DH Instruments ADCS-601, Operation And Maintenance Manual

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ADCS-601™ OPERATION AND MAINTENANCE MANUAL
© 2005 DH Instruments, Inc. Page 152
7.3.4.2 PROCEDURE
Determining the offset of the PG7601 PRT relative to a reference requires a
calibrated temperature probe of adequate uncertainty at ambient temperature
(see Section 7.3.4.1) that can be inserted into the PG7601 mounting post
pressure bore (6.25 mm (< 1/4 in.) diameter bore).
To determine the offset of the PG7601 PRT relative to a reference, proceed as
follows:
Remove the PG7601 piston-cylinder module (see Section 6.6.1).
Press the [ESC] key on the PG7000 Terminal and then select [SPECIAL] ,
<7cal> , <4PCT> . This provides a display of current mounting post PRT
temperature reading, PRT resistance at 0ºC and RPT slope.
Insert the reference temperature probe (usually a PRT) in the the pressure
bore in the PG7601 mounting post (insert vertically, straight down from the
top of the mounting post). The mounting post bore diameter is 6.25 mm
(< 1/4 in.).
Wait 60 minutes for temperature stabilization.
Record the reading in ºC of the reference temperature probe and the
PG7000 Terminal every 15 seconds for 5 minutes. The 5 minutes may be
increased to correspond with a temperature cycle of the test environment if
the environment has a clear temperature cycle time.
Evaluate the results of the readings. If total temperature change of either
indication is greater than 0.05ºC, the temperature instability is too great and
the measurements should be repeated until total temperature change is less
than 0.05ºC.
Resume normal ADCS-601 operation:
Press [ESC] on the PG7601 until its main run screen appears.
Press [PAUSE] on the ADCS Main Tool Bar to resume normal ADCS-601
system operation.
7.3.4.3 CALCULATING AND UPDATING PISTON-CYLINDER
TEMPERATURE SENSOR INFORMATION
Piston-cylinder mounting post PRT information is element specific
metrological data. Uninformed or accidental altering of this information
may lead to out of tolerance measurements. Piston-cylinder module PRT
information should only be edited by qualified personnel as part of the
ADCS-601 calibration or recalibration process.
After performing the comparison process described in Section 7.3.4.3, the new
PRT offset must be calculated and entered.
Calculating the new PRT offset
Calculate the new PRT offset as follows:
Using the data obtained in the comparison process described in Section 7.3.4.3,
average the readings of the PG7601 PRT and average the readings of the
reference temperature probe.
Calculate the difference between the two following:
PG7601 avg. temp. [ºC] – reference avg. temp. [ºC] =
Δ
avg. temp [ºC]