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Mini-AT User Guide
When the microprocessor has completed the updating of its memory registers and item codes, it will update
the LCD with the new corrected volume information. The microprocessor will then power down most of
the main board circuits and transmits corrected volume pulses, if Item Codes 093, 094 or 095 were config-
ured for 'pulse output'. Otherwise, the main board will go back into the 'asleep' mode waiting for the next
uncorrected volume input pulse.
Three other conditions can cause the Mini-AT to 'wake-up' while in the Corrector Mode. They are; a
Mag Wand Input, a Serial Communication Link or a scheduled audit trail log entry. A Mag Wand
Input is caused by passing a magnetic wand across the Mag Read Switch located on the LCD Dis-
play Board. A Mag Wand Input will cause the microprocessor to initiate the Meter Reader Mode. A
'wake-up' caused by a Serial Communication Link will allow the instrument to 'talk' to serial devices
connected to either of the RS-232 ports (local or modem). An audit trail wake-up occurs at regular
time intervals as specified by the user, at Item Code 202. In all three cases, the microprocessor will
initiate a full correction cycle as described above. Except for audit trail wake-ups, after the comple-
tion of the correction cycle, most main board circuits will remain energized while the instrument is
performing the user requested tasks.
Drive Input
A universal mounting bracket, containing a standard digital index for indicating uncorrected volume,
is used to mount the Mini-AT to a meter. A reversing gear mechanism permits changing the index
rotation to match meter rotation (see figures 2 and 3). Input of uncorrected volume is made by
magnetically operated reed switches. A magnet is located on a disc/shaft and is rotated by the meter
output shaft. There is very little torque loading on the meter. The dual input switches allow contin-
ued operation if one switch should fails. Input switch #1 is located along the right edge of the Input
Switch Board (S1) and switch #2 is located just to its left (S2). If a switch failure is detected, an
alarm is displayed.
PCor Pressure System
The PCor pressure sensing system incorporates a precision strain gage pressure transducer, located inside the
Mini-AT enclosure with a 1/4" NPT female case connection. A valve kit with shut-off valve, tubing and fittings
is optionally available to make the pressure connection to the meter/pipeline. A plug-in cable is used to make
the connection from the pressure transducer to the main circuit board at J10. This transducer is used for
calculating the pressure correction factor, item 044.
PLog Pressure System (optional)
The optional PLog pressure sensing system incorporates a separate precision strain gage pressure transducer,
also located inside the Mini-AT enclosure with a 1/4" NPT female case connection. The Plog transducer can
be a different range and type than the PCor transducer. A valve kit with shut-off valve, tubing and fittings is
optionally available to make the PLog pressure connection to the meter/pipeline. A plug-in cable is used to make
the connection from the PLog pressure transducer to the main circuit board at J26. This transducer allows the
logging of a 2nd pressure which is initiated by a time interval (not volume) set by item 401. It is usually used to
monitor the upstream or downstream pressure.
Temperature System
The temperature system consists of a highly stable, solid state transducer, connected to the Mini-AT through
a 6 foot length of armored conductor. The stainless steel probe is 1/4" diameter by 9 inches long and is provided
with a slip-along fitting for the matching thermowell in the meter piping.
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