Pulse Factor Forward And Reverse Numeric Entry; Pulse Width Numeric Entries - ABB COPA-XE Instruction Bulletin

4.5 Pulse Factor Forward and Reverse
Numeric entry
The pulse factor is equivalent to the number of pulses for one
measured flow unit for the external output terminals V8/V9, or
terminals Ux/V8 and for the internal flow totalizer.
Pulse Factor
1.0000
If the pulse factor value is changed, the totalizer value is
maintained in the units selected. The pulse factor can be set in
the range from 0.001 to 1000 pulses/unit. The pulse factor
entered is checked against the selections for the flow range, the
pulse width (0.1 ms to 2000 ms), the totalizer units (e.g. ml, l,
m3) or mass units (e.g. g, kg, t) together with the density
correction factor. If any of these parameters are changed, the
pulse width cannot exceed 50 % of the period of the output
frequency at 100% flowrate (on/off ratio 1:1). If the pulse width
entered is greater it is automatically reduced to 50 % of the
period and the following message is displayed:
Warning! New
Pulse Width
If the output frequency is too small the following message is
displayed:
Error 41
Freq. < 0.00016 Hz
/m3
Electromagnetic Flowmeter
4.6 Pulse Width
Numeric entries
The pulse width (length of the pulses) of the scaled pulse output
can be set in the range from 0.1 ms to 2000 ms. For technical
reasons the pulse width is always a multiple of 0.032 ms. On
the one hand the pulse width must small enough so that at the
max. output frequency (flowrate max. 130 % = 5 kHz) overlaps
do not occur while on the other hand, it must be large enough
so that any connected instrumentation (SPC) can respond to
the pulses.
Example:
Flow range= 100 l/min (Q
max
Totalizer = pulses/liter
100pulses/min
f = -------------------------------------- - = 1.666 Hz
60s
and to cover the case when the flow range end value is
exceeded by 30 %
⋅
f = 1,666Hz 1,3=2.166 Hz (1/s)
On/off ratio of 1:1 (pulse on width = off width)
1
⋅
t = ----------------------- - 0,5= 230 ms
p
1
–
2,166s
It would also be possible to set any value < 230 ms. Counters
usually require a pulse width ≥ 30 ms.
Pulse Width
230 ms
The converter automatically checks the pulse width setting.
If its limit is exceeded, the new value is not accepted and the
following error message is displayed.
Error 46
Entry too large
COPA-XE / MAG-XE
= 100 %, flow range end value)
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