BEKA BA514G, Manual

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8.5 4/20mA output
The BA514G Tachometer can be supplied with a
factory fitted galvanically isolated 4/20mA output
which may be configured to represent any part of the
Tachometer speed display.
8.5.1 System design
The Tachometer 4/20mA output is a passive current
sink i.e. not powered, but it is totally isolated from all
other Tachometer circuits. It is effectively a 2-wire
4/20mA transmitter requiring a minimum supply of 5V
with its current being controlled by the Tachometer
speed display. Terminals C2 and C4 are internally
linked and may be used for joining a return 4/20mA
wire.
Fig 14 Application of 4/20mA output
(Shown without recommended screened cables)
Fig 14 shows a typical application in which a BA514G
Tachometer is transmitting a 4/20mA current to
another instrument.
8.5.2 Configuration and calibration
When a Tachometer is supplied with an optional
4/20mA output the configuration menu is extended
as shown in Fig 15. The 4/20mA output sub-menu
is accessed via the
4-20 oP
function.
The 4/20mA output is controlled by the Tachometer
speed display, the speeds corresponding to 4 and
20mA output are defined in the sub-menu.
Fig 15 4/20mA output configuration sub-menu
8.5.3 Access 4/20mA output sub-menu:
4-20 oP
Access the Tachometer configuration menu as
described in section 5.2. Using the
&
and
*
push
buttons scroll though the menu until
4-20 oP
is
displayed, pressing
(
will then access the 4/20mA
output sub-menu which is shown in Fig 15.
8.5.4 Enable 4/20mA output:
EnbL
This function allows the 4-20mA output to be
enabled or disabled without altering any of the
output parameters. Using the
&
or
*
push button
select
EnbL
in the
4-20 op
sub-menu and press
(
which will reveal the existing setting
on
or
oFF
.
The function can be changed by pressing the
&
or
*
push button followed by the
)
button to return
to
EnbL
prompt in the sub-menu.
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