Installation, Operation & Maintenance Manual Merlin Detector i-S
Iss: 1 170322
7
Wiring: Alarm Relays
These are volt free connections to a BMS (building management systems) or Merlin panel to send an alarm signal
upon pre/alarm levels of gas. Max 1A load @ 12/24V DC or AC.
If you are connecting detector(s) via a GDP panel you will need to use the [C/L]
terminal as an alarm relay. A relay will
change state when in alarm or pre-alarm when gas is detected and if wired/configured to do so.
These terminals can be used in conjunction with other external relays that affect other devices and controls such as
purge fans and audible alarms etc.
Alarm Relay Setting Switch
–
Latch On/Off
It is recommended to leave the alarm relay setting switch on, particularly for flammable detectors!
The switch is left on as a factory set condition!
This switch is used to latch/unlatch an alarm relay.
When turned on the Detector relay will latch permanently on (until Reset) in the event of the detector detecting gas
and entering an alarm state.
The detector will indicate a red dot on the screen when the alarm relay has latched.
The alarm will beep every 10 seconds to alert the user that the detector entered an alarm state.
To reset the Detector, press and hold the touch button for ~3 seconds.
Wiring: 0-10V Analogue Output
This connection is used to regulate external fan speed controllers (supplied separately). Connect direct to fan speed
controllers or via your Merlin panel [0-10V] terminal if available. 0-10V output is driven by the status of gas
concentrations detected.
0-10 Volt Output Range
Gas & Measurement
1V
2V
3V
4V
5V
6V
7V
8V
9V
10V
NG/CH
4
Methane: %LEL
1%
2%
3%
4%
5%
6%
7%
8%
9%
10%
LPG
Propane: %LEL
H
2
Hydrogen: %LEL
CO
Carbon Monoxide: ppm
30
60
90
120
150
180
210
240
270
300
See section:
CO2 Selection Switches
CO
2
0-5000ppm Range
Carbon Dioxide: ppm
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
CO
2
0-2000ppm Range
Carbon Dioxide: ppm
200
400
600
800
1000
1200
1400
1600
1800
2000
CO
2
Selection Switches
These switches configure alarm thresholds of CO
2
(carbon dioxide) only.
There is a legend on the board for quick reference.
X = OFF / O = ON
S1
S2
Pre-Alarm
Alarm
S3
0-10V Output Range
O
O
2800ppm
4500ppm
O
0 - 5000ppm
X
O
1500ppm
2800ppm
O
X
1200ppm
1500ppm
X
0 - 2000ppm (Default)
X
X
800ppm (Default)
1000ppm (Default)
