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Calibration Frequency
35-3010RKA-04H Sample-Draw Detector Head
Calibration Frequency
Although there is no particular calibration frequency that is correct for all applications, a
calibration frequency of every 3 months is adequate for most sample draw detector applications.
Unless experience in a particular application dictates otherwise, RKI Instruments, Inc.
recommends a calibration frequency of every 3 months for the sample draw detector.
If an application is not very demanding, for example detection in a clean, temperature controlled
environment, and calibration adjustments are minimal at calibration, then a calibration frequency
of every 6 months is adequate for the sample draw detector.
If the application is very demanding, for example if the environment is not well controlled, then
more frequent calibration than every 3 months may be necessary for the sample draw detector.
Calibration, Hydrogen Detector
This section describes how to calibrate the hydrogen sensor in the sample draw detector. It
includes procedures to prepare for calibration, set the zero reading, set the response reading, and
return to normal operation.
NOTE:
This procedure describes calibration using a demand flow regulator, a zero air
calibration cylinder, and a hydrogen calibration cylinder.
Preparing for Calibration
CAUTION:
This procedure may cause alarms at the controller. Take appropriate action to avoid
this, such as entering the calibration mode at the controller.
1. Open the housing door.
2. Set a voltmeter to measure in the millivolt (mV) range.
3. Plug the voltmeter into the test points on the LEL transmitter. Plug the positive lead into the
test point labeled
TP+
; plug the negative lead into the test point labeled
TP-
.
4. Use the following formula to determine the correct test points output for the calibrating
sample.
Output (mV) = (calibrating sample/fullscale) X 400 + 100
For example, with a calibrating sample of 50% LEL hydrogen and a fullscale setting of
100% LEL, the correct output for the LEL test points is 300 mV.
300 (mV) = (50/100) X 400 +100
