Trouble detecting hi/low digital input modes.

Hello,
I am a relatively new user to LabVIEW 8.0 and I have the following problem.
I am using an NI USB-6008. I am working with instrumentation that has software controlled limit switches. Before moving a stepper motor, I am attempting to check to see if the limit switch has been reached in which case the circuit would be closed and I should see a ~5V input. However, no matter what I have tried I cannot get the software to detect when this switch is closed. I attempted the barebones coding by simply wiring the same data acquisition configuration directly into an array indicator on a front panel and even when no wires are plugged into the NI USB-6008. Having reached this point I am not sure where I am going wrong.
I have attached the VI for my program as well as the very brief VI I made to try to check the individual port status.
Thanks so much for reading this.
Attachments:
limit switch incorporation.vi ‏513 KB
digital io checker.vi ‏53 KB

Thank you for replying,
I was trying to troubleshoot this issue again and I am not sure if this is the correct term but the voltages were 'floating high' in the sense that instead of a 5V charge being required to be input to view a resultant signal, it actually needed to be connected to the ground to observe an absence of the 5V signal. With that in mind, rewiring the cables on the USB-6008 allowed for everything to work correctly. I feel almost like one of those households calling to complain about their computer not working only to find that the computer isn't even powered on! Nonetheless, thank you for your assistance!

Similar Messages

Daqmx simulated digital input

I'm having trouble using the simulated digital input feature.
I create a simulated digital input in MAX - a simulated NI PCI-6534, single channel, port 0/line 0, acquisition mode is 1 Sample (On Demand)
When I click the "run" button I see the indicator flash on and off as I would expect.
However, when I bring this task in to LbView, I can't get the indicator to flash no matter what I've tried.
No doubt I've missed some basic concept. Can anyone tell me what I'm doing wrong?
(VI attached).
Solved!
Go to Solution.
Attachments:
digItst.vi ‏11 KB

You do not have N channels, you have 1 channel. Use the appropriate DAQmx Read version.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines
Attachments:
digItst_BD.png ‏16 KB

How to I connect Sourcing digital output from My Interface Board to NI USB 6501 channel configured as Digital input

When I connect an input to DI channel of USB 6501 card from my board which has sourcing Output t, iIn the Off state it is not pulled down properly. The volatge on the port in is 2.1V -2.5V based on the pull down resistor on my board. I suspect that it acts as a voltage divider.
The state on the card is still show as "HIGH "state, even my sourcing output driver has a pull down resister. when I use this interface board for PCI mseries devices it works fine. Do the pull down resister on my sourcing output is not worth. Is this because of pull up resister 4.7k inside USB card 6501.
USB 6501 specifications shows the Digital input accepts both source and sink modes. By default the card is in sourcing digital input mode. How do we can convert this in Sinkind digital input mode.
Could anyone Please give your suggestions to overcome this issue .
Thanks you.

You really should not have both a pull up and pull down on the same line. Really weird things can happen. If you insist on having a pull down on your board, then I highly recommend putting a digital buffer chip between the DAQ and your board.
Some boards with DIO have a pull up, while others have pull down. You just have to watch the specs.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines

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 ***

X-Fi Fatal1ty Pro cannot see 5.1 Dolby Digital input via Optical link (mods, please he

X-Fi Fatalty Pro cannot see 5. Dolby Digital input via Optical link. I am pumping my Xbox360 through the Digital I/O dongle and every thing works OK using Dolby Stereo, outputing to my 5. analog speakers. However, it does NOT work when choosing Dolby Digital 5.. My SPDIF tab just says unknown input.
Please help, this is very frustrating...

Ok, for those who also wanted to know the outcome, I though I'd post.
I was told that the dongle cannot decode 5. to analog, but the Dri've Upgrade and the Console Upgrade could (at $80/$80 vs. $5).
Great.
So what I want to know is this:? what chipset or connection is Creative putting in the Dri've Upgrade and Console Upgrade? It seems to me that the card should be doing the decoding, not the type of optical port. If it's getting the signal, then what is the problem? Is is that the flexijack cannot output/input 5. at all, only stereo?
Anyway, the Digital I/O dongle is going back, the thing is useless for my purposes. While I can hear 360 games fine, DVD's on it default to 5. if they have that type of audio, and there is no way to switch it to stereo; it gives me only silence then.
And mods, nothing in my frustration is with you; you seem to be very helpful and responsi've. I just wish the rest of the company would get on the ball.

Fpga detecting falling edges on two digital inputs

Hello LabVIEW-Fans,
I spent a lot of time for fixing my problem...
I want to detect falling edges on two digital inputs. The two inputs sample an identical signal. So the edge detection should
detect the both simultaneous edges at the same time -> in the same loop iteration. But many times the edges are detected
in two following loop iterations.
My goal is to bring the two occurred edges together. No matter if there are differences between 1 and 10 loop iterations. If they
occur in that time window they should be handled as common edges, if not as not common edges.
Import too is, that the timedifferences between two falling edges are calculated. These timediffs should belong together like
the common edges. They must be timeconsistent.
How can I realize that the edges in between the 1-10 loop iterations of the two channels are accepted as common edges?
Thank you for your help.
marco
Attachments:
screenie_fpga_TwoEdgeDetect.png ‏15 KB

Hi M,
Thanks for the post and I hope your well.
So to clarify,
You have Two signals which could have a drift of X number of edges. But because these are related you only one to registor this event in software once, if two edges (one on each channel) happened within X edges?
For example,
Channel A has an Edge then 2 pulses later Channel B has an Edge = Software sees 1 edge?
Channel A has an edge then 12 pulses later Channel B has an edge = software sees 2 edges?
Sorry if I haven't understood.
Kind Regards
James Hillman
Applications Engineer 2008 to 2009 National Instruments UK & Ireland
Loughborough University UK - 2006 to 2011
Remember Kudos those who help!

Producer consumer with analog and digital inputs and outputs

Hi everyone,
I am working on a control system program for some practical test work. Currently I am working on the data acuisition component of the Labview program. My architecture is produced-consumer loops with a que. My system will have analog inputs, analog outputs, digital inputs and digital outputs. It's not a time critical sytem, but I would like all of the data acquisition to be synchronised. I have attached my program as it is at the moment. I am having trouble getting all of the data into the que since I have two data types. Also, I'm not sure if i've synchronised the four read/write sequences correctly. I would greatly appreciate if somebody could take a look at my program and give me some advice. Thanks in advance.
Solved!
Go to Solution.
Attachments:
control_v2_DAQ loop.vi ‏46 KB

Robert, the specific error that I get is:
Error -200462 occurred at DAQmx Start Task.vi:6
Possible reason(s):
Generation cannot be started because the output buffer is empty.
Write data before starting a buffered generation. The following actions can empty the buffer: changing the size of the buffer, unreserving a task, setting the Regeneration Mode property, changing the Sample Mode, or configuring retriggering.
Task Name: Heater testing lab digital outputs
This error occurs at the 'DAQmx write.vi' function. I just want to sent one sample per second, for each channel. I would like the producer and consumer loops to each run once every second.
I have attached part of my code with just the data acquisition and writing. Any help would be greatly appreciated.
Attachments:
control_v2_ML_simple.vi ‏83 KB

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

Audigy 4 Pro digital input 16 - 24

I have a Sony MDS-JB920 minidisc deck hooked up to my Audigy 4 Pro through the external box. Works fine.
However, the Minidisc deck allows one to set both the digital input and output to either 6, 20 or 24 bit. As the Audigy 4 Pro is 24 bit, I've set the deck to 24 bit for both in and out. So far no problems. If I watch the settings panel whilst playing a minidisc however, it indicates that the signal coming from the MD deck is 6 bit, although the deck is set to supply 24 bit through the SPDIF out.
When I put the MD deck on rec mode whilst the PC is supplying audio feed, the MD deck loops it back to the SPDIF input of the Audigy and then the software does display 24 bit signal coming from the MD deck.
This is very confusing to me, does anyone have an explanation?

CMSS is an effect used for stereo sounds, to emulate surround sound for them. It has no effect on the DVDs you're playing as you're just outputting the AC3 signal so the speakers can decode it.
If you're using a digital connection, then CMSS will not have any effect for other sound either, you need to connect through multiple analog connections to get that sound. A standard digital connection (coaxial and optical SPDIF) can only pass over either a stereo PCM signal, or an encoded AC3 stream (like on your DVDs). Normal sound like music or games will only be passed over as stereo PCM, so there is no CMSS effect there.
If you can connect your amplifier through several analog connections, then you can use CMSS aswell, otherwise your amplifier might have it's own upmix option like ProLogic.
Cat

How to wait for a digital input to go high?

I bet the following question is explained somewhere but I don't know how to find it.
Is there an optimal way to wait for a digital input to transition from 0 to 1? I mean, other than creating a loop that continously polls the input line is there a better way to wait for the transition? With all the "event driven" capability of CVI I suspect there's a slick way to do this but I don't know how to find it. I'm willing to RTFM if I know where to look.
thanks

Hi,
I have never done this, but it looks like it is possible to use the DAQmxRegisterSignalEvent function to assign a function that will be called when a "change detection event" occurs.
It works on a task basis, so if I'm not mistaken, you need to put the digital to be tracked into a separate task.
It is not stated if all NI hardware is compatible with this functionality, so try and see if it works for you.
Hope this helps,
Edit: It looks like you have already found the solution by yourself
S. Eren BALCI
www.aselsan.com.tr

Pci1200 digital input output

Hi,I'm a student using labview 6.1 for the first time. I use the digital input/output lines of a pci 1200 card. I use 8 digital input lines placed in one sequence, and 7 digital output lines placed in another sequence. The VI can read the input lines but the output lines give a voltage of 0.5 Volts instead of 5 VOLTS, how can I solve this problem?

What are you writing to the digital output lines in LabVIEW? Writing a Boolean value of False to a digital line will write a TTL logic low voltage and writing a Boolean value of True to a digital line will write a TTL logic high voltage. Make sure you are writing a true Boolean value to the lines you want to output 5 V.
Also, make sure you are not loading down the digital outputs. The digital lines can source 13 mA of current. If you are connecting a small resistance load across the digital outputs, you might be loading down the digital ouputs. I hope this helps.
Regards,
Todd D.
Applications Engineer
National Instruments

Use digital inputs to choose inquiry sequence?

Hello,
Is it possible to use a couple of the NI-1456 CVS TTL Digital Inputs to select which specific Inquiry Sequence should be ran?
I currently own NI Vision Builder for Automated Inspection. I do not own LabView.
I am using a NI-1456 CVS and firewire camera. My solution will use the NI-1456 CVS stand-alone. It will not be connected to a VGA monitor, or to a computer. I intend to use the system to detect flaws in silicon wafers. Due to several possible wafer sizes and shapes, I will have to develop an Inquiry Sequence for each wafer type. I would like to have the NI-1456 CVS unit contain several Inquiry Sequences.
-Rick

Hi Rick -
Actually, this is a very commonly used feature of VBAI! From the Configuration Interface, choose Tools»Configure Inputs/Outputs. This will pop up a settings window for the entire inspection process. The second state (called "Change Inspection?") allows you to configure a Product Selection port. The digital byte written to this port will determine which inspection script to run. From the listbox, you can choose NI CVS/IMAQ IO Product Selection to use your CVS's digital input port for this feature.
More information about this feature can be found int he NI Vision Builder for Automated Inspection Configuration Help, under the following index: Vision Builder AI Tools»Configuring Inputs/Outputs»NI CVS-1450 Series I/O. Note that the ISO inputs are used for this feature, not the TTL inputs.
David Staab, CLA
Staff Systems Engineer
National Instruments

Measure rpm and PWM signals using digital input of NI9401 module

Hi, is there a simple way how measure rpm (to 5000 rpm) and PWM (about f=3kHz) signals using digital input of NI9401 (ultrahigh-speed digital I/O) module plugged in NI 9172 ? I will wellcome any suggestions and VI examples (bether still). I'm begginer using LView 8.2. I apologize for my poor English. Many thanks.

Hi CUA,
Since you have already the right tools, you just need to get started with the software. The NI-9401 will give you access to the counters that are inside the cDAQ chassis 9172.
You need to place the module in slots 5 or 6. You can read in how they work and how to configure them in the counters section of the user guide found here.
Now to measure rpm, you can either measure the period of the signal (seconds) and multiply by 60 to have minutes and the number of ticks per revolution. You can find a shipped example to read period called “Meas Dig Freq-Buffered-Cont-Large Range 2 Ctr.vi” found under Hardware Input and Output » DAQmx » Counter Mesurements
To measure PWM, it is similar procedure and you can read the semiperiod (high time or low time). There is also a shipped example called “Meas Semi-Period.vi” found under the same location.
There is great information for these kind of task at this page or just post back if you need to.
Hope this helps.
Gerardo O.
RF Systems Engineering
National Instruments

HT4061 When proforming the new iPhone update I received an error message-iTunes has detected an iPhone in recovery mode. You must restore this iPhone before it can be used with iTunes. If I choose to restore will i get everthing back. Like my photos et

When performing the new iPhone(IOS6) update I received an error message - iTunes has detected an iPhone in recovery mode. You must restore this iPhone before it can be used with iTunes. Will I lose everything if it goes back to factory settings. Right now my phone wont do anything. It is just showing a cable, an arrow and the iTunes logo.

If you restore from backup.
You should have made sure that everything was on your computer bef ore updating anyway. Did you fail to do that?
All pics taken with iphone should be imported to your computer regularly as you would with any digital camera, most especially before any update/restore/etc. Did you fail to do that?

Convert digital input to a velocity graph

I've set up a hall-effect sensor to measure the velocity of a bicycle wheel as I rotate it. It provides a digital input into labview, from where I can calculate the veloicty based on the rpms. I've managed to find a way to work out the velocity of the wheel after the fact, but is there anyway that I can program labview to show me the velocity in realtime?

Do you have an example of a rolling average? I have used the Passive digital realization filter at http://en.wikipedia.org/wiki/Low-pass_filter . Is this considered a rolling average?
yn = αx + (1 − α)yn − 1
where:
yn is the current output value
yn − 1 is the previous output value
x input value
Δt is the time interval between samples
RC is the time constant
This works pretty good but I would like to use a rolling average with n data points where the n data points are averaged and the array is updated with new measurement value.

Trouble detecting hi/low digital input modes.

Similar Messages

Maybe you are looking for