graph within a daq-chain

[mspeicher]

Hello,

I have a gen dig....vi in the attachement, which realize a continous pulse. How can I display this continuous pulse in a graph instead to connect with a oscilloscope.  Thank you for your help.

Exist a simple way to realize the same programm with two alternate pulses with different frequencys and different durations?

[Jochen]

As the counter is working autonomously in hardware the PC only knows the specs of the pulse train but it can't read back the pulse train from the counter directly. Though there are several options to do that:

1. You could acquire the signal that is generated by the counter with an analog input. This solution works for relatively slow pulse trains as the counter output rate can be as fast as 20 MHz with an M-Series board and 5 MHz with an E-Series board while the AI rate is typically 1 MHz or lower.
2. With an M-Series board you also could acquire the signal with the correlated digital inputs. E. g.  the PCI-6251 can acquire digital data with a rate up to 10 MHz. The sample clock for the DIs needs to be generated either externally or with the second counter.
3. If your generated signal is too fast to be acquired with either the one or the other method or if you don't want or need to acquire the real signal you still could calculate the theoretical appearance of the signal (derived from your pulse specifications) and display it on a graph.

I hope that helps,

Jochen Klier
National Instruments Germany

[mspeicher]

Tank you for the tip but I can't really solve the problem. Maybe you can look at the .vi in the attachement and give me a further advice how I can display the pulse in the diagramm.

Thank you very much

Marco Speicher

[Jochen]

You can't use one task for both operations (AI and CO). You will need to create one task for each operation. Please refer to the shipping NI-DAQmx examples like Cont Acq&Graph Voltage-Int Clk.vi.
Are these your first steps with LabVIEW? Visiting a LabVIEW trainings course could give you a jump start with your application.

Best regards,

Jochen Klier
National Instruments Germany

[mspeicher]

Can you show me in my attached .vi how I connect the Counter output task with the anaolg input task? In advance I thank you very much.

Marco Speicher

[Jochen]

What exactly do you mean by that? Are you talking about synchronizing the I/O operations on a hardware or on a software level? Are you looking for the physical connections on the connector block? By the way: What type of hardware are you using?

Jochen

[mspeicher]

Ok, my IT-enviroment looks as follows:

PCI 6602 then a SCB-68 and then a 2 Channel Pulse Generator..

but on the system I'm working know I have only a simulated device (pci 6602).

The Problem is now to generate a square pulse which changes in frequency and duty cycle after a a determined duration. As I can't see if the square pulse output is like I want so the counter output should (over an analog input) displayed on a waveformgraph. This step is very important because after that I have a possibility to controll myself ( without connecting a osziloskop like I did it before).

So my last attachement is to modify to see on the graph what pulse is generated.

I hope you can help me.Thanx!!!
MARCO 

[Jochen]

Marco,

there is no way to run the example with your hardware (even if it was not simulated). The PCI-6602 is a counter board and does not provide analog inputs! Thus you won't be able to read the signal generated by the output with the method you tried in your example.
You still could use the theoretical approach (calculating from your pulse specs how your signal should look like and displaying these values on a graph).
The simulation mode doesn't simulate the real signal input/output of the hardware. With the real PCI-6602 you could measure the pulse width and the period of your signal (using two additional counters) and display the values but there is no way to do this with a simulated hardware.

Jochen

[mspeicher]

ok, what do you mean with two additional counters. Can you discribe it exactlier.

Alternativ to the waveform graph, I need an indicator that shows me what frequency is running is that possible....