Field-installation Type Dissolved Oxygen Meter (Four-Wire Transmission, Optical Type)
Optical dissolved oxygen sensor with no electrolyte replacement and rugged membrane.
Highly intelligent, including automatic recognition of membrane properties when replacing the sensor cap.
The HD-200FL is an optical (fluorescent) dissolved oxygen meter suitable for monitoring aeration tanks used for sewage treatment, effluent treatment, and other processes. Compared to conventional membrane polarographic type sensors, there is no need for electrolyte (internal fluid) replacement or warming, up. Characteristics of optical sensors are utilized to realize unequaled, improvement in ease of maintenance and reduction in running costs. Moreover, it features enhanced user-friendliness, with sensor caps that have built-in memory and a membrane replacement notification function.
* Lifetime of sensor caps may vary with the environment in which they are used.
Exposing an oxygen sensing membrane that contains a special fluorescent substance with excitation light causes fluorescent light to be emitted.
The light emission intensity will be strongest in the absence of oxygen, and will decrease by quenching if oxygen molecules are present. Light emission time shows the same relationship as strength of light emission intensity, being the longest in the absence of oxygen, and shortest in its presence. Oxygen concentration and light emission time are inversely related, as shown in the diagram below. Light emission time measurement employs the phase difference detection method, which is mostly unaffected by dirt on the sensor surface and changes in sensitivity.
Automatic recognition of parameters eliminates the need to input a distinctive membrane count when replacing the sensor cap (fluorescent membrane).
In the aeration tank (without feedback by DO)
Accumulation of dirt is prevented with its self-cleaning function that uses flow rate of the measurement liquid.
The nose shape of the float
FH-101 (Vertical type)
SFH-201 (Slanted type)
DH-151 series (insertion type)
|Immersion jet washer||Immersion jet washer||Relay box||Mounting brackets|
|Measuring method||Optical (fluorescent)|
|Measuring range||DO: 0 to 20 mg/L Resolution: 0.01 mg/L|
Saturation: 0 to 200% Resolution: 0.1%
Temperature: 0 to 50°C Resolution: 0.1°C
|Repeatability||Within ± 1% of full scale|
|Linearity||Within ±2% of full scale|
|2 points 4 mA to 20 mA DC output isolated type Maximum load resistance 900 Ω|
Range 1: DO concentration: Freely selectable within the measurement range
Range 2: Temperature: Freely selectable within the range from -10.0 to 110.0°C
Alarm: Burnout function (3.8 mA or 21 mA)
Hold: Selectable from previous value hold, optional value hold
|3 points Dry contact output Relay contact, SPDT (1c)|
Signal R1, R2: upper limit alarm, lower limit alarm,
hold, Cleaning (selectable)
FAIL : Alarm
Control operation Control width: 0.02 to 4.00 mg/L (±0.01 to ±2.00 mg/L)
|1 point Wet contact output (connecting power supply voltage output) Relay contact, SPST (1a)|
Contact function: Solenoid Valve Control
|External input||1 point Contact shape: Open connector dry ‘a’ contact|
Contact function: Cleaning Unit Control
|Communication function||RS-485 2-line, insulated input/output (transmission output is not insulated)|
|0 to 50°C|
|Calibration method||Atmosphere span calibration, zero liquid (sodium sulfite) calibration, span liquid (atmosphere saturation liquid) calibration|
|Self-diagnosis function||Calibration error, sensor diagnosis error, converter alarm|
|Operating temperature range||-20 to 55°C (Should not be frozen)|
|Power supply||90 to 264 V AC 50/60 Hz Power consumption: 15 VA (max)|
|Structure||IP65 : 50 A pole or wall mounting|
Case: Aluminum alloy Mounting brackets, hood: SUS304
|Mass||Main unit body: Approx. 3.5 kg Hood, mounting brackets: Approx. 1 kg|
|Regulatory compliance||CE marking, FCC|
＊1 When extending the sensor cable, transmission cable, or contact input cable 30 m or more, the CE marking EMC directive surge test does not apply.
＊2 An arrestor (inception voltage: 400 V) is mounted on the unit for transmission output, contact input, and communications. However, an optimal surge absorber should be installed on the connecting line depending on the surrounding environment, equipment setup, externally connected devices, etc.
|Measurement principles||Optics (fluorescence)|
|Sample water||0 to 50°C|
|Response time||90% response: Within 30 s 95% response: Within 60 s|
|Mass||Approx. 3.0 kg (incl. 10 m cable)|
|Wetted material||NBR, PMMA|
|Mass||Approx. 5.0 g|
|Membrane memory||Built-in memory in the membrane unit, automatic recognition|
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