Interconnections - Fluke 8508A User Manual

It is recommended that the default resolutions are used for calibration purposes. Other
resolutions may be selected and calibration operations performed, but accuracy of
calibration will be degraded if calibration is performed in lower resolutions.
When in CAL mode with the CAL legend appearing on the main display,
the function of the SAMPLE key is modified from normal operation. If
pressed, the SAMPLE key will initiate a calibration operation and
permanently alter the instrument calibration state. To avoid accidental
mis-calibration do not attempt to operate the instrument in External
Trigger mode from the front panel when in Cal, and only press the
SAMPLE key when a calibration operation is intended to be performed.
Enable Calibration
Enter Cal mode
Adc Cal
DCV
ACV
Ohms
DCI
ACI
Frequency
Exit Cal mode
NV input offsets
Set CAL DUE
Disable Calibration
1. To meet user's need, just one range on one function can be calibrated.

Interconnections

The Fluke 8508A-7000K Calibration kit contains a specially designed lead set which
connects directly to the terminals of the 8508A, the 5720A, and the 5725A for the
purpose of 8508A calibration. It is recommended that this lead kit be used to avoid
introducing measurement errors due to interconnections and to duplicate the
configuration used by Fluke for 8508A calibration. Figure 6-1 shows the interconnections
used in detail. If alternate leads are substituted, make sure they are metrology grade leads,
and of adequate voltage and current ratings. Leads should be kept as short as possible,
constructed from low capacitance low leakage dielectric material (PTFE) with low
thermal emf terminations, and exactly duplicate the configuration and interconnections
shown.
When calibrating the 2 G and 20 G resistance ranges the 1 G standard resistor
supplied in the Fluke 8508A-7000K Calibration kit plugs directly into the 8508A front
input terminals, without any interconnecting leads. If alternate resistance standards are
used for resistance calibration, refer to the resistance-measurements section of Chapter 3
Making Measurements for connection details.
W Caution
Table 6-2. Calibration Sequence
General Sequence for Full Instrument Calibration
Set rear panel calibration switch to ENABLE.
Access CALIBRATION menu .
Analog to digital converter alignment. Performed only if required.
Range Zeros and Range Gains (200 mV to 1 kV Ranges).
Range Zeros, Range LF Gains and Range HF Gains (200 mV to 1 kV
Ranges).
Range Zeros and Range Gains:
Ohms: 2 to 2 G Ranges, then LoI Ohms.
Tru : 2 to 20 k Ranges, then LoI Tru .
HiV : 20 M to 20 G Ranges.
Range Zeros and Range Gains (200μA to 20A Ranges).
Range Zeros and Range Gains (200μA to 20A Ranges).
Frequency counter cal at 1MHz
Quit the CALIBRATION menu.
Front & rear non-volatile input offset adjustments:
DCV, Ohms, Tru , HiV (including LoI , 2 & 4-wire).
Set the date for the next external calibration
Set rear panel calibration switch to DISABLE.
Note
1
Calibration and Verification
Routine Calibration
6
6-11