Planning Example: "Air Flow Measurement - ABB AE/S 4.2 Product Manual

®
ABB i-bus EIB / KNX
4.4 Planning example:
"Air flow measurement"
48
Planning and application
In a ventilation system, ventilation flaps should be controlled based on air
flow measurement. The ventilation flaps should be opened at an air flow
of 10 m/s and closed at an air flow of 8 m/s. In addition, an "ON telegram"
should be sent to a visualisation unit at an air flow of more than 30 m/s.
The current air flow should be visible on a display. The sensor should be
monitored with regard to wire breakage. Moreover, a telegram should be
sent to the bus at more than 5% of the maximum value.
Flow sensor:
Signal output:
Measuring range:
Measurement curve:
Connection to channel A
Measurement curve for the sensor:
20,00
16,00
12,00
8,00
4,00
0,00 5,00 10,00
Fig. 37: Measurement curve for the flow sensor
Measurement curve taking all specifications into account:
20
Threshold 1: lower limit
18
16
14
12
10
8
6
4
0,00 5,00 10,00
Fig. 38: Measurement curve for the flow sensor with threshold values
The "Measured value outside range – Channel A" communication object
covers both wire breakage and the demand for a telegram to be sent
at more than 5% above the maximum value.
4–20 mA
0...40 m/s
Linear
Measurement curve of the flow sensor
15,00 20,00 25,00
Measuring range in m/s
Measurement curve with threshold values
Threshold 1: upper limit
15,00 20,00 25,00
Measuring range in m/s
30,00 35,00 40,00
Threshold 2: upper limit
30,00 35,00 40,00