Contacts; Opto-Isolated Interface - ASL INTERCOM VAR8-ACU Product Description

2.6.1

Contacts

2.6.1.1

Opto-Isolated Interface

Contacts 1 to 10 (or 1 to 20 when the VAR8-ACU is fitted with the EXP8 Interface Expansion Board) 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 Router for triggering DVA messages.
Contact Closure to Ground
A simple contact closure to ground may be
connected as shown.
12-40 V
CONTACT INPUT
I
CONTACT
CLOSURE
TO GROUND
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.
12-40 V
ROUTER
CONTACT INPUT
CONTACT
CLOSURE
TO SUPPLY
I
VAR8-ACU and Variants - Product Description
ROUTER
+
-
OPTO ON
WHEN CONTACT
CLOSED
+
-
OPTO ON
WHEN CONTACT
CLOSED
Issue: 02 complete, approved
Positive Voltage Source (+VE going Input)
As per Contact Closure to Supply, but to an
alternatively switched voltage source, such as to a
suitable output from another piece of equipment.
12-40 V
FROM
REMOTE
EQUIPMENT
Page 14 of 44
ROUTER
CONTACT INPUT
+
I
-
OPTO ON
WHEN CONTACT
CLOSED