BEKA BA368C, Руководство пользователя

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Fig 2.6 4/20mA output programme structure
Note: If the counter display calibration is changed
by adjusting the scale factors, timebase or the
position of the displayed decimal point, the 4/20mA
output will automatically be set to give a constant
3.5mA output irrespective of the total or rate
display. The 4/20mA output must therefore
always be recalibrated following recalibration of the
counter.
2.8 OPTIONAL PULSE OUTPUT
The BA368C can be supplied with an isolated
retransmitted pulse output which may be used to
operate remote instrumentation. The pulse output
is only functional when the BA368C is
programmed as a counter with an ‘A : b’ input
count mode (Input A + Input B). See section 2.5.4
This output is a polarised current sink so current
will only flow in one direction. Terminal P1 should
be connected to the positive side of the supply.
Ron = 60
Ω
+ 3V
Roff = 1M
See section 1.9.4.1 for details of intrinsic safety.
2.8.1 Programming and adjustment
The main counter programme menu is extended
as shown in Fig 2.7 to accommodate the re-
transmitted pulse output calibration functions.
How frequently a pulse is generated is defined by
the ‘diUidE’ function. When set to 1, an output
pulse will be generated each time the least
significant digit of the total display is incremented.
This may be reduced in multiples of 10. e.g. if
‘diUidE’ is set to 1,000 the least significant digit
must be incremented 1,000 times before an output
pulse is generated.
Output pulse width is determined by the ‘durAtion’
function which allows the width of the output pulse,
and the minimum time between pulses, to be set
between 2.5ms and 50ms.
The re-transmitted output pulse is not synchronous
with the input pulse. If the two pulse output
functions are set such that there is not enough
time for the BA368C to output the required number
of pulses in real time, they will be stored and
output as quickly as possible.
If the instrument power supply fails or is
disconnected, any untransmitted output pulses will
be lost.
Fig 2.7 Pulse output menu