Hi,
I've been using an arduino to get a reading from a FULL bridge of strain gauges bonded to a steel bar with no trouble. My circuit on the breadboard includes the ina125P amplifier. The schematic is identical to this one: http://cerulean.dk/words/wp-content/handsketch.jpg - which I've been using at the start of this project. It worked fine and I could get the desired signal by changing the gain resistance as necessary. The signal was displayed on a Labview virtual instrument graph.
This time I'm trying to do the exact same thing but with one 120 Ω strain gauge on a rod, in a bridge with three 120 Ω resistors of accuracy 1%. The schematic is the same again - 5V excitation across two terminals, and wired to the amplifier across the other two. However, regardless of how much I amplify the signal, I get absolutely no reading, other than something close to 0V and around 4.67V if wired slightly differently. I consulted a technician and the circuit I have is apparently fine - and the strain gauge itself is functional because I picked up readings from it with a strain gauge card.
Any suggestions as to what I should try?
I've been using an arduino to get a reading from a FULL bridge of strain gauges bonded to a steel bar with no trouble. My circuit on the breadboard includes the ina125P amplifier. The schematic is identical to this one: http://cerulean.dk/words/wp-content/handsketch.jpg - which I've been using at the start of this project. It worked fine and I could get the desired signal by changing the gain resistance as necessary. The signal was displayed on a Labview virtual instrument graph.
This time I'm trying to do the exact same thing but with one 120 Ω strain gauge on a rod, in a bridge with three 120 Ω resistors of accuracy 1%. The schematic is the same again - 5V excitation across two terminals, and wired to the amplifier across the other two. However, regardless of how much I amplify the signal, I get absolutely no reading, other than something close to 0V and around 4.67V if wired slightly differently. I consulted a technician and the circuit I have is apparently fine - and the strain gauge itself is functional because I picked up readings from it with a strain gauge card.
Any suggestions as to what I should try?
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