Displays; Calibration And Set-Up; Calibration, Rv1; Trip Time, Rv2 - Castle group Electronic Orange GA904 Operating Manual

Displays

The GA904 features several indicators to show the current operational state
of the unit and why it has tripped. These include:
A multi-level LED display bar showing the sound pressure level (Lp) relative to
the trip level, which is shown by the top red LED. This is indicated in 3 dB
steps, in three colours, red, yellow, and green. Therefore it is easy to see if the
level is in the trip, warning or safe area of operation.
When a trip has occurred, shown by a red "tripped" LED, the cause will be
indicated by three LEDs. These are "Level", if the sound level is too loud, "Mic"
if the anti-tamper sensor on the microphone cable shows it has been
disconnected and "Ext" if an external trigger input has tripped the unit.
The most important indication is given by the orange coloured remote beacon
which is why the entertainment noise controllers became known as the
"Electronic Orange". The beacon will warn the operators when the trip level is
approached.

Calibration and Set-Up

Although the GA904 will have been calibrated at the factory before despatch
it may need slight adjustment on site due to the positioning of the microphone
and the acoustics of the venue. It may also be necessary to alter the settings
of the unit due to a change of requirements. On the GA904 it is easy to
change between different trip and warning levels without altering the absolute
calibration of the unit. This is achieved by three sets of PCB mounted
switches.
However, it is recommended that the unit is left on its original settings and
only altered if it is advised by an acoustic consultant or local environmental
health officer. Figure 5.2 shows the location of all printed circuit board
adjustments.

Calibration, RV1

This potentiometer gives +/- 5dB adjustment to the calibration level and is
This control should not be
factory set to match the microphone supplied.
adjusted.

Trip Time, RV2

This potentiometer may be adjusted to control the trip period from 1 second
to 10 seconds.
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