Questions tagged [data-acquisition]

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33 views

About best way to perfom checksum

From my knowledge,checksum can be done using Xor or adding the bytes of the frame...i have to create a communication between ATmega32 microcontroller and matlab to perform some functions...which is ...
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27 views

Why isn't my PC recognizing my serial stream from my Arduino Uno?

I installed the instrument control package to Octave and have the Arduino IDE sending a single character to the computer every 100 ms. The device is transmitting on COM3 but the software still doesn't ...
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1answer
104 views

Software oscilloscope

I have been developing a C language software for software oscilloscope which is part of a control software. From timing point of view the software consists of two execution loops. The first execution ...
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0answers
22 views

Settling time of DAQ 6229

i have NI 6229 DAQ and datasheet and i come up across the settling time versus time for different source impedances i would know how is settling time calculated? i was thinking a simple RC network ...
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1answer
24 views

Is there a difference between these device terms?

Is the term "High-Speed Digitizer" same as saying "data acquisition device with high sampling rate"? The definiton I encounter for a digitizer is: " A digitizer is a hardware device that receives ...
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3answers
56 views

ΔΣ ADC Programmable Gain Without Amplifier

There are some ΔΣ ADCs of which one can set an input referred gain. Like if there was a PGA between the input and the ADC, but in fact, there seems to be no PGA between the ADC and the inputs but ...
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33 views

Between PC and multiple microcontoller, data transmit and recieve over wifi

I am working on project, in which 4 microcontrollers are involved and each microcontoller is controlling a data aquisition system that reads 2D array(64×64) of sensors So i want to start the data ...
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1answer
37 views

How to do multichannel ADC data logging

I need to build a system to monitor several (around ~20) voltages over several days. The ~20 voltages need to be measured differentially. Something which could in theory be accomplishes with 3 of ...
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17 views

Disabling menus on MSO2024B

The Tektronix MSO2024B oscilloscope has annoying menus that continually pop up when you adjust the scale , time base, or any other setting on the scope that you need to remove (by clicking waveform ...
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3answers
75 views

Finding equation of curve for NTC type thermistor [closed]

I have an NTC thermistor from the KTM 390 engine which I am trying to interface with the Arduino MEGA. The problem is the sensor has no datasheet. I have got the relation between the temperature vs ...
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1answer
104 views

Is it a good idea to connect ethernet cable's shielding to PCB GND?

Background My project is split over two PCBs for convenience. The first PCB adapts an input signal and converts it to a low-voltage differential signal. There are 4 channels to be measured, so 4 ...
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2answers
99 views

Why is this load resistor connected this way and what could be its value?

There is a potentiometer vane and the diagram includes protection components and looks messy, I simplified it by re-drawing as below: The circle R1, R2, R3 and the gap represents the vane's 10k ...
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4answers
821 views

Need a method for synchronization of galvanically separated microcontrollers

I would like to get some ideas for my problem. I have a HW which has a main processing unit (Beaglebone, host controller) which is connected to four galvanically seperated STM32 microcontrollers. All ...
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2answers
122 views

Why Do Pipeline ADCs have an “Overlap Bit”?

In pipeline ADCs, there is an amplifier after each stage that amplifiers the remainder of the previous stage by 2^(number of previous stage bits - 1). For example, if the flash ADC in the first stage ...
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3answers
278 views

How Can the Quantization Noise of an ADC be Measured using the Digital Output?

The ADC quantization noise is the error signal generated by rounding the sampled analog values of signal. Suppose that we have the digital output of an ADC, how can we measure the quantization noise, ...
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1answer
73 views

Sharing a single ground wire across multiple RTDs

Consider the following, simplified schematic for a single, two-wire RTD sensor: simulate this circuit – Schematic created using CircuitLab The two wires from the RTD sensor plug into pins 1 ...
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2answers
90 views

ADC / data acquisition board - general layout question

For one of my current projects, I am designing a small data acquisition board. However, I am currently not sure about the overall layout of the board. Here are 2 possible variants I came up with. ...
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37 views

Cutting off the negative part of my system acquisition signal

So I made an acquisition system for detecting a pendulum with a photodiode and an LED. Here is the system: LED/PD High Pass Filter Inverting AmpOp Notch Filter Buffer Low Pass Filter My goal is to ...
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2answers
71 views

What could be the reason for these bands in this data acquisition measurement?

Here is zoomed view of 16 channel The first plot looks very peculiar to me hence there are like two forbidden bands(looks like white lines as you see). This also appears if I plot any individual ...
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2answers
60 views

How to measure or estimate the phase delay between two analog input channels of this board?

There is a 16-bit data acquisition board with +/-10V range which multiplexes analog inputs and buffers the data to the PC. Specifications are given here (DAS6036 is the model in question). Now I need ...
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87 views

Whenever two system or sources are coupled they should have same current sink or common reference point (say ground). How to realize this in ECG?

Electrode (Ag-AgCl) are placed at different part and directly fed to positive and negative input of differential amplifier. How can we realize human body and amplifying system have same current sink ...
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2answers
150 views

Is only a firmware limitation the fact that some camera can't store photo in RAW format? [closed]

I was interested in understanding if from the point of electrical engineering storing the RAW data of the sensor directly into the memory of the camera require special hardware. Could be more ...
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38 views

Practical method to measure a data acquisition board's noise floor

Noise floor of a 16 bit system is usually within a few dB of 96 dB. And this is because 20*log10(2^16) = 96dB But I guess this is the theoretical quantization noise floor. So if this was the only ...
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5answers
599 views

Processing ADC conversion result: DMA vs Processor Registers

I have a periodic ADC conversion (every 50 micro-seconds) and I use the result to do some further calculations and update the PWM load registers. The ADC is triggered by the up-down counter of ...
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0answers
99 views

How can I estimate the minimum baudrate for a given bitrate?

My circuit performs data acquisition at 250 samples/s, 24 bits/sample and transmit this information to the local host (PC) through a bluetooth module that implements the UART protocol. As far as I ...
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0answers
48 views

Should I daisy chain start connect or wire separately?

This is related to field wiring schemes and interference. Sometimes tens of transducers are needed to be coupled to a single-ended data acquisition board's analog input channels where the transducers ...
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1answer
49 views

Is there a problem connecting PSU grounds to earth for an isolated signal chain in this scenario?

For a precision and simultaneous analog signal data acquisition; several force, temperature and acceleration transducer outputs are coupled to a daq board input channels through signal conditioning ...
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1answer
70 views

Are there any benefits to amplify the signal for this case?

A force transducer together with its amplifier designed for a full scale load such that it has -5V to +5V range as output. But it is only used with loads outputting -200mV to +200mV. A data ...
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1answer
116 views

Order of write and read in Microprocessor interfaced with ADC

An ADC is interfaced with a microprocessor as shown in the figure. All signals have been indicated with typical notations. Acquisition of one new sample of the analog input signal by the ...
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1answer
95 views

How to conclude the necessity for unbalanced to balanced signal conversion for this scenario?

This is a bit specific system related question about simultaneous data-acquisition for several transducers. Therefore hope you don’t mind for the long intro and the question. It would be too implicit ...
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3answers
625 views

Is star grounding sources necessary for this data acquisition system?

Several single ended output and PSU powered transducers are tens of meters apart from each other outputting 0 to 10V DC like voltages. Some are temperature transducers some are force transducers ect....
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2answers
37 views

Comparing two imbalanced signal transmission

Below shows a perfectly balanced system assuming cables are balanced and twisted: Im wondering if the transmitter is not impedance balanced, would a balanced receiver reject CM interference still ...
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1answer
120 views

Holding signal true for x seconds in LabView

I'm trying to create an automatic startup override system whereby when an ESD override button is clicked, a signal will be held true for 10 seconds overriding my ESD interlocks. This seems like there ...
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0answers
175 views

ADXL343 data read

I am using a ADXL343 accelerometer in one of my designs and I am getting strange readings from the device. Just to be sure, I would like to confirm that I am formatting the data properly. (I get the ...
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3answers
2k views

What is the “Nyquist” rate for sampling the derivative of a signal?

Background: I'm sampling the current through a capacitor. The signal of interest is the voltage across the capacitor. I will digitally integrate the current measurement to obtain the voltage. ...
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1answer
99 views

Re-wiring experimental apparatus: Questions regarding proper ground, DC power supplies, and precision instrumentation

The apparatus consists of a large metal spherical chamber attached to a metal table. There are two electrical enclosures bolted to the table legs. The chamber is outfitted with multiple servomotors, ...
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1answer
2k views

RS485 to RS232 conversion?

I need to connect a sensor that uses a RS485 transmission to RS232 or something I can read through the com ports on my data logger. I can't use usb ports or virtual com ports due to the program I am ...
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1answer
64 views

Scaling up NTC measurement through Multi-Channel Ohm meter

For a test bed, we want to measure temperatures with NTC sensors (~10kOhm at RT) for the range 10°C to 70°C. Our test machine accepts auxiliary signal through CAN-bus, so we used a Raspberry with a "...
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5answers
856 views

How is binary data 'split'?

If one computer sends data, for example 001101, how does the other computer know, where one bit starts and the other one ends? If you were just to monitor the change, you would get 0101, which is ...
0
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1answer
53 views

Wiring an on-off switch to the inputs of a daq

I have the following reed switch sensor: I need to connect this switch to counter input of this daq hardware. The only info is the following: How should I connect this to the counter-input? Any ...
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1answer
199 views

Data acquisition microcontroller approach

I'm prototyping a data acquisition device which interfaces with 64 discrete inputs; 32 analogue and 32 digital (user-configurable as either ON/OFF measurement or frequency/duty measurement). I'm ...
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1answer
55 views

How does isolation prevent input signals to float/saturate for differential ended inputs?

A differential ended input data-acquisition board has the following architecture: Here more information. Through screw terminals it takes the voltage inputs and each input first goes to a signal-...
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1answer
62 views

Tape archival data acquisition

I have some old tapes (the compact cassette variant) and an old Technics deck. I want to digitally archive these tapes as best as I can. The original deck is from the late 80s and contains a standard ...
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1answer
32 views

Investigating the cause of the drift for this system

A force-torque transducer data acquisition system is shown below: As shown in the above illustration, basically a six-axis transducer is powered and amplified by an interface electronics and then the ...
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3answers
185 views

Is there a need for buffering in this case?

.. will be updated soon (in construction with a more accurate information) If the ADC (or the data.acq device) have 100 kohm input impedance, how much accuracy would I lose? Do I need to buffer this ...
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1answer
55 views

Experimenting interference effects for different measurement systems

This is about for low level signals interference/noise being observed with single ended data acquisition inputs but not with diff inputs. Basically there are three data acquisition boards, where one ...
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1answer
132 views

Confusion with grounding floating sources to be used with a differential ended data acquisition board

Regarding this paper, I first tried to wire single-ended floating sources to a diff ended data acquisition board. But because of some power supply related issues and not wanting to make another ...
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1answer
147 views

Noise due to stray voltages in a data acquisition system

A single ended earth grounded data-acq. board on the left in the below illustration has inputs coupled by BNC cables coming from force transducer amplifiers A1, A2, A3, A4 as shown on the right: If ...
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1answer
432 views

How can I transmit a TTL signal to a computer?

I am designing a data acquisition system including a sensor that outputs a TTL pulse signal (3 wires: power supply, common, and signal). I am trying to determine how to send this signal to a program ...
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1answer
156 views

How to explain this solution to the common-mode voltages?

One of my previous question revealed that a variable voltage test device's power supply which is an AC/DC adapter, and is SMPS type which causes common-mode voltages. A solution given by tying the ...