BEKA BA458C, Manual

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Fig 6 Batch controller powered by a galvanic
isolators with input in hazardous area.
Fig 7 Batch controller protected by galvanic
isolators with input in the safe area.
4.3.2 Inputs
When the batch controller is powered from a
galvanic isolator, the pulse and analogue
inputs remain the same as described in
sections 4.2.2 and 4.2.3. Only when the input
transducer or source is in the safe area, as
shown in Fig 7, are galvanic isolators required
in the input circuit.
Any EEx ia IIC certified galvanic isolator may
be used providing that the safety parameters
of the isolator terminals are compatible with the
safety parameters of the batch controller input
terminals to which it is connected. The
galvanic isolator must also be able to transfer
the required type of input into the hazardous
area.
4.3.3 Switch outputs
WARNING
These switch outputs should not be
used for critical safety applications.
When the batch controller is powered from a
galvanic isolator, the switch outputs remain the
same as described in section 4.2.4 Only when
the switch output is required in the safe area is
a galvanic isolator required. A wide variety of
switch transfer isolators are available with a
selection of relay and solid state outputs.
Again the output parameters of the galvanic
isolator must be less than the maximum
permitted input parameters of the batch
controller switch.
4.4 External switches
For applications requiring the batch controller
to be operated via large industrial push-
buttons, four external switches may be
connected as shown in Fig 2. Unlike the front
panel pushbuttons, each external switch has a
dedicated operating and configuration function.
Switch
number
Switch function when
Operating Configuring
S1 Start Down
S2 Stop Up
S3 Reset P
S4 Menu E