I know, you can adjust "ALL" or "DC+OHMs" or "AC" separately...
But can you adjust only one specific range (maybe by reading calibration data and writing modified data back by IEEE)?
Problem is:
Some devices look very nice at first verification of DCV but for example OHMs is not very well, and after running ALL or DC+OHMs calibration, DCV is often no longer as nice as before (but still in tolerance). So I'd like to only correct specific cal data of the bad ranges, not to degrade the other ranges...
If you calibrate the 2000 over GPIB, it is possible to stop and save the constants after each section, for example you can calibrate only DC Volts, but not Ohms or Amps, or DC Volts and Ohms but not Amps and so on.
Cheers
Alex
Do you know the commands to read and write cal memory over GPIB?
Do you mean the STEP commands?
Is it possible to change the step's sequence or use only one specific step and leave the other steps out?
That's a good question, also to me. My K2k is spot on, except the ohms-range in 2- and 4-wire.
I have an other pretty new 34461a, and it would be enough for me, to match the K2K with it over the Front-Panel without destroying any other calibrations. So, i wont to sync the ohms as shown in Table 2-4. But only these manually over the front-panel, because i didn't own GPIB.
Knows someone whether that is possible or not?
My K2k is spot on, except the ohms-range in 2- and 4-wire.
... it would be enough for me, to match the K2K with it over the Front-Panel without destroying any other calibrations. So, i wont to sync the ohms as shown in Table 2-4. But only these manually over the front-panel, because i didn't own GPIB
As I understood front panel calibration you can select ALL, DC or AC adjustment, but even if you select DC or AC you have to do all DC or all AC steps. So you cannot adjust OHM ranges only without adjusting DC ranges using front panel adjustment.
I can use GPIB for adjustment, so I can try using single steps next monday, when I'm back in the lab.
So you cannot adjust OHM ranges only without adjusting DC ranges using front panel adjustment.
That's right. But maybe it's possible to
- confirm stored calibration values in DC-range, after that
- edit old calibrated values to my comparatively resistors?
I do not trust me there before ask someone, who knows the precise behaviour at this point.
You can print current cal values with :CAL:PROT:DATA? and you can also dump the contents of the EEPROM holding these constants.
TiN has a
page where he matched these printed constants with range and EEPROM position for a 2001, I suppose this would be similar for a 2000, too. Based on this info you could match the 2000 constants to EEPROM positions.
Then, even if you calibrate all the DC ranges for example, you could take the constants for only those ranges you wanted to change and combine it with the original dump (and update the checksum).
You can print current cal values with :CAL:PROT:DATA? and you can also dump the contents of the EEPROM holding these constants.
That's interesting, and maybe first third of my idea of reading out data, modifying and writing back.
So I hope this (undocumented?) command will also be accepted by K2000 instead of K2001.
Based on this info you could match the 2000 constants to EEPROM positions.
Then, even if you calibrate all the DC ranges for example, you could take the constants for only those ranges you wanted to change and combine it with the original dump (and update the checksum).
That's exactly I wanted to do, but how to write it back via GPIB? Couldn't find that info in TiN's article.
Low-level calibration must be run completely in order listed in SM, otherwise meter will become upset and reject new calculated values. That's why I couldn't calibrate 2001 before without actual 5700, even though I could run comprehensive cal for 2V/20V/20K/1Meg. But that does nothing for current ranges, so not enough
I'd say easiest for hobbyist is to read and decode calibration ROM format with constants (you can read floating values by :CAL:PROT:DATA? query over GPIB, but can't save to cal rom).
Calculate values, correct checksum and then write calibration ROM back to meter by external I2C programmer (I've used TL866 with sucess on my 2001s/2002, however I just read/wrote cal dumps when swapped analog boards between digital boards, didn't modify them).
But I doubt you get much improvement to justify the effort, as even if you leave meter run for few weeks, it will already drift few ppms here and there (still within specs), so it's bit much to expect ppm-level accuracy from 6.5d or 7.5d meter
Low-level calibration must be run completely in order listed in SM, otherwise meter will become upset and reject new calculated values. That's why I couldn't calibrate 2001 before without actual 5700, even though I could run comprehensive cal for 2V/20V/20K/1Meg. But that does nothing for current ranges, so not enough
I have two K2015 and run calibration on DCV only on both of them successfully over GPIB over a year ago. And I have to say that the pair did not drift more than 2-3ppm over the last year on the 10V range (for both polarities, relative to the Fluke 731B and to each other).
Cheers
Alex
Thanks, then maybe it is possible to adjust OHMs without DCV and DCI...
Thanks, then maybe it is possible to adjust OHMs without DCV and DCI...
AFAIK, no. You can adjust DCV and OHMs without DCI however. You can stop after each section, but it is not possible to omit previous sections.
Cheers
Alex
So I hope this (undocumented?) command will also be accepted by K2000 instead of K2001.
It worked on my K2000.
It also worked on our K2000:
-> :CAL:PROT:DATA?
<- 000000000000000,000000000065536,000000000131072,000000000262144,
+2.80139022E-02,+2.79885267E-01,+2.80409202E-02,+2.80206289E-01,+2.21998012E-04,+2.80265378E-02,+2.79947302E-01,+2.23955920E-04,
+2.80460661E-02,+2.80265575E-01,+2.79812724E-02,+1.95714865E-01,+2.21985116E-04,+2.81516577E-02,+2.81274673E-01,+1.44984279E-02,
+2.89400902E-01,+9.96900700E-01,+9.51774776E-01,+1.00000000E+03,+9.99992750E+02,+1.00000000E+01,-.00000000E+01,+1.00000000E+02,
+1.00004000E+03,+1.00003100E+04,+1.00003300E+05,+1.00005000E+06,+1.00000000E-02,+1.00000000E-01,+1.00000000E+00,+1.70665764E-06,
+1.42404839E-06,-1.49228284E-06,+1.44140224E+00,-1.44140690E+00,+1.44174146E-01,-1.44000000E-01,+3.91960805E-05,+2.31473738E-05,
+6.65775360E-06,+3.36417312E-06,+3.12786205E-06,+9.17295721E-02,+9.99932947E-01,-3.10369291E-06,-3.01380997E-06,-3.18616930E-06,
-3.21216084E-06,+2.63244887E-06,+1.41688556E-01,+1.41701498E-01,+1.41725512E-01,+1.41730279E+00,+9.17000000E-02,+7.21282856E-07,
+7.11801862E-07,+1.45795051E-02,+1.44722663E-03,+1.44661439E-02
I tried to completely skip the voltage steps, but on first resistance step an error message of Met/Cal appeared:
E566: Error Infomation from instrument on board 1 at IEEE-488 address 16: -200,"Execution error"
So it is correct, what Alex said:
If you calibrate the 2000 over GPIB, it is possible to stop and save the constants after each section, for example you can calibrate only DC Volts, but not Ohms or Amps, or DC Volts and Ohms but not Amps and so on.
After DC calibration step 1 (short circuit)
data changed:
-> :CAL:PROT:DATA?
<- 000000000000000,000000000065536,000000000131072,000000000262144,
+2.80139022E-02,+2.79885267E-01,+2.80409202E-02,+2.80206289E-01,+2.21998012E-04,+2.80265378E-02,+2.79947302E-01,+2.23955920E-04,
+2.80460661E-02,+2.80265575E-01,+2.79812724E-02,+1.95714865E-01,+2.21985116E-04,+2.81516577E-02,+2.81274673E-01,+1.44984279E-02,
+2.89400902E-01,+9.96900700E-01,+9.51774776E-01,+1.00000000E+03,+9.99992750E+02,+1.00000000E+01,-1.00000000E+01,+1.00000000E+02,
+1.00004000E+03,+1.00003100E+04,+1.00003300E+05,+1.00005000E+06,+1.00000000E-02,+1.00000000E-01,+1.00000000E+00,-1.80025973E-02,
+1.42404839E-06,-1.96618187E-06,+1.44140224E+00,-1.44140690E+00,+1.44174146E-01,-1.44000000E-01,+1.28192249E-03,+2.31473738E-05,
+8.03198807E-05,+4.33596652E-04,+1.80058006E-02,+9.17295721E-02,+9.99932947E-01,-1.18587169E-06,-3.01380997E-06,-1.68443618E-04,
-6.47645151E-04,+1.63911853E-02,+1.41688556E-01,+1.41701498E-01,+1.41725512E-01,+1.41730279E+00,+9.17000000E-02,+7.13192580E-07,
+7.04379845E-07,+1.45795051E-02,+1.44722663E-03,+1.44661439E-02
After repeated DC calibration
step 1 (short circuit, minor changes) +
step 2 (open circuit) data changed:
-> :CAL:PROT:DATA?
<- 000000000000000,000000000065536,000000000131072,000000000262144,
+2.80139022E-02,+2.79885267E-01,+2.80409202E-02,+2.80206289E-01,+2.21998012E-04,+2.80265378E-02,+2.79947302E-01,+2.23955920E-04,
+2.80460661E-02,+2.80265575E-01,+2.79812724E-02,+1.95714865E-01,+2.21985116E-04,+2.81516577E-02,+2.81274673E-01,+1.44984279E-02,
+2.89400902E-01,+9.96900700E-01,+9.51774776E-01,+1.00000000E+03,+9.99992750E+02,+1.00000000E+01,-1.00000000E+01,+1.00000000E+02,
+1.00004000E+03,+1.00003100E+04,+1.00003300E+05,+1.00005000E+06,+1.00000000E-02,+1.00000000E-01,+1.00000000E+00,-1.80025424E-02,
+1.42404839E-06,-1.90490749E-06,+1.44140224E+00,-1.44140690E+00,+1.44174146E-01,-1.44000000E-01,+1.80057645E-02,+2.31473738E-05,
+1.80057681E-02,+1.80057355E-02,+1.80057540E-02,+9.17295721E-02,+9.99890577E-01,-1.17139226E-06,-3.01380997E-06,-1.17101140E-06,
-1.17514280E-06,+1.80071211E-02,+1.41688556E-01,+1.41701498E-01,+1.41725512E-01,+1.41730279E+00,+9.17000000E-02,+7.42359147E-07,+7.30116279E-07,+1.45795051E-02,+1.44722663E-03,+1.44661439E-02
I better interrupt at this point. It's getting to complicated and time-consuming checking all changes after each additional step without an easy way to write back modified data for one specific range. Programming over I²C is no alternative for every-day-calibration-job.
BTW: What is going on at step 2 (open circuit) adjustment?
Step 1 (closed circuit) is clear, it is for offset correction.
Steps after step 2 are also clear, that's for gain correction.
But open circuit? I don't know...
Finally I managed to totally mess up DCV ranges...
Tried to adjust manually and via GPIB, without success.
Any idea to set it back to "default values"?
It looks like I need a programmer to try to reanimate that K2000 via I²C.
Any suggestions for a good value programmer?
Finally I managed to totally mess up DCV ranges...
Tried to adjust manually and via GPIB, without success.
That i've feared. You prevented me to make my k2k useless.
Thanks for that, even if it doesn't help you for now...
You prevented me to make my k2k useless.
So my posting wasn't senseless...