Mini-At Operating Modes; Corrector Mode; Meter Reader Mode - Honeywell Mini-AT User Manual

Mini-AT Operating Modes

While in service, the Mini-AT is always in one of four operating modes. The operation of the instrument in each
state is well defined and suited to a particular purpose. The four states are referred to as "Operating Modes"
and are:

Corrector Mode

Meter Reader Mode

Level 1 Access Mode
Level 2 Access Mode
In all four Modes, the Mini-AT may be receiving and processing uncorrected volume, pressure and the
temperature input from the meter. The Level 2 Access Mode was originally intended to be used in the meter
or instrument shop, however, it is common practice for field use also.
Note: The Mini-AT can only enter Meter Reader Mode, Level 1 Access Mode, or Level 2 Access Mode from
Corrector Mode. If the instrument is in Meter Reader Mode, it must be brought back to Corrector Mode to
enter Level 1 or Level 2 Access Mode. The same is true if the Mini-AT is in Level 1 or Level 2 Access Mode,
the instrument must be brought back to Corrector Mode to enter Meter Reader Mode.
Corrector Mode
The Mini-AT normally operates in the Corrector Mode. The other three modes always return to the Corrector
Mode when completed. The corrected volume continuously appears on the LCD display while the uncorrected
volume is displayed on the mechanical index in the mounting bracket.
Uncorrected volume pulses are detected by magnetically actuated reed switches at each meter revolution. The
instrument electronics are normally in a standby (asleep) mode, but are activated (wake-up) by an input pulse
generated from the reed switches. During a wake-up, the instrument measures the gas pressure and temperature,
then calculates the correction factors and updates the corrected volume on the LCD display. The electronic
circuitry returns to the asleep mode to conserve battery power until the next full rotation of the meter output shaft.
Meter Reader Mode
This mode provides the meter reader the ability to view instrument item values in addition to the
corrected volume without opening the door. By running a magnet activator along the right edge of the
display window on the door, the meter reader can scroll through a sequence of readings. These readings
include up to 18 parameter values, alarms, live gas pressure and live gas temperature, if desired.
At the time the meter reader activates the unit with the first mag wand input, the unit updates all
measurements and then displays the LCD Display Test. This is to verify that all seven segments and
decimal points of the eight digit LCD are functional. The uncorrected volume continues to totalize on
the mechanical index. When the instrument receives a mag wand input while the last Meter Reader List
item is displayed, the unit will return to the Corrector Mode. If the Meter Reader List sequence has not
been completed, the unit returns to the Corrector Mode automatically after a one minute timeout period
(unless the instrument is displaying live pressure or live temperature, in which case, the time-out period
is 10 minutes). Input pulses that accumulated while in Meter Reader Mode will be processed just prior to
returning to Corrector Mode.
Level 1 Access Mode
Mini-AT User Guide
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