Honeywell Mini-AT User Manual page 62

8) With zero pressure applied to the selected pressure transducer, perform the "Pressure Zero
Calibration". The pressure displayed in green on the computer's screen is a live reading. This permits
the user to determine if the pressure has stabilized so that a sample may be obtained. Click the
"Average Pressure Now" button when it becomes active (text changes from gray to black) to
obtain a sample of the applied pressure.
9) When the software displays the "Average Pressure", the value should be changed to match the
pressure reference by clicking the "Change" button when it becomes active. Enter the pressure value
for the zero reference pressure (usually 0.0) and then click "OK". The Mini-AT will calculate the
required difference (offset), store this calculated value at Item Code 017 (or 414), display the new
value for item 017 (or 414) and the previous value at item 018 (or 415), before returning to a live
pressure reading.
10) Compare the displayed pressure to the reference pressure. If the Mini-AT's pressure reading is
not acceptable, click the "Average Pressure Now" button again to obtain another pressure sample.
The program will continue to loop back to the live pressure reading. Obtain as many pressure
samples as necessary until an acceptable pressure reading is displayed.
11) If the Mini-AT's zero pressure reading is acceptable, click the "Span" button to change to the Span
Calibration sequence.
12) The screen title should have changed to; "Pressure Span Calibration". At this point, the software is
waiting to sample the applied pressure that exceeds the zero reference pressure by at least 50% of
the rated pressure transducer range. Increase the pressure applied to the Mini-AT to the span
reference pressure.
Example #1; If the zero reference pressure on a 100 PSI transducer equals 0.0 PSI, then the span
reference pressure must be between 50.00 and 100.00 PSI.
Example #2; If the zero reference pressure on a 600 PSI transducer equals 0.0 PSI, then the span
reference pressure must be between 300.00 and 600.00 PSI.
13) The span calibration also displays a live pressure reading to allow the user to determine if the span
reference pressure has stabilized. When the pressure has stabilized, click the "Average Pressure
Now" button when it becomes active to obtain a pressure sample.
14) If the average pressure reading is not equal to the span reference pressure, click the "Change" button
when it becomes active. Enter the pressure value for the span reference pressure and then click
"OK". As the computer screen updates, the Mini-AT will calculate the required span (gain), store
this calculated value at Item Code 020 (or 417), display the new values for items 017 (414) and 020
(417), display the previous values at items 018 (415) and 021 (418) before returning to a live pressure
reading. Obtain as many pressure samples as necessary until an acceptable span pressure reading
is displayed.
15) Compare the average pressure reading to the span reference pressure. If the average pressure reading
is acceptable, the pressure calibration process is complete. As a suggestion, recheck the pressure
zero reading and any number of pressure points within the transducer range, or click "Done" to exit
the calibration sequence.
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Mini-AT User Guide