Obtaining a TTL input signal via DIO lines of 7334

Hi
How can I obtain a TTl input signal from a source via the DIO lines of the 7334 .
Thanks
Mal

I do not quite understand your question.
If you want to know what kind of signal a DIO line will detect properly: the signal has to be less than 0.8V to detect a low state and more than 2.0V to detect a high state. This is compatible with outputs of all TTL logic circuits.
If you have some other circuitry (source) with different specifications for the digital signal you can simply connect a switching transistor in open collector circuit. The DIO lines have pull-up resistors, and when the transistor is switched the DIO input will be tied to less than 0.8V (low level).
Anyhow, if the high output level of your source is more than 5V (there are many control systems with 24V output level) it is better to use galvanic isolation to avoid damage of the motor controller. You can use a relay, or better an opto-isolator. You have to design the series resistor of the opto-isolator such that the input gets proper current to drive the LED (usually 10mA will be sufficient for most optocouplers). If the opto-isolator has an open collector output configuration it can be connected directly to the 7344 DIO line.
Of course you always have to provide a common GND connection between the 7344 board and your signal source (or the open-collector transistor in case you use this configuration or an opto-isolator).

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Error -10401 appears when I try to read in my Encoders (TTL-Signal) via a LabView-"nuDrive 2SX-411" and Motion Controller Card

Hy there.
Im using two "Haidenhain ERN 420" Encoders with TTL-Output Signal
A NI-Motion Controller 7334 with an NI-"nuDrive 2SX-411"
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Phil,
It looks to me according to the error that you were trying to use DAQ functions to access the Motion controller. The Motion controller uses its own functions. There are two for reading position:
Functions Palette >> Motion & Vision >> Flexmotion >> Trajectory Control >> Read Position.
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C:\Program Files\National Instruments\LabVIEW 6.1\examples\Motion\FlexMotion\One Axis.llb\One Axis Move with Position Monitor.vi
Make sure that you have configured and initialized your board properly in MAX.
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Nestor
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Apparent altered DIO line input state on 4351 when using driver instead of NI MAX

Hi,
I'm using an NI4351 PCI DAQ card with the Ni435x driver and LabWindows/CVI v5.5 (on Windows 98) to capture digital logic states on the DIO lines. I first used NI's MAX utility to establish a virtual DAQ input channel from 'Data Neighborhood'. When I tested this channel from the utility by connecting the DIO line to 5V or GND via a 10K resistor, the respective logic levels were registered. In LabWindows, I use the 'NI435X_Init' and 'NI435X_Configure_Digital_Lines' driver functions to respectively initalize the DAQ card and set one of the DIO lines as an input, with the rest being set as outputs. However, I cannot read the input line using 'NI435X_Read_Line' unless I directly connect th
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I am unsure which format, if either, is correct and would be grateful for any help on this anomaly. Thanks.

Hi Kevin,
Yes, if I connect an input channel directly to 5V, the software reads a logic high and continues to read this level even when I disconnect the channel and leave it "floating". The state changes to logic low only when I connect the channel directly to GND and then it stays at this level, even if I disconnect it from GND. In other words, the states seem to 'latch'. Nothing happens if I connect via the 10K resistor - the channel simply remains at the logic level it was last set to after I momentarily connected it directly to 5V or GND.

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

Output signal high at DIO lines of 7330

Hi
I am using Labview 7.1 with Ni motion controller. I am trying to detect the output signals at the auxiliary DIOports of the card using the attached programme in the NI example finder. My board ID is 1 (thats what was allowed by the programme) and I put port 1 , to check the DIO lines of it. I checked pin 10 (port 1-bit 0) and pin 44 (port1-bit 1) using an oscilloscope. The output is high at 5volts.
I changed the DIO pin polarity switches to active low status but the output remains the same.I fiddled with the set and reset buttons of the programme, initialize the card but nothing changes. Any idea on how to figure whats wrong?
Thanks
Mal
Attachments:
Auxilliary Digital Output.vi ‏57 KB

Hi
Thanks for the reply. Sorry for the delay in response as I was on vacation. I tried your programme but the result remains the same. The output is always high.
Max shows the card is working properly. It also shows the board type as 63. But the programme only takes in board ID as 1. How can set the direction using MAX and save the settings?
I tried the write 1 point example programme on axis 1 ,line 1 and tested the signal on pin 44 and 42 (oscilloscope ground), and toggled the line but the output is high. But when I stopped the programme with the STOP button it gave an error message 70102 with a possible cause the setting doesn't match the line direction?
The oscilloscope ground was firmly connected to pin 43 or 42 of the board for all tests.
I appreciate your help.
Thanks
Mal

NI-5122 measure trigger frequency of TTL trigger signal

I have two signal channels and a TTL trigger signal on my NI-5122. The frequency of the tigger signal is between 5 and 30 Hz. Before I want to sample the two signal channels I need to know the actual trigger frequency to calculate and set sampling rate and number of sampling points. I use LabView 7.1
What's the best way to measure the frequency (5-30 Hz) of the TTL signal connected to the 5122 trigger input?
many thanks for your help.
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Jason V,
thanks for your help. So there is no programable counter on the 5122...
My freuqency is constant and I need an accuracy of <1%.
What I did meanwhile:
I make a loop of e.g. 10 triggerevents.
I record the times when the trigger events occur.
After the loop I fit a line to the time vs. iteration number.
This gives a pretty good value for the period, hence I get the inverse frequency.
I need 10-30 trigger events to be accurate.
For 10 Hz this makes 1-3 seconds init at the start of each measurement.
I can reach a relative error as low as 1e-4. That's o.k.
I did some more tweaking to allow for missed trigger events.
The whole VI works fine to retrieve frequencies up to 100 Hz.
For higher frequencies I am limited due to the millisecond resolution of LabViews 'Tick' vi.
====
For higher frequencies I would program a counter:
Start a measurement for 1000 scans and measure the time for that.
However, this is not accurate enough for low frequencies and short recording times (10-30 trigger events).
====
I also thought about Fourier transforming the signal itself and locating the peak frequency.
Same as above: This is only accurate when I record many periods.
====
The fastest and most accurate solution would be to sample the trigger signal itself.
Then I would need only one period and could detect the trigger slopes with microsecond resolution.
However, I need both input channels for recording simultaneous signals.
Conclusion:
(1) The NI-5122 does not has a programable counter on board
(2) For my application I found a solution tht works.
MarkusMessage Edited by Nepu on 03-09-2005 02:04 AM
Message Edited by Nepu on 03-09-2005 02:07 AM

USB-6008 DIO Lines...

I have a USB-6008 that I'm using to develop an application with. The development language used is C# (.NET 2003 with Measurement Studio 7.0). Right now, I have the device successfully reading from the counter input. Since this program reads rising edges from the counter input, I can get the frequency of the input signal and cause something to happen should the frequency rise above a certain threshold.
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My question is - how can I gain access to ALL of the lines of a particular port?
Thanks,
tsc

I just figured out the lines of the port - of course this will happen once I've posted a question. If others run into the same type of problem, here's how to access each individual line of a selected digital port:
line 0 - 0x01 (binary: 0000 0001)
line 1 - 0x02 (binary: 0000 0010)
line 2 - 0x04 (binary: 0000 0100)
line 3 - 0x08 (binary: 0000 1000)
line 4 - 0x10 (binary: 0001 0000)
line 5 - 0x20 (binary: 0010 0000)
line 6 - 0x40 (binary: 0100 0000)
line 7 - 0x80 (binary: 1000 0000)
all lines off - 0x00 (binary: 0000 0000)
all lines on - 0xff (binary: 1111 1111)
// create a task...
result = DAQmxBaseCreateTask("DigitalPort0 Task", out dioTaskHandle);
// create a channel - I'm using Port 0 in this example)...
result = DAQmxBaseCreateDOChan(dioTaskHandle, "Dev1/port0", "", 1);
// turn off all digital lines to the port selected (I do this when starting up)...
result = DAQmxBaseWriteDigitalScalarU32(dioTaskHandle, true, 1.0, 0x00, out reserved);
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result = DAQmxBaseWriteDigitalScalarU32(dioTaskHandle, true, 1.0, 0x01, out reserved);
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result = DAQmxBaseWriteDigitalScalarU32(dioTaskHandle, true, 1.0, 0x20, out reserved);
I hope this will help someone else out using this device and Measurement Studio for .NET.

NI 6509 PXI TTL Input Impdeance

I have a requirement to measure a TTL logic signal with a 5.1K ohm load. The specification for a PXI version of the board has high input impedance as a default condition. What is the actual impedance and can I just put a 5.1K ohm resistor across the inputs? Are there pull up/down resistors like the PCIe version? Can the default be changed?
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This answer contains a lot of analog electronics stuff, but an understanding of basic analog circuitry is crucial if you are dealing with line impedances or terminating resistors.

Directv HD signal via component into a 24" iMac help?

Greetings,
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Message was edited by: den.thed

Acquiring two input signals simultaneously

Hi,
I have an LVDT and a force sensor (both attached to a motor) plugged into my SC board and I am trying to read out & save the output data from both sensors simultaneously while the motor is in motion. The SC-2350 board is connected to the laptop via DAQCard 6036E . Two questions:
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Hello Dani,
I assume, based on your position sensors and the image you posted, that you are using counters to acquire your data. Is this correct? If so, it is important to note that you cannot add multiple counter operations to a single task because they have different timing requirements and all channels in a single task must share the same timing and triggering. In fact, if you attempt to add a second counter channel to a DAQ Assistant for a counter operation, you will receive the following error when you try to close the configuration window:
So, you will have to use two different tasks to acquire your counter data. You can do this either by using two separate DAQ Assistants or by using two different tasks in the NI-DAQmx sub-VIs in LabVIEW. Since you are trying to compare the phase difference between the two measurements, you will also need to synchronize the operations so that you are reading from both counters simultaneously. There are several resources online which discuss synchronizing counters, and I have linked some that I thought might be useful below:
KnowledgeBase 1JPES6LL: How Do I Synchronize a Buffered Quadrature Encoder Measurement to a Signal
KnowledgeBase 3GGATSCC: Hardware Counter Start Trigger for Counter Synchronization
It would probably be easier to use the NI-DAQmx Sub-VIs to implement this synchronization because they give you more control over specific parameters of your task. You can use the NI Example Finder to browse some examples which use the NI-DAQmx sub-VIs for counters. You can open the NI Example Finder by going to Help>>Find Examples... in LabVIEW. Once in the NI Example Finder, you can find the counter examples by selecting the Browse tab and navigating to Hardware Input and Output>>DAQmx>>Counter Measurements; then you can select the Position category (shown below) to find the Position measurement examples.
Let us know if you have any other questions about taking position measurements.
Message Edited by Matt A on 04-09-2008 03:55 PM
Matt Anderson
Hardware Services Marketing Manager
National Instruments
Attachments:
Error -200147.jpg ‏32 KB
Example Finder Position.jpg ‏124 KB

Wiring a SCB-68 to measure the frequency of a TTL pulse signal

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Ultimately I want to be able to put this measured frequency into a Labview program with a controllable gate period.
Thanks in advance
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You might want to search the Knowledge Base on the NI's Support Pages for "Cable Mapping for a 68 Pin Connector to a 50 Pin Connector". This should take you to a link that will explain the mapping of a 50way to 68way cable and subsequent lines you are looking for ( reference sub link 68F50M), I guess you have SH6850 cable connected from the AT-MIO16 card to the SCB-68.
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Regards
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[SOLVED] How to Crop an MP4 Video via Command-line?

I have ffmpeg, mpg123, and mencoder. Does anyone know of a way I could use any of those to crop an mp4 video via command-line? I am trying to take off the black space above and below a video. Thanks in advance!
Last edited by tony5429 (2009-04-12 00:12:57)

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Hi my name is Gestur. I'am trying to generate a finite pulse train with the counters on my E serie 6036E DAQ board - which works fine - but at the same time, reading and writing to and from DIO lines. This has been giving me problems. I've building a test program which works with cases, where like case0 writes a low level to a DIO line. In case1 i start the counters, generating my finite pulse train. Then i notice that the same DIO line that earlier was lowered, is high again.
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Kind regards Gestur
Attachments:
SamlingPRO.vi ‏236 KB
SamlingPRO#2.vi ‏170 KB

HI,
The attached VI's have some missing sub-VI's. Can you use the VI Library manager and gather all the components together into one .llb?
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Attachments:
Arduino Visa FG.vi ‏20 KB
Arduino Visa FGV SubVI.vi ‏26 KB

I can't tell you anything because you haven't shown me anything of what you are doing.
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Hello all,
I'm completely new to all this so I will try my best here to give all the details needed.
So, I am using a Mac mini (2013 model: i7 overclocked at 2.6, 16 gbram) and a focusrite saffire pro 24DSP. Overall both are in perfect working order.
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I'm sure I am just missing something out?
Thanks in advance :-)

I've plugged into the interface a mic and an electric guitar.
I'm not sure what I did but the guitar is coming through (though it shows no signal on the interface). Mic input level on line, mic registers a tiny bit of sound when I hit the mic (on only one channel) but doesn't register any vocals when mic input is turned up to the max.
Odd thing: stereo/mono button reversed that is when the button is pushed in it equals stereo on the head phones when it says it should be mono and when the button is left unpushed it equals mono when it says it should be stereo.
Monitor is on and volume is at max.
GB system preferences don't list Input 1 or/and 2. Where do I find them?
I've tried everything I can think of. It feels as if I just need to find the right switch but I don't know where to look...

Obtaining a TTL input signal via DIO lines of 7334

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