analog output in micro and miliseconds pallete without using counters

[bobogool]

Hello all,

I am new in this forum and also in Labview, so I need your help.

I want generate an Analog signal on Analog outputs of PXI 6704 that respect the time condition from my photo and that I will describe:

T1=150 microseconds

T2=200 microseconds

T3=500 milliseconds

V1=0 V

V2=10 V

Another important condition I must repeat the sequence   T1+ T2 N times (in my example is two times).All conditions (T1, T2,T3,V1, V2 and N) I must have their control of the front panel so I can change their values anytime when I want.

Very important T1, T2  must be in microseconds .I mention this like very important because here is my problem I can’t do this part of signal in microseconds time pallet.

I wait for your help. 10x

Bobogool

[Dan_K]

Hello Bobogool,

You cannot perform the operation you desire with this device. The NI 6704 only supports static updates to the analog output channels, which means that you cannot load a waveform into memory and you are instead dependent upon the PC to perform voltage changes. Given the fact that a Windows OS has ms determinism you would not be able to generate accurate signals.

Instead you should look at another PXI device such as a PXI 6251 which has hardware timed analog outputs and could generate a complex analog signal with clocking, making the output highly deterministic. The only issue would be the generation of the necessary waveforms in LabVIEW given your parameters, and this would not be terribly difficult.

Attached is code that generates a waveform, when generated at 1 MHz would perform the way you have specified.

[bobogool]

Hello again,

Assuming i don't need to control parameters from the front panel and also i don't need to generate a signal with an amplitude greater than 5, V can i generate the form of the signal that i want with the output counters ?Maybe with 2 pulses

one for generate fist part of the signal in microseconds time pallete and another one to generate second part of the signal in milliseconds time pallete and both placed ent to end( but i don't know how to placed together)I hope not i think at stupid things

However thanks you for your reply!

[bobogool]

i  forgot something important.If you can help me with an VI example please save him like LABVIEW 8.5 VI because i don't have next version of Labview.

[Dennis_Knutson]

What output counters are you referring to? The ones that the device does not have?

Before you use something, it would be recomended that you look at the basic capabilities.

[Dan_K]

Hello bobogool,

As I said before, you really do need to be looking at a different device for this application, a PXI-6251 would be an excellent choice for either your previous situation or the second you mentioned. As Dennis mentioned your PXI-6704 doesn't have any onboard counters while the PXI-6251 does.

As for the generation of the signal, if 5V was sufficient, I would use clocked Digital Output rather than Counter Pulse Generation. You would still be using the counter, but only as a clock for the Digital Output. The waveform generation would be very similar to the attached example (now in LV 8.2), but with different data types for digital generation.

Let me know if you run into any further questions.