Fluke 5626/5628 - Manual (Page 12)

calibrated using a primary standard that has been calibrated in a primary
calibration laboratory using known intrinsic values.
2.3 Calibration
In order for any instrument to be used as a standard it must be calibrated.
The PRTs are calibrated in Hart Scientific's calibration laboratory and pro-
vided with a NIST traceable “Report of Calibration”.
At the time of purchase, the 5626 and 5628 are calibrated over their entire
range (–196°C to 660°C) at specified ITS-90 fixed points. Generally, a sec-
ondary PRT is calibrated by comparison method. All PRTs calibrated by Hart
Scientific are calibrated using standard calibration techniques.
2.4 Recalibration
The recalibration of the 5626/5628 Secondary PRT should be scheduled ac-
cording to the user’s company Quality Assurance requirements. Normally, a
PRT is recalibrated annually. Unless the PRT is used only over a limited
range, calibration over the full range of the PRT (–196°C to 661°C) is recom-
mended. For information on recalibrating your 5626 or 5628, contact Hart
Scientific’s Customer Service department for an RMA number and current
pricing (see Section , Before You Start).
Depending on the user’s Quality Assurance requirements, the PRT drift
should be checked periodically at the Triple Point of Water (TPW). Section
8,Troubleshooting, provides information on drift with respect to mechanical
shock and oxidation. If the R
tp
cannot be restored after annealing to within
calibration tolerances, a full recalibration should be scheduled.
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5626/5628
User’s Guide