Environmental Monitoring System (EMS-5X, 10X and OS) Instruction Manual
14
3.2
Relays and Sensors
Although multiple sensors and sensor types may be connected to the unit, there must always be
an
end of line (EOL) terminating resistor
at the end of the sensing circuit to allow for
cable break
monitoring
and
alarm reference set point
. The unit relies upon a terminating resistor of value
47k ohms
.
The unit should be
powered OFF
when making connections. Sensors should be installed so that they remain
accessible for maintenance
.
3.2.1
Relay Functions and Triggers
Relay Function
Description and Triggers
1-10
Individual zone
Software configurable. Used to operate auxiliary devices.
11
Common Alarm /
Fault
Relay latched upon alarm until acknowledged by User or Engineer.
✓
Zone cable break
✓
Zone Alarm
✓
interface board / Outstation
communication failure
✓
Ethernet connection failure
✓
Modbus TCP/IP connection failure
✓
Motherboard communication
failure
12
Cable break
Relay latched upon alarm until acknowledged by User or Engineer.
✓
Zone cable break
13
Alarm
Relay latched upon alarm until acknowledged by User or Engineer.
✓
Zone alarm
14
Configurable
User configurable to latch on Alarm (13) and/or Cable Break (12). Relay
latched only when alarm or cable break present in real time.
✓
See Alarm (13) and/or Cable Break (12)
15
Watchdog
Relay normally energised. De-energised upon any system fault.
✓
Motherboard loss of power
✓
Interface Board / Outstation
loss
of power
✓
Complete power failure to EMS
✓
Motherboard communication
failure
✓
Interface Board / Outstation
communication failure
16
Spare
Unused
Not applicable
Table 3:
Relay Functions and Notes / Triggers
3.2.2
Reboot Relay
The
reboot relay switch SW1
must be returned to the
OFF
position when testing of or updates
to the EMS have been completed.
Power to the
TFT LCD Touch Screen Computer
is supplied via a
re-boot relay.
If communications between
the Motherboard and the touch screen are lost for more than
60 seconds
, this relay will operate to
re-boot
the computer
.
This function can be bypassed by
switch SW1
for testing purposes or when
updating
the EMS software. When
the switch is in the
OFF
position the relay is bypassed and power is permanently supplied to the touch
screen.
