5500A/EP Enhancement Package
Users Manual
8
Calibrating an Instrument
The DMMs specified in this manual can be adjusted and verified to traceable results, by
following the procedures in this manual. Essentially, there are two major steps to
Calibration, which are:
1.
Characterizing the 5500A.
Before you perform any calibration procedure with the 5500A/EP you must
characterize the 5500A’s outputs. The characterization procedure first performs a
zero calibration on the 5500A and an automatic calibration (AUTOCAL) on the
Hewlett Packard 3458A. After the calibration procedures are complete, the Hewlett
Packard 3458A is used to measure the 5500A’s actual output at cardinal points
defined by the UUT procedures. This data is stored in a correction file within
MET/CAL.
The characterization is valid for 24 hours as long as the temperature remains within
±
2
o
C and the humidity does not change more than
±
10% RH. For convenience, you
can run the characterization unattended overnight, and the characterization will be
valid for the next workday. Or start the characterization procedure at the beginning
of each workday.
2.
Adjusting and Verifying the DMM.
Once the characterization is complete, the DMM adjustment and verification
procedures can be performed, provided the MET/CAL procedures have been
installed and compiled on the PC. The MET/CAL program prompts you through the
connection process, allowing for a stabilization period to eliminate thermal emfs in
the system. It also automatically performs a zeroing operation on the 5500A.
Setting up the Equipment
The 5500A/EP is designed to work with the same hardware configuration for both the
characterization of the 5500A, and adjustment and verification of the DMM. The only
difference between the two setups is the use of a Hewlett Packard 3458A for
characterization. Once characterization is complete, you simply disconnect the Hewlett
Packard 3458A and replace it with the DMM you are calibrating, using the same
connections.
Find a location where you can permanently keep the setup. Your location must provide
space for the 5500A calibrator, room to place the switch accessory in front of the 5500A,
and ample room on top or preferably to the left of the 5500A to place the DMM or the
Hewlett Packard 3458A.
Note
When the switch accessory is in operation, high value resistances, which
are highly susceptible to noise pickup, are being sourced. The switch
accessory’s leads contain shielding, and an additional capacitive filter is
available to provide additional filtering. To minimize noise pickup, remain
at a distance of at least 0.5 meters from the switch accessory during
operation.
Warning
Hazardous Voltage may be present on any Input or Output
terminal of the 5500A/EP switch accessory. To avoid electrical
shock, do not use this accessory unless every lead is
terminated as shown in this manual.
