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Several factors can prevent the sensor from generating or transmitting pulses:

 Incorrect wiring: Wrong connection of supply (+), signal, or ground (–) can destroy the integrated Hall IC.

Incompatible signal type: The electronics used cannot process NPN signals. Use compatible electronics.

Flow too low: The flow rate is below the minimum value required for the turbine to rotate and generate pulses.

Missing pull-up resistor: Without a pull-up resistor between “+” and “signal” in the evaluation electronics, no signal is detected.

Incorrect supply voltage: Too high a voltage can destroy the Hall IC; too low a voltage prevents pulse generation.

Moisture near electrical contacts: Can cause short circuits and damage the Hall IC.

Mechanical stress on contacts: Can break the electrical connection between the contact and Hall IC.

Electrical current spikes: Surges through the cable can destroy the Hall IC.

Lock code activated: Contact the sensor supplier for assistance.

Several factors can affect the accuracy and repeatability of the measurement:

Incorrect installation position: Follow the installation orientation specified in the data sheet.

Missing calibration: The system has not been calibrated for pulses per liter.

Air in the system: Air bubbles prevent accurate and repeatable measurement.

Magnetic fields nearby: External magnetic fields can disturb the turbine’s rotation.

Flow rate too high: Excessive flow shortens the life of the turbine bearings and causes measurement errors.

Flow rate too low: The sensor must operate within the linear range stated in the data sheet.

Pressure setbacks or fluctuations: Tubing expansion or unstable pressure reduces measurement precision and can lead to leaks or damage.

Unsuitable liquid: High viscosity or solid particles may block the turbine.

Wrong flow direction: Install according to the indicated flow direction.

Pulsating flow: Rapid start/stop pumping cycles negatively affect accuracy.

Contamination: Deposits such as lime, beer stone, or coffee fat on wetted surfaces impair measurement accuracy; regular cleaning is recommended.

Inductive interference: Avoid running signal cables parallel to power lines to prevent electrical interference or damage to the Hall IC.

The following factors can impair or permanently damage the sensor:

Blowing air through the sensor: The turbine bearings can be destroyed within seconds.

Chemical incompatibility: If the wetted materials are not resistant to the medium, the sensor may leak or fail completely.

Inductive interference: Avoid routing signal cables parallel to high-power lines to prevent electrical damage.

Faulty sensor on delivery: Every sensor is function- and leak-tested before packaging. If a defect is still detected, contact the sensor supplier with a detailed description of the issue and application.

You can find detailed installation instructions in the respective data sheet.

All data sheets are available for download under Resources.

The number of impulses per liter indicated in the data sheet was determined using water under laboratory conditions. Due to the dependence on various factors, this value should be considered as a guideline. The following factors can have a direct impact on the number of impulses per liter:

• Diameter of the nozzle
• Viscosity of the medium
• Temperature of the medium
• Type and hardness of the pipes (e.g., hoses, tubes)
• Conveyance method (e.g., pump, pressure vessel)

We recommend calibrating our flowmeters within your complete system under real conditions.

Calibrate your flowmeter using the following instructions:

1. Preparation
   • Place an empty container with a capacity of approximately 1 liter on a scale and then tare it.
2. Perfoming the Measurement
   •  Allow the liquid to flow into the container and record the number of impulses.
3. Record Weight
   • Weigh the filled container again and note the weight in grams [g]. Example: The weight of the medium (water) is 885 g.
4. Calculate Impulses per Gram
   • Calculate the impulses per gram [Imp/g] by dividing the measured weight by the number of
     counted impulses. Example: With 723 impulses and a weight of 885 grams, the calculation is: 723 Imp ÷ 885 g = 0.817 Imp/g. For the weight per impulse [g/Imp], divide the measured weight by the number of impulses: Example: 885 g ÷ 723 Imp = 1.22 g/Imp.
5. Calculate Impulses per Liter
   • To obtain the impulses per liter [Imp/l], multiply the calculated impulses per gram [Imp/g] by
     the specific weight of the medium [g/l]. Example: 0.817 Imp/g × 1000 g/l = 816 Imp/l (Specific weight of water: 1000 g/l

For technical support, you can reach us here: techsupport@digmesa.com, +41 32 332 77 77

Find more contact options.

The ideal flow sensor depends on several factors such as the application area, desired flow range, and pressure range. For thorough advice, please contact our sales team at sales@digmesa.com, +41 32 332 77 77

For an optimal consultation, please provide us with information about the following factors:

1. minimum/maximum flow 
2. duration of a cycle/operating time and amount of cycles
3. temperature
4. pressure
5. liquid
6. electrical circuit (NPN/PNP, pull up resistor R1.2K)
7. process connection (Inside or outside thread, John Guest, hose nipple, etc.)
8. electrical connection (MSD, Kabel, C-Upper part, LED, etc.)
9. magnets (Liquid contacting, 2 or 4 magnets)
10. MSD yes/no
11. standards
12. cost

Yes. We ensure that our products meet all relevant safety and quality standards. Our flow sensors are CE and NSF certified. Additionally, we have ISO certifications.

All certificates are listed under Resources.

Yes. Each of our flow sensors is individually function- and leak-tested before packaging to ensure the highest quality.

To place an order or get a quote, please contact our sales team directly: sales@digmesa.com, +41 32 332 77 77

We know that sometimes off-the-shelf isn't enough to fullfill every need. That’s why we offer Customized Solutions – tailored to your specific needs.

For more information, contact us at: sales@digmesa.com, +41 32 332 77 77