Installation guide

VAR4 / VAR12 / VAR20 - Product Description
3.7.1.2 Monitored
It may be used to interface resistively monitored
contacts.
This interface enables the VAR Router to monitor
the interface to the Fire Panel or other contact
closure. The contacts must be fitted with
6k8/470R resistors. This method of monitoring
has been used extensively in the past and is
prevalent in continental Europe.
ROUTER
ANALOGUE
CONTACT
INPUT
Cabling to Contact
+5V
4k7 ohms
0V
THRESHOLD= 2.5V
3.7.2 Opto-Isolated Interface
Contacts 11 through to 62 use an opto-isolated interface. The contact is asserted when the opto-isolator is
turned on. These may be used to interface a simple closure, or as a Sounder Circuit Interface that is suitable
for connecting the Fire Alarm to the VAR Router for triggering DVA messages.
3.7.2.1 Contact Closure to Ground
A simple contact closure to ground may be
connected as shown. Note that the external pull-
up to 24 V is not needed if none of the contacts
on the port are set up for routing. If any contacts
are set up for routing, then the global internal pull-
ups on all contacts of the port are disabled in
order to provide a true volt-free interface for the
routing functions.
ROUTER
CONTACT INPUT
I
OPTO ON
WHEN CONTACT
CLOSED
+
-
12-40 V
CONTACT
CLOSURE
TO GROUND
3.7.2.2 Contact Closure to Supply (+VE going Input)
In this method a contact closure is not made to
ground, but to a supply, with a fused connection
do ground. This may be appropriate, depending
on the signal source.
Note that for reliable operation it is recommended
that the 0 V reference is taken back to the 0 V of
the equipment that supplies the +VE signal.
ROUTER
CONTACT INPUT
I
OPTO ON
WHEN CONTACT
CLOSED
+
-
12-40 V
CONTACT
CLOSURE
TO SUPPLY
Issue: 03 complete, approved
Page 28 of 68