BEKA BA374NG, Manual

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Fig 4 Transferring status output to safe area.
3.2.9 Control outputs (optional)
Each of the two factory fitted optional control outputs
is a galvanically isolated single pole solid state
switch as shown in Fig 5. The outputs are polarised
and current will only flow in one direction. Terminals
A1 and A3 should be connected to the positive side
of the supply.
Ron = less than 5 Ω + 0.7V
Roff = greater than 1M Ω
Note: Because of the series protection diode some
test meters may not detect a closed alarm output.
Fig 5 Equivalent circuit of each control output
Each control output is a separate galvanically
isolated Ex nA circuit with the following input
parameters:
Ui = 30V dc
Ii = 200mA
This allows each control output to switch any dc
circuit providing that in normal operation the
maximum supply voltage is not greater than 30V dc
and the switched current is not greater than 200mA.
Providing that the BA374NG Timer or Clock is
correctly installed in Zone 2 the two control outputs
may be used to switch suitably protected equipment
located in a Zone 1 or 2 hazardous area, or
equipment located in a safe area.
Fig 5 shows a typical application in which a Zone 2
mounted BA374NG configured as a Timer is
measuring the time that a Zone 2 contact is closed.
Control output 1 is switching an Ex e sounder in
Zone 1 and control output 2 is switching a safe area
sounder.
Fig 6 Typical control output application
(Shown without recommended screened cables)