ENMET EX-5150-MOS - Manual (Page 13)

EX-5150-MOS ENMET Corporation
11
5.2.1 Zero Adjust
A ZERO function should be performed only when the EX-5150-MOS sensor/transmitter is exposed to fresh air. If the air at
the sensor is in question, use a cylinder of 20.9% oxygen to provide a clean air reference. Attach the cylinder to the calibration
adapter, fill the humidifier bowl halfway with water and allow gas to flow over the sensor for 3 – 4 minutes.
Enter the maintenance menu by placing the magnet over M ENU switch for 2 to 4 seconds. See Figure 5, EX-5150-MOS
Maintenance Menu flow chart.
The second menu available is the Zero.
Tap the S ELECT switch to perform a Zero.
If the Zero is successful, Cal OK appears on the display and in 1 – 2 seconds, display will change to Span.
If you wish to Span the sensor Tap the
S ELECT switch you are now ready to apply gas. Proceed to gas span step 2
If you wish to Exit the maintenance menu, Tap M ENU switch until Exit is displayed, then tap S ELECT switch to return to
the instrument Normal Gas Display
If the Zero is Not successful, sensor is outside of safe parameters to be zeroed, the display will read Bad Zero. Repeat
Section 5.2.1 Zero Adjust making sure to use a cylinder of 20.9% Oxygen.
5.2.2 Gas Span
It is recommended that the Zero Function be performed first.
Enter the maintenance menu. See Figure 5, EX-5150-MOS Maintenance Menu flow chart.
1. Tap the M ENU switch once to show Span on the display.
2. Tap the S ELECT switch to perform a Span procedure. The display will alternate between the calibration gas concentration
and a signal level.
3. Attach the associated calibration gas cylinder to the regulator and calibration cover. See to Figure 3.
4. Open the valve to apply the calibration gas to the sensor.
5. Watch for the signal level to stabilize. Refer to Table 4 for typical response times.
6. Once the signal level has stabilized, the EX-5150-MOS will automatically lock in the calibration data and:
If the Span is successful, Cal OK appears on the display momentarily, then advances to Alarm 1. Remove calibration
gas. To exit maintenance menu tap the
M ENU switch until Exit appears, then tap the S ELECT switch.
If the sensor is outside of acceptable parameters, Bad Span is displayed momentarily, then returns to Span.
Remove calibration gas. Tap the
M ENU switch until Exit appears, then tap the S ELECT switch. Check span gas and
repeat calibration in 30 – 60 minutes.
If the sensor did not respond to gas, Same mV is displayed momentarily, then returns to Span.
Remove calibration gas, tap the M ENU switch until Exit appears, then tap the S ELECT switch and try calibration
again in 30-60 minutes.
If the sensor will not calibrate See Section 5.4.
N OTE : Some software revisions require the S ELECT switch be tapped to accept the signal.
7. Calibration is complete.
Table 2: Calibration Time
Sensor Type Calibration Gas Concentration Calibration Gas Application Time
MOS PPM 3 – 4 minutes
MOS % LEL 1 – 2 minutes
5.2.3 Exit Maintenance Menu
Exit maintenance, by tapping on the M ENU switch until Exit appears on the display. Tap the S ELECT switch to return to the
instrument Normal Gas Display.
N OTE : You can change the Calibration Gas Level. H OLD the magnet over the S ELECT switch for 2 – 4 seconds
The M ENU switch changes digit indicated by underscore cursor
The S ELECT switch locks underscored digit and moves to next digit