Before we look at what a load cell amplifier is let’s see what exactly a load cell is. A load cell is an electronic device that converts force into an electrical signal which can then be measured. In simplistic terms it is a device that allows us to weigh items and loads – measuring the force gives us the weight. So where does the amplifier come into it? The electrical output through a load cell is usually a few millivolts which isn’t that much and requires the output to be put through an amplifier before the output can be used. This is a little like talking through a microphone, if you were in a room of 400 people and started to talk to them normally not many people would be able to hear you, if you were to use that same voice and talk through a microphone, the sound will be amplified throughout the whole room so everyone could hear. It’s the same with load cells, reading the signal through a load cell can be quite difficult because it so low, an amplifier makes it easier.
What are some of the different types of Load Cell Amplifiers?
As with any product there are always different varieties to choose from, either from different brands or different types of amplifiers. You could choose between Digital Load Cell Amplifiers and Analogue Load Cell Amplifier. The amplifier you should choose should depend on the load cell, for example if you are using a digital load cell you should use a digital load cell amplifier. When you first buy your amplifier it will need to be calibrated to your load cell so they are in sync, usually when you purchase the amplifier with a load cell together the company calibrates this for you.
Typical Features of a Load Cell Amplifier
Before purchasing your amplifier check the features to ensure it is ideally suited to its usage and it can be used with load cell you have in mind. A typical specification for a load cell amplifier may look like this:
Digital Load Cell Amplifier:
- Non-volatile tare and peak hold facilities
- DIN rail mounted, 11-25V DC supply with digital display, Zero and Tare buttons
- 600 readings per second transmitted, Reading between -99,999 and + 99,999 counts
- 4-20 mA analogue output, 3 programmable Logic Inputs and 3 Logic outputs,
- RS422/485 interface. Fast easy calibration using the load cell mV/V sensitivity
- 18 bit resolution, linearity better than 0.002%, selectable filter 0.25 - 19.7 Hz
- Designed to drive 4 off 350 Ohm load cells ±3.2mV/V maximum
