Failure Relay - Bosch LA3-VARI-B Installation Manual

28 en | Connector and wiring details
5.6 External control input (10)
The VARI's internal memory has provision for an "emergency" configuration preset (Preset 7
by default) to be stored, and automatically recalled and loaded under certain programmable
conditions. This is a useful facility where the VARIs are being used as part of an emergency
evacuation system. (See VariControl "Help files" for more information on Presets.) The
emergency preset may also be recalled by an external DC voltage at the External control input.
The External control input is isolated by an opto-coupler. The emergency preset will be loaded
either on a logic high (5 – 24 VDC) or a logic low (2 VDC) at the input (programmable in
VariControl).
Connector type: 3‑pole, 3.81 mm-pitch:
Pin
4
5
6
5.7

Failure relay (11)

If continuous monitoring of the VARI via the RS‑485 network is not implemented, a simple
monitoring function can be realised with the Failure relay. This has two NC (Normally‑Closed)
contacts, which open when a fault condition arises. The definition of "fault condition" in this
context is programmed by the VariControl software when the unit is configured (see
VariControl "Help files" for more information). One set of contacts is fitted with internal
resistors to permit impedance-sensing fault-monitoring equipment (such as the supervised
control inputs of Bosch Praesideo units) to be interfaced. Note that one side of each contact
set is paralleled and brought out as the 'C' pin of the external connector.
Normal operation
Fault condition
Connector type: 3‑pole, 3.81 mm-pitch:
Pin
1
2
3
2018.06 | V1.3 |
Function
n/c
+ VDC
- VDC
Pin 3 > Pin 1
Short-circuit
Open-circuit
Function
C
NC (impedance-sensing)
NC (hard switching)
Installation manual
Pin 2 > Pin 1
10 kohm
20 kohm
VARI-directional array
Bosch Security Systems B.V.