If I'm writing in the wrong section, please help me to understand the write section.
You cannot read the temperature from that output. You can only read if the temperature is in "normal" or "abnormal" range. The document you linked to does not define what "normal" and "abnormal" mean, or how to change that, if it can be changed.
Duplicate topics mergedRather than start a second topic you could have reported your original to a moderator and asked for it to be moved
Use digitalRead() to read the signal.
Unless the output is in "pulse mode" in which case use pulseIn(). I have no idea what the advantages of one mode would be compared to the other. The document does not explain them or how to change the mode.
(revised) To read the normal/abnormal signal from that device with an Arduino Uno, use the circuit diagram in the upper right corner of the posted photo. Connect the upper (collector) lead to a 10K resistor, which is in turn connected to Arduino 5V. Connect the lower (emitter) lead to Arduino GND. For safety, as the diagram shows, you can use a 10K resistor between the collector and any digital input on the Arduino. MAKE SURE that you know which device output lead is the collector, and which is the emitter.Use digitalRead() to read the signal.
how can I convert this to celsius
how can I convert this to celsius?