Digital input configuration

Good Morning,
I am trying to get the picks of a signal of variable frequence, that goes until 24 Hz. When I acquire with 1 sample on demand, I loose some picks. When I try to configure "N samples", it tells me to configure external clock, and when I choose "diclock", it doesn't work. How can I configure it?
Thanks

Take a look on your other post.
http://forums.ni.com/t5/Digital-I-O/digital/m-p/2196408
Abel Souza
Engenheiro de Aplicações
National Instruments Brasil

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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.
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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.
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Hello Suresh,
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Hi,
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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.
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Dear all,
I want to acquire digital input (21 bits with external clock = 50 kHz) with a PCIe-6343 NI board. Using the DAQ assistant under Labview, I selected the advanced timing with the sample clock time parametrized as External. However, it is also possible to select the Rate of the acquisition. In my case, i want to get the data at the rising edge of the external clock signal, so at a frequency of 50 kHz. How can I do that ? I just need to put a Rate of 50 kHz ?
thanks for your help.
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Cedric,
dddsdsds wrote:
[...]In my case, i want to get the data at the rising edge of the external clock signal, so at a frequency of 50 kHz. How can I do that ?[...]
You answered your question already. If you want to use an external clock, you have to configure the timing source of your task to be external. In order of proper buffer configuration, you should enter 50kHz as rate in addition to the external configuration, but this will not influence the speed of the acquisition (since it is "clocked" externally!)
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Hi everyone,
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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
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Attachments:
control_v2_ML_simple.vi ‏83 KB

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.
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Hello!
DAQmx Version 7.3
I want to read the digital inputs of a NI6220. There is no matter of timing,
I only want the actual state.
I get the error code -200077 from the StartTask, that means:
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Property: DAQmx_SampTimingType
Requested Value: DAQmx_Val_SampClk
Task Name: MyDigital
Status Code: -200077"
How do I have to configure this device correctly? I didn't find the source with the properties.
Thanks in advance
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Here is the pseudo-code I use:
deviceName                  = "Dev1";
taskName                    = "MyDigital";
rate                        = 1.0;
lengthDataPerChannel        = uint32(2);
lines                       = "Dev1/line0:15";
nameToAssignToLines         = "DigitalChannel";
lineGrouping                = DAQmx_Val_ChanForAllLines;
numSampsPerChan             = int32(1);
readArray                   = uint32(255);
arraySizeInSamps            = uint32(1);
reserved                    = uint32(0);
status1     = DAQmxCreateTask(taskName,taskHandle);
status2     = DAQmxCreateDIChan(taskHandle,lines,nameToAssignToLines,lineGrouping);
status3     = DAQmxCfgSampClkTiming(taskHandle,"OnboardClock",rate,DAQmx_Val_Rising,DAQmx_Val_FiniteSamps,lengthDataPerChannel);
status4     = DAQmxStartTask(taskHandle);
printf("Handle, Status: %d; %d; %d; %d, %d\n",taskHandle,status1,status2,status3,status4);
for n = 1:10
    pause(1);
    status1   = DAQmxIsTaskDone(taskHandle,isTaskDone);
    status2   = DAQmxReadDigitalU32(taskHandle,numSampsPerChan,0,DAQmx_Val_GroupByScanNumber,readArray,arraySizeInSamps,sampsPerChanRead,reserved);
    status3   = DAQmxStopTask(taskHandle);
    status4   = DAQmxStartTask(taskHandle);
    printf("Status: %d(%d); %d(%d); %d; %d, %d\n",status1,isTaskDone,status2,sampsPerChanRead,status3,status4);
    printf("Readarray = %d\n", readArray);
end
status1    = DAQmxStopTask(taskHandle);
status2    = DAQmxClearTask(taskHandle);
printf("Status: %d, %d\n",status1,status2);
I get the following printout:
Handle, Status: 530841864; 0; 0; 0, -200077
Status: 0(1); -200077(0); 0; -200077, Readarray = 0
Status: 0(1); -200077(0); 0; -200077, Readarray = 0
Status: 0(1); -200077(0); 0; -200077, Readarray = 0
Status: 0(1); -200077(0); 0; -200077, Readarray = 0
Status: 0(1); -200077(0); 0; -200077, Readarray = 0
Status: 0(1); -200077(0); 0; -200077, Readarray = 0
Status: 0(1); -200077(0); 0; -200077, Readarray = 0
Status: 0(1); -200077(0); 0; -200077, Readarray = 0
Status: 0(1); -200077(0); 0; -200077, Readarray = 0
Status: 0(1); -200077(0); 0; -200077, Readarray = 0
Status: 0, 0

Hello!
thank you, John, for your hint. I tried the second part (ctr0internaloutput), but
still get the same error (-200077).
Here is the way I actually tried:
Variables as in my former email, additional these here:
taskNameCounter             = "CounterTask";
counter                     = "Dev1/ctr0";
nameToAssignToChannel       = "CounterChannel";
units                       = DAQmx_Val_Hz;
idleState                   = DAQmx_Val_Low;
initialDelay                = 0.0;
freq                        = 10.0;
dutyCycle                   = 0.5;
status1 = DAQmxCreateTask(taskNameCounter,taskHandleCounter);
status2 = DAQmxCreateCOPulseChanFreq(taskHandleCounter,counter,nameToAssignToChannel,units,idleState,initialDelay,freq,dutyCycle);
status3 = DAQmxStartTask(taskHandleCounter);
printf("Handle, Status: %d; %d; %d; %d\n",taskHandleCounter,status1,status2,status3);
Then the code of my former eMail, but I changed only one line to this:
status3     = DAQmxCfgSampClkTiming(taskHandle,"/Dev1/ctr0internaloutput",rate,DAQmx_Val_Rising,DAQmx_Val_FiniteSamps,lengthDataPerChannel);
The error is the same as before (the startTask of the normal taskHandle returns -200077).
o.k. then stop and delete all tasks.
Can you give me more details or an example?
Thanks!
Ralph

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Hi CUA,
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I need to have a callback function invoked when a state change occurs on serveral digital inputs (interlocks, kill button etc.).
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Hello John. Thank you for contacting National Instruments. It looks like you are using the callback incorrectly. I found an example that uses the callback in Visual C++ with Traditional DAQ. This isn't the same setup as you are using, but it should give you a good idea of how to setup the callback. Please let me know if you have any questions. Have a great day!
Marni S.
National Instruments
Attachments:
DAQEvent3VC6.zip ‏5 KB

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+1 for another instance of this being "a huge problem" and "it's driving me nuts!"

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I have a daqpad 6015 configured with all digital inputs. The input impedance appears way too low. It pulls down my signals to about a volt from 5V. I know the impedance is supposed to be 'high', the manual is very vague on this subject. Could the board be damaged? Analog I/O is functioning perfectly??? 5V is right where it should be...
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Hello Wave_Man. Thank you for contacting National Instruments. The high impedance talked about in the manual is referring to the impedance on the input of the board, not the signal being input into it. A small impedance is actually preferred. What I think is happening is that your ground on your signal is different than your ground on you daqpad. When you connect them you should see 5 V. Please let me know if you have any questions. Have a great day!
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Dear All!!
With the following vi. I'm trying to receive a 5V signal in a digital input, using a usb-6009 device.
I would like to use the 5 VCC supply, available in pin 31 of the same device and send it to pin 17, representing line0 of port0. During execution, 'm physically connecting and disconnecting these pins in order to see the difference in a led indicator. Unfortunatelly, the led is always on, even if both pins are disconnected.
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Attachments:
proof.vi ‏38 KB

Hi Miren,
"the led is always on, even if both pins are disconnected"
RTFM?!
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Best regards,
GerdW
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Kudos are welcome

Digital input configuration

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