30
Fig 17 Pulse output menu
9.4.1 Intrinsic safety
The pulse output is an optically isolated
separate intrinsically safe circuit which has
zero output safety parameters. The output
therefore complies with the requirements for
simple apparatus. This allows terminals P1
and P2 to be connected to any intrinsically safe
circuit protected by a certified Zener barrier or
galvanic isolator providing the output
parameters do not exceed:
Uo =
28V dc
Io
=
100mA
Po =
0.7W
The maximum equivalent capacitance and
inductance of the BA334D pulse output is:
Ci
= 20nF
Li
= 20µH
To determine the maximum permissible cable
parameters, these figures should be subtracted
from the maximum cable capacitance and
inductance specified by the system certificate
of the circuit connected to the BA334D. Fig 16
shows how the pulse output circuit may be
powered from the BA334D supply to drive a
counter in the safe area via a diode return
barrier.
9.5 4/20mA output
The BA334D can be supplied with an isolated
4/20mA current sink which may be
programmed to produce an analogue output
proportional to the whole or part of the rate
display.
9.5.1 Intrinsic safety
The 4/20mA current sink has been certified as
a separate intrinsically safe circuit complying
with the requirements for simple apparatus.
This allows terminals C1 and C2 to be
connected to any intrinsically safe circuit
protected by a certified Zener barrier or
galvanic isolator providing the output
parameters do not exceed:
Uo =
28V dc
Io
=
100mA
Po =
0.7W
No system certificate has been issued for this
output as the system certificate for the circuit to
which it is connected remains valid.
Fig 18 Application of 4/20mA output
Summary of Contents for BA334D
Page 12: ...12 Fig 7 Dimensions and terminal connections ...
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