Q46H-62/63 Residual Chlorine Monitor

Residual Chlorine Monitor - detects free or combined chlorine from 0-200 ppb up to 0-200 ppm. Standard PID loop, relays, and 4-20 mA output signals. Automatic pH compensation to maintain highest accuracy at pH levels up to 9.5. Dual Chlorine/pH monitoring system. 

Chlorine Information



Monitoring Free or Combined Chlorine!

 The Q46H/62-63 Residual Chlorine Meter provides accurate and reliable free or combined chlorine monitoring for your treatment systems.  The Q46H offers a variety of output including 4-20mA output (x2), PID control, three adjustable relays, and digital communications. Digital communication through Profibus DP, Modbus RTU, Modbus TCP, or Ethernet IP.

 Q46H/62-63 Residual Chlorine Monitor Specifications

Sensor Type

 Membrane-covered Polargraphic (flow type or submersible)


0-2.000, 0-20.00, or 0-200.0 PPM

Response Time

 90% in 60 seconds


 0.5% of selected range or 0.02 PPM


 0.3% of selected range or 0.01 PPM

Zero Drift

 < 0.01 PPM/month

Analog Output

Two isolated 4-20 mA, 500 Ώ load max. (3rd output optional)

Relay Output

Three SPDT, contacts rated 6 amp @ 250 VAC, 5 amp @ 24 VDC (3 additional low power SPST non-isolated relays optional)

Operating Conditions

 0-50-deg C


 NEMA 4X (IP-66) Polycarbonate, V-0 flammability


 4 digit, 0.75” numeric LCD with 12 digit second line, LED back light


 6 lbs. (2.7 Kg), includes flowcell and accessories 

Sensor Cable

 25 ft. (7.5 m) standard

Temperature Limit

 -5-55-deg C

Pressure Limit

 0-50 PSIG (Pressure controlled to fixed value)

Flowcell Materials

PVC & 316SS


  • All systems are supplied w/one package of membranes, one 120 cc bottle of electrolyte, & one spare parts kit containing 3 each of all o-rings & special screws.

  • Suffix D, 2, 3, or 4 allow Q46H to supply outputs for both chlorine & pH.

  • Flowcell for Cl2 / pH combo systems should be kept within 25 ft of monitor.

  • Buffer packet for pH 4 & 7 supplied with opt. 2, 3 or 4, suffix D.

  • Pipe mount requires two 2” U-bolts (47-0005).


Q46H/62-63 Features

  • Free or Combined Chlorine - Monitors are factory set for either Free or Combined Chlorine, but can easily be converted from one to the other in the field.

  • AC or DC Power Options - Power options include universal 90-260 VAC or 12-24 VDC

  • Analog Output -  Two isolated 4-20 mA outputs are standard, with an option for a third output if required. Default setting provides analog outputs for Chlorine and pH.

  • PID Output - Standard PID control function assignable to one analog output.

  • Relay Outputs - Three SPDT relays are standard

  • Clear Display - Back-lit large LCD display provides clear visibility in any lighting conditions. A scrolling second line on the display provides additional information and programming prompts.

  • Dual Chlorine/pH Monitoring- Even when pH correction is not required, adding a pH sensor converts the monitor to a dual analyzer, providing 4-20 mA outputs for both Chlorine and pH.

  • Flexible Mounting - NEMA 4X (IP-66) enclosure is suitable for wall, pipe, or panel mounting.

  • Economical Operation - Reagent-less operation and low parts cost makes the Q46H the best choice for chlorine monitoring.

  • Automatic pH Compensation - For free chlorine monitoring under widely varying pH conditions, automatic pH compensation may be added to maintain the most accurate measurements at pH levels up to 9.5.

  • Flexibility - Programmable range options from 0-200 PPB up to 0-200 PPM.


Sensor & Flowcell Options

 There are two available types of chlorine sensors, submersion and flowcell. Free chlorine monitoring should always use flowcell systems. Sealed flowcell and low-volume flowcell sensors are available as well.

Submersible combined chlorine sensors can be used for meausing total chlorine in wastewater effluent. Direct measurement with a submersible provides dependable monitoring without the need for sampling and chemicals.

Sealed Flowcell

The sealed flowcell allows for a controlled flow of water that can then be pushed under slight pressure to a drain location.  Water flow must be well controlled externally to a flowrate of about 400 cc/min.  Variable flowrate or pressure will cause unstable readings in the sealed flowcell.  A special flow control element can be purchased ahead of this device.  It is part number 55-0048.

Slight pressure, up to 2 PSI is acceptable on the cell to allow water to drain to a remote location through tubing.

 Constant Head Flowcell

The dissolved chlorine dioxide sensor will provide the best performance when used with the constant-head flowcell.  Water pressure on the sensor and water flow are automatically controlled via the gravity flow chambers in the flowcell.  Water flows of 400 - 500 cc/min will be used.

Low-Flow Flowcell

Low-flow sensor flowcell is used to reduce the amount of water used for chlorine detection in water. This is a great option for applications where low water flow rates are required. Sample water flow rates of 150 – 300 cc/min can be used with the low-flow flowcell.

Passages in the low-flow flowcell are very small, therefore, clean water is required. Flow rate can be measured and controlled by a rotometer installed on the inlet side of the flowcell. Water flow should not vary more than 5 cc/min.

Flowcell Sensor

The Flowcell Sensor is used for each of the flowcell systems shown above. There are threads on the sensor body that allow the sensor to thread into the low-flow sensor flowcell and the sealed flowcell. The long smooth end will fit snugly in the constant-head flowcell and seal with o-ring seals integrated into the constant-head flowcell.

Submersion Sensor

For submersible applications we offer the submersion sensor. This sensor can be dropped into a tank of water for chlorine measurements in water. This sensor could also be mounted into the side of a tank permanently.

Ensure no more than 2-3 PSI of water present is pressure on the sensor at any time. Water pressure must also be consistent for accurate measurements of chlorine in water.




 Sensor Stabilization

 Chlorine sensors require up to 8 hours of stabilization at first installation or after membrane change. A sensor polarizer can be used to stabilize a spare sensor so it can be used within a few minutes of installation. Polarizers plug into the sensor connector and require no adjustments.



Q46H Chlorine Monitor Brochure

Q46H Chlorine Monitor Specs

Chlorine Information 

More Information
Manufacturer ATI
Call For Price Yes
Gas Chlorine (Cl2)
4-20 mA Output Yes
Relays 2 Alarm Relays + 2 Control Relays
Voltage Output None
Power Requirements 100-240V, 50/60 Hz; 12-24 VDC
Datalogging No
Warranty 1 Year
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