The QR-508A dissolved oxygen controller is paired with a fluorescence dissolved oxygen controller

The outdoor waterproof and dustproof design is suitable for wall installation, coil installation and round pipe installation

Provide contact points for the automatic electrode cleaning device and program setting output

It is equipped with a backlight sensor and has both automatic and manual backlight setting functions

With automatic correction; Manual and automatic temperature compensation functions

The password lock and combination key enter the setting and calibration mode design to enhance security protection

It features the RS-485 standard MODBUS communication protocol and can be directly connected to digital systems

Name	Dissolved Oxygen Sensor
Model	QR-508A
Measuring Principle	Fluorescent method
Range	0-50mg/L or 0-500% saturation
Accuracy	0-20mg/L: ±1% or ±0.2mg/L ＞20mg/L: ±5% or ±0.6mg/L
Response Time	20S
Maximum Water Depth	30m
Temperature Range	0-50℃
Sensor Interface	RS-485, Modbus protocol
Power	0.1W (brush off), 0.8W (brush on) Power supply: DC9-24V, ≥1A
Mounting	NPT3/4 thread, immersion installation
Sensor Dimension	Φ48mm×197mm
Self-cleaning System	Integrated self-cleaning brush
Cable Length	10m (default), customizable
Calibration	1-point or 2-point calibration
Fluorescent Cap Service Life	1-year guaranteed service life (normal operation)
Housing Material	316L (titanium alloy optional)

Note: All technical parameters above are tested in laboratory standard solution environments. Sensor lifespan and maintenance/calibration frequency depend on actual field conditions.

Ac power supply: 100V to 240VAC±10%, 50/60Hz

Dc power supply: 20 to 40VDC

Operating temperature: 0-50℃

Instrument dimensions: 144mm×144mm×115mm (H×W×D)

The protection grade complies with IP65 (NEMA 4)

Installation methods: wall mounting, panel mounting, and round pipe mounting

Hollowed-out dimensions: 138mm×138mm (H×W)

Weight: 0.8Kg

The fluorescence dissolved oxygen meter is based on the principle of fluorescence quenching. When blue light shines on fluorescent substances, it excites them and emits red light. Because oxygen molecules can carry away energy (quenching effect), the duration and intensity of the excited red light are inversely proportional to the concentration of oxygen molecules. By measuring the phase difference between the excited red light and the reference light and comparing it with the internal calibration value, the concentration of oxygen molecules can be calculated.