Castle group Electronic Orange GA904 User manual

www.castlegroup.co.uk
Operating Manual
Electronic Orange
GA904

Thank you for buying a Castle product, I am sure you will find both the goods and
the service to be of the highest quality but if not, then please feel free to write to
me personally and I will ensure that your needs are dealt with immediately.
This manual is designed to show you the operation of the goods you have
purchased and a very brief insight into acoustics itself. If you would like to
become a competent person in the eyes of the law, then you may like to know
more about our Competent Persons training course for Noise at Work
Regulations. You can visit www.castle-training.com to find out more.
It is my intention for Castle Group Ltd to provide a wide range of technical health
and safety products and Services of the highest standard. If you would like to
know more about any of our other products and services then please telephone
on [phone] or visit www.castlegroup.co.uk
Simon Bull
Managing Director

Copyright
This manual is copyrighted with all rights reserved. Copying in part or in whole is
prohibited without the prior written consent of Castle Group Ltd.
Precautions
Only operate the instrument as described in this manual.
These are precision instruments, protect from shocks and vibrations.
Ambient conditions for the operation of the unit are as follows:-
Temperature: -10C to +50C
Relative Humidity: 30 to 90%
Protect the unit from extremes of temperature and humidity, direct sunlight
and air with a high salt or sulphur content.
Do not use any solvents or cleaning agents on the instrument. Use only a
soft dry cloth or a soft cloth lightly moistened with water when necessary.
Do not allow any conductive objects, such as wire or metal particles to enter
the unit.
Do not try to disassemble the instrument or attempt any repairs as this will
invalidate your warranty. Take a note of the condition of the instrument and
contact your authorised Castle service station.
To ensure continued precision performance of your instrument have it
checked and serviced at regular intervals.
Contacting Castle Group
This manual contains complete operating instructions for the Noise Activated
Warning Sign, read it carefully and you will quickly become familiar with your
instrument and its operation.
If you do encounter problems with the operation of your instrument please feel
free to contact customer support with your enquiry on: -
Telephone:
[phone]
Fax:
[phone]
Website:
www.castlegroup.co.uk
Email:
[e-mail]
[e-mail]

Contents
Introduction............................................................................................... 1
Instrument Description ........................................................................ 1
Installation................................................................................................. 2
Power Rating Limitations............................................................................................ 2
Items Supplied.................................................................................................................. 3
Additional Items Required .......................................................................................... 3
Mounting the GA904 ................................................................................................... 3
Mounting the Orange Beacon Warning Light................................................... 4
Mounting the Microphone.......................................................................................... 4
Microphone Wiring........................................................................................................ 4
Wiring to the Orange Beacon .................................................................................. 5
Auxiliary Contact Wiring.............................................................................................. 5
Power Wiring to the GA904..................................................................................... 5
AC, DC, Power Output Wiring................................................................................... 6
Controls...................................................................................................... 7
Operating Modes............................................................................................................ 7
Displays ............................................................................................................................... 8
Calibration and Set-UP ......................................................................... 8
Calibration (RV1)............................................................................................................. 8
Trip Time (RV2) ............................................................................................................... 8
A and B Frequency Weighting (SW2) .................................................................. 9
Trip Level (SW3) ............................................................................................................. 9
Warning Level (SW4)................................................................................................... 9
PCB Identification ................................................................................ 11
Technical Specification ...................................................................... 12
Accessories............................................................................................ 13
Warranty and After Sales Service................................................ 14
Instrument Details .............................................................................. 14
Instrument Disposal ........................................................................... 15
Disclaimer............................................................................................... 15

Page 1
Introduction
The GA904 Electronic Orange is a system for use where amplified sound
could give rise to complaints about noise from neighbours. If the sound level
should exceed the trip level the unit will remove power from the stage or
amplifier system. The orange beacon warning light gives an indication of the
noise level to enable the stage manager or the person in control of the
amplifier output to regulate the sound level below the maximum permitted.
A problem associated with amplified sound is the possible environmental
effects outside the premises and the annoyance and nuisance caused to
adjoining residential premises. In this case external levels are related not only
to the internal levels but also the degree of insulation offered by the structure
of the premises.
This can only be changed by costly and often prohibitive changes to the
building. However, it is clear that for any given structure, control of the
internal sound levels will affect the external levels.
In many cases these external levels may well be the determining factor for
levels inside the building and for this reason the GA904 was designed. Castle
Group invented the first “Electronic Orange” Entertainment Noise Controller in
1971, since then it has become an industry standard, recommended by
many Local Authority Environmental Health Officers.
The GA904 has been developed from the original “Noise Limiter” and now
offers even more control.
Instrument Description
The sound in the entertainment venue is detected by an independent
microphone installed in the body of the room in such a way that the sound
detected is predominantly that of the amplifier system output.
Once installed, the microphone signal is received at the control box of the
GA904 and processed by a sound measurement system. If the pre-set trip
level is approached a warning is given, set by the warning level control, to
allow the operator to turn the volume down. If the trip level is exceeded the
trip timer will switch power off the amplification equipment for a pre-set time.
After this pre-set time the power will always be restored regardless of the
sound level unless you are using the manual reset function (see page 10).
The unit itself has a built in 20 second mute function to ensure this. When the
mute time has expired, the unit will resume measuring the sound level and
the power will be cut if it is not turned down. The process would repeat if the
volume is not turned down. The reason for the mute function is to allow the
operator of the amplifiers or discotheque time to respond by manually turning

Page 2
down the amplifier output and to ignore any momentary increase in level
caused by the patrons when the power to the amplifiers has been removed.
However, the function of the “Electronic Orange” is not so much to interrupt
entertainment as to provide adequate notice of excessive levels in order that
they may be controlled to below the required maximum. The warning beacon
gives up to 12dB warning that the trip level is being approached.
Other features include a three colour LED bar graph display showing SPL
(sound power level) which makes monitoring the level easy; a choice of
standard “A” weighting or “B” weighting characteristics which is more
effective for bass control. Outputs are available for remote analogue or digital
displays. In addition to the standard measurement microphone input the
facility is provided for an external trigger input from, for example, a contact on
a fire door. In addition, the device is fitted with an anti-tamper circuit and the
cause of a cut-off is clearly indicated by the “Level”, “Microphone”, and
“External” indicators.
Installation
WARNING:
THE GA904 SHOULD BE WIRED TO THE MAINS POWER SUPPLY BY A
QUALIFIED ELECTRICAL INSTALLATION ENGINEER.
MAINS VOLTAGES ARE PRESENT IN THIS UNIT.
The warning above applies to any work carried out on the main body of the
GA904 unit, as live terminals are exposed inside the box.
The only exception to this rule is the area inside the hinged door on the left of
the instrument, which is provided to allow the appropriate authority to make
any adjustments to the trip time and level which are found necessary. There
are no mains voltages present in this section of the GA904 enabling the unit
to be set up in safety. For more information see Section 4.
Power Rating Limitations
The maximum rating of the GA904 control box is 30 Amps. This is limited by
the current switching capacity of the relay inside the unit. Hence the unit can
switch a mains ring fused at 30 Amps.
However the maximum current is also limited by the cable running to and
from the control box, hence the mains input must incorporate a fuse no
greater than the current carrying capacity of the cables.

Page 3
WARNING:
MAXIMUM CURRENT 30 AMPS OR THE RATING OF THE MAINS CABLE,
WHICHEVER IS THE LOWEST.
The maximum power rating can be increased by using an external contactor
controlled from the GA904. In this case the maximum power rating will be
the contactor power rating.
Items Supplied
The following components are supplied with GA904:
a) Control box –White box marked GA904.
b) Orange beacon warning light.
c) Microphone complete with 10 metres of cable to connect to the control
box.
d) Two plastic seals for security (fixed to hinged door when the instrument is
calibrated).
e) 2 keys for the Manual/Auto/Override switch. (NB Two keys are supplied
by Castle Group Ltd with each switch. Duplicates are not kept by or available
from Castle Group Ltd.)
f) Microphone mounting clip.
g) Padlock (for added security). (NB Two keys are supplied by Castle Group
Ltd with each padlock. Duplicates are not kept by or available from Castle
Group Ltd.)
Additional Items Required
a) Mains cable to divert the power supply to the control box and from the
control box to the stage.
b) Light duty twin cable (12 volt/200mA for the signal to the beacon)
Mounting the GA904
The white control box can be mounted at any convenient point using screws
in the holes provided. See figure 3.1.
It should be borne in mind that:
a) The microphone cable run to the control box should be as short as
possible.
b) Reduce expensive mains power cable runs by inserting the control box with
the shortest possible diversion of stage power.

Page 4
c) The control box should be visible to person operating it so that any
trip condition can be easily reset.
d) Occasionally performers or the audience may be tempted to vandalise the
equipment if the performer refuses to turn his volume down and the unit
keeps tripping. The unit should not be too readily available to the audience.
Mounting the Orange Beacon Warning Light
This may be mounted at any convenient point where it may be seen by the
audience and the person in control of amplifier volume. This is 12 Volt D.C.
and no difficulties have been experienced with cable of up to 50 metres.
Mounting the Microphone
The microphone should be mounted in the body of the room out of tampering
fingers and directed towards the main source of the sound. Special care
should be taken to avoid audience pick-up, as a premature or undesirable cut-
off could be caused by mounting (for example) over a club bar where shouting
customers or applause could be unrepresentative of the overall sound level in
the room. The microphone should be mounted on a vibration free mounting
such as the microphone mounting clip supplied.
Microphone Wiring
The microphone lead connects directly to the microphone using the
connector provided. This connector is a switch craft type A3-M with the
following connections.
Pins 1 –screen
Pin 2 –signal (blue or white)
Pin 3 –pre-amp power (red or black) 12 volt
The other end of the cable must be connected to the terminal block on the
PCB as shown below:
J11/1 –Screen
J11/2 –Signal (blue or white)
J11/3 –Preamp power (red or brown) +12 volt
The microphone cable should be inserted through the far left slot in the lower
bottom of the case. A cable grip is provided which should be placed around
the cable approximately 150mm (6 inches) from the bare ends of the cable.
This should then be pushed home through the slot to hold the cable tight and
prevent it from pulling out. It may be necessary to compress the cable grip
using a pair of pliers to insert it through the slot.

Page 5
While the 10 metre cable provided is adequate for most installations, longer
cables are available to order, or screened twin cable may be used on the
connector supplied, up to a maximum of 30 meters.
In long cable runs, take special care to separate the microphone signal cable
from electric power cables, especially those to fluorescent light fittings.
Wiring to the Orange Beacon
The Orange beacon warning light should be connected to the GA904 main
body using 2-core cable rated at 1A. The connections are:
J9/1
J9/2
Auxiliary Contact Wiring
A normally closed door contact may be wired to the GA904 such that if the
door is opened the GA904 will trip.
The connections are:
J8/1
J8/2
Note that the unit is supplied with a shorting link between these connections.
The link must be kept in place if the door contact feature is not used. The link
should be removed if a door switch is used.
Power Wiring to the GA904
No additional items are required if the control box can be conveniently wired
into the mains circuits(s) which supply all the amplifiers in use. The simplest
installation is made by taking power from a wall socket which normally
supplies the amplifiers. Where possible the unit should be fed from a
switched junction box, fused at the current capacity of the cable, and the
output of the GA904 then taken to all the available sockets on the stage. In
this way any visiting discotheque or group can only use the controlled sockets.
The GA904 should be wired to the main power supply by a qualified
installation engineer. See earlier warning. The power cable should be fed in
through the far right hand gland nut and screwed firmly to the right hand
connector block.
Controlled power output to the stage is taken from the left hand connector
block and fed through a gland to the left of the power input. See figure 3.1.

Page 6
AC, DC, Power Output Wiring
These signals are available for connecting chart recorders, tape recorders,
or external displays etc. The connections are as follows:
J10/1 -12
J10/2 0V
J10/3 +12V
J10/4 AC Output
J10/5 DC Output
J10/6 2.5V Reference Voltage

Page 7
Controls
When the instrument has been installed it requires virtually no control and is
by nature automatic. However please read the following notes on the three
modes of operation and the various displays provided for ease of use.
Operating Modes
There are three main modes of operation key selected as shown below:
NOTE: The instrument is supplied with two keys. These keys are individual to
your instrument. Please make copies in case these keys are misplaced.
Castle Group does not keep spare keys and cannot supply replacements.
Manual
When the level has exceeded the trip level indicated by the top red LED on the
multi-level display, then the unit will trip. This will be indicated by the power
being removed and a red “tripped” light. In the manual position power must be
restored by pressing the reset button, which is prompted by the reset LED
being illuminated.
Auto
When the unit has tripped as above, the power will be restored automatically
after a pre-set delay. This delay time is user adjustable between 1 to 10
seconds. When the power is restored a mute function prevents the unit from
a further trip for 20 seconds from the beginning of the trip period. This mute
or disabling of the microphone input is necessary to allow the operator of the
amplifiers a reasonable time to adjust the level and ignore any momentary
increase when power.
This is normally the preferred mode of operation.
Override
In this mode power output is maintained even during a trip condition. This
should only be used when it is no longer necessary to control the level of
sound in the hall and surrounding buildings. The GA904 unit would not
normally be left in this position, but it may be useful if the situation with
annoyance to neighbours changes and is no longer a problem. Also a bypass
function may be useful when other equipment is being installed, tested or
repaired.
All the above modes are controlled by the keyswitch on the front panel and it
is suggested that the unit normally be left in the “auto” mode and the key
retained safely by the building manager and not left for any unauthorised
person to tamper with the function of the equipment.

Page 8
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
factory set to match the microphone supplied. This control should not be
adjusted.
Trip Time, RV2
This potentiometer may be adjusted to control the trip period from 1 second
to 10 seconds.

Page 9
A and B Frequency Weighting, SW2
This is a two way switch which selects the required frequency weighting. The
switch must be switched right for “A” weighting and left for “B” weighting.
Figure 5.1 shows the “A” and “B” frequency weighting characteristics.
Trip Level, SW3
This switch is used to set the trip level from 75dB to 112.5dB in 2.5dB
increments.
Warning Level, SW4
This switch is a four way slide switch selects when the warning beacon will
switch on. The level is relative to the trip level and may give a warning –3, -6, -
9, or –12dB down from the trip level.
The following tables show the switch position against trip level, and warning
levels.

Page 10
Trip Level
Switch SW1
dB
1
20dB
2
10dB
3
5dB
4
2.5dB
75
X
X
X
X
77.5
X
X
X
O
80
X
X
O
X
82.5
X
X
O
O
85
X
O
X
X
87.5
X
O
X
O
90
X
O
O
X
92.5
X
O
O
O
95*
O
X
X
X
97.5
O
X
X
O
100
O
X
O
X
102.5
O
X
O
O
105
O
O
X
X
107.5
O
O
X
O
110
O
O
O
X
112.5
O
O
0
0
O = Open (Up) X = Closed (Down) *Factory Set
Warning Level dB
(WRT Trip Level)
Switch Position
SW4
-12
1
-9
2
-6
3*
-3
6

Page 11
PCB Identification
The diagram below shows the position of the following components on the
PCB.

Page 12
Technical Specification
TRIP RANGE
75dB to 112.5dB in 2.5dB steps switch selectable
+/ - 5dB calibration control (factory set)
WARNING RANGE
-3, -6, -9, -12dB down on trip level select switch
TRIP TIME
1 second to 10 seconds user adjustable (potentiometer)
MUTE TIME
20 seconds from beginning of trip time
POWER SWITCHING
The GA904 will switch a 240V 30A load
OPERATING MODE
Manual: When tripped unit must be manually reset
Auto: When tripped unit automatically resets after trip time
Override: Power output is maintained even during trip condition
Manual, Auto, Override are keyswitch selectable
FREQUENCY WEIGHTING
A and B
TIME WEIGHTING
Slow 1000mS
DISPLAYS
Analogue bar graph display showing sound pressure level
Trip indication with trip source
Warning indication
Manual reset prompt
In the interest of continued development, Castle Group Ltd reserve the right
to change any specification without due notice.

Page 13
Accessories
The following are a list of available accessories and spare parts which can be
ordered from Castle Group Ltd.
01ZL1011-10 10m Microphone Cable
01ZL1011-20 20m Microphone Cable
01ZL1011-30 30m Microphone Cable
01MK376PXLR Microphone assembly for GA904
70MIS01730 Microphone Stand
01MC1 Microphone Clip
70MIS01510 Plastic Seals
70MIS00280 12V Bulbs for Beacon
67CON01410 Connector Strain Relief Bush
01PADLOCK Padlock for GA904
68SWI00700 3 Position Key Switch

Page 14
Warranty and After Sales Service
Castle Group Ltd design and manufacture precision instruments, which if
treated with reasonable care and attention should provide many years of
trouble free service. In the event of a fault occurring, during the warranty
period, the instrument should be returned to Castle Group Ltd, in its original
packaging, or to an authorised agent. Please enclose a clear description of
the fault or symptom.
Details of the warranty cover are available from Castle Group Ltd or an
authorised agent.
All instruments are designed to meet rigid British and International
Standards. An annual calibration is recommended to ensure that these high
standards are maintained. This is particularly important for cases in which
instrument readings are to be used in litigation or compliance work.
For warranty and service return to: -
The Service Department
Castle Group Ltd
Salter Road
Cayton Low Road Industrial Estate
Scarborough
North Yorkshire
YO11 3UZ
Telephone: [phone]
Fax: [phone]
Email: [e-mail]
Web: www.castlegroup.co.uk
Any misuse or unauthorised repairs will invalidate the warranty.
Instrument Details
For your records and for future correspondence with Castle Group Ltd
regarding your instrument, please complete the following details: -
Instrument Model
Instrument Serial Number
Purchase Date

Page 15
Instrument Disposal
The symbol shown here can be found on your instrument and
means that the product is classed as electrical or electronic
equipment and should be disposed of at the end of its life separately
to your commercial or household waste.
The Waste of Electrical and Electronic Equipment Directive (2002/96/EC)
has been established to help reduce the influx on landfill sites and effectively
treat hazardous substances by using best practices for the recovery and
recycling of products.
There are various collection systems in place within the EU for the disposal of
your product. To find the nearest UK waste recycling point in your area, enter
your postcode in the website www.recycle-more.co.uk
For more information please contact your local authority, the dealer where
you purchased your product or Castle Group Ltd.
Disclaimer
Whilst every effort is made to ensure the accuracy and reliability of both the
instrument described and the associated documentation, Castle Group Ltd
makes no representation or warranties as to the completeness or accuracy
of this information.
Castle Group Ltd assumes no responsibility or liability for any injury, loss or
damage incurred as a result of misinterpreted or inaccurate information.
Any documentation supplied with your product is subject to change without
notice.
HB/0904/025/A4 Rev D