EMSYST | FAQ / DOCS

Please, send the order to the manufacturer (best by e-mail) with following specifications: Type of sensor, measurement range and direction of load Type of output in case you order the sensor with build-in signal conditioner Number of pieces Required time of delivery Order example: EMS30 – 1 kN – tension, 2 pcs. EMS150E – 5 kN – compression, 4 – 20 mA, 5 pcs. In case of request for different parameters than those listed in the datasheet e.g. different temperature range, cable length etc. it is necessary to consult the order by telephone or email before its sending.
Please, send the order to the manufacturer (best by e-mail) with following specifications: Type of signal conditioner Sensitivity of sensor connected to the conditioner Type and range of output Number of pieces Required time of delivery If you want to set up the signal conditioner to force sensor (when you buy signal conditioner with force sensor as a pair) Order example: EMS168, 1,5 mV/V, 0 – 10 V, 3 pcs. EMS170, 2 mV/V, 4 – 20 mA, set up to EMS100 – 10 pcs. It is possible to order signal conditioner with different parameters (e.g. filtering frequency). Please contact the manufacturer.
The product’s certificate with parameters measured at the quality control is supplied to each sensor. It is also possible to order product’s certificate from independent test room. This certificate will be paid extra and the delivery period will extende by 2 weeks.
The product complain is always handled individually. Please, contact us (call us) before you send the product back. In many cases the complaint can be solved after consultation. If the consultation will not be helpful, we will agree on the next steps.

Sensitivity of strain gauge sensor and load cell is measured in mV/V (millivolt per volt) and it is equal to output voltage of sensor with 1V power supply and nominal load. Standard sensors are made with sensitivity from 1 mV/V to 3 mV/V, the normal/common value is 2 mV/V and 1.5 mV/V. The datasheets include the nominal values. The exact value differs can differ slightly from nominal value. For example, the sensor with nominal sensitivity of 2 mV/V can have exact value of 1.9836 mV/V. The exact value is stated in the protocol supplied together with the sensor.
Sensor output voltage depends on three factors: sensor sensitivity C(mV/V) excitation of sensor Uc(V) load force Fx Output voltage of sensor with nominal range Fn can be calculated with this formula: Us = (C * Uc * Fx) / Fn. Example. Sensor sensitivity is C = 1.9836 mV/V, the range Fn = 5 kN. Sensor is supplied by 10 V DC voltage and loaded with force Fx = 3.5 kN. Output voltage will be: Us = (1.9836 * 10 * 3.5) / 5 = 13.89 mV. If Fn = 0 kN, output voltage is Us = 0 mV. If nominal range Fx = Fn = 5 kN, then Us = 19.836 mV. That means the output voltage depends on load and it is changed linearily in range 0 ... 19.836 mV. Note: Sensor zero balance is omitted from calculation.
The measured force must never exceed the range specified by the sensor manufacturer, even for a short time. This can permanently damage the sensor. For this reason, we do not recommend useing the entire range of the sensor but keep a reserve. For static loads, we recommend that the force does not exceed 75% and for dynamic loads 50% of the range.
The type of material from which the sensor body is made is chosen according to the range of the sensor. In general, sensors made of aluminum are less suitable for permanent loads because they have a higher creep rate.
Each force sensor can measure force in the direction of compression and tension. The only limitation is their mechanical design, for example the absence of threads by which the sensor could be pulled. Sensors manufactured by our company are calibrated in one direction of force. This means that the measurement in the opposite direction will be slightly more inaccurate. The calibration direction is specified by the customer when ordering.
The accuracy of the sensors is expressed by the accuracy class. Our company manufactures sensors with an accuracy class of 0.5 and 0.2. Example: For a sensor with a range of 1kN and an accuracy class of 0.2, the error is ± 2N.
The output from the strain gauge force sensor depends on its sensitivity and excitation. It is generally equal to a few millivolts. The signal conditioner amplifies this output voltage to the level of the industry standard (0 ... 10V) or converts it to a current output (4 ... 20 mA) and also supplies the sensor with a stable voltage. The sensor can work and measure even without a signal conditioner, but this combination is used most often.

06/2021	Declaration of Conformity - Force Sensors (CE)	Keywords: CE, declaration of conformity, conformity
06/2021	Declaration of Conformity - Signal Conditioners (CE)	Keywords: CE, declaration of conformity, conformity
05/2019	How to connect the strain gauge force sensor?	Keywords: sensor connection
01/2017	Electrical interference and methods of its suppression in the measuring chain	The article describes general manifestations of interference and methods used to suppress it in practice. It is focused on interference in the measuring chain with strain gauge force sensor. Keywords: electrical interference, noise, shield, galvanic separation
02/2016	Strain gauge load cell parameters and recommendations for proper selection	The article explains the main parameters of strain gauge force sensor in terms of their practical use in selecting the appropriate type for a particular application. Keywords: measurement range, sensitivity, nonlinearity, hysteresis
01/2016	Principle of function of strain gauge force sensor	This paper describes the basic principles of function of strain gauge force sensor, the design of sensor and its connection to the electronic unit. Keywords: spring body, strain gauge, k-factor, electronic bridge, signal conditioner

A	The accuracy is the sum of all sensor errors under certain predetermined conditions. It is given as a percentage of the sensor range.
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C	Sensor creep is a change in the output signal of the sensor under long-term static load.
D	It is a load (force) that changes very quickly over time. They are e.g. vibrations or shocks.
E	The voltage output depends directly on the excitation of the sensor. It is usually selected in the range of 5 to 15 V. At higher excitation, the sensor begins to heat up, which can affect the accuracy of the measurement.
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H	Hysteresis is also referred to as a reverse error. As a result of this error, the sensor describes a different trajectory during unloading than under loading.
I	Insulation impedance is the minimum value of the resistance between the sensor body and any conductor of the sensor connection cable. It usually has a high value, at least 100 MΩ.
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N	Nonlinearity is the deviation of the trajectory when loading the sensor from a linear line.
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P	It is a load (force) that does not change over time or changes only very slowly.
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R	The measuring range is the largest force that the sensor is able to measure without risk of damage. It can be measured in the direction of compression, tension, or in both directions.
S	The sensitivity of the sensor is a parameter that indicates how big the output signal is when loaded with a nominal (maximum) force. It is given in units of mV/V. Static load is the application of force to the sensor without additional faults, e.g. vibration or shock. The strain gauge is a meander-shaped electrical resistor that adheres to the sensor body. Stretching, resp. the compression of the body is transmitted to the strain gauge, which consequently changes its resistance. By measuring the resistance of the strain gauge, we can measure the force acting on the sensor body. The term strain gauge often (incorrectly) refers to the entire sensor.
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U	This is the maximum force at which changes in the structure of the sensor body do not yet occur. Exceeding this force can permanently damage the sensor.
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Z	Zero balance is the non-zero voltage at the sensor output at zero load.

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