ASL453/24
Electronical air flow switch for air (SLF + ASL)
Evaluation Units for SLF3 sensor
Evaluation Unit, output SPDT 230V 8A, Power supply 24V
SWL
Air flow monitoring
The SLF... sensor can be used in combination with an ASL… evaluation device to monitor the flow in the air (e.g. in air-conditioning systems).
The switching point is adjustable. While the fan starts up the switch-on bypass is active. The bypass duration (2 – 60 s) is adjustable.
Function
The air flow monitors work according to the calorimetric principle. A thermistor is heated up. As heat is withdrawn by the flowing air, the thermistor resistance alters. The change in resistance is evaluated. As the resistance also depends on the temperature of the medium, the difference must be determined by a second thermistor. The difference is compensated and in this way the switching point is kept stable. Suspended materials adhering to the sensor can have an insulating effect and so affect the measurement result and hence the defined switching point. Therefore it is advisable to remove any dirt during routine maintenance operations.
Switch-on bypass
While the plant is being started up (still no airflow present), the output contact is activated and the flow condition signaled. The time for the switch-on bypass is adjustable from 2-60 s. The start-up or switch-on bypass starts when the unit is switched on. If an external start button (normally closed contact) is connected (to the Z-Z terminals), the start-up bypass begins when the (locking) button is pressed.
Type Supply voltage
SLF3 Sensor, 35 mm –
SLF15 Sensor, 150 mm –
ASL453 Evaluation unit 230 V AC
ASL453/24 Evaluation unit 24 V AC/DC
Technical data of sensor:
General
Fast-reacting air flow sensor with movable flange for installation in air ducts. With
temperature compensation, suitable for media with rapid temperature changes.
Medium temperature -20…+100°C
Compensation behavior (Reaction speed on change in medium temperature) fast, approx. 0.3 s
Installation depth 35 resp. 150 mm
Sensor tube diameter 10 mm
Sensor tube material nickel-plated brass
Measuring element
Insensitive to moisture (can be cleaned inwater). Sensitive to mechanical deformation (care must be taken when cleaning with hard objects).
Protection class IP67
Electrical connection
Terminal strip accessible after removal of cover. 3-wire connection to evaluation unit
Mounting conditions
The sensor tip should be placed in the midst of the pipe and must be bathed completely from the medium. Please provide a straight pipe: 5x the pipe diameter before and after the sensor device.
Technical data of evaluation unit:
Power supply 230 VAC or 24 VAC/DC
(see Product Summary)
Power consumption approx. 3 VA
Contact load
Relay, single pole 8 A, max. 250 VAC
Ambient temperature 0 – 60°C
Flow rate
Adjustable from 0.1 to 20 m/s for gaseous media
Response time 1…5 s
Temperatures > 80 °C, degree of contamination and flow velocity will reduce the response time.
Repetition accuracy
<2%, relative to the flow rate directly on the sensor.
Switching hysteresis approx. 2% of overall range
Max. cable length between sensor and evaluation unit
100 m, for shielded cable 1.5 mm2
Sensor protection
In case of breakage or interruption of the
sensor wires, the unit switches off or an
interruption of flow is signaled.
Type of construction Standard housing N 45
Weight approx. 0.35 kg
SLF3 |
Electronical air flow switch for air (SLF + ASL) | - Price - |
ASL453 |
Evaluation Units for SLF3 sensor | - Price - |
ASL453/24 |
Evaluation Units for SLF3 sensor | - Price - |
SWF62 |
Electronical flow switch for liquid and air (SWF + ASW) | - Price - |
SWF62L |
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ASW454 |
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ASW454/24 |
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