Figure 6-1
- Using Calibration Gas
22 • MRLDS-250 Infrared Gas Detector I&O Manual
026-1315 Rev 4
6.4.
Adjustment Using
Calibration Gas
Adjustment Using Calibration Gas requires a gas
cylinder with the appropriate gas and concentration.
Note that a calibration kit if offered that consists of a
calibration gas cylinder and a flow regulation valve
with flexible non-absorbent tubing.
NOTE: For improved accuracy
and response, the gas detector
should be protected from excess
drafts while performing the
adjustment. Excess air circulation
may dilute the applied calibration gas and lead
to a lower than expected response.
Step
Adjustment Using Calibration
Gas Cylinders
1
Connect the regulator to the test gas
port using 3 mm or 1/8” inside
diameter tubing.
Table 6-2
- Bump Testing
2
Enable parameter
P.-17
Gas Test
Mode (see
Section 5,
Configure the
Gas Detector
). When enabled, the
display continuously cycles through
the following:
• CAL is displayed briefly.
• Next, the gas group number or gas
type (based on product code) is
displayed.
• Then four dashes (----) are
displayed.
After gas is applied and the 75 PPM
squelch level is exceeded, the live
concentration replaces the four
dashes.
NOTE
: The analog outputs, relay
activity, and RS-485 ppm
reporting are suspended in Gas Test
Mode to prevent false alarms.
3
Expose the gas detector to gas from
the cylinder. Monitor the 4-digit LED
display reading.
4
Wait for the PPM reading to stabilize.
This should take approximately 4-6
minutes. Minor changes (less than 5
PPM in 10 seconds) are considered
stable readings. Compare the
response value with the calibration
gas concentration.
5
Adjust the gas detector displayed
value by using the UP or DOWN
buttons to increase or decrease the
value shown. Adjust until the reading
is within ± 2% of the calibration gas.
For example, if the calibration gas is
1000 PPM, the gas detector is
adjusted properly when the displayed
reading is between 980 and 1020
PPM.
6
Press the Enter button to store the
new adjustment. Turn off the
calibration gas and remove the tubing
from the calibration port. If no further
changes to the other Parameters are
required, press and hold the
information button for 5 seconds to
exit the Parameter list.
Step
Adjustment Using Calibration
Gas Cylinders
Table 6-2
- Bump Testing
