Triggering and synchronization

[Rajab84]

Hi everyone

I'm in the process of wiring my data acquisition system.  I'm using Cdaq 9178 with NI:9203 and Ni :9472. 

  the dig. output from Ni9472 will be used  to energies Solenoid valves  through Solid state relay( vi was written to open them sequentially). Ni9203 willbeusedtoacquireanalogcurrent4to20mAfrom7devices.

I used daqmax for the valve vi( digital out put) and daq assistance for acquiring the analog current. I know it shouldn't be a problem to trigger the device measurements (through daq assistance)  but how to get the valve control Vi synchronized (which uses daq max)??

My question is 

How to use external signal(through PIF0 port) for triggering (both) the device measurement and the valve control vi.??

Best Regards 

[Rajab84]

Hi

I've attached a pic. of my Vi.

Could anyone help me with triggering and synchronization?? 

How to get both loops starting at same time using external trigger.

Is it Ok to use daq assistance to acquire simultaneous  measurement from different devices?? Is it better to use Daqmax??

I shall be grateful for any help you offer. 

Best Regards 

Rajab 

[JamesKent]

Hi Rajab,

Triggering the digital output is fairly simple in that you can use a DAQmx Trigger VI to setup the device to trigger off a suitable PFI line. I have attached an example that is shipped with LabVIEW that illustrates this concept for you to look at.

In terms of triggering, you can use the daq assistant to setup triggering. Using the DAQmx VI's will offer you more control and there are some fantastic resources on our website for you to follow for getting started with DAQmx, which I have linked below:

http://www.ni.com/white-paper/5434/en/

Setting up the DAQ Assistant for trigger is fairly simple, you just have to set it to either N Samples, Continuous Samples or HW Timed Single sample, and you can use a digital edge trigger off a PFI line, as shown below.

Best Regards,

James Kent

[Rajab84]

Hi JamesKent

Thanks for your reply, Could you please check the attached pic. I'm getting different errors, one of them is regarding the buffer is empty?? The other is about the buffer  size, (the current is 1 , it should be 2). I found out that I should configure the wtite function to multiple channels. However when I do so I'm not getting the right respond.

I just want to make clear what I want: 

 I'm acquiring analog signal(current) from 7 devices, at the same time the digital output signal should energies solenoid valves 1 at a time. The arrangement can be found in the attached pic.)

so the acquisition and energies the valves should start at the same time using a trigger.  The measurement should be continues while the valves are substantially opened. 

Regards 

Rajab 

[aranS]

Hi Rajab,

I'm a bit unclear about what it is you are trying to achieve?

Could you please provide the vi you have created along with the error numbers for the errors you are encountering?