Automatic Material Testing Using a 24-bit High-Precision Load Cell Input Card
Automatic material testing aims on material quality control applications for a wide range of industries, for example: automotive, electronics, safety, fitness, leisure, medical, textile, packaging�Kand so on. A typical automatic material testing system consists of several main functions: signal conditioning, transducer excitation, transducer measurement, LVDT measurement, and actuator control to a stepper motor or hydraulic system. The system integration of all required functions normally involves multiple subsystems.
To speed up system integration, material testing professionals look for potential solutions combining the functionality of accurate load change measurement, displacement, and motor control. One solution is an alternative data acquisition card. The challenge to the development of this DAQ card is not only the integration of multiple functions on a single module, but also enabling high resolution in order to achieve accurate transducer and displacement measurements.
The Solution: ADLINK 24-bit Precision Load Cell Input Card (Available in Q1 2008)
The integrates all required control and measurement functions in one module, thus assisting material testing systems manufacturers to reduce the integration curve and speed up product the time-to-market. It offers an on-board amplifier and 4-channel load cell inputs with excitation capability of 2.5 VDC and 10 VDC. The load cell input card is capable of transducer measurements with sensitivity from 1.0 mV/V to 4.0 mV/V and an accuracy of 1/200,000 counts. The 4-channel general purpose 24-bit high-resolution analog inputs are designed for high-accuracy LVDT measurements. The features 3-channel pulse generators and 3-axes AB phase encoder inputs for step motor control, and 2-channel analog outputs with a 16 bit resolution for hydraulic systems control. In addition, there are 8-channel isolated digital inputs and isolated digital outputs for external device control and sensor input.
A load cell is a transducer converting a weight or load change into a measurable electrical output. Load cells can be categorized based on either the type of output signal: pneumatic, hydraulic or electric, or the means of force detection: bending, shear, compression, or tension. The strain gage based load cell is most commonly used while traditional mechanical load cells, such as hydraulic load cells and pneumatic load cells, are used for certain applications; ex: precision measurements, applications related to intrinsic safety and hygiene, applications without any power supply, and so on. Stain gage load cells offer accuracies from 0.03% to 0.25% of full scale that are suitable for most industrial applications.