Installation guide

VAR4 / VAR12 / VAR20 - Product Description
The RS485 data link to the Remote I/O Units is fully monitored. In the event of communications failure, the
VAR Router will log a fault. The fault code identifies the specific unit or units that are affected.
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• The maximum recommended distance for the RS485 data link is 1 km.
• Only the last physical Remote I/O Unit in the chain should have the RS485 termination
enabled.
• A single RS485 bus supports up to 3 Remote I/O Units.
3.9.1 Analogue Inputs
Each analogue input channel may be assigned as
either a Programme Selector, a Volume Control,
an ANS Sensor, or a Fault Input.
The Programme Selector and Volume Control
functions use a 12 step resistive ladder switch
arrangement shown in Figure 10.
ASL produces a range of Selector and Volume
Control products that are suitable for standard
wall plate mounting.
The fault input is simply a contact closure to
ground, which operates as described in Section
“3.7.3.2 External Faults”.
Figure 10 BMB01 Analogue Inputs
+5V
4k7 ohms
ANALOGUE
INPUT
Cabling to Contact
0V
12
11
10
2
1
3.9.1.1 Programme Selector Operation
The application of the Programme Selector function is to allow remote selection of alternative sources to a
specific zone or zones. Normally the programme selector will be mounted within the zone and allow selection
of alternative sources, such as different background music sources.
It is possible to assign a particular Programme Selector to be associated with one, or any group of, VAR
Router outputs. It is then possible to assign which input each position of the Programme Selector
corresponds to.
The connection between the Remote I/O Unit and the Programme Selector is monitored, so that open and
short conditions on the cabling are detected and logged by the VAR Router. The VAR Router fault report
identifies the specific Remote I/O Unit and the particular analogue channel number affected.
In the event of such a fault, the routing defaults to that set up on position ‘1’. Normally this would correspond
to all routes being ‘off’.
The same default operation occurs in the event of RS485 communications failure to the Remote I/O Unit.
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There should be only one Programme Selector associated with an output or group of outputs.
Associating an output with more than one Program Selector would cause unpredictable results.
Issue: 03 complete, approved
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