Fluke 8588A Operator's Manual page 74

8588A/8558A
Operators Manual
4-wire PRT uses True Ohms so zeroing is not required.
Connect the PRT probe to the Product in the same way as when making
resistance measurements, using the appropriate connection shown in Figure 19.
Select the corresponding 2-, 3-, or 4-wire probe type using the (Probe)
softkey. Fluke Calibration recommends that Ext. Guard is ON (, 
(Ext. Guard)).
The 3-wire PRT connection is actually a 4-wire measurement, and
requires a short between the low terminals as depicted in Figure 19.
70
Note
Figure 19. PRT Connections
Note
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