Analog or Digital Load Cells?

By: Brody McCuiston

analog or digital
There are always questions when talking about “load cell types.” Often customers bring this up when determining their needs for weighing applications. To put it simply, there are two main types of load cells, Analog and DigitalBoth have pros and cons, but the main difference between the two is how their signals are processed.  Signal strengthsignal content, and data sample rate are the main elements that vary between the two load cell options…..

Signal Strength: 

Digital load cells use strain gauge signals that begin as analog electronic voltages. The digital load cell contains an analog to digital processor (A/D processor),  which converts these voltages into digital signals; the digital signal uses a signal range that is proven to lessen the fluctuation rate that occurs using a strictly analog range. The result is a more accurate (stronger) signal reading from the digital load cell compared to the analog cell. This means that digital load cells transmit data more effectively and quickly with terminals and PLC.

Signal Content:

Electrical voltage is processed and read by analog load cells, then the output is displayed as a weight reading.  Digital load cells function differently, in that each load cells transmits binary values, similar to other electronic devices. This binary data is less likely to incur outside interference from extreme temperatures, radio frequencies, and other factors that may hinder the accuracy of the weighing process. Simply speaking, digital load cells are typically more accurate than analog cells.

Data Sample Rate:

Data sample rate is basically the ‘time’ it takes for the load cell to send a signal out for the weighing information to be read/processed/displayed.  Analog load cells process weight information continuously, in real time; Digital cells process information in bits (many times per second)

Analog load cells often are cheaper options on up front cost, however digital load cells are proven to last twice as long with more advanced capabilities and less of a likelihood of breaking down. These load cells are hermetically sealed and designed where a junction box, which often retain water and moisture, is not needed. Digital load cells also have better diagnostics, better lightning protection, and better accuracy.