that 0.1 Ω shunt for this. That would be figure B-1 A.

author: little.tesla
author_rank: Regular Contributor
timestamp: October 19, 2022, 09:20:01 am
content: I have a 66312A with option J03/J04 (I think the option J04 is adding the compensation R-C inside the instrument) and I've performed the calibration procedure some time ago. With this options installed the unit can not be operated without the 25 uF cap in series with a 0.25 Ohm resistor across the sense lines at all. My unit oscillates without it. The AC current calibration is anyway only performed internally by the instrument.Have you tried to perform the calibration?

author: Nanitamuscen
author_rank: Contributor
timestamp: October 19, 2022, 04:01:40 pm
content: To be honest, I just do not understand how to perform an AC calibration.Today I will try to calibrate the peak current, at negative 5 A.(Calibration peak current was successful)

author: Nanitamuscen
author_rank: Contributor
timestamp: October 20, 2022, 10:10:31 am
content: When trying to calibrate the AC, it writes "out of range"

author: bateau020
author_rank: Frequent Contributor
timestamp: October 20, 2022, 11:04:14 am
content: Just grasping straws here, but1) you chose the correct device type under the "hidden" 0+9 menu?2) mode switch is set to "normal"?3) did you do a *RST before calibrating? changing to a non-standard setting can provoke that cal reply.4) you disconnected everything (but keep sense connected to out)?Unless the calibration is different from the standard types, that AC calibration (CAL:CURR:MEAS AC) does not require entry, meaning that it only requires the circuit to be in spec. But if it does, enter in Volts or Amps, not in milliAmps, even when the screen shows milliAmps.

author: little.tesla
author_rank: Regular Contributor
timestamp: October 20, 2022, 11:31:10 am
content: I've collected the relevant HP 66332A instruction manual sections as screenshots with the relevant data as basis for an easier discussion.Negative Current calibrationUse a 1K1 resistor with a full scale voltage of 20V. Note the polarity of the supply! It says negative, but this is to be understood relative.AC calibrationThis are the instructions without the J02 option as basis, but you need to do something as described below when running this calibration step.With J02 option you have to bypass the resistor R353 (1R5) with a 0R1 Ohm.Be aware of the warning below.Did you perform this steps as shown?

author: Nanitamuscen
author_rank: Contributor
timestamp: October 20, 2022, 11:53:57 am
content: @bateau0201) Yes, it is correctly exposed2) I have a block with the J02 option, which means there is no switch as such3) Yes, of course4) Yes, that's rightCAL: CURR: MEAS AC does not require the input of values, it just outputs an error@little.teslaCalibration of negative current does not pass if done according to the scheme with a load resistor, but passes if it is done according to the scheme with a 0.1 Ohm shunt resistor.Yes, I disconnected all the wires for calibration CAL: CURR: MEAS AC, but I did not disconnect the sensor jumpers.Please do not forget that my instance has the J02 option! I have an Agilent 66332a without this option and it goes through full calibration without any problems.

author: little.tesla
author_rank: Regular Contributor
timestamp: October 20, 2022, 01:15:16 pm
content: This sounds weird with the negative current calibration. I can think of some options:- FW changed (compare the FW version of your J02 unit with the one without this option)- HW changed, maybe as a result of an option (even other than J02 and undocumented)- Something is brokenI think the negative current and AC calibration are independent of each other.For the AC calibration, did you bypass the resistor R353 (1R5) with a 0R1 Ohm? (R353 could have a different refdes in 66332A)During "normal" operation, do you have the 25 uF cap in series with a 0.25 Ohm resistor connected across the sense lines? Does it oscillate without it? If it oscillates, it would confirm that you have the same option J02 as in the 66312A.Another option would be to check the components which change for the J02 option.

author: Nanitamuscen
author_rank: Contributor
timestamp: October 20, 2022, 04:27:11 pm
content: Where is this resistor located? If on the A1 board, next to the u310 operational amplifier, then it has a completely different nominal value of 619k. Apparently, the resistor code in 662 is different.I will attach the service manual for the full picture.Yes, that's right, without a capacitor and a resistor, it oscillates with a frequency of 115 kHz and an amplitude of 2 V.Software versions in my blocks:Agilent 66332a A.01.03HP 66332A J02 A.00.03

author: little.tesla
author_rank: Regular Contributor
timestamp: October 21, 2022, 08:05:56 am
content: OK, the oscillation confirms that you have the J02 higher bandwidth option. The software versions are very different, the HP 66332A J02 has a very old version. This could explain the differences. Maybe somebody else can give some insights regarding differences in the software.I've attached below the relevant section from the schematic with the mentioned resistor R353 on the 66312A. It's expected that the value is different on the 66332A, since it's rated for a higher current.

author: Nanitamuscen
author_rank: Contributor
timestamp: October 21, 2022, 02:30:09 pm
content: Resistor r353 in my case is called r445 and has a value of 0.51 ohms. I'll try to bypass it with a 0.1 ohm resistor. Thanks.