Keithley 2701, Service Manual

Page: 33 / 168

Model 2701 Service Manual Performance Verification 1-19
Follow these steps to verify DC voltage accuracy:
1. Connect the Model 7700 CH1 H and L INPUT terminals to the DC voltage calibrator as
shown in
Figure 1-8 .
NOTE Use shielded, low-thermal connections when testing the 100mV and 1V ranges to
avoid errors caused by noise or thermal effects. Connect the shield to the
calibrator’s output LO terminal.
Figure 1-8
Connections for Model 7700 DC volts verification
2. Install the Model 7700 in Slot 1 of the Model 2701, then turn on the power and allow
the unit to warm up for two hours before proceeding. Be sure the front panel INPUTS
switch is set to the REAR position.
3. Select the DC volts function by pressing the DCV key and set the Model 2701 to the
100mV range. Close Channel 1 by pressing the CLOSE key and then keying in 101.
4. Set the calibrator output to 0.00000mV DC and allow the reading to settle.
5. Enable the Model 2701 REL mode. Leave REL enabled for the remainder of the DC
volts verification tests.
6. Source positive and negative and full-scale voltages for each of the ranges listed in
Table 1-9 . For each voltage setting, be sure that the reading is within stated limits.
7. Press the OPEN key to open Channel 1.
Table 1-9
Plug-in module DCV reading limits
Range Applied DC voltage* Reading limits (1 year, 18° to 28°C)
100mV
1V
10V
100V
1000V 100.0000mV
1.000000V
10.00000V
100.0000V
300.000V 99.9935 to 100.0065mV
0.999963 to 1.000037V
9.99965 to 10.00035V
99.9946 to 100.0054V
299.976 to 300.024V
*Source positive and negative values for each range.
H L H L
AMPS
H L H L H L H L H L H L
LO
CH21 CH22 CH11 CH12 CH13 CH14 CH15 CH16
H L H L H L H L
CH17 CH18 CH19 CH20
SENSE
(OHMS, 4 WIRE)
INPUT
(V, 2 WIRE)
H L H L H L H L
CH7 CH8 CH9 CH10
H L H L H L H L
H L H L H L H L
INPUT SENSE CH1
CH2 CH3
CH4
CH5
CH6
CH1
Output HI
Output
LO
Calibrator (Output DC Voltage)
Note: Use shielded, low-thermal cables
for 100mV and 1V ranges.
Model 7700