SI5012
Flow monitor
6
4 Function
The device detects flow based on the calorimetric measuring principle and switches the output.
For the factory setting the switch point is at LED 7 and the device is set to normally open. The output
can be switched to normally closed function. The switch point LED indicates the switching status:
orange = output closed; red = output open.
With normal flow, the output has the following status:
•
output closed for normally open function
•
output open for normally closed function.
Fig. 1: Flow ≥ SP / normally open function
Fig. 2: Flow ≥ SP / normally closed function
If the flow velocity decreases, the switching status changes when the value falls below the switch point
SP minus the hysteresis.
Fig. 3: Flow < SP / normally open function
Fig. 4: Flow < SP / normally closed function
The hysteresis changes with the flow velocity and it is essentially influenced by the set
monitoring range. It is 2...5 cm/s for the setting 5...100 cm/s (= factory setting), it increases with
higher flow velocities.
The typical response time of the device is 1 ... 10 s. It can be influenced by the setting of the switch
point:
•
Low switch point = quick reaction with rising flow.
•
High switch point = quick reaction with falling flow.
See: Changing the switch point (
13).
