Flow vision FC100 - CA User Manual page 32

Flow Meter | FC100-CA
Electromechanical pulse counter (see fig. 21)
The FC100-CA driver output comprises an integral safety circuit which when isolating the counter
operating coil will limit overvoltages caused by inductance.
The counter should be able to process a counting frequency of ≥10 Hz as the pulse length is 50
ms (±1%) continuously.
It should therefore be ensured that the counter can be increased by one during the time available
If a separate relief network is preferred to the integral network, care should be taken when process-
ing the max. frequency of 10 Hz to ensure the energy stored in the operating coil has dissipated by
the time the counter output is switched on again. The time to do this should be below 40 ms, making
due consideration to switching times and pulse variations.
Typical circuit (example 2)
XSE
1 2 3 4
t - pick-up time
ON
t - time constant of breaking current
L
Note:
• As there will be a reset pulse available at the output in the moment the supply voltage of the
FC100-CA is applied, make sure that the counter is switched on delayed or set to zero after it
has been switched on.
32
INSTALLATION
XAO
1 2 3 4 5 6 7 8 1 2
i
C
XAH
3 4 5 6 7 8
zener voltage
U
C
U
V
t t t t
L ON
inductance of the counter drive
fig. 21