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APPLICATION EXAMPLES:  Temperature or analog function Clock & timer combination Lighting schedule Time control

Temperature  Control : In this example ventilation fans are operated to lower the indoor temperature when it exceeds the specified ranges. A temperature sensor (thermocouple or Pt100) and the Alpha series' analog input (0 to 10 V), Offset Gain, and Schmitt Trigger are used to control the ventilation fans.

The second fan is controlled via a Delay Timer which sets a certain time difference between the starting time of the two fans.

Contents of Control:

1. When the automatic mode button (S1) is pressed, the automatic operation of the ventilation fans starts. If the indoor temperature exceeds 40 °C, the fans rotate until the temperature falls below 30 °C. This automatic operation continues until the stop automatic mode button (S2) is pressed.
2. When the manual mode ON/OFF button (S3) is pressed during the automatic operation, manual mode is entered. The fans operate according to the status of the button (S3).
3. When the manual mode ON/OFF button (S3) is set to ON, the fans rotate, and when it is set to OFF, the fans stop.
4. Fan 2 starts 30 seconds after fan 1 has started.

How to use a temperature sensor (thermocouple or Pt100) with the ALPHA series and how to convert a value into degrees [°C]:

a) Using a temperature sensor (thermocouple) with the Alpha series
The electromotive force is too small. Therefore, it needs to be converted into 0 to 10 V using a dedicated signal converter (available from specialist suppliers).

b) Converting the value into degrees [°C]
In this example -20 to 80 °C have to be converted into 0 to 10 V. Set the following linear function calculation in the Offset Gain function block to convert the input voltage into an analog value

Installing and Wiring

Program: