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Note: Make sure the calibration adaptor and all other
fittings have been removed from the detector before it
is returned to service.
3.7
Manual calibration procedure
It is also possible to calibrate the ZoneGuard manually using
the four buttons on the instrument keypad.
3.7.1 Manual Fresh air "zero" through
keypad buttons
1. Make sure gas readings are given in numbers. If the
display shows “OK”, then the ZoneGuard is currently
being operated in the “Text Only” mode. To change
over to Basic mode, simultaneously hold down the "+"
and"-" keys as discussed in section 2.9.3.
2. Make sure the ZoneGuard system has been turned on
and operating for a sufficient period of time for the
sensor readings to have stabilized fully
before
initiating
manual calibration procedures.
If the sensor has just been replaced, the ZoneGuard
should be turned on and allowed to stabilize for the
following period of time prior to performing any of the
calibration options.
Sensor Stabilization
Period
Oxygen 1
hour
LEL 5
minutes
All Toxic sensors
available for ZoneGuard
15 minutes
3. Make sure the sensor is located in fresh, contaminant
free atmosphere or use a cylinder of Zero Air to supply
atmosphere to the sensor.
4. Press the keypad button marked "Cal". The “GAS
ZERO” calibration message will appear on the
instrument LCD.
↔
5. Press “Cal” to automatically zero the instrument. The
LCD will show the message “ZERO WAIT” while the
adjustment is being made.
↔
6. After completion of the zero adjustment the ZoneGuard
will automatically return to the current gas readings
screen.
7. The manual fresh air zero adjustment can be canceled
at any time prior to completion by pressing the Mode
button. Pressing the Mode button causes the calibration
values in the memory to remain unchanged from the
last time a fresh air adjustment was made. An
information screen is displayed briefly which verifies that
the zero values have not been changed. The instrument
will then return to normal operation.
↔
3.7.2 “Manual” span calibration through
keypad buttons
Span calibration procedures using buttons on the instrument
keypad are only necessary when the adjustment necessary
to restore accuracy is outside the permissible window of
adjustment for “One Button Auto Calibration” procedures.
Span calibration using the keypad buttons may only be done
while in the Basic operating mode.
1. Make sure gas readings are given in numbers. If the
display shows “OK”, then the ZoneGuard is currently
being operated in the “Text Only” mode. To change
over to Basic mode, simultaneously hold down the "+"
and"-" keys as discussed in section 2.9.3.
2. Make sure the ZoneGuard system has been turned on
and operating for a sufficient period of time for the
sensor readings to have stabilized fully
before
initiating
manual calibration procedures.
If the sensor has just been replaced, the ZoneGuard
should be turned on and allowed to stabilize for the
following period of time prior to performing any of the
calibration options.
Sensor Stabilization
Period
Oxygen 1
hour
LEL 5
minutes
All Toxic sensors
available for ZoneGuard
15 minutes
3. Turn the instrument off by pressing and holding the
Mode button.
4. While holding down the "Cal" button, press the Mode
button to turn the ZoneGuard back on. A screen
showing the message “SPAN” will be displayed which
alternates with the sensor readings.
↔
Press the Mode button at any time to cancel the calibration.
5. Screw the regulator into the cylinder and connect it to
the detector using the short section of tubing and the
calibration adapter. The regulator will automatically
begin flowing calibration gas at the correct flow rate as
soon as it is screwed into the cylinder of gas.
6. Allow the readings to stabilize. When the readings
stabilize, use the "+" and "-" keys to raise or lower the
readings to match the concentration printed on the
calibration cylinder label.
7. Make sure the correct cylinder of gas is attached before
attempting to adjust the span! If the concentration of
gas reaching the sensor is too low to allow the
instrument to be adjusted, or if the wrong type of gas is
applied to the sensor being adjusted, the alarms will be
