Fluke 8508A - Interconnections

8508A
Users Manual
Table 6-2. Adjustment Sequence
General Sequence for Full Instrument Adjustment
1
Enable Calibration
Enter Cal mode
Set rear panel calibration switch to ENABLE.
Access CALIBRATION menu .
HVlin Cal Corrects linearity of the 1 kV DC range. Performed only if required.
Adc Cal Analog to digital converter alignment. Performed only if required.
DCV Range Zeros and Range Gains (200 mV to 1 kV Ranges).
ACV Range Zeros, Range LF Gains and Range HF Gains (200 mV to 1 kV
Ranges).
DCI Range Zeros and Range Gains (200µA to 20A Ranges).
ACI Range Zeros and Range Gains (200µA to 20A Ranges).
Frequency Frequency counter cal at 1MHz
Ohms Range Zeros and Range Gains:
Ohms: 2 Ω to 2 GΩ Ranges, then LoI Ohms.
TruΩ: 2 Ω to 20 kΩ Ranges, then LoI TruΩ.
HiVΩ: 20 MΩ to 20 GΩ Ranges.
Exit Cal mode
NV input offsets
Quit the CALIBRATION menu.
Front & rear non-volatile input offset adjustments:
DCV, Ohms, TruΩ, HiVΩ (including LoI , 2 & 4-wire).
Set CAL DUE Set the date for the next adjustment
Disable Calibration Set rear panel calibration switch to DISABLE.
1. To meet user's need, just one range on one function can be adjusted.
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 adjusting the 2 GΩ and 20 GΩ resistance ranges the 1 GΩ 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 adjustment, refer to the resistance-measurements section of Chapter 3
Making Measurements for connection details.
The Fluke 8508A-7000K Calibration kit also contains two precision low-thermal emf
4-wire shorting devices for use when performing the non-volatile input offset adjustments
at the front and rear input terminals. These devices link the input terminals in the
following order: Input Lo to Input Hi to Sense Hi to Sense Lo. If these devices are not
available it is recommended that a U-shaped piece of thick bare copper wire be used to
link the terminals in the same manner.
6-12