Tensiometer Calibration

A tensiometer is a device used to measure tension in cables, wires, threads, belts, and more. Tensiometers are commonly designed to use 3-rollers, where the material travels through the rollers. Depending on the strength of the material it causes a deflection in the center roller that is connected to the load cell and that tension is displayed on an analog or digital display. Single roller tensiometers and sonic tensiometers also some of the designs available in the market.  Tension in a material may also be determined from the frequency of vibration of the material under stress.

Tensiometers are available both as portable handheld devices or as fixed installation on the factory floor. These are necessary to build up a tension-controlled closed loop.

 

Following are common types of tensions meters are used in the industry:

 

Digital Aircraft Cable Tension Meter

Aircraft keep flying safely with aircraft tension meters. These meters are the fastest, easiest way to verify accurate cable tension. You can get your aircraft off the ground and into the air with maximum performance and safety, minimum cost, and time. These instruments are designed to quickly check the tension on aircraft cables of various lengths and thicknesses.

 

Aircraft cable meters have the following features:

 

Tensiometers measure the tension in a cable, wire, or rope and typically display the subsequent reading on a dial scale. Users depend on tensiometers to provide accurate data, as incorrect tension information can be a safety risk for equipment and personnel. Over time tensiometers lose their accuracy as a result of misuse, physical damage, over-stretching, and corrosion. The tensiometer should be inspected for any physical damage before use.

 

How do the Tensiometers work?

Tension is the pulling force applied to a material when moving it from one location to another. This could be winding electrical coils, laying electrical cable, installing optical fibers, twisting processes, etc. The longitudinal force is applied on a series of 3 rollers which creates a perpendicular fixed force vector to the tension force vector. The sensor measuring the tension is coupled to the middle roller. This force is detected by the sensor and causes a change in its output voltage signal. This deflection is quite small, but still, it is sufficient enough to determine the tension.

 

Sensors in Tensiometers

The sensors in the tensiometers are electro-mechanical sub-assemblies that can measure tension forces applied to various types of materials. These sensors are most commonly used to measure the tension in materials as they are moved dynamically during the test process. In this device, the active tension measuring sensor is a load cell or a strain gaged transducer, which is attached to the roller in a housing designed to form the Tensiometer device.

 

How much deflection is required in the material to measure the tension

The deflection angles can be typically from 15° to 90° per side. The sum of these angles is called the warp angle. The tension sensor is designed for a specified wrap angle. With the increase of wrap angle, there is a corresponding increase in the deflection force on the sensor.

When you are selecting a device you will need to choose the maximum tension in your material and the expected wrap angle, as these sensors are designed for the tension capacity. The 3-roller design is the most convenient and easy to use. The single roller design is also available which lets you use your existing rollers by placing the sensor in the path between two of the rollers to obtain fixed deflection points.

 

The mounting position of the tension sensor

The tension sensor may be mounted in any position or orientation as long as the indicated direction of force is maintained. You can place the 3 roller meter anywhere in your materials path as its faceplate sensor and the force direction is fixed at the factory. However, in a single roller design, the force vector direction is marked on the sensor and the sensor must be placed between two fixed rollers to create a 3-roller system. The sensor is designed to deflect in one direction only. The sensor should be mounted to a rigid surface that will not deflect or bend.

 

Need for a signal conditioner

Since the tension sensor is not an active electronic device, a regulated precision power source is applied to it. This power is referred to as the excitation voltage. This signal changes as the force/tension to the sensor changes. This signal is measured by the signal conditioner. The signal is then mapped to real-world units such as grams, pounds, Newton, etc. This data can then be used to provide a digital display of the tension or the data may be sent to a PLC for computer analysis and display.

 

Is the calibration of the sensor required?

It is recommended for some applications that the device may be calibrated before use as the calibration done with the actual material used in your application will give you the most accurate results.  In the case of a 3-roller device, it is normally calibrated at the factory. This calibration is sufficient for most users, which means you can simply install and use it without recalibrating the device. With a single roller sensor calibration is necessary.  After installing the sensor on the device the calibration will approximately be correct for the wrap angle that is created. Single roller devices are tested and calibrated at the factory based on the expected wrap angle, so they should be re-calibrated with your application for accurate results.

 

How to calibrate the tension sensor?

The tension sensor is calibrated by testing it with known tension loads. The tensioned material is passed through the device path and a tension is created by suspending a known weight from one end of the material. The device will measure the output and display the result. It is used to create a calibration point.

To determine the signal span two calibration points are required. The first point is a no-load point and creates a 0 point. The second point is with a known load applied which is at least 50% to 100% of the sensors full-scale range. These two points are used to create the calibration slope. If necessary suitable adjustments are made to improve the accuracy of the readings.

 

e2b calibration provides reliable and cost-effective calibration services for your Tensiometers. Our verifiable and traceable services are unmatched in the industry.  We are ISO-17025: 2017 compliant and registered with ANAB. We are also ANSI/NCSL Z540-1-1994 certified. We are NIST Traceable Wide scope of ISO/IEC 17025 accreditation. Please contact e2b calibration for more information about our on-site calibration services.

 

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