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Some steps in the following procedure involve the calibrator
outputs at lethal voltages. Use extreme care not to touch any
exposed conductors.
1. Warm up all equipment for the period specified in the manufacturer's manual.
The 720A and 752A should be allowed to "soak" in the lab environment for at
least 8 hours prior to use for best results.
2. Self calibrate the 720A and 752A in accordance with their instruction manuals.
3. Connect the equipment as shown in Figure 3-2
5440B
720A
Figure 3-2. DC Source Characterization Setup, Part 1
If the 845A( ) is not grounded through the power cord, a connection must
be made to the 5440B ground as shown.
4. Set the ratio dials of the 720A to represent the certified value of the 732A. (For
example, 10.000123 V becomes 1.0000123 on the 720A).
5. Set the 845A( ) to the 30 mV range and the OPR/ZERO switch to ZERO.
6. Set the 5440B to 11 V, OPERATE. Set the 845A( ) OPR/ZERO switch to OPR,
reducing the range switch until the largest on-scale reading is obtained. Edit the
5440B output until a null is indicated on the 845A( ). Again reduce the range
switch setting until the largest on-scale reading is obtained, editing the 5440B
output for a null. Repeat this procedure until you obtain a null of 1 V. Set the
845A( ) OPR/ZERO switch to ZERO. The 5440B/720A combination is now
calibrated in absolute voltage relative to the 732A.
For the remainder of this procedure, the 5700A EXT GUARD must be
selected (keycap LED lit), and the strap between V-GUARD and GROUND
must be removed.
X W Warning
845A( )
Note
Note
Calibration and Verification
Periodic Calibration
732A
elu017.eps
3
3-9
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