Digital Load Cells versus Standard Analog Load Cells Presently, there are no true digital load cells available to the weighing industry for truck scales. All load cells sold as "digital" load cells are actually analog strain gage load cells with added electronics, to convert the analog signal to a digital output signal within the enclosure of the cell. So, what are the benefits or disadvantages of placing electronics in the load cell for the purpose of creating a digital output signal? Accuracy of Digital Load Cells versus Standard Analog Load Cells Some companies will state their digital load cells are more accurate than an analog cell. Reality is these digital cells go through the exact same testing processes to receive the exact same accuracy approvals (NTEP class IIIL, 10,000 div) as standard analog load cells. Adding electronics in the load cell enclosure does not improve the accuracy and is an attempt to mislead the public. Reliability of Digital Load Cells versus Standard Analog Load Cells A typical digital load cell can have ten (10) times more components and solder connections than a conventional analog load cell. The relationship between failure and the number of components and solder connections is common knowledge in electronics manufacturing. Components and solder connections can be a major source for failures in the high vibration and shock environment of typical truck scale applications.

Some digital load cell manufactures will also use twist on connectors to connect the load cell cable to the cell. These connectors are a huge source of failure due to the natural hostile environment of truck scale applications. Best practice if to have one continuous piece of waterproof cable integral to the load cell. Ideally, the cable entry and load cell body should be truly hermetically sealed. This provides a more reliable protection from moisture ingress, which will damage and eventually ruin a load cells. Figure 1: Example of a 50,000 lb digital load cell.

Standards Currently, there is no industry standard protocol for digital load cells. This means that each different digital load cell manufacturer has their own digital load cell language and are not interchangeable with any other manufacturers digital load cells. Replacement parts are therefore limited to the scale manufacturer and their regionally authorized dealer. This creates a huge disadvantage for the truck scale owner by severely limiting their service options. The most popular designs of analog load cells are interchangeable and available from many load cell manufacturers. Scale service and maintenance can then be provided by any reputable scale service company. Alternatives to Digital Load Cells The ability to individually communicate with digital load cells and therefore individually troubleshoot each load cell is a real advantage digital load cells offer. However, this same ability to communicate and troubleshoot individual load cells can be accomplished using standard analog load cells and Digital Junction Boxes. Digital junction boxes are offered by a number of scale manufacturers as a better solution to proprietary digital load cells. These digital junction boxes are designed to work with all conventional analog load cells, regardless of manufacturer. This provides the very best of both worlds; the use of proven high reliability, readily available conventional analog load cells and all the benefits of individual communication and individual load cell troubleshooting.