The ARGES Turbidity Sensor by Keynes Controls is a single-channel instrument that can detect and report turbidity levels in the range of 0.5 - 2000 NTU. The ARGES Turbidity Sensor has been designed to be used as a stand-alone laboratory instrument, as part of a multi-parameter device inside a Keynes Controls SONDE, and can be connected directly into a plant-wide SCADA system using the MODBUS protocol.
All of the Keynes Controls manufactured fluorometers supply measurements directly in engineering units. The stainless steel construction enables the sensors to be long-term deployed for remote applications.
The turbidity sensor optics should be cleaned before a new measurement using the ARGES Brush interface. The ARGES Brush unit can be fitted into any of the multi-parameter housings.
Measurement Integrity
All of the ARGEs sensor range have the serial numbers and the last calibration date stored internally. The user can access this information for reporting purposes. The sensors can be redeployed at any time with the calibration and serial number records are retained in the sensor.
Further Information
| Turbidity 4 | NTU Water at the Consumers’ taps | --- | UK DWI Drinking Water Standard |
| 0 - 0.318 | NTU | --- | Distilled Water |
| <10 | NTU | --- | Fresh Water |
| >100 | NTU | --- | Unsafe for most aquatic life |
To provide a sense of scale, water with a turbidity of 1 NTU is crystal clear, water at 5 NTU has a tiny trace of discolouration, and water at 100 NTU is brown and opaque. The standard is less than 10 NTU for rural streams and rivers and less than 30 NTU for urban lakes and ponds.
Applications Software
The ARGES Turbidity Sensor by Keynes Controls is supplied with a copy of the Keynes Controls Q-LOG application software.
Our Q-LOG software runs on the widely recognized Windows Operating system. You have the ability to calibrate, adjust instrument network address, and effortlessly display measurements on a series of panel meters and charts. Conveniently store results in text based files for quick analysis in spreadsheets.
The Q-LOG software can be used to test the sensor prior to its deployment, be that as a stand-alone device or part of a multi-parameter sensor SONDE.
In-situ measurement, no sampling, no reagents
• Direct SI Unit output of parameters
• Optical window with coating to minimize clogging
• Real time measurement
• Automatic compensation for temperature effects
Measurements
The ARGES Turbidity sensor can be used as a stand-alone device or as a part of a multi-parameter solution. For stand-alone operations simply connect the sensor to a media converter and make measurements. The industry standard SDI12 commands are used to configure, calibrate and make measurements.
For multi-parameter applications then ensure that each instrument has a unique address, connect the sensors to a digital network and using the simple command set take measurements. When using the instruments in a multi-parameter housing simply install the instruments onto a sensor port and secure. Only a single network connection fitted to the top of the unit is required to communicate with all the instruments.
Keynes Controls manufacture a range of media converters that can be used to connect the sensors to a Windows PC. Free applications software for the ARGES range of sensors is available for download. The ARGES range of sensors all support MODBUS network operations. A MODBUS master is used to read measurements. There are many third party MODBUS readout units that can be used to act as a local display.
Any combination of the ARGES sensors can be installed into 3-Sensor and 7-Sensor SONDE housings and connected to a data acquisition system via the gold plated wet mate subsea connector mounted on the top of the housing.
The ARGES Turbidity Sensor by Keynes Controls can be used a stand-alone sensor, or part of a multi-parameter package in the SONDE housing. The image below shows the multi-parameter SONDE on test using the Keynes Q-LOG software displaying turbidity results to the screen. The same results can be transmitted via an Internet logger across the internet.
The images below show a measurement site on the Blackwater River where the turbidity level was monitored. The ARGES Turbidity sensor was pre-calibrated and fitted into a multi-parameter housing and the complete system lowered into the river.
Calibration Period
All of the sensors are factory-calibrated before shipment. The advanced design of the sensors means that the time between re-calibration of an instrument is minimised. Keynes Controls recommends a check calibration every 2 years. The user can adjust the calibration for a specified range to improve accuracy for dedicated tasks. A range of calibration solutions manufactured by Keynes Controls are available from the online shop.
There are two standard units for reporting turbidity - Formazin Nephelometric Units (FNU) and Nephelometric Turbidity Units (NTU). The ARGES Turbidity Sensor by Keynes Controls is set to use NTU by default.
Improved Results
The ARGES Turbidity Sensor by Keynes Controls is an intelligent sensor and stores calibration factors internally. The sensor can be re-calibrated over a smaller restricted range if the samples are under investigation are know to be of a limited range.. For example, local river water turbidity levels have never been observed to be over 50 NTU, then the sensor can be re-calibrated to a maximum level of 50 NTU. A recalibrated instrument will then provide a more accurate reading for the actual river turbidity levels compared to a full 0 - 2000 NTU instrument.
Optional Accessories
Keynes Controls manufactures a range of accessories that can be used with the ARGES range of chemical sensors.
A range of USB-media converters can be used to connect individual as well as multi-parameter housings to a Windows operating system computer. Free Applications Software is available for sensor configuration and making measurements.
The ARGES Brush mechanism can be individually controlled to make multiple cleaning operations for the fluorometer optics.
Additionally, the sensors can be secured into the SONDE housing and locked into place. A locking nut secures the sensor to the housing base unit. A protective shade cap screws into the base of the unit and is used to prevent stray light for affecting the optical measurements. The shade cap also protects the sensing elements from damage. Eyelets can be screwed into the top of the SONDE housing to enable securing cables to be used to lower and secure the instruments into place.
Product Features
| TYPE | RANGE (Typical levels) |
| Solid state ISE sensor | |
| Concentration range: | 0 to 2000 NTU - Other ranges on request. |
| Resolution: | 0.01 NTU |
| Accuracy: | +/- 2 % of reading. +/- 0.5 NTU which ever is greater |
| Stand-alone and SONDE Multi-parameter operations |
|
| Calibration Period | Approximately 2 years, depending on usage. |
| pH Range | 0 - 14 |
| Operation | Photometric |
| Digital Communications | SDI12 / RS485 / MODBUS Digital Communications |
| Depth | 200 m |
| Simple Calibration | Multi-point Calibration Point Optional |
| SI Units |
NTU / Degree C - other turbidity units on request |
| Analogue Output |
0-2 V DC - proportional to concentration |
Sensor Deployment
The ARGES Turbidity Sensor by Keynes Controls can be installed into any of the SONDE ports and used in collaboration with any of the other supported sensors. A network connection is made using the waterproof connector. This is the same connector that is used in the SONDE as is used on the individual sensors themselves.
Once the sensor is enclosed in the SONDE housing unit, the sensor is ready for effortless deployment into the water, providing precise measurements to the connected devices.
For long term applications where any of the ARGES fluorometer sensors are being used within water then a submersible brush unit should be used to clean the sensor optics before a measurement is taken. Any contamination of the optics due to debris in the water source can affect the results.
Deployment example:
Specifications
| ENVIRONMENTAL CHARACTERISTICS | ||||
| Turbidity | MDL 0.5 NTU | Range 0 - 2000 NTU | ||
| Other ranges by request. | Ambient Range: 0 - 50 Degree Celsius | |||
| Water Temperature: 2 to 60 Degree Celsius | ||||
| Precision | 0.01 NTU | |||
| PHYSICAL DIMENSIONS | ||||
| Length x Diameter: 22 x 220 mm | ||||
| Pulse Width |
|
Weight: 97 g | ||
| Wiper Trigger | SDI12 Command | aM! - measurement commend starts scan | Maximum Depth : 200 m | |
| Excitation | Infra-red | Built-in Network Types: | ||
| Housing | 316 Stainless Steel | MODBUS / SDI12 / RS485 | ||
| Focal Point | 1 cm In-front of sensor faceplate | |||
| Data Output | SI Units | Supply Voltage: 10 - 18 V DC Standby Current 12mA |
Supported Commands
| Most commonly used commands | ||
| Description | Master | Sensor Response |
| Send ID | aI! | a13KEYNESVWRDOA001\r\n |
| Address Query | ?! | a\r\n where a = Address |
| Start Measurement | aM! where a = Address | a0261\r\n |
| Concurrent Measurement: | aC! where a = Address | a0261\r\n |
| Get Measurement | aD! where a = Address | a+Turbidity (NTU)+Temp (Degree Celsius) |
| Read Serial Number | aXSN! | Instrument Response a+Serial-number |
| Calibration Date | aXCD! | Instrument Response a+date |
Built-in Communication Options
The ARGES Turbidity Sensor by Keynes Controls supports SDI-12, RS485 and MODBUS digital communications as standard, enabling the sensors to be directly connected to data logger for remote web based reporting, onto Wi-Fi and Local Area Networks using the RS485 option, and directly into SCADA applications using the MODBUS.
MODBUS Operations
ALL of the ARGES range of chemical sensors support MODBUS network operations The sensors act as a slave unit only and can communicate to suitable controllers and SCADA systems that support the MODBUS Protocol. The sensors support 16 and 32 bit registers. .
The ARGES sensors can be connected to a PC based system using the optional USB-485-Pro media converter. This device can power the chemical sensor and supports the correct timing protocols for data transmission for MODBUS and standard RS485 network communications.
WARNING:
Favourable measurements made by this equipment do not guarantee that a water sample is safe for human or animal consumption. The ARGES Intelligent Submersible Fluorometer sensors can not detect the presence of harmful bacteria or toxins. If in doubt, ALWAYS TREAT SUSPECT WATER PRIOR TO CONSUMPTION.