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Recent content by Auric_

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    Selection of the reference voltage supply circuit and filtering circuit at the reference voltage inputs of the ADC during strain measurement

    I apologize, I'm a little out of the forum communication space. A little about the results and the accumulated tasks: the ripples in the last and penultimate picture of post 43 (AC mode of the oscilloscope - oscillations on the excitation wires of the measuring bridge) are definitely caused by...
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    Selection of the reference voltage supply circuit and filtering circuit at the reference voltage inputs of the ADC during strain measurement

    I slightly adjusted the diagram from TIDA-00765 with the realities, it’s easier than pulling it out in pieces from my diagram. For power supply, 24V is taken and supplied to DC/DC, then to the LDO stabilizer, where it is reduced to 3.3V. The power supply to the processor is decoupled using...
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    Selection of the reference voltage supply circuit and filtering circuit at the reference voltage inputs of the ADC during strain measurement

    I didn’t understand the question: did I draw the wrong conclusion based on the test with a short-circuited ADC input or, on the contrary, should I do such a test? If anything, I did a test with a shorted input, I didn’t make a list of sample values, but I saw on the display that the low-order...
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    Selection of the reference voltage supply circuit and filtering circuit at the reference voltage inputs of the ADC during strain measurement

    My board allows the use of AC excitation, but at the moment I am trying to reduce noise with DC excitation (I don’t change the polarity using the keys), since AC excitation itself is used for slightly different purposes (fighting with parasitic thermocouples and other unipolar/unidirectional...
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    Selection of the reference voltage supply circuit and filtering circuit at the reference voltage inputs of the ADC during strain measurement

    I've tried several tests. The first was to work with grounding, the manipulation does not have much effect now, because yesterday I attached the cable shield from another cable to this one (changing the cable itself is problematic, I twisted the existing one and placed it inside the shield...
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    Selection of the reference voltage supply circuit and filtering circuit at the reference voltage inputs of the ADC during strain measurement

    I put on a protective cable screen and twisted the wires from the sensor. As I already wrote, I bought it cheaply on Aliexpress, the sensor “out of the box” turned out to be completely unprepared for work. Once placed in a protective cable shield, the drift changed the picture significantly. I...
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    Selection of the reference voltage supply circuit and filtering circuit at the reference voltage inputs of the ADC during strain measurement

    I did this project based on it, although apparently TI decided to confuse me a little :). There is quote from it about filtering: As a tradeoff, a differential mode 3-dB cutoff frequency of 689 Hz and a common mode 3-dB cutoff frequency of 14.5 kHz was chosen, which gives the absolute minimum of...
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    Selection of the reference voltage supply circuit and filtering circuit at the reference voltage inputs of the ADC during strain measurement

    the first graph is the initial data of instantaneous values (weight in grams on an empty platform), the second graph is a running average with averaging of 6 values, the third graph is also averaging of 15 values. In the graphs, to understand the time axis, 40 samples is one second, that is, the...
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    Selection of the reference voltage supply circuit and filtering circuit at the reference voltage inputs of the ADC during strain measurement

    I'll try, but for now there are difficulties - the RS485 channel most likely will not provide the required polling frequency to create a date logger, at least for now, the program that I have cannot keep up, requests are sent via Modbus, this also loads the channel with additional data upon...
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    Selection of the reference voltage supply circuit and filtering circuit at the reference voltage inputs of the ADC during strain measurement

    since this is a hobby, or rather study combined with a hobby, I don’t have specifications, but I can list my initial guidelines, which I use as a guide in general: as I wrote earlier, I assembled the diagram based on TI Designs TIDA-00765 (Schematic - TIDA-00765), search engines will provide...
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    Selection of the reference voltage supply circuit and filtering circuit at the reference voltage inputs of the ADC during strain measurement

    For now, I will try to answer only on this point: if I understood your comment correctly, then you are saying that I need to hold the signal longer, as the measurement will not have time to complete, but I am talking about the delay time from changing the polarity to sending a command to the ADC...
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    Selection of the reference voltage supply circuit and filtering circuit at the reference voltage inputs of the ADC during strain measurement

    Hello again. I tried controlling the excitation of the weight sensor using the UCC27525, judging by the oscillogram, I made the delay equal to 1 ms after switching the polarity. Depending on the polarity, I change REF0 or REF1 as the channel for measuring the reference voltage, and the polarity...
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    Selection of the reference voltage supply circuit and filtering circuit at the reference voltage inputs of the ADC during strain measurement

    I just can’t understand how the ADC will behave. I plan to do the excitation for a quick assessment without alternating current, and when the weight is close to being gained, switch the direction of the excitation current and measure the weight value in pairs of measurements with one and the...
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    Selection of the reference voltage supply circuit and filtering circuit at the reference voltage inputs of the ADC during strain measurement

    I apologize if this is a stupid question, but using the documentation I did not find a clear understanding. I want to implement alternating current excitation of the load cell on the ADS1220, but for correct measurement it is necessary that the REFP signal be greater than REFN. I planned to...
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    Why a popular circuit for opto-isolating 24 V inputs to 5V/3.3V is a divider before optocoupler LED?

    Thank you, colleagues, for the advice, I did the calculation using the example from Toshiba, but I have a desire to work with a transistorized optocoupler, at the output I will put a buffer element with a Schmitt trigger at the input, such as 74HC..., and there is a problem - I don’t quite...
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