Read digital input

To read the data sent via a 'printf' use VISA Read, Did I want to know that I could use in LabView function to see if a digital input is active on a microcontroller?
Thank you

Hello, since this question is LabVIEW-related it should better be posted in the appropriate board.
In any case, LabVIEW has a complete set of functions to operate on the RS232 channel and is equippend with all fucntions that are normally used to decode messages coming from external device. Nevertheless, keep in mind that when speaking about two independent device, the interaction between them depends on how both behave. That is, if the microcontrolles sends informations about its I/O then yes, LabVIEW is capable of reading these informations. In order to have some more concrete help you will need to supply some more informations about the messages your device sends on the serial cable.
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Similar Messages

Is LabView able to read digital inputs from maxon motors controller, EPOS2?

Hello,
I would like to ask that if LabView is able to read any digital inputs directly from a maxon motor controller, EPOS2. As i have tried making a new VI from the maxon example VI, but the difference is that i've added a input control. But the program doesn't seems to work.
That's why i would like to ask if LabView can read a direct digital input from the maxon motor controller.
Thank You & Regards,
ParkyPak
Attachments:
sensor.vi ‏34 KB

Hello Parky,
I understand now. I check on the motion controller and it is connected through USB to your computer. In term of controlling the motion controller, you are using some LabVIEW library from maxon. The photosensor is connected to the motion controller may be as a switch or as a limit switch.
In order to read the value of the Digital input port, you may need to take a look of the libraries to check on what function call and the supported command to check the digital input port. If this is not successful, then question or referring to examples from Maxon motors would be the best.
I hope that this helps.
James
- Meadow -
LabVIEW 7.0 - 2011, Vision, RT, FPGA
TestStand 3.0 - 4.5

PCI 7330 Read Digital Input

I have a 4 Motion Axis PCI 7330 card, and I am operating 2 motion axes with it. This system is operating a drill system that will send back a signal once the drill has reached it's full drill length (completed the hole). I have tried to use the "Read Digital I/O Data" VI for this but I can't seem to read in a signal. IS THERE AN EASY WAY TO DO THIS?
For this VI the voltage to the port will be zero until the drill sends back the voltage signal that it has completed the drill. So all that it needs to do is read that there is a voltage (so anything other than 0) across this line.
Thanks

Hello,
The Read Digital I/O data VI should be an easy way to do this, but something may be going wrong in the code. Can you post/explain what you have done so far? You also may want to try posting in the Motion Control forum. There may be more people there that have done what you are trying to do, so you might get more responses.
-Erik S
Applications Engineer
National Instruments

Creating VI for MCB2300 to read digital input

Hello,
I am a student working on a project to use embedded Labview (2009) on a MCB2300 (LPC2378) to do multiple tasks. I have some experience in Labview, but I am a fast learner. I was able to get the board to produce an LCD response to the potentiometer, using my PC's computer as the controller.
I eventually want the microcontroller running an embedded VI to read signals in and produce outputs. I was able to create a new target for the LPC2378 and view all the elemental I/O's that go with the chip.
Right now I am stuck on calling the Microcontroller's I/O's in Labview. For right now, I want to apply a test voltage with an external PS to one of my input pins on the microcontroller and have it respond by producing some message on the LCD (or spitting out a signal on some other output pin). I have the chip grounded properly.
I don't need help on the LCD callout so much as I need help on getting the microchip's I/O's working. There are so many sub VI's provided by Kiel that I don't really know where to begin.
If anybody can steer me in the right direction or even show me an example VI that uses the microcontroller's pins, I am sure I could pick it up and go from there.
Let me know if you need any additional information. Thanks for your time.
Mark

Hi Mark,
Many of these examples can be accessed via the NI Example Finder. To open the Example Finder, go to Help»Find Examples.... When the Example Finder loads, browse to Toolkits and Modules»ARM»Keil. There are a few folders in that directory that have some great examples that can get you on your way.
Aaron P
National Instruments
Applications Engineer
http://www.ni.com/support

Reading a PWM and determining pulse width using a digital input pin on a NI 9425 DAQ

Hello!
I have been experimenting with LabVIEW for about a week now and have run into a brick wall. I have found a fairly effective way of reading a PWM signal through an analog input and determining the pulse width. However, it is becoming necessary for this project to do this same thing using a digital input. I've been playing with this for about a day now and am not making much headway.
For reference, I will be using a 9524 device
Any ideas?

Also, if it is helpful at all, I've attached two vi's. One, functions just as I need it to - but it doesn't involve data aquisition. The second should be similar to the first, but is non functional - I keep getting an error that my amplitude is zero.
Any thoughts?
Attachments:
DigitalEdgeDetectionKnown.vi ‏47 KB
DigitalEdgeDetectionRead.vi ‏148 KB

How can an unconnected indicator read an FP digital input?

SYSTEM DESCRIPTION:
A Dell desk top computer with a Field Point system attached. There are a variety of modules including analog input, 2 digital inputs, relay out, Strain gage input, quadrature input. The system is running XP. The Labview program is written in v6.1.
PROBLEM
In an application written by others, I have found 4 front panel indicators that react to Field Point digital inputs. On the block diagram, the indicators are not wired to anything. They have no local variables and no global variables associated with them. How can they be reacting to the FP inputs? The problem is that one of the indicators reacts to the wrong input and I need to fix it. See "In(Rescue)Limit, In(Cargo)Limit, 4067 Out Limit and EStop".
Also, when the vi is launched, it starts up the FP system and the vi has no FP vi's in it and none of the sub-vi's have any FP vi's in them either. Any clues how this could be working?
I have attached the vi. There are other vi's in this project, just too many to include unless more information is needed.
Thanks,
Chris Dreike
Advantage Automation, Inc.
[email protected]
310-214-2175

Chris,
It doesn't look like you attached the VIs.
You can use front panel DataSocket binding to link an indicator or control to a FieldPoint ethernet item. Right-click on the indicator and choose Data Operations>>DataSocket Connection.
Regards,
Aaron

How to acquire serial data on a digital input line with good performance?

Hello,
we have a performance problem with our realtime controller. Our objective is, to read a 24-bit long digital waveform from a digital input line. To do this, we supply a clock signal (236 KHz) to the PFI1 Line of our DAQ Board. On each rising edge of the clock, a new bit is set on the digital input DI0.
Our hardware which transmits the data, is triggered through a digital output from our realtime controller. On each edge on this output, the hardware starts a serial transmission of 24-Bits.
Everything works fine except the bad performance of our realtime controller. We want to acquire the 24-Bits in a 1ms timed loop. To measure performance we wrote a test program. In that, we only triggered the hardware and transfered the data to the realtime controller. The task which is doing this job, has a approx. CPU-Load of 30%, which is, in my humble opinion, very high. The task is not waiting for data or anything else! We have earlier implemented a control which is also using a 1ms timed loop. This control is sampling 2 analog input signals, 2 counters. Futhermore it's sending telegrams with CAN and doing many calculations. The strange thing is, this much huger program has a CPU-Load of 25%. Does anybody know where the problem is?
For the better understandig I attached our test-program to this text.
We're using:
PXI-8175 realtime controler
PXI-6221 Multifunction DAQ
Thanks!
Regards,
Crest!
Attachments:
dig_test.zip ‏51 KB

Hello,
First of all 30% CPU-Load is normal because the DAQmx-driver needs a lot of resources.
In your programm you should place a wait (for example with 1ms) into the while-loop which causes
lower CPU-Load.
If this is not enough you should build your vi like in the following example.
Regards,
Christian
Attachments:
Read Dig Port.vi ‏51 KB

I was given an assingment, but have no idea where to begin. The assingment is to create a text file using notepad with all of my digital inputs and some how make those imputs show up on my digital indicators on my control pannel

I was given an assingment, but have no idea where to begin. The assingment is to create a text file using notepad with all of my digital inputs and some how make those imputs show up on my digital indicators on my control pannel.
When it was explained to me it didn't sound to hard of a task, I have no LabVIEW experience and the tutortial sucks.

StevenD: FYI, I did NOT give you the one star rating. I would never do that!
StevenD wrote:
Ow. Someone is grumpy today.
Well, this is an assignment, so it is probably homework.
Why else would anyone give HIM such an assigment, after all he has no LabVIEW experience and the tutorials are too hard for him?
This would make no sense unless all of it was just covered in class!
This is not a free homework service with instant gratification.
OK! Let's do it step by step. I assume you already have a VI with the digital indicators.
"...but have no idea where to begin".
open notepad.
decide on a format, possibly one line per indicator.
type the document.
close notepad.
open LabVIEW.
Open the existing VI with all the indicators.
(are you still following?)
look at the diagram.
Who made the program?
Does the code make sense so far?
Is it a statemachine or just a bunch of crisscrossed wires?
Where do you want to add the file read?
How should the file be read (after pressing a read button, at the start of the program ,etc.)
See how far you get!
Message Edited by altenbach on 06-24-2008 11:23 AM
LabVIEW Champion . Do more with less code and in less time .

Triggering an event with a digital input

Hello all,
I'm writing my first Labview program. I used an architecture I found on the forums here, and it has been very helpful in getting me started. This architecture uses two while loops, one containing an event structure and one containing a case structure. (This is a queued state machine architecture, I believe).
Part way through the programming, we decided we needed a sensor to make sure the part was in the test fixture during the test. If the part is removed during the test, we'd like to safely stop the test. So basically, I need to monitor a digital input (on an NI-USB-6525 module) and enter the "Stop" case if the digital input turns off. I would also like to make sure this digital input is on before entering the "Start" case. I don't care if the input changes state when the test is not running, nor do I care about its state during the "Exit" case.
I'm really not sure how to add this functionality to my "stop" case. I don't even know if it's possible. I've been researching DAQmx events, but I haven't found an example or answer that aligns with my particular problem.
I've attached my code. It's incomplete right now - I still have a large number of steps to add. I wanted to get this issue figured out before I programmed any more steps. A preview of the code showing the basic architecture is shown in the picture below.
Does anyone have any ideas or suggestions for me, or questions if my problem is unclear? Also, if you see anything else in my code that will be problematic, please let me know.
Thanks in advance!
Attachments:
Main_Loop_072412.vi ‏195 KB

I should also add that I looked into event dynamic registration, but it seemed incompatible with my issue. I don't want my top loop to run only when an event triggers it - I want it to run all the time so that it can immediately respond to button presses. Also, most of the triggering I found was based on value change. I care about the actual value, not just that it changed.
I don't want to do anything that will bog the code down too much since it is important that the system respond immediately to inputs, especially to the stop or exit button presses.
I'm sure I am missing something very basic here. I'm used to ladder logic, where everything is simple and straightforward.

Digital Input Cannot Display this Video Mode Optimum Resolution 1280 x 1024 60hz.

HP Pavilion h8-1360t, Windows7 home premium 64-bit, AMD Radeon HD 7570 graphics card.
error message: Digital Input Cannot Display this Video Mode Optimum Resolution 1280 x 1024 60hz.
I get the error message as soon as Windows opens and the desktop displays. Then it goes black with that message. I've been using the computer for awhile and I had it so that when I maximized a window it would go across both screens. I have two monitors on the graphics card. Somehow I changed the settings so that a program would maximize to one monitor or the other. That is how I want it to work. Maybe I activated HydraVision. Now I have the problem when I start.
Also now when I boot to Safe Mode I get the message that there is no AMD graphics driver installed, or it is not functioning properly. I have tried to update it and the computer tells me I have the most recent version installed. I would like to uninstall it and reinstall it, but I'm a little worried I won't get it installed and be without video. Something like that happened to me once before years ago.
Could someone tell me what I should do please?
Thanks,
Jim Allen

HP support is here:
http://www8.hp.com/us/en/contact-hp/contact.html
In safe mode you should uninstall the driver, then try to boot normal again.
Then check if driver was installed by win7.
If not go go AMD website and download latest driver for your card.
V.
*** Say 'Thanks' with Kudos ***

Monitors with Digital Inputs

What monitors are available that accept the Toslink input directly? Do the keyboard and on-screen volume controls still work with this arrangement?

I believe Tannoy make a set of the Elipse range of speaker with digital inputs as well. I have no idea why you would want to do this though. I suspect the gains in quality would be tiny if anything at all. You'd be better to spend more money on something less techy and get something that really sounds great!

How can I use 4 DIO lines as digital input in a E series-SC 2050-ER8 set up ?

I have a DAQ system with an E series DAQ card that is connected to SC-2050 and ER8. I want to use 4 DIO lines (out of 8) for digital input. How can I do this?

Hello Suresh,
There are a variety of ways to accomplish this. If you are using LabVIEW, you will use the DIO Port Config VI and the DIO Port Read VI. You will use the line direction map input of the DIO Port Config VI to setup which 4 lines you want to be the input lines. The LabVIEW shipping example entitled 'Dig Multi-line Direction (E) VI' shows how to use the lines of the digital port on an E-Series device for input and output.
If you are using NI-DAQ function calls, you can use the Dig_Line_Config and Dig_In_Line calls to configure a digital line for input and then read from that line.
I hope this helps.
Regards,
Todd D.
NI Applications Engineer

Can't change sample rate for digital input on Mac Pro

Hello all,
on my Mac Pro with 10.4.10 I can't change the sample rate for the digital input. Whenever I choose 48000 or 96000 Hz it returns to 44100 Hz after a few seconds. Feeding a 24 bit/96000 Hz signal from an external ADC into the optical input doesn't help. No input signal is available for digital recording software such as Sound Studio or Cubase. After changing the sample rate in audio midi configuration to 96000 Hz the sound can be heard for a few seconds but when the setup returns to 44100 automatically the signal is, of course, lost.
I've deleted all relevant preferences and restarted with resetting paramter RAM. Still the same. With external hardware such as M-Audio Firewire equipment setting the sample rates works properly.
Thanks to all for helpful clues.

Hi,
when E&M signaling is configured on digital interface like the VWIC is, 2 or 4 wires operation is not applicable because there are no wires at all, and reported only for compatibility with the analog E&M card.
Consequently, you cannot configure that and it will not make any difference to effect of the connection.
Please rate post if it helps!

Simultaneous Digital Input and Output from NI 9403

Hi,
I was wondering if it is possible to digital output through one line in this module(NI 9403) while simultaneously reading from 10 other lines?
Basically what I need is for line0 to always be closed(true), and read lines1:10 - at very least 1sample/second.
I have attached a stripped down version of my code illustrating my error. I thought I was getting the error because the two tasks were using different clock configurations, but I tried using the same inputs and that doesn't work for me.
Any input is greatly appreciated.
Thank you
Attachments:
Digital I-O.vi ‏22 KB

Hi Matthew,
The behavior you're seeing is expected for the 9403 module, since it is a serial module. The DAQmx help has the following restrictions in the Digital I/O Considerations for C Series Devices section.
Timed digital input/output restrictions:
You cannot use parallel and serial modules together on the same hardware timed task.
You cannot use serial modules for triggering.
You cannot do both static and timed tasks at the same time on a single serial module.
You can only do hardware timing in one direction at a time on a serial bidirectional module.
So you can only do timed input or output at one time, but not both. However, based on the VI you attached and the description of what you want to do, you don't necessarily need both timed tasks in your loop. You can create a static output task to update that one line and after that, you can just start your timed input task on the rest of the lines. This should maintain the state on the DO line, since you're not acquiring from it.
Cheers,
Cristina
Cristina

How to force digital input sample rate?

Does anyone know how to force a Digital Input sample rate and/or tell Core Audio which conversion clock to use... internal or external? Apparently both things can be done from Pro Tools, but I don't have it. My problem is locking onto an A/D converter's 48K Toslink output. I can set 48K in 'Audio - Midi' setup and the audio is perfect, but a few seconds later Core Audio returns to the default 44.1K. I need to force it to stay at 48K, or clock on the signal rather than internal clock.

Braver,
Let me clarify a few things. First, the 6733 supports correlated digital I/O. This means that the digital operation does not have its own clock. You can correlate the digital operation with the AO clock, which will allow a digital operation up to the max AO rate. You can generate a pulse train with an onboard counter and use that as your digital clock source. Also, you can use a completely external clock source to achieve the max digital rate of 10MHz. The knowledge base, linked below, points you to a couple of examples that ship with LabVIEW. Be sure and read the documentation associated with each example.
Knowlege Base
As for
the example CDI Single Point clocked by Counter (E).vi, notice how the output of...

Read digital input

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