Macurco RD-xx User Manual
REV – 2.1
[34-2900-0511-7 ]
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Figure 7-1 Calibration Connection
4.
Turn on the regulator to start the gas flow and wait with the gas applied continuously.
5.
When the gas concentration reaches 1000ppm the display will flash back and forth between “FAn” and ALr (if both
Alarm Relay and Fan Relay are activated). Note: If the Fan relay does not change state within 5 minutes, there are four
possibilities:
a.
The gas cylinder is empty, check the pressure gauge. Replace the gas cylinder if 25psi or less.
b.
The detector has fan relay delay set to 3 or more minutes. Set fan relay to 0 minutes and repeat the test.
c.
The detector needs field calibration or servicing (return unit to the factory for servicing).
6.
Remove the gas from the sensor. Proceed to Test the Alarm relay or replace the top cover. Fan relay test is complete.
7.4.3
Testing the Alarm Relay
1.
Connect the 1200ppm cylinder of Refrigerant to the regulator.
2.
Check the pressure gauge. If there is 25psi or less the cylinder should be replaced.
3.
Place the test hood over the gas sensor. Turn on the regulator to start the gas flow.
4.
Fan relay should activate according to the Fan Relay delay settings.
5.
When the gas concentration reaches the Alarm Relay setting, (i.e. 1000ppm) the display will flash “ALr”. The buzzer will
sound indicating “Alarm” if the buzzer is turned “On”.
Note: If the Alarm relay fails to operate within 5 minutes, there are three possibilities:
a.
The gas cylinder is empty, check the pressure gauge. Replace the gas cylinder if 25-psi or less.
b.
The detector needs field calibration or servicing (return unit to the factory for servicing).
6.
Remove the gas from the sensor after Test. Proceed to Test the 4-20mA output or replace the top cover. Alarm relay
test is complete.
7.4.4
Testing the 4-20mA loop
1.
Connect the 1200ppm cylinder of Refrigerant to the regulator.
2.
Check the pressure gauge. If there is 25-psi or less the cylinder should be replaced.
3.
Place the test hood from the regulator over the gas sensor. Turn on the regulator to start the gas flow.
4.
The Fan relay should activate according to the Fan Relay Delay settings.
5.
The Alarm relay should activate if reading is above 1000ppm.
6.
The 4-20 mA output should output 4mA in clean air and 20mA when in Alarm.
Note: If the 4-20mA output does not change within 5 minutes, there are three possibilities:
a.
The gas cylinder is empty, check the pressure gauge. Replace the gas cylinder if 25-psi or less.
b.
The detector has 4-20 mA option set to “OFF”. Set 4-20mA option to “bAS or EnH” and repeat the test.
c.
The detector needs field calibration or servicing (return unit to the factory for servicing).
7.
Remove the gas from the sensor. Re-assemble the RD-xx (make sure the LED is aligned with the front case hole). 4-20
current loop test is complete.
7.5
Field Calibration Procedure
Note:
For optimum calibration results, the unit should be in clean air, in a low ambient air flow and have uninterrupted power
for 7 days.
RD-xx has “CAL” top level menu that can be used to perform field calibration. ‘tSC’, ‘Spn’ and ‘End’ are sub-menu within “CAL”
menu. ‘tSC’ is read only menu and represents the time since last calibration. If you enter this sub-menu, it will display value in
format Y.MM. “MM” are for months and “Y” for year. E.g. if the value is 0.05 then it has been 5 months since the unit was last
calibrated. ‘Spn’ sub-menu is used during field calibration procedure as described in following procedure. ‘End’ sub-menu is
used to exit out of ‘CAL’ menu.
