RKI Instruments 35-3010RK-06-02 - Manual (Page 22)

18 • 35-3010RK-06-02 Sample-Draw Detector
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 oxygen and CO detector
applications and every 6 months for most infrared CO
2
applications. Unless experience in
a particular application dictates otherwise, RKI Instruments, Inc. recommends a
calibration frequency of every 3 months for the oxygen and CO detectors and every 6
months for the infrared CO
2
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 oxygen or CO detectors and
every 9 to 12 months is adequate for the infrared CO
2
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
oxygen and CO detectors and every 6 months for the infrared CO
2
detector.
Calibration, CO Detector
This section describes how to calibrate the CO detector 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 CO
2
in
nitrogen calibration cylinder, and a 3-gas calibration cylinder.
Preparing for Calibration
CAUTION: This procedure may cause alarms at the monitoring device. Take appropriate action
to avoid this, such as entering the calibration mode at the monitoring device.
1. Open the housing door.
2. Set a voltmeter to measure in the millivolt (mV) range. It will be used in the
calibration of the CO channel.
• When checking the mV output of the CO channel, plug the voltmeter leads into
the test points in the AMP 1 section of the main circuit board. Plug the positive
lead into the test point labeled CAL+1; plug the negative lead into the test point
labeled CAL-1.
3. Use the following formula to determine the correct test points output for the CO
calibrating sample.
Output (mV) = (calibrating sample/fullscale) X 400 + 100
For example, with a calibrating sample of 50 ppm CO and a fullscale setting of 300
ppm CO, the correct output for the CO test points is 166 mV.
166 (mV) = (50/300) X 400 +100