Installation & Operation Manual Merlin GDP2X
GDP2X - IOM Iss: 7 03-21
6
Board Connections Overview
POWER / LINE IN 100-240vac mains power supplied to the [POWER/LINE IN] connector using a 3-core cable and
fused at 3A. On connecting the mains supply to the panel the power LED indicator will light up – this is located on the
front cover.
VALVE OUT 100-240vac electrical power output from the [VALVE OUT] connector using a 3 core cable can be
connected to a gas solenoid valve which can shut the gas supply on alarm status. Refer to your valve manual for more
information.
DETECTOR CHAIN 24vdc power supply and MODBUS communication data cables are wired up to 8 detectors,
chained in parallel up to approx. 100 yards from the panel depending on the chain configuration, wire type for power
and condition. For more information see section: Wiring your detector.
EM STOP Open/close connections for external shut-off buttons. If using multiple shut off buttons, wire in parallel.
HEAT SENSOR Open/close connections for heat sensors/thermal links.
BMS OUTPUT Volt free connections are available on the board for Building Management Systems.
This is a relay that changes state in alarm or when the gas line is on/off and can be used in conjunction with the 24vdc
output and other external relays that affect other devices and controls such as purge fans and audible alarms etc.
FIRE PANEL Open/close connections for fire alarms/panels.
SOUNDER-STROBE 24vdc connections for an external sounder alarm/ strobe lighting to activate on alarm.
Wiring your Detector
24vdc power and MODBUS communication cables wired to terminals marked [DETECTOR CHAIN + - D+ D-].
[SHEILD WIRE] detector terminals used for earthing/grounding and shield wires connected to any earth/ground
terminal on the control panel. Twist the shield wire to avoid stray shield wires. If the detector does not have dedicated
shield wire terminals, shield wires connect to the 24vdc negative terminal [-] on both detector and panel.
A shielded and twisted 2 or 4 core cable is used to wire the MODBUS
terminals [D+ & D-). The shielding can be of 2 types: braided [mesh of thin
conducting wires] or foil (consisting of a thin sheet of metal covering the
twisted wires). One example of such cable is BELDEN 3082A.
Any cable with
similar characteristics can be used to connect all the devices together.
If you are encountering noise or irregular problems with a bus link, the problem is likely related to grounding,
incorrect shielding or wiring mains power cables next to data cables.
The detector must be earthed/grounded for electrical safety and limit the effects of R/F & EMC interference!
Where cable runs may exceed 100 metres from one control panel – Contact your supplier!
Ensure the 120ohm termination resistance switch is turned on at each end of a cable run!
