15
1.5.5.5. Universal output
The flow meter has a non-isolated universal output that can operate
in frequency, pulse and logic modes.
The functions of the universal output, operating modes, output pa-
rameters and output disconnection are defined by the software settings.
The diagram of the output terminal stage and the description of its
operation are given in Appendix B.
In the frequency mode, a pulse sequence of meander type with a
duty cycle of 2 is given to the open output, the frequency of which is pro-
portional to the current value of the flow rate. It is possible to scale the
frequency output operation by software setting the
Maximum output fre-
quency
or
Output conversion factor
, as well as the lower and upper
flow limit values of
Lower limit by flowrate
and
Upper limit by flowrate
,
corresponding to the sequence frequency of 0 Hz and the maximum fre-
quency, respectively. The maximum possible value of
Maximum output
frequency
is 1000 Hz in ADJUSTMENT mode and 10 Hz in WORK and
SERVICE modes.
Error frequency
is pulse sequence frequency (not more than 10
Hz), which will be formed at the output if the measured value of the flow
rate exceeds the value of Q
max
for this DN flow meter. The target value of
Error frequency
must be at least equal to the target value of
Maximum
output frequency
. To disable the alarm frequency output function, set
Error frequency
to 0 Hz.
In pulsed operation mode, a pulse burst is given to the open output
every second, the number of which, considering
Pulse weigt
, corre-
sponds to the volume value measured in the previous second. The max-
imum possible pulse repetition rate in the burst (of meander type with a
duty cycle of 2) is 1000 Hz in ADJUSTMENT mode and 10 Hz in WORK
and SERVICE modes.
For correct operation of the flow meter's universal output there is
a procedure of automatic calculation of
KP
parameter (pulse/m
3
) in fre-
quency mode and
Pulse weigt parameter
(m
3
/pulse) in pulse mode.
KP
parameter is calculated based on user-defined values of
Q lower
limit
,
Q upper limit
and
Fmax
,
Pulse weigt
parameter is calculated on
the basis of defined values of
Q upper limit
and
Pulse width
in the
range:
- From 1 to 1000 ms
– in ADJUSTMENT mode
- From 100 to 1000 ms
– in WORK and SERVICE mode.
In the logic mode, the presence of an event (or its certain condi-
tion) at the output corresponds to one level of electrical signal at the out-
put, and the absence of an event (or its other condition)
– to another level
of signal.
The active signal level (
Active level
), i.e. the level of the signal cor-
responding to the presence of an impulse (event), is set by setting the
High
or
Low
value
in any operation mode. The electrical parameters of
the signal levels are given in Appendix B.
When released from production, the typical values of universal out-
put parameters are set: pulse type, passive mode, pulse weight
– 0.0025
m
3
/pulse.
