Note: Try to complete tasks 4.1.2, 4.3.1, 4.4.1, 4.4.2, 4.5, and 4.6.1 before coming to the WorkINGLab so that you have more time for the experimental part.
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4.2.1 Measure the voltage with the multimeter across the strain gauge for both the unloaded and loaded beam. What is the difference in voltage between loaded and unloaded beam? Hint: you can even measure at the screws of the luster terminal as they are in contact with the clamped wires (fig. 6).
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4.3.2 Insert your value for zeroMVinput and your value for mV/digit into the Arduino code. You will need to provide those values in Vips later. 💾 (Please insert your code where the comments mention it and then uncomment those parts!)
Execute the Arduino-program. Pick the correct port and open the serial monitor. Make sure the baud-rate is set correctly! (Check the “Serial.begin(…);” statement.
Set the calibration value to set the zero balance: For this, you need to know the ADC-value for the 0mV input. Then try to achieve a reading "Result in digits" as close to this value as possible, by entering a's or z's to the serial monitor.
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Matriculation number
If you had a 10mA current source like in fig. 3, what voltage change would you expect across the strain gauge for a 1‰ strain of the beam?
unit: [V]
relevant section: 4.1.If you had a 10mA current source like in fig. 3, what voltage change would you need to measure, if you want to resolve the maximum strain of 1‰ to 100 steps?
unit: [V]
relevant section: 4.1.Give the ADC-value for the 0mV input.
unit: [none]
relevant section: 4.3.How many mV/digit does the Arduino measure when using the HX711 as ADC?
unit: [mV/digit]
relevant section: 4.3.What voltage change would you measure for a 1‰ strain at 5V supply voltage in a quarter-bridge setup?
unit: [V]
relevant section: 4.4.What voltage did you measure in the quarter-bridge setup? Type the voltage difference between loaded and unloaded beam!
unit: [V]
relevant section: 4.4.Can the setup from task 4.5 compensate temperature?
select from:
- yes
- no
relevant section: 4.5.Can the setup from task 4.6 compensate temperature?
select from:
- yes
- no
relevant section: 4.6.Calculate the stress you applied in task 4.6.2
unit: [MPa] or [N/mm²]
relevant section: 4.6.4