Burkert Flowave 8098, Operating Instructions Manual

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Outputs – Parameter
Type 8098 FLOWave L
→
Choose the process value associated to the digital output
If the high value is equal to the low value, the digital output is deactivated.
→
Set the high value of the frequency range
→
Set the process value which is associated to the high value of the frequency range
→
Set the low value of the frequency range
→
Set the process value which is associated to the low value of the frequency range
The
New settings
are displayed.
→
Save.
The digital output is configured as a frequency output.
18.5.4 Configuring a digital output as a pulse output
When the digital output is configured as a pulse output, it transmits:
• either a number of pulses proportional to the measured volume ( pulse/volume ),
• or 1 pulse each time a set volume of liquid has been measured by the device ( volume/pulse ),
• or a number of pulses proportional to the measured mass ( pulse/mass ),
• or 1 pulse each time a set mass of liquid has been measured by the device (
mass/pulse
).
By default, the value of the parameter pulse/volume is set for the full scale of the flow-rate meas -
urement range. Observe the following rules to adapt the value of the parameter pulse/volume to
your flow-rate measurement range:
• Make sure that the maximum flow rate value (in litres per second) multiplied by the pulse per litre
value is lower than 2000 pulses per second. Pulses above the 2000 pulses/s limit are not trans -
mitted immediately but are accumulated. The accumulated pulses are transmitted as a block
when the 2000 pulses/s limit is no longer exceeded.
• The pulse output of the device is connected to an input of another equipment, for example a PLC.
Take into account the frequency of the input, because it can be lower than the maximum pulse
frequency that you have set.
Calculation example for the number of pulses per volume:
Consider a device with DN40 ISO process connections. The following device data are needed:
• maximum measurable flow-rate at a liquid velocity of 10 m/s:
925 L/min
→
Read the maximum flow-rate value in
Outputs Parameter Output 1: analog
or
Output 3: analog Settings Current settings 20 mA value
or on the test
report that is delivered with the device.
• default number of pulses per volume unit:
100 pulses/volume unit
Data for your application with a maximum measurable flow-rate of 400 L/min = 6.6 L/s
• number of pulses per volume unit with a safety margin of 5 %, in order to not exceed 2000 Hz:
(2000 – 5 % x 2000) / 6.6 L/s = 287 pulses/litre
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