A load cell is a device that is capable of measuring the force or the load applied to it. The device works by converting the force into electrical signals which the users can measure. The measuring and conversion parts are handled by the use of a strain gauge and a data logger respectively.
When you apply force to a load cell, it transmits to the strain gauge that is placed in the configuration of a Wheatstone bridge. The force causes deformation on the strain gauge. The device measures the extent of deformation and converts it to electrical signals.
A data logger takes data from the load cell and stores the data for later use. It essentially acts as a bridge between the computer and the load cell.
Choosing the Right Companion for Your Load Cell
When selecting a data logger for your application, its specifications are of high importance. Some important features to look out for when buying a data logger are:
Input parameter type
A data logger used for load cell applications must be capable of measuring different combinations of the input parameters. These include pressure/intrinsically safe, bridge/strain, shock/vibration, etc. While most data loggers are compatible with most types of signals. It is usually recommended to use data loggers designed for specific signal types.
Number of channel inputs
There are two fundamental types of data loggers based on the number of input channels available - single-channel and multi-channel. With multi-channel data loggers, handling more complex and demanding applications is easy. A 32-channel portable data logger from Omega is capable of handling 16 true differential or 32 single-ended universal analog inputs for voltage, current or resistance measurements.
Several industrial applications have space constraints. In such cases, the size and the form factor of a data logger becomes a critical parameter. Whether the application requires data loggers that can fit through a small opening or large devices mounted on a vehicle or equipment, OMEGA has a wide range of compact as well as large data loggers with models for most input types.
Accuracy and Repeatability
The accuracy of a data logger is dependent on the type of measurement application. In case if there is a need to make precise weighing measurements, the accuracy is of prime importance. However, if the data logger is supposed to be used for long-time monitoring or less-critical applications, the accuracy will have a minor role.
However, it is important to note that data logger accuracy is not the same for a full range of measurements. Manufacturers usually provide a curve diagram or operating environment conditions such as temperature range and humidity within which the data logger will remain accurate.
Along with accuracy, data loggers must also have high repeatability. This essentially means that the data logger will produce the same results when used in similar measurement conditions.
In many applications, a data logger is required to collect data as fast as possible. In such scenarios, the speed of data acquisition or the sampling rate is critical. However, with higher sampling rates, the memory requirement also increases. As such, when selecting a data logger, it is important to determine the sampling rate and the sample duration. Knowing these values will help you calculate the memory requirements. For example, an application that requires a sampling rate of 1 per second and a test duration of 1 hour will need 3600 samples.
Getting the support from your manufacturer just when you need it is important to ensure that you receive value for your investment in a data logger. A manufacturer should offer the service and must be able to provide spare parts for your data logger when you need them.
Some additional criteria that must be taken into account while selecting a data logger for load cells include:
- Compensation for the read values based on temperature
- Maximum number of readings that it can store
- The battery life of the device
- Type of memory: Always prefer non-volatile memory
- Water and weather resistance