Det-Tronics PIRVOLHV Volumetric Infrared Hydrocarbon Gas Process Monitor for Heavy Hydrocarbons - Manual (Page 12)

10 3 .1 95-8632
CaLIBRaTION
In the event the PIRVOLHV 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 mA, and does not require
application of span gas.
NOTE
Zero drift will be indicated by a constant offset in
one direction either above or below 4 mA. 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.
Calibration procedure
To perform a zero calibration of the PIRVOLHV, follow the
sequence described in Table 3.
NOTE
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 PIRTB with magnetic Cal Switch
is being used, this is accomplished by holding
the Cal Magnet near the side of the termination
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.
MIRROR ASSEMBLY
MIRRORS (2)
WINDOWS
ELECTRONICS ASSEMBLY
HYDROPHOBIC FILTER
SAMPLE DRAW CUP
UL APPROVED O-RINGS
C2032
Figure 12—PIRVOLHV Disassembly for Cleaning