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Feature #955

Updated by tin about 6 years ago

Using Keithley 2001 K7 unit 
 Room temp: 24.3°C (HEL-700 RTD set to 999.999 ohm on same Keithley unit) 
 20V Range : ±18ppm + 8 counts (Keithley 2001) + absolute ± 100ppm from Tektronix Cal lab. 
 10V : ±18ppm + 8 counts (Keithley 2001) + absolute ± 54ppm from Tektronix Cal lab. 
 2V Range : ±18ppm + 4 counts (Keithley 2001) + absolute ± 13ppm from Tektronix Cal lab. 
 200mV Range : ±25ppm + 12 counts (Keithley 2001) + absolute ± 2.1ppm from Tektronix Cal lab. 

 8/FEB/2014 

 h2. Initial cal 

 1. Zener voltage 1557 - adjustment R1 to set zener voltage. Must be within 100uV 
  
 |            |Temperature     |Zener voltage Vz| Zener current Iz| D ppm    | Meas uncertainty                          | 
 |Label       | 23 to 25C      |    6.1698 V        |    7.5 mA ?         |          |                                           | 
 |Measured    | 24.3 C         |    6.169113 V      | Not measured      | -111.3 | ±18ppm + 8 counts & absolute ± 100ppm     | 
 |Adjusted    | 24.3 C         |    6.169801 V      | Not measured      |    0.16    | ±18ppm + 8 counts & absolute ± 100ppm     | 

 2. Adjust R2 for zero offset, all decades set to zero, DVM on output terminals (local sense) 

 |Measured Vos    | 24.3 C         |     -0.01629 mV     | 
 |Adjusted        | 24.3 C         |     -0.00203 mV     | 

 2A. Adjust R2a for sense "0" offset. Set all decades to zero, polarity to plus, range 10V. 
 Remove sense link from Black (LO) terminals and measure black terminals. Adjust to be less than 1 mV 

 |Measured Vszo | 24.3 C         |     0.81512 mV    | 
 |Adjusted        | 24.3 C         |    -0.00101 mV    | 

 3. Adjust R3 to set feedback current accurately as required for accurate Vout 

 Dial 1V on second decade, using 10 position. DVM on output terminals, output read as 1.0000 +- 50uV 

 |Measured Voi    | 24.3 C         |    0.9998574       | -142.6 ppm | 
 |Adjusted        | 24.3 C         |    1.0000004 V     | 0.4 ppm      | 

 h2. 4. Linearity adjustment of 1st decade 

 Set setting same as step 3. Set 2nd decade to zero. 

 5. Set 2V on 1st decade. Adjust P2 pot to output. Set 1V on 1st decade, adjust P1 to 1V. 
 Vc - after initial cal settings done. 

 |Measured 2V     | 24.3 C         |     1.9997686      | -115,7 ppm | 
 |Measured 2Vc    | 24.5 C         |     2.0000546      |     27,3 ppm | 
 |Adjusted        | 24.5 C         |     1.9999995      |      0,3 ppm | 
 |Measured 1V     | 24.5 C         |     0.9998835      | -116,5 ppm | 
 |Measured 1Vc    | 24.5 C         |     1.0000144      |     14,4 ppm | 
 |Adjusted        | 24.5 C         |     1.0000001      |      0,1 ppm | 

 6. Set 4V on 1st decade to adjust P4. Set 3V to tweak P4. 

 |Measured 4V     | 24.5 C         |     3.999532       |    -117    ppm | 
 |Measured 4Vc    | 24.5 C         |     4.000046       |     11,5 ppm | 
 |Adjusted        | 24.5 C         |     4.000003       |     0,75 ppm | 
 |Measured 3V     | 24.5 C         |     2.999645       | -118.3 ppm | 
 |Measured 3Vc    | 24.5 C         |     3.000038       |     12.7 ppm | 
 |Adjusted        | 24.5 C         |     2.999994       |      -2 ppm    | 

 7. Set 6V on 1st decade to adjust P6. Set 5V to tweak P6. 

 |Measured 6V     | 24.4 C         |     5.999280       | -120 ppm     | 
 |Measured 6Vc    | 24.5 C         |     6.000030       |      5 ppm     | 
 |Adjusted        | 24.4 C         |     6.000007       |    1,2 ppm     | 
 |Measured 5V     | 24.4 C         |     4.999398       | -120 ppm     | 
 |Measured 5Vc    | 24.5 C         |     5.000027       |    5,4 ppm     | 
 |Adjusted        | 24.4 C         |     5.000003       |    0,6 ppm     | 

 8. Set 8V on 1st decade to adjust P8. Set 7V to tweak P8. 

 |Measured 8V     | 24.4 C         |     7.999022       | -122,3 ppm | 
 |Measured 8Vc    | 24.5 C         |     8.000021       |      2,6 ppm | 
 |Adjusted        | 24.4 C         |     8.000002       |      0,3 ppm | 
 |Measured 7V     | 24.4 C         |     6.999138       | -123,1 ppm | 
 |Measured 7Vc    | 24.5 C         |     7.000018       |      2,5 ppm | 
 |Adjusted        | 24.4 C         |     7.000001       |      0,2 ppm | 

 9. Set 10V on 1st decade to adjust P10. Set 9V to tweak P10. 

 |Measured 10V    | 24.4 C         |     9.998775       |    -122,5 ppm | 
 |Measured 10Vc | 24.6 C         |    10.000050       |        5 ppm    | 
 |Adjusted        | 24.6 C         |    10.000002       |      0,2 ppm    | 
 |Measured 9V     | 24.4 C         |     8.998888       |    -123,5 ppm | 
 |Measured 9Vc    | 24.6 C         |     9.000053       |      5,9 ppm    | 
 |Adjusted        | 24.6 C         |     9.000001       |      0,1 ppm    | 

 h2. Range set to 100mV 

 Set setting same as step 3. Set decades to zero. 

 5. Set 20mV on 1st decade. Adjust P4 pot to output.  

 |Measured 20mV | 24.4 C         |     19.99800       | -100 ppm | 
 |Measured 20mVc| 24.7 C         |     19.99994       |     -3 ppm | 
 |Adjusted        | 24.7 C         |     19.99998       |     -1 ppm | 

 6. Set 40mV on 1st decade to check 

 |Measured 40mV| 24.4 C         |     39.99562       | 
 |Adjusted       | 24.7 C         |     39.99952       | 

 7. Set 60mV on 1st decade to check 

 |Measured 60mV| 24.4 C         |     59.99295       | 
 |Adjusted       | 24.7 C         |     59.99938       | 

 8. Set 80mV on 1st decade to check 

 |Measured 80mV| 24.4 C         |     79.99011       | 
 |Adjusted       | 24.7 C         |     79.99916       | 

 9. Set 100mV on 1st decade to check 

 |Measured 100mV| 24.4 C        |     99.98775       | -122,5 ppm | 
 |Adjusted        | 24.7 C        |     99.99878       |    -12,2 ppm | 

 h2. Range set to 10mV 

 5. Set 2mV on 1st decade. 

 |Measured 2mV | 24.4 C         |     1.99891        | -545 ppm | 
 |Adjusted       | 24.7 C         |     1.99926        | -370 ppm | 

 6. Set 4mV on 1st decade to check 

 |Measured 4mV| 24.4 C         |     3.99777        | 
 |Adjusted      | 24.7 C         |     3.99837        | 

 7. Set 6mV on 1st decade to check              

 |Measured 6mV| 24.4 C         |     5.99670        | 
 |Adjusted      | 24.7 C         |     5.99758        | 

 8. Set 8mV on 1st decade to check              

 |Measured 8mV| 24.4 C         |     7.99581        | 
 |Adjusted      | 24.7 C         |     7.99631        | 

 9. Set 10mV on 1st decade to check             

 |Measured 10mV| 24.4 C        |     9.99467        |    -533 ppm    | 
 |Adjusted       | 24.7 C        |     9.99544        |    -456 ppm    | 

 Measured means before calibration 
 Adjusted - after calibration 

 --- 

 Perf log, 4-wire connect 

 |              |KI2001 Cal, 8.FEB.14|KI2002 2TC, 21.2, 16.MAR14| 
 |10Vrng, 0V    |    -0.00203 mV    2030 |    0.000477 mV     477         | 
 |10Vrng, 1V    |    1.0000001 V    0.1    |    1.00000936 V    9.36        | 
 |10Vrng, 2V    |    1.9999995 V    0.3    |    2.00001817 V    9.1         | 
 |10Vrng, 3V    |    2.999994 V    -2      |    3.0000062 V     2           | 
 |10Vrng, 4V    |    4.000003 V    0.75    |    4.0000161 V     4           | 
 |10Vrng, 5V    |    5.000003 V    0.6     |    5.0000156 V     3.12        | 
 |10Vrng, 6V    |    6.000007 V    1.2     |    6.0000224 V     3.73        | 
 |10Vrng, 7V    |    7.000001 V    0.2     |    7.0000183 V     2.61        | 
 |10Vrng, 8V    |    8.000002 V    0.3     |    8.0000277 V     3.46        | 
 |10Vrng, 9V    |    9.000001 V    0.1     |    9.0000222 V     2.47        | 
 |10Vrng,10V    | 10.000002 V    0.2     | 10.0000374 V     3.74        | 

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