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Normal
In the normal operating mode, the 4 to 20 milliampere
signal level corresponds to the detected gas
concentration. The PIRVOL continuously checks
for system faults or initiation of calibration, and
automatically changes to the appropriate mode.
Fault
Faults detected during warmup, normal operation, or
calibration are indicated by the current loop output as
shown in Table 1.
Calibration
The PIRVOL-LT is calibrated at the factory for
detection of methane. PIRVOL-VR is calibrated for
propane. No field calibration is required under normal
circumstances.
In the event the PIRVOL optics are fouled and
complete optics disassembly for cleaning is required,
device re-zeroing may be required after re-assembly.
Refer to the "Calibration" section for details.
A momentary connection of the calibration lead
wire to DC negative (common) of the power
supply initiates the zero and span calibration
sequence. When wiring the PIRVOL, use care
to isolate it from accidental contact with the
junction box and/or other conductors.
CORRECT
Figure 5—Recommended Orientation of PIRVOL Detector
4.1
NOTE
INCORRECT
INSTALLATION
DEVICE MOUNTING ORIENTaTION
It is highly recommended that the PIRVOL be installed
in the horizontal position. See Figure 5.
JUNCTION BOxES
The PIRVOL is designed to be threaded into a junction
box, which is then mounted to a solid, vibration-free
wall or post.
Det-Tronics offers two junction box styles for use
specifically with the PIRVOL:
• Tall Cover Model (junction box cover includes a
window). See Figure 6.
• Short Cover Model (junction box uses solid cover).
This junction box can also be used for detector
separation. See Figure 7.
GENERaL WIRING REqUIREMENTS
The wiring procedures in this manual are
intended to ensure proper functioning of the
device under normal conditions. However,
because of the many variations in wiring
codes and regulations, total compliance to
these ordinances cannot be guaranteed. Be
certain that all wiring complies with applicable
regulations relating to the installation of electrical
equipment in a hazardous area. If in doubt,
consult the authority having jurisdiction before
wiring the system.
The use of shielded cable in conduit or shielded
armored cable is recommended for optimum RFI/EMI
protection. In applications where the wiring cable
is installed in conduit, the conduit must not be used
for wiring to other electrical equipment. To assure
proper operation, the resistance of the connecting
wire must be within the specified limits. The maximum
distance between the PIRVOL and power source is
determined by the power supply capability and wire
size. See Figure 2 to determine the proper wire size
and maximum wiring distance allowed.
It is important that moisture not be allowed to come in
contact with the electrical connections of the system.
The use of proper piping techniques, breathers,
glands, and seals are required to prevent water
ingress and/or maintain the explosion-proof rating.
6
NOTE
95-8522
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