Keysight Technologies 34959A Service Manual page 60

3 Calibration Procedures
–10 Vdc Adjustment Procedure (Optional)
The –10 Vdc calibration electronically enhances the Internal DMM's a-to-d
converter linearity characteristic. This adjustment should ONLY be performed
after servicing the A-to-D converter or replacement of the calibration RAM.
You will need an input test connector as described in
1 If a zero calibration has not been performed recently, perform one before
2 Configure the instrument as follows:
3 Measure and note the voltage offset present at the end of the measurement
4 Connect the input cable to the calibrator output and set the calibrator to
5 Perform a +10V dc gain calibration.
6 Send an adjustment to the instrument. The adjustment value is the sum of the
7 Reverse the cable connections to the calibrator to create a –10 Vdc voltage
8 Perform a –10V DC gain calibration. Be sure to allow time for thermal offsets
9 Send an adjustment to the instrument. The adjustment value is the sum of the
10 When the adjustment finishes, verify that new readings fall within ± 30 µV of
60
beginning this procedure (see
DC VOLTS
10 V range
6½ digits
INTEG 100 PLC
INPUT R > 10 G
cable by shorting the ends of the cable. Be sure to use a copper wire and allow
enough time for the residual thermal offset to stabilize (usually about 1 minute).
output +10V. Allow enough settling time for any thermal offset voltages to
stabilize (usually about 1 minute).
calibrator output and the measured offset (from step 3). For example, if the
calibrator output is 10.001 volts and the measured offset is 10 µV, send the
value +10.001010 volts. When the adjustment finishes, verify that new
readings fall within ±20 µV of the calibrator output plus the offset.
standard. You must physically reverse the cables. DO NOT switch the output
polarity of the calibrator.
to stabilize (usually about 1 minute).
calibrator output and the measured offset (from step 3). Using the previous
example values, enter 10 µV minus 10.001 volts or –10.000990 volts.
the calibrator output minus the offset.
page 56).
[SENSe:]VOLTage[:DC]:RANGe 10
[SENSe:]VOLTage[:DC]:NPLC 100
[SENSe:]VOLTage[:DC]:IMP:AUTO ON
"Input Connections" on page 46.
Keysight 34980A Service Guide