XTC601 User’s Manual
Michell Instruments
31
CALIBRATION
3.4
Calibration Pressure / Flow Rate
General Purpose units:
•
Sample Inlet Pressure: Constant from 0 to 2 barg (0 to 29 psig)
•
Sample Flow Rate: Stable from 100 to 500 ml/min (0.25 to 1.0 scfh)
Ex or GP units with flame arrestors:
•
Sample Inlet Pressure: 50 to 350 mbarg (0.5 to 5 psig)
•
Sample Flow Rate: 270 to 330 ml/min (0.57 to 0.7 scfh)
3.5
1-Point Calibration
This is a single point offset overlaid on top of the factory calibration. It is designed to
correct minor drift and minor changes during transit. This calibration makes the unit
very accurate at the calibration point and improves accuracy throughout the range.
The calibration gas should be of a value that is within the main area of interest.
Example: if main points of interest for a 0–25% range instrument are around the 6%
area then a suitable calibration gas to apply would be around 6.5% gas.
1. Apply the calibration gas and purge the unit for at least 5 minutes.
View the chart until a flat line shows for 1–2 minutes.
t
t-2
21
6
%
t
t-2
7
6
%
Figure 31
1-Point Calibration Page
2. Press
ENTER
ENTER
to open the Passcode Page –
1919
1919
Passcode. Navigate to
the Field Cal page using the
Up
Up
(
) button. Press
ENTER
ENTER
to highlight
CAL TYPE and set to 1 POINT. Press
ENTER
ENTER
to de-select.
3. Press
ENTER
ENTER
to highlight REF GAS 1 and use the
Up
Up
(
) and
Down
Down
((
) buttons to match the value of the concentration of the calibration
gas.
NOTE: This value only needs to be set when using a new
gas cylinder.
Press
ENTER
ENTER
to de-select.
4. Ensure the Adjusted value at the bottom of the page has stabilized
NOTE: The value displayed does not change but there will be
a ~ symbol next to 'Adjusted' while the reading is stabilizing.
When the ~ symbol disappears the reading will be stable and
the next change can be made.
5. Press
ENTER
ENTER
to highlight ACTUAL 1 value and press the
Up
Up
(
) button
