ARGES Type Sensor
Electrical Conductivity (often abbreviated to Conductivity or EC) measures ions’ concentration within a sample under investigation. The term for the measurement unit of conductivity is Siemens. The Keynes Controls ARGES Conductivity sensor is a submersible instrument that can be used as a stand-alone, and as network device. The ARGES Conductivity sensor can be fitted into a multiarameter SONDE Housing. Only a single network connection is used to communicate with all the sensors in the multiparameter housing Each ARGES Sensor can be individually controlled using industry standard SDI12 commands.
The ARGES Conductivity sensor supports direct connection to the SDI12, RS485 and MODBUS networks. SDI12 is often used by data recorders. The RS485 network can be used for larger applications and to add the sensors onto Wi-Fi or local area networks. MODBUS is a common protocol used by plant wide SCADA applications.
ISOLATION
The sensor element of the ARGES Conductivity sensor by Keynes Controls is isolated to prevent any current flow between measurements. This prevents contamination of the sensor element and maintains the long active life of the device. When no measurement is being made the sensor is in its lowest power mode.
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.
The ARGES Conductivity Sensor by Keynes Controls can be used as a stand-alone device or as a part of a multi-parameter solution. Keynes Controls currently manufacture 7 port and 3 port sensor housings. An optional submersible brush unit is available for cleaning the fluorometer optics and this can be fitted into any port within the housings.
The images below show real-time conductivity results, a multiparameter sensor configuration, and the complete ARGES kit ready for deployment.
Only a single network connection fitted to the base of the housing is required to communicate with all the internal sensors. The internal sensors will automatically detect the network traffic and start operations. All of the sensors support SDI12, RS485 and MODBUS communications.
Product Features
| TYPE | RANGE (Typical levels) |
| Solid state ISE sensor. | |
| Measurement range: | 5.0×10-5 - 1.0 mol/L -- xxx×10 ppm |
| Chloride Resolution: | 0.0005 Mol |
| Chloride Accuracy: | +/- 10% of Reading or 2 ppm |
| Built-in Digital Networks |
SDI12 / RS485 / MODBUS (16 & 32 Bit Registers) |
| Sensor life: | Approximately 6 months, depending on usage. |
| pH Range | 2-12 |
| Isolated Electrodes | |
| Sensor Element | Isolated between measurements |
| Interference IONS | CIO, I, CN, BF |
The ARGES Conductivity sensor
The ARGES Conductivity sensor by Keynes Controls can be used to determine:
- EC - Conductivity - micro-Siemens/cm
- TDS - Total Dissolved Solids - SI Units ppm
- Salinity - SI Units ppt parts per thousand
In addition to this, the ARGES Conductivity Sensor can report in SI Units Electrical Conductivity (EC), Total Dissolved Solids (TDS) and Salinity in the same sensor.
The TDS Total dissolved Solids parameter is commonly assigned using a scale factor based upon the calibration solution in use. The most calibration solutions are NaCL (Sodium Chloride), KCl (Potassium Chloride) and the 442 Natural waste.
The Keynes Controls ARGES sensor can be set to use any scaling factor and this value is assigned using the device setup software.
WATER CONDUCTIVITY RANGES (Typical levels)
| WATER TYPE | RANGE (Typical levels) | MEASUREMENT |
| De-ionized water: | 0.03 - 0.05 | μS/cm |
| Distilled water: | 1 - 5 | μS/cm |
| RO Permeate range: | 400 - 750 | μS/cm |
| Sea water: | 45 - 55 | mS/cm |
| Brine Rejection Range: | 90 - 95 | mS/cm |
Product Features
| CONDUCTIVITY SENSOR | ENVIRONMENTAL CHARACTERISTICS | ||
| Range | 0 - 100000 (mS/m) - milli-Siemens | ||
| Resolution | 0.1 μS/cm | Built-in Temperature Sensor | |
| Accuracy | ± 0.5 % of reading | Water Temperature: 0 to 60 °C | |
| Automatic Range Adjustment | Maximum Depth: 100 m | ||
| Process Electrodes: | Reference Electrode | ||
| Material: | PVC / Stainless Steel | PHYSICAL DIMENSIONS | |
| Fast Start Time | <0.5 Sec | Length x Diameter: 22 x 220 mm | |
| Isolated Sensor Elements | Weight: 97 g | ||
| Settling Time |
1 sec | ||
| Wiper Trigger | SDI12 Command | ||
| Conductivity | SI Units - µS/cm | Built-in Network Types: | |
| Full Digital Operation | SDI12 / RS485 / MODBUS Digital Communications | ||
| Total Dissolved Solids | TDS SI Units - ppm | Power Requirement | |
| Simple Calibration | Voltage Range: 10-15 V DC | ||
| Salinity | SI Units - ppt | Standby Current: 0.8 mA Typical | |
| Free Windows Applications Software | Reading: 16 mA Typical |
Supported Commands
Most Used Commands - SDI12
| Description | Master | Instrument Response |
| Start measurement | aM! | a05\r\n where 05 = time delay before measurement sent |
| Send ID | al! | a14KEYNESCOISO000014\r\n Part description assigned by Keynes |
| Address Query | ?! | Where a = ID number - 0 - 9 (standard) / (a..z) Enhanced SDI-12 0 - 9 / a - z for RS485 |
| Change Address | aAb! | where a = Initial address and b = Final address |
| Start Measurement | aM! | Make a measurement - a = address of sensor Example 1M! starts a measurement for sensor with ID=1 |
| Concurrent measurement: Used for starting a measurement for all the sensors in a SONDE or on a digital network. |
aC! | Start a measurement for sensor on address 'a'. |
| Read Serial Number | aXSN! | Instrument Response a+Serial-number |
| Calibration Date | aXCD! | Instrument Response a+date |
Sensor Settling Time
The sensor takes time to settle once deployed into a new water sample. For relatively low conductivity readings the sensor takes only a few minutes reach its steady level results. In practice allow up to 1 hour for the sensor to settle before long time measurements are taken.
For high level conductivity measurements such as when used to monitor brine, allow up to 2 hours for the sensor to settle before taking long term measurements. Take the above sensor settling times as approximate only.
Calibration Period
The ARGES Conductivity sensor by Keynes Controls should be test calibrated at regular periods. This operation is simple to undertake using the calibration solution, a beaker and the applications software.
Calibration Soultion
Calibration Solution Point: 1800 S KCl 3000 ppm 442 (2027 ppm NaCl)
Keynes offer a calibration Potassium Chloride KCL kit for the conductivity sensor and this available from the on-line store. The calibration kit covers the most common operating range of the sensor and covers three measurement points. One of the calibration points is taken using distilled water to give a reference of 0, and a 1000 micro-Siemens solutions give the additional calibration point. Conductivity measurements can be effected by temperature so it is recommended to calibrate the sensor at, or around the temperature for which it is to be used.
Storage and Handling
When not in use the ARGES Ph sensor head should be kept hydrated with the protective cap attached.
Storage temperature range : 2 - 60 Degrees Celsius.
Clean the sensor in distilled water before use.
Keep the sensor hydrated at all times.
Engineering Results - SI
The Salinity and TDS (Total Dissolved Solids) results are based upon the measurement of Conductivity. The Salinity and TDS calibration factors can be adjusted using the QLOG software to use other factors upon demand. The factory set parameters are those commonly used with this sensor. Any new calibration factors are stored into the sensor.
Before Sensor is Used
It is important that The ARGES Conductivity sensor by Keynes Controls is cleaned before deployment. The cleaning operation is to remove any contamination. The sensor head should be soaked in di-ionised water to remove any trace of previous solution.
Built-in Communication Options
The ARGES Conductivity sensor by Keynes Controls supports SDI-12, RS485 and MODBUS digital communications as standard enabling the it to be directly connected to Data Logger for remote web based reporting, onto Wi-Fi and Local Area Networks using the RS485 option. The MODBUS and RS485 option are often used to connect sensors to a PLC Controller and Display Units,. The MODBUS protocol enables the sensors to be used directly by most SCADA applications software.
MODBUS Settings
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
Keynes Controls manufactures a range of accessories that can be used to connect the ARGES range of sensors to a Windows computer system and enable the sensors to be used in Laboratory applications, multi-parameter instruments and calibration operations.
The optional USB media converter can be used to connect The ARGES Conductivity Sensor by Keynes Controls, or a multi-parameter instrument containing the Conductivity Sensor to a Windows PC. Free applications software enables measurements to made and results displayed. The QLOG software can be used to adjust the instrument configuration.
The ARGES Conductivity sensor by Keynes Controls is integrated into the free Q-LOG Applications software.
Our Q-LOG software runs on the widely recognised 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.
Our highly accurate sensor provide conductivity and local temperature readings in SI units (Engineering units). Customise the SI units based on your instrument's capabilities, including support for multiple units like turbidity , all easily managed through the device setup.
WARNING:
Favourable measurements made by this equipment do not guarantee that a water sample is safe for human or animal consumption. The ARGES sensors can not detect the presence of harmful bacteria or toxins. If in doubt, ALWAYS TREAT SUSPECT WATER PRIOR TO CONSUMPTION.