14
Gasmaster 1
with a toxic gas detector (2-wire): 21 hours
Gasmaster 1
with an oxygen detector (2-wire): 16 hours
Gasmaster 1
with a mV pellistor flammable gas detector:
12 hours
Gasmaster 4
with four toxic gas detectors (2-wire):
10 hours
Gasmaster 4
with four oxygen detectors (2-wire): 4 hours
Gasmaster 4
with four mV pellistor flammable gas
detectors: 3 hours
Gasmaster incorporates protection to prevent
the internal batteries being damaged by being
deeply discharged. When operating from internal
batteries, Gasmaster will display a “Warning -
battery low” fault message when the battery
voltage drops to 22 V. When the voltage drops
to approximately 20 V, the batteries will be
automatically disconnected. The batteries will only be
re-connected when the external power supply is
re-instated, and will take approximately 18 hours
to fully re-charge.
Note: The internal batteries may not be charged
efficiently when Gasmaster is powered from an
external dc supply, and therefore the back-up
function may not work if the external supply fails
Please contact Gas Alarm Systems for further advice.
2.12 Commissioning
Note: it is strongly recommended that persons
intending to commission a Gasmaster system first
read and understand the Operating instructions
provided in section III. Operation.
When all field devices have been connected and
powered-up, commissioning can commence. Gas
detectors should be calibrated according to their
instructions, fire detectors should be tested using
appropriate tools.
Alarms should be simulated and actions noted to
ensure that the system operates as intended. All
warning devices should be checked, and interfaces
with auxiliary equipment should also be verified. The
test and View menu’s are provided for this purpose (see
page 24 on page 27.
2.12.1. Commissioning mV pellistor
detectors
It is essential for these types of detectors that the
correct ‘head voltage’ and balance is set before
attempting to zero and calibrate the sensor.
To set the head voltage, measure the voltage across the
‘+’ and ‘-‘ terminals at the detector and adjust the ‘HEAD
VOLTAGE’ potentiometer on the appropriate Gasmaster
input module. Check the detector instructions for
voltage settings: 2 V dc is typical for an Xgard Type 3 or
4 detector.
Allow the sensor to warm-up for 1 hour and then adjust
the amplifier balance as follows: connect a meter set
in the dc mV range to test-points TP12 and TP13 on
the Gasmaster mV pellistor input module. Adjust the
‘BALANCE’ potentiometer until the meter reads ‘300
mV’.
The sensor is now ready for zeroing (having first
checked no flammable gas is present) and calibration.
2.12.2. Zero adjustment and calibration
Calibration must be carried out separately on individual
gas detectors on Gasmaster. Follow calibration
instructions supplied with each detector. Ensure at all
times the local legislation and codes of practice are
complied with.
Allow detectors to stabilise for at least one hour before
commencing calibration. Refer to detector manual for
more information.
Gasmaster provides Zero and Calibration Wizards to
enable you to carry out calibration easily. These are
accessed through the Operator Display Panel and
Menu System. Section III. Operation provides detailed
information on the menu structure and operator
buttons.
Zero adjustment
1. From the normal operating display, press the
Continue button to enter the menu system.
2. Use the Up
and Down
buttons as
necessary to
select Supervisor and press Continue
.
2. Installation
Summary of Contents for Gasmaster
Page 12: ...9 2 Installation ...
Page 28: ...25 Menu system overview ...
