Questions tagged [data-acquisition]
The data-acquisition tag has no usage guidance.
49
questions
0
votes
0answers
47 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 ...
-1
votes
2answers
131 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 ...
0
votes
0answers
36 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 ...
1
vote
0answers
40 views
Reliable methods to read data off a flash chip?
I'm trying to read data off of flash chips on a variety of embedded devices I have, and I'm currently using an FTDI FT2232H and flashrom (with soic-8 clips and probes) to extract the data as they are ...
5
votes
5answers
492 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 ...
1
vote
0answers
71 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 ...
0
votes
0answers
41 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 ...
0
votes
1answer
45 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 ...
0
votes
1answer
68 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 ...
2
votes
1answer
67 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 ...
0
votes
1answer
79 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 ...
7
votes
3answers
460 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....
0
votes
2answers
35 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 ...
0
votes
1answer
49 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 ...
1
vote
0answers
105 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 ...
12
votes
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.
...
4
votes
1answer
89 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, ...
1
vote
1answer
753 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 ...
0
votes
1answer
48 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 "...
6
votes
5answers
755 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
votes
1answer
45 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 ...
0
votes
1answer
51 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 ...
0
votes
1answer
53 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-...
1
vote
1answer
61 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 ...
0
votes
1answer
31 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 ...
0
votes
3answers
164 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 ...
0
votes
1answer
52 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 ...
0
votes
1answer
78 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 ...
1
vote
1answer
114 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 ...
0
votes
1answer
269 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 ...
0
votes
1answer
92 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 ...
0
votes
2answers
156 views
Is this definitely common-mode interference and how can I model and filter it?
A test device which can output voltage between 0 to 10V by a knob is powered by a DC adapter which converts 220V rms(meaning 311V amplitude) 50Hz AC to DC. Device is not a commercial and its adapter ...
3
votes
2answers
765 views
Confusion with different recommendations about wiring floating single-ended output sources to differential inputs
I'm trying to configure single-ended floating sources to differential inputs of this data acquisition board which of course uses an instrumentation amplifier and have differential inputs. So I had to ...
0
votes
1answer
137 views
Using differential and single-ended inputs simultaneously in a data acquisition system
Below is the wiring setup I plan to use:
Basically the black rectangle in the middle is this data-acquisition board which has 16 diff ended inputs.
The blue rectangle on the left is a six-axis ...
0
votes
1answer
199 views
is it possible to design a SD 3.0 controller in UHS-ii/uhs-i mode using simplified specifications?
I've been for while looking to store a sampled data up to the rate of 30MBytes/s, an SD 3.0 host controller core in uhs-ii/uhs-i mode fits the requirements.
i'm not planning to buy SD full spec and ...
0
votes
1answer
92 views
A question about differential ended settings for single ended inputs
Reading this documentation, what could be the reason to use 10k if one uses differential ended input settings for signal sources?:
I dont know why they recommend 10k but I had 6 channels going to ...
1
vote
6answers
96 views
What is the need for amplifier stage in a data acquisition hardware?
Below is a typical data-acquisition block diagram:
As you see above after the multiplexer there is an instrumentation amplifier IA.
This IA stage can be shown in more detail as below:
Since this is ...
1
vote
1answer
164 views
How to interpret this CAN bus data and find an equation?
I am trying to reverse engineer the data sent from an old CAN bus data logger. It sends a single ID which is selectable from a dip switch.
The only bit of data I am struggling with is the RPM
I plan ...
0
votes
0answers
45 views
Question about earth grounds for remote control of VFD via a DAQ system
A single-ended earth grounded PCI data acquisition board's analog inputs and outputs are controlled by a PC.
The daq board has also analog outputs. One of the analog output is controlling the motor ...
2
votes
1answer
90 views
Wrong voltage measured with a DAQ in presence of a RC filter
I'm using a DAQ from National Instruments. Testing my LabView software I noticed that when I plug a 1.5V DC battery in the analog input channels if I connect an RC filter (R=56 kΩ, C=10 uF) to the ...
0
votes
1answer
255 views
Why are high-sampling-rate data acquisition boards so expensive? [closed]
An example would be the NI USB-6366.
My guess is that it's primarily due to the analog-to-digital converter (ADC) since it should be the component responsible for the high rate conversion, even ...
1
vote
1answer
3k views
i2c data rate calculation
I want to estimate the throughput of i2c lines and this is the calculation I have done:
Hardware architecture:
MCU <---> i2c mux TCA9548A <---> 8 i2c based IMU sensors MPU6050
What am I ...
0
votes
2answers
97 views
Displaying data in engineering units on desktop [closed]
Suppose I have 100 numbers of DSPs whose ADCs are converting analog data into digitals ones. The data may be current,voltage, frequency etc. Now DSP deals with counts only it does not understand ...
1
vote
1answer
121 views
Oscilloscope stop getting data
I have a Rigol DS1000Z, and I'm using it to sort of log data. I have a wavelength tunable laser that creates an electrical pulse (start of pulse is start of sweep, end of pulse is end of sweep), and ...
0
votes
1answer
33 views
Reverse Polarity Protection for DAQ box
Firstly, I am a ME seeking advice from EE's. I have a Quadvolt voltage data acquisition box from Omega (P/N: OM-CP-QUADVOLT-30V) http://www.omega.com/pptst/OM-CP-QUADVOLT.html, that I intend on using ...
2
votes
3answers
1k views
4 Wire Strain Gauge to 2 Wire Conversion/Connection
I have the WK-06-12BT-350 ohm WK125BT Strain gauge from Vishay the Gauge comes equipped with 4 wires ( High endurance lead wires). The following document describes a similar gauge:
Strain Gauge
is it ...
1
vote
2answers
88 views
where to insert a thermocouple simulator in a circuit?
I have a thermocouple that's connected through several runs of thermocouple wire into a USB adapter and into a laptop where it gets logged. I'm seeing some error in my readings and would like to use ...
1
vote
5answers
634 views
“Multiplexing” thermocouples to an IO board
I'm trying to solve a problem on a project for one of my customer, 'cause we are having hard times to find an appropriate solution.
He needs something really simple (more on this later) and as we are ...
0
votes
1answer
66 views
Worried about channel ghosting in DAQ system - Need unit gain buffer?
I am working on a redesign of a test box we have at work. There is a transmitter that is sending data to a recording system (in my case the dewetron trendcorder with Trion BNC modules). We previously ...
