Model IR400
23
4.3 HazardWatch Mode
The IR400 is compatible with the General Monitors HazardWatch System and can be calibrated
via the system interface for HazardWatch. To support calibrations initiated in HazardWatch, the
IR400 must be configured in the HazardWatch Mode. This mode prevents aborted calibrations
from being recorded as successful calibrations and ensures accurate logging in the
HazardWatch System.
To use this feature, purchase a HazardWatch-configured IR400 or change the mode via
Modbus. See the Modbus manual available from the General Monitors website for Modbus
commands.
4.4 Gas Check Mode
1.
Send Modbus or HART gas check command.
2. When the unit enters gas check mode, AO will be kept at 1.5 mA. Apply a 50% LEL gas
using a gas check kit with portable purge calibrator equipment.
•
NOTE:
If the manual solenoid calibration input is configured, send the Modbus
or HART command to turn on the solenoid.
3. Once the detector is placed in gas check mode and the gas is applied, monitor the % LEL
reading for the detector to see if it is functioning properly using the FMD or IR4000S
display or Modbus/HART commands. When the reading is stabilized, it should be 50%
LEL if the gas from the check kit is applied.
4. Remove
the
gas.
•
NOTE:
If the manual solenoid calibration input is configured, send the Modbus or HART
command to turn off the solenoid.
The unit will return to normal operation when the concentration drops below 5% full-scale.
Since the IR400 zeros before calibrating, you must remove the gas completely before going to
calibration mode.
4.5 Detector Response Time
A valid response time of a gas detector must take into account a static gas presence as it
occurs in the field with a gas leak. Tests performed on site use a flow method to verify detector
function only as gas enters the optical path, with its splashguard in place, slowly. With regard to
the specified time response stated on page 3 of the manual, this specification is obtained by
testing the gas detector, with a splashguard, in accordance with CSA performance
requirements. A chamber is filled with a known concentration of gas (static) and the IR400 is
then exposed to the gas. This method is defined by the approval agencies and allows us to fill
instantaneously the optical path of detector to achieve the stated response times for the IR400.
It is not practical to perform this type of test in the field since a potentially explosive gas (100%
LEL) is used.
T response times: According to CSA C22.2, T50 equals time to 50% of full-scale meaning 50%
LEL and T90 which is 90% of the final reading.
CSA C22.2 Section 6.9 states:
Beginning with the gas sensing element in clean air it shall be suddenly exposed to a prepared
mixture of gas in air having a concentration corresponding to 100% of the full scale gas
Summary of Contents for IR400
Page 2: ......
Page 15: ...Model IR400 11 Figure 5b IR400 Mounting Dimensions with a European Box ...
Page 20: ...Model IR400 16 Figure 7 Wiring Diagram from IR400 to Control Equipment ...
Page 41: ...Model IR400 37 9 6 Engineering Documentation ...
Page 45: ...Model IR400 HART Field Device Specification for Point IR Gas Detector ...
Page 78: ...Model IR400 Infrared Point Detector for Hydrocarbon Gas Applications Modbus programming guide ...