IGD 2-Wire Systems, Installer'S Manual

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49
Installation Requirements for No-Volt Release Modules
No Volt-Release modules are fitted in situations where user intervention is required after resetting a gas
alarm before a signal is re-instated.
An example of its use would be where an output from the gas detection system is being used to control a
gas supply to a process. On detecting a gas leak the system shuts off the gas supply. If a normal relay is
used then on resetting the gas alarm the relay will also re-set and automatically bring back on the gas
supply. This may not be desirable. For example if the gas supply is feeding bunsen burners in a lab, then
there may be a number of open taps which would potentially leak unburnt gas if the supply automatically re-
instates. By fitting a no-volt release module to control the power to the gas valve this then requires manual
re-set of the supply before it is re-instated. With the module fitted, to re-instate the supply; there must be no
gas alarm or other alarm on the system controller, the e-stop on the no-volt release must be in the safe
position. At that point the supply can be manually re-instated.
TOCSIN
650 OR
750 Series
Controller
L1
L2
Port 1 to 4
Cable Screen or
Drain Wire
L1 L1
L2 L2
To next 2-Wire
device, not a
terminator is
required if this
is an end of
line device
Unit provides a volt free contact rated at max 30A 250V AC
Note this is a volt free contact designed to switch an external load powered
from an external supply.
Operation of the relay can be
either normally open or
normally closed configurable on
commissioning
Base Add:
01