The easiest one is to sample 10 or 20 values and make the average out of it. This guide is the best i found on the web so far! The reason is quite simple: changes in temperature will change the resistance of the strain gage. I'm thinking in use the OPA 2777, with 5V alimentation because it has a lower offset voltage (20 uV). My DAQ has a range of -10V to 10V for analog input. Then upload the code to Arduino and open the serial monitor. 100 grams, but with an accuracy of 0.1 grams), so I thought that this one is suitable for me. The load cell in your kit is referred to as a cantilever configuration load cell in that measures the bending force applied to one end of the unit. The problem is that you cannot set data acquisition rate in deterministic way like you do with DAQ made on purpose. Do i need to use different potentiometer or capacitor? As you can see, the load cell has some screw threads, so we could mount it on a base plate. Anyway you can build your own cascade amplifier/conditioner using a general purpose rail to rail op-amp (there are thousands LM7301, LT1677, AD 8505...). Sampling rate is not important in this case. Digital load scales are another miracle of modern-day engineering and design. Your choice is really good for high precision measurements since noise plays a relevant role into determining resolution (and accuracy as well). 1) your ADC does not have enough resolution to measure the output of ina128p when below 100 mV And it is also hard to find a good linear regression: with very low loading, the output is non-linear. MyRIO connects exactly in the same way as DAQ. Well this is a good question and thanks for asking! first let thank you for having appreciated this tutorial. I have been playing around with this circuit and am using a 10 turn 10kOhm potentiometer. This is easily achieved by moving the wire of the INA125 from pin 14 to pin 15. Then, if necessary, implement the step-up thing. (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){ I am using a NI USB-6002 DAQ which can provide 5V from one of the pins. This configuration provides a linear amplification (in other words, let the amplified signal to be a multiplication of the original signal) only if the amplifier sees a symmetric power supply. So forget to play with load cells as you can do with INA125P. However my advice is to use 5V supply in order to avoid temperature drift. Building a low cost strain gage load cell amplifier, Disclosing steppers: a guide to discrete motion, http://www.ni.com/labview/signalexpress/daq.htm, http://www.ti.com/lit/ds/symlink/ina125.pdf, http://www.analog.com/media/en/technical-documentation/data-sheets/5B38.pdf, http://www.analog.com/media/en/technical-documentation/application-notes/AN-683.pdf, http://www.smdsensors.com/Products/Low-Range-Force-Sensors-Grams-to-10s-of-Grams-Full-Scale/, http://it.mathworks.com/discovery/arduino-programming-matlab-simulink.html, http://sine.ni.com/nips/cds/view/p/lang/it/nid/212478, http://www.smdsensors.com/Products/S215-Ultra-Low-Profile-Miniature-Single-Point-Load-Cell/, http://www.phidgets.com/products.php?product_id=3132, http://hlhsensor.en.made-in-china.com/product/tbynXgWcYMaE/China-Micro-Load-Cell-CZL928F-.html, http://www.mechtechplace.net/wp-content/uploads/2017/09/gerb_LC01.zip. Another question about gain resistance of 10k ohm/10 turns This has been extremely helpful for some of my hobby projects. One more thing alberto, If i need a VREF 10V I need to supply the INA125 with a symmetrical voltage source of +-15v? HX711 module is a Load Cell Amplifier breakout board for the HX711 IC that allows you to easily read load cells to measure weight. The load cell is a straight bar load cell (sometimes called a strain gauge). Your application is definitely manageable by INA 125 or 128, since you need an amplification gain of about 500 (which is a fair value for those ICs) and, furthermore, since you are working with PLC, the level of noise is easily manageable with a lowpass filter. So the first thing is to pick the right transducer. You can download the code of this project from below. Now imagine that the right-side cell is mounted to the base and the left side is where the load is placed, this configuration deforms the strain gauge load cell because of the giant hole in the middle. For this circuit, since it works perfectly, I spent some time on generating a wonderful PCB (which is always better for measurements, since you have less noise). thanks for having appreciated this tutorial. To make it short, I can give you a rule of thumb: if you need n levels for your measurements application, you need to provide at least 3*n levels at your ADC, to let you reach the desired precision for your application. Is there a way to solve or improve this problem by hardware? The fore mentioned block scheme is valid for both LabView and SignalExpress. As far as I know, no bidirectional force sensing. I used it several times for general purpose robotics and they work. My suggestion in your case is to go in any case for a symmetric supply since it is fundamental for measurement precision, even if you sense forces mono-directionally. Secondly, my advice is to check that the wiring is working with a multimeter: check the continuity of circuitry and then check if the load cell is powered with 2.5 Volts. So my question is: Why does increasing the gain resistor also increase the no-load voltage? Correlated noise is killed most of the times by low pass filters. On Saturday I will upload a video tutorial for this circuit. If the difference between set weight and measuring weight is greater than or equal to 50gms, the buzzer beeps with a 200-millisecond delay (slowly). also, since a bowl will be placed on top of the load cell to determine if the dog has food or not in its bowl. Products, our weight scale, INA125P is the most advanced tutorials load. More thing Alberto, Congratulations for the PCB i actually i have uno/mega/due... 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