Figure 8: calibration adapter, 0ppm 0ppr 0ppm 0ppp – ENMET AM-5150 User Manual

Page 14

AM-5150

ENMET Corporation

5.2 Calibration of the AM-5150

Sensor Purge: Prior to calibration some

MOS

(Metal Oxide Sensor) sensor should be purged. A sensor purge is performed to

clean the

MOS

sensor of molecules that may have settled on the sensor.

Press and hold the

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.

OTE

Software revision may cause variations of display output.

Figure 8: Calibration Adapter

Menu

Select

Sensor
Enclosure

Sensor

Gas Cylinder

Regulator

Humidifier

Calibration Cup

To Cal Cup

Top View of Humidifier

To Regulator

0ppm

0ppR

0ppm

0ppP