9
3.5 Power supply
The input safety parameters for the BA384NG Rate
Totaliser power supply terminals 1 and 2 are:
Ui
=
30V dc
Ii
=
100mA
This allows the BA384NG to be powered from any
dc supply which in normal operation has an output
of less 30V and 100mA. See section 4.1 for power
supply recommendations.
3.6
Pulse input terminals
The BA384NG Rate Totaliser has two pulse inputs, A
and b, that may be individually configured for use
with different types of flowmeter. Each input is a
separate Ex nA circuit, although the negative side of
each input is internally connected to the negative
side of the power supply and the reset terminal RS2.
See Fig 1. The two inputs should not be connected
in parallel.
For flowmeters with sensors that require energising
to determine their state, such as a switch contact,
open collector or a 2-wire proximity detector in a
turbine flowmeter, fitting an external link between
terminals 3 & 4 of the BA384NG for input A and
between terminals 7 & 8 for input b, connects an
internal 7V, 6mA supply to the respective input.
Energising is not required when a BA384NG input is
connected to a voltage pulse source.
Fitting an energising link changes the safety
parameters of each BA384NG input as shown in the
following table which also shows the types of
flowmeter sensor requiring energising (link fitting).
Safety parameters
Input Output
Type of input Link
*
Ui Uo Io
Switch contact
Yes
15V
10.5V 9.2mA
Proximity detector
Yes
15V
10.5V 9.2mA
Open collector
Yes
15V
10.5V 9.2mA
Magnetic pick-off
No
30V
1.1V 0.5mA
Voltage input (low)
No
30V
1.1V 0.5mA
Voltage input (high) No
30V
1.1V 0.5mA
*For input A link terminals 3 and 4
*For input b link terminals 7 and 8
3.7 Remote reset terminals
The BA384NG total display may be reset by
connecting the external reset terminals RS1 and
RS2 together for more than one second. The two
reset terminals have the following safety parameters
in normal operation:
Ui
=
30V
Uo
=
3.8V
Io
=
1mA
3.8 Pulse output
The BA384NG Rate Totaliser has an isolated pulse
output which may be configured to synchronously
retransmit either of the two pulse inputs, or a
scaleable pulse when the least significant digit of
total display is incremented.
The pulse output is a passive unpowered open
collector which is isolated from all other Rate
Totaliser circuits. The output has the following Ex nA
safety parameters:
Ui
=
30V dc
Ii
=
100mA
This allows the pulse output to be connected to any
dc circuit providing that in normal operation the
maximum supply voltage is not greater than 30V dc
and the current is not greater than 100mA.
3.9 Certification label information
The BA384NG Rate Totaliser certification
information label is fitted in a recess on the top outer
surface of the instrument enclosure. It shows the
ATEX, IECEx and ETL certification information plus
BEKA associates name, location, year of
manufacture and the instrument serial number.
BA384NG Certification information label
