Figure 6: calibration adapter – ENMET PID-Guard User Manual
Page 14
PID-G
UARD
ENMET Corporation
12
5.2.3 Gas Span Calibration
It is recommended that the Zero Function be performed first.
Do not perform a calibration unless span gas is applied to sensor. Calibration can be aborted by pressing and holding the
M
ENU
button for 3 – 4 seconds.
Calibration is the process of setting the instrument up to read accurately when exposed to a target gas. The Zero function sets
the clean air reference point and the Span function sets the sensitivity of the instrument.
Initial Calibration:
Wait 3 – 4 hours after initially supplying power to the
PID-G
UARD
instrument before initial calibration.
The
PID-G
UARD
has been precalibrated at the factory, and initial field calibration should result in only fine tuning to circuit, as
well as a way to check that installation is successful. It is not necessary to open the enclosure to make adjustment. The
calibration functions are operated with pushbuttons from outside the enclosure through the
MENU
and
SELECT
switches.
Calibration Zero and Span functions are two separate procedures. They operate independently of each other. It is
recommended that the Zero procedure be done prior to the Span procedure.
ENMET
Corporation recommends at least quarterly calibration of the
PID-G
UARD
instrument.
Calibration equipment is available from
ENMET
Corporation to calibrate the
PID-G
UARD
instrument.
•Calibration adapter, a length of tubing with a regulator for the gas cylinder on one end, and a quick release fitting to connect
to the sample input of the
PID-G
UARD
on the other.
•Gas cylinder, Zero gas 20.9% oxygen or Span gas, typically 10ppm Isobutylene
Generally, a cylinder of 20.9% Oxygen is used to provide a Zero point or fresh air reference for the calibration.
A cylinder of calibration gas is used to provide the Span reference point for calibration. Calibration and Span point varies
depending on target gas and range of instrument, if necessary see special calibration addendum.
Figure 6: Calibration Adapter
Input Port Fitting
Gas Cylinder
Calibration adapter
Output Port Fitting
Menu
Select