User Manual

Display Hold
There may be situations where you want to temporarily retain a reading. The Model 477A
includes a Display Hold feature which fr eezes the curr ent r eading and holds it in the display until
cleared. To activate this operation, momentarily press the HOLD/MEMORY key when the pres-
sure you want to save is displayed. A HOLD indicator will appear in the display to indicate that
the reading shown is frozen. To return to normal operation, press the HOLD/MEMORY key
again.The HOLD indicator will disappear and the current pressure will again be shown.
Memory Function
A memory function is included in the Model 477A that allows you to store up to 40 pres-
sure readings for later review or recording. This feature is especially valuable for making a tra-
verse of duct velocity pressures with a Pitot tube or for multipoint pressure measurements. The
readings are stored in non-volatile memory so they will be retained even if the unit is shut off or
the battery is removed.
Storing Pressure Readings
To store a reading, press and hold the HOLD/MEMORY until ST01 is displayed then release
the key. Next, press ZERO/STORE key to save current reading to ST01 memory location. A
beep will sound indicating that the reading has been saved. As each r eading is saved, the mem-
ory location display will advance to the next number. To resume pressure measurement, press
the HOLD/MEMORY key again. Note that in the memory mode, the display zero function is not
available. To zero the display, you must first exit the memory mode and then press the
ZERO/STORE key.
Viewing Stored Readings - Selecting a Location
To view the contents of memory, press and hold the HOLD/MEMORY until RD01 is displayed
then release the key. Next, press UNITS/LOC to view other memory location. To resume pres-
sure measurement, press the HOLD/MEMORY key again.
Clearing Memory
To clear the contents of memory, press and hold the HOLD/MEMORY until CLR is displayed
then release the key. Next, press ZERO/STORE key to clear all previously stored readings.
During this operation - - - - will be displayed. Once memory is cleared, the current pressure will
be displayed.
Exiting Memory Mode
To exit the memory mode press the HOLD/MEMORY key again and the unit will return to
normal operation.
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