AQUALABO Version Monobloc Pheht Numerical Sensor
FAQs
- Q: How often should I calibrate the PHEHT sensor?
- A: It is recommended to calibrate the sensor at least once every [specific time frame] or as indicated by usage patterns.
- Q: What is the significance of the CE mark on the sensor?
- A: The CE mark signifies that the product complies with European health, safety, and environmental protection standards.
General
In order to maintain and ensure the good working order of the PHEHT sensor, users must comply with the safety precautions and warnings featured in this manual.
Assembly and activation:
- Assembly, electrical connection, activation, operation, and maintenance of the measuring system must only be carried out by specialist personnel authorized by the user of the facilities.
- Trained personnel must be familiar with and comply with the instructions in this manual.
- Make sure the power supply complies with the specifications before connecting the device.
- A clearly labeled power switch must be installed near the device.
- Check all connections before turning the power on.
- Do not attempt to use damaged equipment: it may represent a hazard and should be labeled as faulty.
- Repairs must only be carried out by the manufacturer or by AQUALABO after-sales service department.
Marking on the body of the sensor:
The marking on the body of the sensor indicates the serial number of the sensor (for traceability) and the LOGO CE.
| 1 | Datamatrix (contains the serial number) |
| 2 | Serial number PHEHT sensor: SN-PPHOX-YYYY X : version YYYY: number |
| 3 | CE mark |
Characteristics
Technical characteristics.: The technical characteristics can be modified without advance notice.
| pH | |
| Measure principle | Combined electrode (pH/ref): special glass, Ag/AgCI ref. Gelled electrolyte (KCI) |
| Range | 0 – 14 pH |
| Resolution /Accuracy | 0,01 pH; ± 0,1 pH |
| Linearity | R2 >0.99 (2<pH<10) |
| Response time | T90 < 20s (variation pH4/pH9) |
| Redox | |
| Measure principle | Combined electrode (Redox/reference): Platinum tip, Ag/AgCI AgAgCl. Gelled reference (KCI) |
| Range | – 1000 to + 1000 mV |
| Resolution/Accuracy | 0,1 mV; ± 2 mV |
| Response time | T90< 5s |
| Temperature | |
| Technology | NTC |
| Range | 0,00 °C to + 50,00°C |
| Resolution/ Accuracy | 0,01 °C; ± 0,5 °C |
| Linearity | R2 >0.99 |
| Response time | T90< 50 s |
| Sensor | |
| Storage temperature | 0°C to + 60°C |
| Protection | IP 68 |
| Interface | Modbus RS-4851 as standard or SDI-122,3
1,2. sensor responds in Modbus/SDI12 mode including during standby 3. Using and connecting the SDI12 bus can increase standby consumption up to 100 µA depending on the level of the line (up or down). Consumption is not increased if line SDI12 is disconnected or released at 0V (Modbus RTU only) |
| Measurement Refresh rate | Maximum < 1 second |
| Signal interface | Modbus 1 RS-485 or SDI-12 2,3
1,2 The sensor responds in Modbus / SDI12 including during Standby 3 The use and connexion of SDI12 bus may increase the standby power consumption* up to 100uA depending on the level of the line (high or low). The consumption is not increased if the SDI12 line is disconnected or released to 0V (Modbus RTU only) |
| Sensor power-supply (RS485 and SDI12) | 5 V 1,2 to 12 3,4 V DC (warm-up time 100 ms)
1 Absolute minimum 4.5V with 1m of cable, boot, and precision not guaranteed under 5V 2 Minimum voltage subjected to cable length-related losses 3 13V Absolute maximum with a more than 2 mA continuous overconsumption 4 Small overconsumption between 12V and 12.5V |
| Typical Consumption at 5V (RS485) Applicable when using “low power mode”
Recommended for low power mode (1 measure uses less than 10 µWh) Subject to modifications in case of internal parts evolution |
Automatic standby less than 10 μA* (50 μW)
Maximum peak current: 500 mA (1 ms) / 41 mA (6.5 ms) Maximum current during the measurement: 25 mA (125 mW) Average current during the measurement: 17 mA (85 mW) Average current RS485 (1 meas. / seconde): 4.8 mA (24 mW) Average current RS485 (1 meas. / 10 seconde): 0.5 mA (2.5 mW) Continuous power mode average current RS485: 17 mA continuous (85 mW) |
| Typical Consumption at 12V (RS485) Applicable when using “low power mode”
Never exceed 12.0V for low power (1 measure uses less than 25 µWh) Subject to modifications in case of internal parts evolution |
Automatic standby less than 12 μA* (144 μW)
Maximum peak current: 500 mA (1 ms) / 60 mA (6.5 ms) Maximum current during the measurement: 25 mA (300 mW) Average current during the measurement: 17 mA (204 mW) Average current RS485 (1 meas. / seconde): 4.8 mA (57.6 mW) Average current RS485 (1 meas. / 10 secondes): 0.5 mA (6 mW) Continuous power mode average current RS485: 17 mA continious (204 mW) |
| Typical Consumption at 12.5V (RS485) Applicable when using “low power mode”
Not recommended for low-power Subject to modifications in case of internal parts evolution |
Automatic standby less than typical 15 μA* (187.5 μW) max 1 mA
Maximum peak current: 500 mA (1 ms)/ 62.6 mA (6.5 ms) Maximum current during the measurement: 25 mA (312.5 mW) Average current during the measurement: 17 mA (212.5 mW) Average current RS485 (1 meas. / seconde): 4.8 mA (60 mW) Continuous power mode average current RS485: 17 mA continious (312.5 mW) |
| Sensor | |
| Dimensions | Diameter: 27 mm; Lenght: 171,5 mm |
| Weight | 350 g (sensor + 3 m cable) |
| Material | PVC, DELRIN, special pH glass, platinum, polyamide |
| Pressure | 5 bars |
| Cable | Coaxial armored, Polyurethane, bare wire, or Fisher connector |
CE compliance.
- Under the article 11 of the directive 89 / 336 / EEC relative to the electromagnetic compatibility.
- We declare that the digital sensor of the range DIGISENS sensor PHEHT Monobloc was tested and declared in compliance with European standards when used in continuous power mode.
- Standard tests: NF EN IEC 61326-1: 2021-06
- NF EN IEC 61326-1 (2021-06)
- Electrical equipment for measurement, control, and laboratory use – EMC requirements –
- Part 1: General requirements.
NORMATIVE REFERENCES [1]
- NF EN 55011: 2016-06 +/A1 : 2017-06 +/A2 : 2021-04
- Industrial, scientific, and medical equipment – Radio-frequency disturbance characteristics – Limits and methods of measurement.
- Immunity: Radiated immunity EN 61000-4-3 Industrial environment – Criteria A
- ESD (Electrostatic discharge) EN 61000-4-2 Industrial environment – Criteria B
- RF Common mode EN 61000-4-6 Industrial environment – Criteria A
- Surge EN 61000-4-5 Industrial environment – Criteria B
- Fast Transients EN 61000-4-4 Industrial environment – Criteria B
- Disturbance: EN 55011B
- Radiated emissions – EN 55011 Group 1 – Class A
- Conducted emissions – EN 55011 Group 1 – Class A
Identification of the measurement process composed of:
- one probe
- Ponsel’s cable. EN 61000-4-5
Commercial Name: DIGISENS range
- Manufacturer AQUALABO
- 90, Rue du Professeur P. Milliez
- 94506 Champigny sur Marne
- Responsible UE: AQUALABO
- 90, Rue du Professeur P. Milliez
- 94506 Champigny sur Marne
Description
Product Overview
- The combined sensor PHEHT is based on a principle of measuring of difference of potential between a reference electrode (Ag/AgCl) and an electrode of measure (Special pH glass for the measure of pH, and a ring of platinum for the ORP measurement).
- The returned measure is given for a temperature of 25 °.
- The PHEH Monobloc sensor has been designed to perform in lakes and rivers, seawater with conductivities of 55 mS/cm, and wastewater with conductivity higher than 200 mS/cm.
- This sensor features a “long life” reference. The Plastogel® PONSEL technology increases the lifetime of the probe and the need to refill.
- This sensor has been designed also for handheld and in situ applications which have been the most difficult situations for a pH/ORP sensor in terms of sensor resistance, quick time response, minimal flow dependence, and low power consumption.
- The sensor features excellent interference immunity thanks to the integrated preamplifier and digital signal processing. The measured value for pH is automatically compensated with the temperature, and transferred without interference to the connected display unit and controller via a digital interface. As a result, the plug-and-play function of the system is enabled without the need for recalibration. The sensor also includes a logbook containing the last ten successful calibrations in the form of a ring buffer.
Applications
- The compact and robust sensor is particularly well suited to the following typical areas of application:
- Industrial and municipal sewage treatment plants
- Wastewater management (nitrification and de-nitrification)
- Surface water monitoring
- Drinking water monitoring
Construction and dimensions.
- Strainer of protection
- Sensor body with measurement electronics
- Cable bushing
- Securely connected connection cable
Communication.
Modbus RTU registers.
The link protocol must correspond to MODBUS RTU. See document:
- Modbus_over_serial_line_V1_02.pdf
- Modbus_Application_Protocol_V1_1a.pdf
- Modbus memory for PONSEL digital Sensors: SENSOR_TramesCom_xxx_UK.xls (refer to AQUALABO website)
The Modbus memory plane is identical for each parameter of the Sensors. The Modbus protocol for the Sensors allows you to measure the parameter (+ temperature) of the Sensor and to calibrate the parameter (+ temperature). Furthermore, there are certain numbers of functions such as:
- Select the averaging value
- Read the Sensor description
- Return to default coefficients
- Modify the Sensor address
- Information on measures conducted (Out-of-specification measures, measures in progress, etc.).
- Date and name of the operator who performed the calibration etc.
To have more information on the open PONSEL’s Modbus protocol please consult the last version of the following documents :
- the pdf file: Modbus_SpecificationsVxxx-EN
- The Excel file: Digital sensor Frame_XXX_UK
SDI12 frame.
- A list of SDI12 registers is available for network communication. Refer to the AQUALABO web site for more information.
Temperature Compensation
- The pH measurement is dependent on parameters:
- The temperature of the measurement medium
- This dependency is stored in the sensor’s measurement electronics in the form of functions.
- The sensor can therefore determine the pH of the measurement. medium, in order to digitally transmit the influencing factors above, in compensated form, to the transmitter/controller.
- The temperature compensation is automatic and managed directly by the sensor via the integrated sensor of temperature (NTC).
Sampling rate
- PHEHT sensors do not carry out any continuous measurements, but it is possible to measure all 500 mS.
Installation
Sensor installation option
For the installation of the sensors in condition of immersion or in-pipe insertion, we advise using accessories adapted and proposed by AQUALABO.
Accessories for immersion installation.
- In immersion conditions, it is necessary to maintain the sensor by the body and not to leave the sensor suspended by the cable at the risk of damaging the sensor
- AQUALABO proposes a range or pole (short and long version) in order to install the sensor in open basins. It can be positioned a considerable distance from the basin edge with the bracket suspended on a chain, for example.
Please note the following when planning your set-up:
- The fitting must be easily accessible to allow the sensor or the fitting itself to be maintained and cleaned regularly
- Do not allow the fitting (and thus also the sensor) to swing against and hit the basin edge
- When working with systems involving pressure and/or temperature, ensure that the fitting and sensor meet all relevant requirements
- The system designer must check that the materials in the fitting and sensor are suitable for the measurement (chemical compatibility, for instance)
| Material | PVC |
| Admissible temperature | 0 to 60 °C |
| Pressure max. | 5 bars |
Short pole
The short pole is available in 2 versions: a version with an elbowed shutter. The nozzle of support is included in the offer.
|
PF-ACC-C-00609 |
STRAIGHT SHORT POLE
FOR PHEHT Monobloc SENSOR (1495 mm, ELBOWED SHUTTER) |
version with shutter for mounting with chain The nozzle of support is included in the offer.
|
PF-ACC-C-00614 |
STRAIGHT SHORT POLE FOR PHEHT MONOBLOC SENSOR (1550 mm, RING SHUTTER) |
Long pole
The long poles are available in elbow version, for installations in aeration basin, and straight, for applications in open channels. Every pole is equipped with an elbowed shutter and with waterproofness joints. The lower part includes a nozzle that is adapted to the sensor which assures its mechanical support.
Elbowed pole with elbowed shutter
|
PF-ACC-C-00608 |
90° ELBOW LONG POLE FOR PHEHT MONOBLOC SENSOR (2955 mm, ELBOWED SHUTTER) |
Straight long pole with elbowed shutter
|
PF-ACC-C-00611 |
STRAIGHT LONG POLE FOR PHEHT MONOBLOC SENSOR
(2745 mm, ELBOWED SHUTTER) |
Mounting accessories for pole.
The elements of fixation for the poles are flexible and specially studied to adapt themselves to the different configurations of assembly.
Pole kit fixation
| NC-ACC-C-00009 | POLE FIXATION KIT FOR NUMERICAL SENSOR (ON LOW WALL) |
| NC-ACC-C-00010 | POLE FIXATION KIT FOR NUMERICAL SENSOR (ON LIFELINE) |
| NC-ACC-C-00011 | POLE FIXATION KIT FOR NUMERICAL SENSOR (ON VERTICAL AXIS) |
| PF-ACC-C-00272 | VERTICAL AXIS FOR NUMERICAL SENSOR POLE (TO BE FIXED ON SOIL) |
Accessories kit
Accessories kit for assembly of poles with chain.
| NC-ACC-C-00012 | SHORT POLE FIXATION KIT FOR NUMERICAL SENSOR (ON LOW WALL) |
| NC-ACC-C-00013 | SHORT POLE FIXATION KIT FOR NUMERICAL SENSOR (ON LIFE LINE) |
| NC-ACC-C-00014 | SHORT POLE FIXATION KIT FOR NUMERICAL SENSOR (ON VERTICAL AXIS) |
Accessories for PVC pipe-mounting
- Every system of assembly is delivered with an adapter (and the appropriate joints) and one T of assembly (90 ° for PHEHT sensor) to stick on a 50 mm diameter pipe.
- Its special design type ensures the correct inflow to the sensor, thus preventing incorrect measurements.
- Please note the following when planning your piping set-up:
- The fitting must be easily accessible to allow the sensor or the fitting itself to be maintained and cleaned regularly.
- We recommend bypass measurements. It must be possible to remove the sensor through the use of shut-off valves.
- When working with systems involving pressure and/or temperature, ensure that the fitting and sensor meet all relevant requirements.
- The system designer must check that the materials in the fitting and sensor are suitable for the measurement (chemical compatibility, for instance)
Accessories for stainless steel pipe-mounting
- The accessories of assembly for stainless pipe are proposed with an adapter and its joints with or without the systems of clamp / Nipple.
- The acceptable maximum pressure for the sensors is 5 bars.
- The system of assembly can be delivered with or without a stainless steel clamp.
- The adapter is compatible with a 51 mm diameter external clamp
- Mounting system for PHEHT sensor (PF-ACC-C-00612)
- adapter
- PHEHT sensor
Accessories of Assembly
Installation of the sensor in the accessories of assembly
Insertion in a pole.
The sensor is mounted on the relevant fitting as described below, using a sensor holder, which can be used both for the short and long pole:
- Remove the protective cap on the sensor and insert the sensor (2) into the nozzle (1) as far as the stop.
- Insert the sensor cable into the fitting pipe (6) and completely feed through.
- Screw the sensor holder with the union nut (5) onto the fitting pipe (6) and tighten until handtight.
Insertion into the PVC in-pipe mounting system.
- Unscrew the union nut (3) from the PVC flow fitting (1).
- Guide the sensor cable through the union nut on the fitting.
- Insert the sensor (2) into the fitting as far as the position shown in the middle image above.
- Screw the union nut onto the fitting as far as the stop.
Insertion into the Stainless steel in-pipe mounting system.
- After welding the clamp on the stainless steel pipe, remove the clamp from the system and remove the PVC adapter.
- Unscrew the union nut from the adapter.
- Guide the sensor cable through the union nut on the adapter and insert the sensor with the mounted locking ring into the flow fitting as far as the stop
- Reposition the adapter in the nipple, and re-screw the union nut.
Electrical connections
The sensor could deliver within version bare wire on 3, 7, 15 m, or on another length (up to 100 m).
VNote:
- Never exceed a voltage of 10VDC (absolute maximum rating) on communication lines RS485, A, or B, under penalty of irreversible destruction of the transceiver component RS 485.
- SDI-12: respect the voltage value described in the associated standard (nominal: 5 VDC)
- Always connect ground + shield first.
- Always connect V-(black) +Shield(Green/Yellow) from the sensor to both V-/0V/GND from power supply AND GND from the RS485/SDI12 master to avoid sensor destruction (as defined by RS485 standard).
Startup and Maintenance
Initial startup
- Once the sensor is connected to your terminal, the sensor is settled in its accessory of assembly and the parameterization has been carried out on the display unit, the sensor is ready for initial startup.
Note:
- For measurement, you must eliminate bubbles trapped under the pH glass bulb.
- During the introduction of the sensor in measurement environment, wait for the sensor’s temperature stabilization before measure processing.
The glass electrode is vulnerable to:
- chemicals (organic solvents, acids and strong bases, peroxide, hydrocarbons),
- mechanical treatments (impacts).
- The redox potential electrode is sensitive to sulfide adsorption on platinum.
Started:
- Remove the black cap of protection (by holding the sensor head downward and by unscrewing the hood towards the right).
- The sensor is delivered dry, and the pH glass must be rehydrated so that the measures are optimized.
- After dry storage, rehydrate the pH bulb for 12 hours (one night) in a standard solution pH4 or in the cleaning solution delivered from AQUALABO Control (PF-CSO-C-00010).
Calibration
- The sensor is calibrated to specification at the factory. The frequency of calibration depends on the application (depends on the fouling of the sensor, on the conductivity of the environment.).If calibration is required, let the sensor come to equilibrium with the process before calibration. Do not calibrate the sensor at setup.
- After the cartridge is replaced, calibration should be carried out.
- It is also advisable to regularly clean the sensor in a cleaning solution (PF-CSO-C-00010) (see Chapter Maintenance 5.3).
- With two-point calibration, the zero point (offset with standard solution) and slope (second standard solution) of the sensor are calibrated. This calibration method offers the greatest possible level of accuracy and is particularly recommended.
pH calibration. Offset calibration.
It is carried out as follows:
- The sensor beforehand cleaned (to see chapter maintenance 5.3) is immersed in a first standard solution (PH 7.01 at 25 °C for example) to determine the zero point (offset). Maintain the standard solution under agitation and wait for the sensor to put itself in equilibrium with the temperature of the standard solution.
- The pH of the standard solution varies with the temperature, note the temperature of the solution and refer to the board of variation of the pH according to the temperature to fix the pH value to be calibrated.
- For example, for a standard solution pH 7.01 at 25 °C if the temperature of the standard solution is 20°C the value of the pH is 7.03.
| Standard PH 7.01 at 25°C | °C | °F | pH |
| 0 | 32 | 7.13 | |
| 5 | 41 | 7.10 | |
| 10 | 50 | 7.07 | |
| 15 | 59 | 7.04 | |
| 20 | 68 | 7.03 | |
| 25 | 77 | 7.01 | |
| 30 | 86 | 7.00 | |
| 35 | 95 | 6.99 | |
| 40 | 104 | 6.98 | |
| 45 | 113 | 6.98 |
- Washing (with clear water) and drying the sensor with a soft cloth or an absorbent paper.
Slope calibration.
- The sensor slope is determined by positioning in a second pH buffer solution.
- Immerse the sensor in the selected standard solution, maintain the standard solution under agitation, and wait for the sensor put itself in equilibrium with the temperature of the standard solution.
- The pH of the standard solution varies with the temperature, note the temperature of the solution and refer to the board of variation of the pH according to the temperature to fix the pH value to be calibrated.
- For example, for a standard solution pH 4.01 at 25 °C if the temperature of the standard solution is 20°C the value of the pH is 4.00.
| Standard PH 4.01 at 25°C | °C | °F | pH |
| 0 | 32 | 4.01 | |
| 5 | 41 | 4.00 | |
| 10 | 50 | 4.00 | |
| 15 | 59 | 4.00 | |
| 20 | 68 | 4.00 | |
| 25 | 77 | 4.01 | |
| 30 | 86 | 4.02 | |
| 35 | 95 | 4.03 | |
| 40 | 104 | 4.04 | |
| 45 | 113 | 4.05 |
- Check the Redox potential.
Wedging of the offset.
- The first step in the calibration is to set the offset by exposing the sensor to air. The default value of this calibration standard is set at 0 mV and cannot be changed. Wait for the stabilization of the measure and validate the point of calibration.
Validation of the slope.
- Immerse the sensor in the selected standard solution (240 mV for example), maintain the standard solution under agitation, and wait for the sensor to put itself in equilibrium with the temperature of the standard solution.
- Washing (with clear water) and drying the sensor with a soft cloth or an absorbent paper.
Maintenance
- The maintenance schedule shows minimum intervals for regular maintenance tasks. Perform maintenance tasks more frequently for applications that cause electrode fouling.
- Note: Do not disassemble the probe for maintenance or cleaning.
- The sensor must always be kept clean, particularly in the area around the pH bulb and the platinum disk (Redox measurement).
- The presence of a biofilm on the pH bulb can lead to measuring errors.
- For the pH bulb, A dirty bulb should be cleaned with warm, soapy water.
- For the redox measurement, clean the platinum disk to optimize the measures of redox potential.
- If the sensor is put out of operation, it should be rinsed before being stored, and the protective cap should be fitted with the protective case and a moist absorbent surface (like cotton).
Cleaning.
- Rinse meticulously the sensor and the bulb with clear water.
- For pH glass: if deposits like biofilm or mud persist, put the sensor in a cleaning solution (1SN004) for a few hours and rinse profusely before use.
- Avoid using a soft cloth or an absorbent paper because the glass ball is extremely vulnerable to friction.
- For the Redox part, clean the platinum disk with an abrasive moist paper (type P1200 or P220) and rinse the electrode with clean water.
- The electrolyte ” PLASTOGEL ” ® communicates directly with the outside environment without interposition of capillary or porous. There is thus no risk of closing or dismantling of the reference.
- Plastogel tends to become impoverished in KCl according to the use of the sensor PHEHT. When the Plastogel is exhausted, the probe does not answer any more the variations of pH and is very slow to stabilize.
- In that case, it is necessary to proceed to the change of the sensor.
CONTACT INFORMATION
- AQUALABO After-Sales Service
- AQUALABO
- 115 Rue Michel MARION
- 56850 CAUDAN
- FRANCE
- Tel.: + 33 (0)4 11 71 97 41
- AQUALABO
- 90 Rue du professeur P. Milliez
- 94506 Champigny sur Marne France
- Tel.: +33(0)1 55 09 10 10
- Version 1.1
- Update: March 2024
Documents / Resources
 |
AQUALABO Version Monobloc Pheht Numerical Sensor [pdf] User Manual Version Monobloc Pheht Numerical Sensor, Monobloc Pheht Numerical Sensor, Pheht Numerical Sensor, Numerical Sensor, Sensor |
