2-Point Pressure Calibration (Absolute Transducers); 2-Point Pressure Calibration Procedure (Absolute Transducers) - Honeywell Mini-AT User Manual

2-Point Pressure Calibration (Absolute Transducers)

2-Point Pressure Calibration (Items Required)
- Mini-AT
- Pressure Source and fittings (capable of providing pressures of at least 50% of the Mini-AT's
pressure transducer range)
- Pressure Reference (accuracy to equal or exceed the accuracy or the Mini-AT's pressure system)
- Computer (IBM Compatible)
- Mini-AT Link Software (or MasterLink32)
- I/O cable, p/n 40-1629
- Barometer

2-Point Pressure Calibration Procedure (Absolute Transducers)

Make certain that the Pressure Compensation Coefficient listed in item codes 301 through 332 (341 through
372 for PLog) are for the pressure transducer installed. Also verify that Item Code 087 (or 408) is the desired
pressure unit. Item Code 138 (or 411) matched the transducer serial number label and Item Code 112 (or 407)
is set for Absolute type transducer. Refer to figure 19 when pressure calibrating the Mini-AT. Since the two-
point calibration is mostly a software function, references to the appropriate sections in the Mini-AT Link (and
MasterLink32) software are included.
1) Connect a pressure source and pressure reference to the selected Mini-AT pressure connector.
(PCor or PLog)
2) Using serial cable p/n 40-1629, connect from the computer's serial port to the Mini-AT's RS-232
port.
3) Start Mini-AT Link (or MasterLink32) software on the computer.
4) Enter the access code for Level 1 or Level 2 when requested. The default Level 1 Access Code is
11111, the default Level 2 Access Code is 22222. It is strongly recommended to change the access
code at the time of installation and there after change periodically (requires Level2 Access).
5) Select "Calibrate" from the main menu.
6) Select "PCor Pressure Calibration" or "PLog Pressure Calibration" from the sub-menu. Note: In
MasterLink32 first select "Pressure" then a box will appear for selecting PCor or PLog.
7) If a communications link has not yet been established, the software will attempt to link to the
Mini-AT. If the access code of the Mini-AT is not the default of '33333', a box will appear requesting
the user to input the Instrument Access Code. Enter the access code when this box appears.
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 on that a sample may be obtained.
Click the "AveragePressureNow" button when it becomes active (text changes from gray to
black) to obtain a sample of the applied pressure.
9) Obtain the current local atmospheric pressure reading using a barometer or by some other
means. When Mini-AT Link displays the absolute "Average Pressure", the value should be
changed to match the current atmospheric pressure reading by clicking the "Change" button
when it becomes active. Enter the current atmospheric pressure value and then click "OK",
making sure the units are comparable, i.e. PSIA. 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 (414) and the previous value at item 018 (or 415), before returning to a live,
absolute pressure reading.
10) Compare the displayed pressure to the atmospheric pressure. If the Mini-AT's absolute 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.
Mini-AT User Guide
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