Keithley SourceMeter 3A 2420, Service Manual

Page: 39 / 136

Calibration 2-9
7. Press ENTER. The Model 2420 will 200mV and simultaneously display the fol-
lowing:
DMM RDG: +200.0000mV
Use
, , , ,
ENTER, or EXIT.
8. Note and record the DMM reading, and then adjust the Model 2420 display to agree
exactly with the actual DMM reading. Use the up and down arrow keys to select the digit
value, and use the left and right arrow keys to choose the digit position (or use the num-
ber keys, 0-9, +/-). Note that the display adjustment range is within ±10% of the present
range.
9. After adjusting the display to agree with the DMM reading, press ENTER. The instru-
ment will then display the following:
V-CAL
Press ENTER to 000.00mV
10. Press ENTER. The Model 2420 will source 0mV and at the same time display the following:
DMM RDG: +000.0000mV
Use
, , ,
,ENTER, or EXIT.
11. Note and record the DMM reading, and then adjust the Model 2420 display to agree with
the actual DMM reading. Note that the display value adjustment limits are within ±1%
of the present range.
12. After adjusting the display value to agree with the DMM reading, press ENTER. The
unit will then display the following:
V-CAL
Press ENTER to Output -200.00mV
13. Press ENTER. The Model 2420 will source -200mV and display the following:
DMM RDG: -200.0000mV
Use
, , ,
, ENTER, or EXIT.
14. Note and record the DMM reading, and then adjust the Model 2420 display to agree with the
DMM reading. Again, the maximum display adjustment is within ± 10% of the present
range.
15. After adjusting the display value to agree with the DMM reading, press ENTER and note
that the instrument displays:
V-CAL
Press ENTER to Output -000.00mV
16. Press ENTER The Model 2420 will source -0mV and simultaneously display the following:
DMM RDG: +000.0000mV
Use
, , , ,
ENTER or EXIT.
17. Note and record the DMM reading, and then adjust the display to agree with the DMM
reading. Once again, the maximum adjustment is within ±1% of the present range.
18. After adjusting the display to agree with the DMM reading, press ENTER to complete
calibration of the present range.
19. Press EXIT to return to normal display, and then select the 2V source range. Repeat steps
2 through 18 for the 2V range.
20. After calibrating the 2V range, repeat the entire procedure for the 20V and 60V ranges
using Table 2-3 as a guide. Be sure to select the appropriate source range with the EDIT
and RANGE keys before calibrating each range.
21. Press EXIT as necessary to return to normal display.