AM-5150
ENMET Corporation
17
5.3.1 Sensor Replacement Calibration
Sensor Purge:
Prior to calibration some
MOS
(Metal Oxide Sensor) sensor should be purged. A sensor purge is preformed to
clean the
MOS
sensor of molecules that may have settled on the sensor.
Press and hold the
S
ELECT
switch, 3 to 5 seconds, if the purge feature is operational 0ppP appears in the display. If the
AM-
5150-MOS
is equipped with the purge feature, the display will alternate between 0ppm and 0ppP and the green Power/Fault
LED will flash.
Example of purge display
In approximately 2 minutes the purge function will be completed and the display will, alternate between 0ppm and 0ppR
indicating the instrument is in recovery mode. Recovery mode lasts approximately 5 minutes.
Example of purge recovery display
When the purge cycle is complete, the display will become stable at 0ppm and the green Power/Fault LED will stop flashing.
Calibration is the process of setting the instrument up to read accurately when exposed to the target gas. The Zero function sets
the clean air reference point and the Span function sets the sensitivity of the instrument.
Initial Calibration:
Wait at least 3 – 4 hours after initially supplying power to the
AM-5150
instrument before initial
calibration, overnight is preferred. The
AM-5150
has been pre-calibrated 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
AM-5150
instrument.
Calibration equipment is available from
ENMET
Corporation to calibrate the
AM-5150
instrument.
•
Calibration adapter, a length of tubing with a regulator for the gas cylinder on one end, and a calibration cup to connect to
the sensor of the
AM-5150
on the other.
•
Gas cylinder, Zero gas 20.9% oxygen or Span gas, factory determined, varies by intent.
Generally, a cylinder of 20.9% Oxygen is used to provide a Zero point or fresh air reference for the calibration.
N
OTE
:
Software revision may cause variations of display output.
After entering the Maintenance menu, press and hold the
M
ENU
button for 2-4 seconds while viewing the Zero menu.
After 2-4 seconds, an F will appear on the far right hand side of the display. The F indicates that the instrument is in Factory
mode.
Perform the calibration Zero and Span procedures as outlined in Section 5.2. Be sure that the F is present when selecting the
Zero and Span functions.
The Factory calibration sets a calibration window for future standard instrument calibrations.
0ppm
0ppR
0ppm
0ppP
