General Monitors IR400, Manual

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Model IR400
17
4.0 Operation and Configuration
The methods used to operate and configure the IR400 will vary depending on whether you are
using the IR400 as part of an IR4000M monitoring system, or as a stand-alone unit attached to
a junction box and control room devices, or to an IR4000S. Separate instructions are provided
in this chapter for each situation.
•
If your IR400 is part of an IR4000M system
, you can operate and configure both the IR400
and the IR4000 using the IR4000 menu options and LED display. You can also send
Modbus or HART commands to the IR4000 from connected control room devices, to
perform all the menu-driven functions, plus additional ones.
•
If your IR400 is a stand-alone unit attached to a junction box
, you can use the magnetic
switch attached to the junction box for zeroing and calibration. You can also send Modbus
or HART commands to the IR400 from control room devices to perform zero, calibration,
gas checks and configuration tasks.
•
If your IR400 is a stand-alone unit attached to an IR4000S display device
, then you can
use the IR4000S menus for operation and configuration.
•
NOTE: This chapter describes how to use the junction box magnetic switch for stand-
alone IR400 operation; the IR4000 manual describes how to use the IR4000 menus
for IR400 system operation and configuration.
4.1 Zeroing, Gas Check Tests, and Calibration
Each IR400 is calibrated at the factory. However they will need occasional zeroing as well as
gas check tests and calibration after initial installation to make sure they are working properly.
Before zeroing or calibration, always check that the optics path is clear and the windows are
clean. These are the most important operations to ensure that the IR400 is measuring
accurately.
Depending on your system configuration, you can use menus, Modbus/HART commands or
magnetic switch selection to initiate zeroing, gas checks and calibration, as described later in
this chapter. Some general guidelines are provided here that are useful no matter what method
is used.
•
NOTE: The IR400 is factory calibrated and needs no initial calibration. However, if the
unit is to be installed at altitudes greater than 1000 ft (308 m), it must be re-calibrated
on-site.
•
NOTE: Entering Gas Check, Zeroing, or Calibration mode sends a 1.5 mA output
signal that disables the IR4000M and IR4000S Warning and Alarm relay circuits.
4.1.1 Using Zero Air
If you suspect that combustible gasses are present, it is necessary to purge the sensor
environment with zero air before zeroing the unit, starting the gas check, or starting calibration.
4.1.2 Zeroing Guidelines
Zeroing the IR400 detector is necessary periodically in order to eliminate any background gas
fluctuations. You may wish to purge the sensor environment with zero air before zeroing the
unit.