UV Flame Detector AC230V QRA75.A27 PLC Module

Overview

QRA75.A27 is an ultraviolet (UV) flame detector, commonly known as electric eye or photoelectric tube. It is commonly used for flame safety monitoring of burners, boilers and other equipment. The core is adapted to gas and oil combustion scenarios. It has a built-in UV photoelectric tube with dual electrodes. It only reacts to ultraviolet light in the 190-270nm spectral range and can accurately identify gas flames and yellow/blue fuel flames. It can monitor the combustion status by detecting ultraviolet signals in the flame, and at the same time cooperate to control the ignition spark, and will not accidentally trigger the hot refractory bricks, sunlight or lighting light in the combustion chamber, thereby ensuring the safe operation of the combustion equipment.

FAQ:

1. What are the wiring methods and pin definitions between QRA75.A27 and the combustion controller?

As a UV flame detector, QRA75.A27 is often adapted to LFL, LME, LMV and other series of Siemens combustion controllers. Its pins are defined as a fixed 3-pin design. The wiring must match the corresponding interface of the controller and must follow the anti-interference wiring specifications:

1. Pin definition: Pin 1 (L) is connected to the AC230V live wire, pin 2 is connected to the flame detection signal terminal of the controller, and pin 3 (N) is connected to the neutral wire;
2. Wiring method: corresponding to the UV interface of the controller, special models need to be connected to the RC unit;
3. NOTE: Route high voltage cables separately, away from other conductors.

2. What abnormalities will occur if the ambient temperature of QRA75.A27 exceeds the range?

The normal operating temperature range of QRA75.A27 is – 20℃~+60℃. Exceeding this range will affect its photoelectric components, circuits and signal transmission, etc., thus causing a series of abnormalities:

1. High temperature (>60℃): UV photoelectric tube sensitivity decreases, signal fluctuations, circuit failure, and controller interlock shutdown;
2. Low temperature (<-20℃): signal delay/distortion, mechanical action lag, false alarm due to frost on the glass window, difficulty in starting.