7. MAINTENANCE OF TRACEABILITY AND RECALIBRATION
Page 175
© 2007 DH Instruments, a Fluke Company
See Section 1.1 for ambient relative humidity sensor specifications.
7.5.5
TH PROBE ADJUSTMENT
7.5.5.1
TH PROBE TEMPERATURE SENSOR
PURPOSE
To view and adjust the output of the TH probe(s) temperature sensor.
OPERATION
In GFS Tools use [Tools], [Remote Communications] to set up communications
with the LCM and send the command “!KEY=15”. The LCM display will change
to show the output of the two TH probes (see Figure 112). Note that the output
of TH2 is indicated by “p1” on the LCM display, and TH 3 is indicated by “p2”.
A one point verification against a temperature reference is all that is needed.
If a full adjustment is desired, at least two points should be selected within the
range of the sensor and encompass the range of measurements the sensor may
encounter during normal operation.
To adjust the values of the Adder and/or the Multiplier use GFS Tools and select
the [Setup], [Calibration], <TH Probe #2> or <TH Probe #3> tab (see Figure 113)
to access a screen in which the values of the Adder and Multiplier can be edited.
Normally, only the Adder is adjusted. From here, press OK and wait while the
coefficients are uploaded to the LCM. When the upload is complete, cycle the
power on the LCM, and the LCM enclosure sensor reading should reflect the
newly applied calibration coefficients.
See
Section
7.5.4 for an explanation of Adders and Multipliers and their use in
adjusting internal sensors.
See Section 1.1 for TH probe sensor specifications.
1.
Current relative humidity reading of the first probe, TH
Probe #2.
2. Current temperature reading of the first probe, TH
Probe #2.
3.
Current relative humidity reading of the second probe,
TH Probe #3.
4.
Current temperature reading of the second probe, TH
Probe #3.
39.47% 22.41°C p1
38.99% 22.53°C p2
Figure 112: LCM TH probe front panel display