Permanent Routes; Remote I/O Units; Rs485 Connections - ASL INTERCOM VAR8-ACU Product Description

2.6.2

Permanent Routes

It is possible to program specific inputs to be permanently allocated to specific outputs. Such routes are
'permanent' unless overridden by a higher priority input. These routes are restored once the higher priority
input is removed.
The typical scenario is background music, which may want to be assigned to certain areas. For example, to
route music to the shop-floor areas in a factory complex unless another broadcast was active. It is possible
to allocate any output to any audio input by means of the permanent route mechanism.
If concurrent permanent routes are required to disparate zones, for example to route different music to two
different areas, then the background music input can be used for one source and Mic/Line Inputs should be
used for the additional music sources.
A permanent route does not cause a busy indication on any microphone, otherwise all zones
would appear permanently busy in a scenario where background music feeds all zones.
2.6.3

Remote I/O Units

The VAR8-ACU is able to support the connection of up to 6 Remote I/O Units (BMB01).
The BMB01 units provide additional analogue and opto-isolated digital inputs. This extends the control and
interfacing capability of the system. The BMB01 units are interfaced via a power and RS485 data link that
can be up to 1 km long, in order to interface to remote equipment.
2.6.3.1

RS485 Connections

The VAR8-ACU provides a single RS485 bus. Up to 6 Remote I/O Units may be connected in total, each
with a unique address, which is set up using an internal rotary switch.
Figure 3 Connections on RS485 Bus
RS485
VAR8-ACU
1
REMOTE I/O
The RS485 data link to the Remote I/O Units is fully monitored. In the event of communications failure, the
Router will log a fault. The fault code identifies the specific unit or units that are affected.
•
The maximum recommended distance for the RS485 data link is 1 km.
•
Only the last physical I/O unit in the chain should have the RS485 termination enabled.
VAR8-ACU and Variants - Product Description
2 3
REMOTE I/O REMOTE I/O
Issue: 02 complete, approved
Page 17 of 44
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REMOTE I/O REMOTE I/O
= 120 ohm
TERMINATION FITTED