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BASI
5.1.2
Frequency output
Frequency output is provided via galvanically
isolated NPN transistor switch. Voltage drop on the
switch is 1 V during on state. Maximum switched
voltage is 50 V. Maximum switched current should
not exceed 100 mA. Positive output is on terminal
FREQ, negative output is on terminal COM.
Frequency range of the output is 10 Hz to 12 kHz.
Note 1: Frequency, impulse and status outputs are
galvanically connected to each other and
galvanically isolated from other electronic
circuits.
Note 2: Active frequency output uses the power
supply of the current output. Total current
consumption from this power supply must
be less than 40 mA. Active frequency output
is galvanically connected to current output.
Note 3: In case of using this output as a passive,
external source and current limiting is
necessary.
5.1.2.1 Mode
The frequency output can be programmed in one of following modes:
a) Off
b) Positive Flow
c) Negative Flow
d) Absolute Flow
e) On Positive
f)
On Negative
g) On In
h) On Out
i)
Dose On
j)
Dose Off
k) On<F2
l)
On>F2
m) Fixed
If setting the flow limit is chosen, hysteresis H can be set too. Hysteresis is a tolerance field on one side of
flow limits PF1 and PF2. The output status changes (indicates crossing over the pre-set limit), when the
immediate flowrate crosses over the value PF2 (or goes below limit PF1). The output status comes back to
the default status, when the immediate flowrate decreases under the value PF2-H (or increases over limit
PF1+H) again.
Mode g ) with non-zero hysteresis:
Operation manual
output is not active (HI state).
frequency 1000*Flowrate/Qf [Hz] is generated for positive flowrate
direction.
frequency -1000*Flowrate/Qf [Hz] is generated for negative flowrate
direction.
frequency 1000*abs(Flowrate)/Qf [Hz] is generated for both flowrate
directions.
output is HI in case of negative flow and LO in case of positive flow.
output is HI in case of positive flow and LO in case of negative flow.
output is LO, when flowrate is higher than PF1 and lower than PF2,
otherwise it is HI.
output is HI, when flowrate is higher than PF1 and lower than PF2,
otherwise it is LO.
output is LO, when programmed dose is being measured and HI when the
dose is out.
output is HI, when programmed dose is being measured and LO when the
dose is out.
output is LO, when flowrate is lower than PF2, otherwise it is HI.
output is LO, when flowrate is higher than PF2, otherwise it is HI.
frequency output is adjusted to fixed value (10 ... 12000 Hz)
OFF
ON
PF1 PF1+H
Electromagnetic flowmeter BFM921
PF2-H PF2
25
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