Detcon PI-700 0-500ppb - Manual (Page 10)

Model PI-700 0-500ppb
PI-700 0-500ppb Instruction Manual Rev. 0.0 Page 6 of 53
2.3 Sensor Contaminants and Interference
PID VOC and toxic gas sensors will respond to any gas with an ionization potential <10.6eV. This is not a
selective measurement technique, and hence can be used to measure a wide range of gases.
Some of the most commonly present gasses that potentially cause PID interference are listed in Table 2 Gas
Factor Table (refer to Section 9). The presence of cross-interference gases in an area does not preclude the
use of this sensor technology, although it is likely that the sensor will experience false high readings should
exposure occur.
Some heavy organic molecules may be polymerized onto, or strongly adhere to, the optical filter of the lamp.
When this occurs, the lamp will require cleaning or replacement.
Relative Response Gas Matrix
Table 2 Gas Factor Table shows the response of the PID sensor to a long list of components. It includes the
compound name, synonyms/abbreviations, and chemical formula. It also lists the 10.6eV Response Factor
(the measure of how strong the signal from the sensor is in reference to Isobutylene gas). Isobutylene gas is
the standard reference used with PID sensors, the lower the Response Factor, the stronger the signal.
2.4 Mounting Installation
The PI-700 sensor assembly is designed to be mounted on a flat surface. The assembly comes on a 13” X 14”
mounting plate and is ready to be mounted using 1/4” Bolts. A ¾”NPT Port is provided on the side of the
Mini Condulet for power and signal wiring. A 1/8” Tube fitting is provided for Sample Port gas entry. The
PI-700 should be vertically oriented so that the sensor points straight down.
AIR
FLOW
SPAN
PGM2
ZERO
PGM1
MODEL
PI-700
detcon inc.
VOC
14" 12.5"
11.5"
13"
3
4
" NPT Port
Ø0.265"
Mounting Holes
Aluminum
Condulet with
Pump
Mini
Condulet
with TPA
0-1LPM
Rotameter
PI-700 0-500ppb
Sensor Assembly
Sample Chamber
Sample
Port
Air Flow
Figure 7 Outline and Mounting Dimensions