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UL APPROVED O-RINGS
MIRROR ASSEMBLY
CaLIBRaTION
In the event the PIRVOL optics are fouled and
complete dis-assembly is required for cleaning, a
zero calibration of the device may be required. This
procedure ensures the signal output level is at 4
milliamperes, and does not require application of span
gas.
Zero drift will be indicated by a constant
offset in one direction either above or below 4
milliamperes. The presence of background gas
would be indicated by a small but constantly
changing output.
IMPORTANT CALIBRATION NOTES
Ensure that the detector has been operating for
at least two hours before calibrating.
Do not open the explosion-proof enclosure
when power is applied to the system unless the
appropriate permits have been procured.
4.1
Figure 12—PIRVOL Disassembly for Cleaning
NOTE
SAMPLE DRAW CUP
WINDOWS
HYDROPHOBIC SCREEN
MIRRORS (2)
Calibration Procedure
To perform a zero calibration of the PIRVOL, follow the
sequence described in Table 3.
The calibration sequence is initiated by
momentarily connecting the calibration lead
to the negative lead (common) of the power
supply using either the Cal Magnet or an
external switch. If the Det-Tronics junction box
with magnetic Cal Switch is being used, this is
accomplished by holding the Cal Magnet near
the side of the junction box for one second. The
location of the Cal Switch is shown in Figure
10. An alternate way of accomplishing this is to
install a pushbutton switch between the yellow
lead and the power supply common.
Factory calibration is recommended for complete
device calibration. Contact Det-Tronics for additional
information.
11
ELECTRONICS ASSEMBLY
B2032
NOTE
95-8522
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