GMI PS500 Manual Del Usuario página 108

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PID SENSORS
A PID sensor measures volatile organic compounds (VOC's)
in the atmosphere by Photo Ionisation Detection. The PS500
instrument uses PID sensor technology to detect VOC's.
What is a Volatile Organic Compound (VOC)?
A VOC, is a chemical compound that is significantly
vaporised at ambient temperatures.
How can a VOC be measured?
A lamp, located inside the PID sensor, emits high energy
light causing the VOC to break down into positively and
negatively charged ions. The negatively charged ions can
be measured and are proportional to the concentration of
the VOC.
Maintenance and Cleaning of PID sensors
PID sensors require periodic maintenance and will
depend on the environment being measured.
When the measured VOC concentrations are low, monthly or
even less frequent maintenance maybe adequate.
P I D s e n s o r l a m p s c a n b e c l e a n e d a n d i n t e r n a l
components replaced. Refer to the PS500 Instruction Sheet
'PID sensor - maintenance and cleaning' (Part No. 66582)
for details.
A PID sensor must be calibrated after any cleaning or
maintenance procedure.
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