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A compact electronic module which makes compliance with the Australian
Standards exacting conditions simple, safe and cost effective
The Johndec Failsafe Control System and pressure sensor is a
compact electronic module containing all switches and timers to
enable a fume cupboard to comply with Australian Standards 2243.8,
3000, 2430.3.6 Appendix 'A' and 1482 and therefore be classified
as non-hazardous.
This in turn allows the use of flammable liquids and gases to
be used together with Bunsen burners and other non fire proof
electrical equipment such as hot plates, etc.
Design
Johndec FE2000 Fume Control System for fume cupboards is wholly
designed and manufactured in Western Australia.
A compact electronic module which makes compliance with the Australian
Standards exacting conditions simple and safe.
The Johndec Fume Control System is a compact intelligent microprocessor
module with built in pressure switch, all of the functions are
controlled by the software stored in the unit EPROM and hosted
by the microprocessor. The use of software control allows significant
operational flexibility with scope for tailoring operations to
particular user requirements and to implement future upgrades.
The system also incorporates pre purge, post purge, emergency
isolation of services to comply with AS2243.8, AS3000, AS2430.3.6.
The microprocessor control module has a fully programmable system
incorporating a green backlit 20 character x 2 line liquid crystal
display (LCD). The display allows Alphanumeric messages to be
displayed by highlighting critical safety issues to the operator.
The display shows current status of the gas, power supplies,
exhaust fan, sprays and scrubber pump (if fitted) of the fume
cupboard in the form of clearly legible messages on the (LCD)
and also by means of a light emitting diodes (LED) located on
the front panel. Special attention has been given to the front
of the panel, to keep the display uncluttered and use of visual
and audible cues when user response is needed. Unexperienced personnel
or students are guided by the preplanned legible instructions
while the experienced operators can choose any option and program
in the unit to suit their requirement.
An internal battery backup supply is contained within the module.
On power failure the device will automatically time the length
of the power failure. If the fan is in pre purge, normal operations
or post purge mode it will automatically restart the fan, sound
the alarm and indicate the length of the power failure. This feature
is required for compliance with AS2243.8.
Full diagnostic and setup screens are provided for commissioning
and testing of the fume cupboard. On powering up of the fume cupboard
the panel will perform a diagnostic program. It will report any
failures along with a re-programmable service, contact phone number
on the (LCD) display.
If an extraction failure or other emergency sequence such as
an over-temperature should arise, the program of the Johndec FE2000
can automatically execute its emergency shut down sequence. It
will isolate the gas and power while allowing the exhaust fan
to continue operating as required by AS2243.8 thus setting the
fume cupboard into a safe mode. At the same time the panel will
activate an audible and visual alarm with the offending item on
the (LCD).
An emergency isolation switch is included on the panel. In emergency
situations the operator simply presses the switch and thereby
isolates the power and gas outlets in the fume cupboard. This
is reported on the screen and the alarm will be activated.
The panel is highly integrated onto a single PCB with touch sensitive
keys, (LCD) display, (LED) indicators, relays and audio visual
buzzer are self contained along with the embedded microcontroller
thus enhancing the overall reliability of the device. The graphic
panel is designed with key features which are colour coded for
ease of identification in emergency situations.
The RS485 serial communication electrical standard was chosen
for its ability to allow multiple devices to share multi-drop
cable. This has proven to be effective over extended distances
and in electrically noisy environments. The RS485 multi-drop communication
channel makes communication between an external data terminal
or computer and the Johndec internal processor possible, thus
allowing remote control of the panel and retrieval of the status
data of the fume cupboard. This allows the maximisation of energy
saving features, reporting to central data logging devices, access
by building management systems, remote emergency shutdown or start-up,
reporting the sash position of the fume cupboard and delivering
a signal proportional of the air volume passing through the fume
cupboard.
Therefore allowing the air-conditioning within the room to adjust
and deliver the required air volume. Infact, the versatility of
this feature is bounded only by the user's imagination.
Controls contained within the Johndec FE2000 are as follows:
Light
On and off switches are provided for the light with individual
(LED) indicators and is complete with a relay to connect directly
to the fume cupboard light fitting.
Fan
On and off switches are provided for the fan with individual (LED)
indicators and a 20 minute timer to allow the fume cupboard to
be "post purged" when the "off" switch is
activated. The "post purge" mode operation is also indicated
by a (LED).
Remote Indicator
A further replay is provided for wiring directly to a remote "fan
off" indicator (alarm light) if desired.
Spray Bar
An "auto" switch with (LED) indicator which allows the
spray bar (usually fitted behind a back baffle) to automatically
operate for the required 15 minutes "post purge" when
the fan is switched off. The "post purge" mode is indicated
by a further (LED) indicator. A "manual" switch is provided
to allow an operator to activate the spray bar at any time, if
user so desires. Terminals and relays are provided for wiring
to a water solenoid valve fitted in the supply to the spray bar.
Pre Purge
Terminals and relays are provided for wiring directly to a gas
solenoid valve to be fitted in any gas supply and to a 16 Amp
contactor fitted in the 240 Volt power line to any power outlets
on the fume cupboard. When the fan is turned "on" a
(LED) will indicate that the power/gas is "off" until
the necessary one minute "pre purge" has been completed,
after which a separate (LED) will indicate that power/gas is "available"
Post Purge
When the fan is turned "off" the (LED) will indicate
that the fan is now in its necessary 20 minute "post purge"
mode. Supplies to any power/gas will be immediately cut as indicated
by a (LED).
Pump
Terminals are provided for wiring direct to a fume scrubber recirculating
pump (if fitted). (LED) indicators are provided to indicate when
the pump is "off" in the necessary 15 minute "post
purge" mode and when the pump is operating.
Fan Boost
A "fan boost" switch is provided for when the fume cupboard
is supplied with an Airconserver Bypass Damper. On activation
of this button a maximum extraction rate across the fume cupboards
face will be achieved regardless of sash position. A green (LED)
will indicate when "fan boost" is activated. To deactivate
press the "fan boost" switch. If the fume cupboard is
not supplied with an Airconserver Bypass Damper the "fan
boost" will always be activated.
Door
These switches operate the fume cupboard sash if fitted with "Autosash".
By pressing the "up triangle" the fume cupboard sash
will go to the fully open position. The "down triangle"
will go to the fully closed position. The switch with the circle
will stop the door in any position. In addition, the fume cupboard
can be fitted with an attendance sensor located on the top facia
on the fume cupboard. If the fume cupboard is unattended for a
period of 2 minutes the "attendance sensor" will command
the sash to fully close, ensuring maximum saving of conditioned
air.
Audio / Visual Alarm
A terminal and relay are provided for wiring from the Pressure
Sensor, which is connected to the exhaust duct via a small flexible
tube. In the event of a large variation or extraction failure
within the fume cupboard exhaust duct, the power and gas supplied
will automatically shut down, a 75 dB alarm within the module
will be activated and a larger indicator light will start flashing.
Remote Warning
Also provided is a further relay for wiring direct to a remote
alarm or lights if desired. This feature is ideal for indicating
an extraction failure in situations where a separate alarm system
is required e.g. in a passage way or a security office.
Alarm Mute
An "alarm mute" switch is provided to turn off the alarm
in the module. Activation of this switch will not turn off the
flashing warning lights or any remote warning device. After alarm
is muted power/gas will remain shut off until fault is corrected.
Reset
This reset switch is used to manually reset the alarm system.
After any fault is rectified one cannot reset the alarm system
until the fault is rectified.
Emergency Isolator
This emergency isolator required by the Standards, will when activated,
isolate electrical power to any power outlets fitted to the fume
cupboard and any gas supply via a 240 volt contactor and solenoid
valve installed in the gas supply line. Operation of this "emergency
switch" does not interrupt the supply to the exhaust fan
and is indicated by the (LCD) & (LED).
Heat Sensor
Input terminals are provided within the module to provide wiring
from a heat sensor fitted inside the fume cupboard. In the event
of overheating within the fume cupboard chamber, the heat sensor
circuit will provide for shutting down supplies, activating the
fire alarm system and activation of spray bar (if fitted).
Commissioning Programme
Concealed within the control module is a special code eto access
for maintenance staff only, which allows the in built timer to
be bypassed to enable commissioning adjustment and rectification
of any faults. Hence maintenance can be carried out without the
delay of waiting until timers run out. Refer to switches listed
below.
Enter
This switch is to enter and activate the menu driven functions
for engineering set up, a special code is required to access some
of these functions.
Escape
This switch is used to escape the previous level in the menu driven
system, only requires activation during emergency, commissioning
or programme change.
Arrows
These switches are to advance to the left or right of the menu
driven function.
Help
This switch is provided to further assist the operator diagnose
any problems which are not displayed on the (LCD) if the solution
cannot be found the (LCD) will display the telephone number to
contact for service.
Battery Backup
The Johndec FE2000 fume control system has a built in battery
backup, so when a mains power failure occurs, the audible signal
will sound for 20 minutes.
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CONTROLS