synchronization of two PCI 6602 using RTSI cable and traditional ni-daq

[pchemjjang]

I am using the Traditional NI-DAQ currently and trying to synchronize two PCI 6602.

I have seen some threads about synchronization of two or more PCI 6602 using RTSI cable but they are using DAQmx.

Since I have a program written in Traditional NI-DAQ already, I cannot use DAQmx for now.

Could anyone help me on this?

Thanks.

[Kevin_Price]

There's a vi named "Route Signal.vi" you'll need to use.  You may need to dig into the online help for all the details, but that's where you should start.

Essentially, the approach I always used boiled down to something like this:

1. On paper, define which RTSI lines will carry which timing signals.

2. One of your tasks will use "Route Signal.vi" to *push* the signal up to the RTSI line.  (Example: route board1/ctr0 output up to RTSI 0)

3. The other task will use "Route Signal.vi" to *pull* the signal down from the RTSI line.  (Example: route RTSI 0 to board2/ctr1 source)

The routing system isn't infinitely flexible.  The extended online help for "Route Signal" should have a link that defines which types of routings are supported for different families of hardware.

-Kevin P.

[pchemjjang]

In fact, I am trying to use 4 DMA transfer and that is why I thought I would need to synchronize two PCI-6602 cards.

Is there any other way?

Or if using two PCI-6602 is not too complicated, I prefer using two PCI-6602.

Anyways, I would really appreciate it if someone could help me on this.

Thanks.

[pchemjjang]

Another thing I want to ask is as follows.

I read from other threads saying that there will be a delay between the master and the slave using two PCI-6602 cards synchornized by a RTSI cable.

How much delay is there?

microsecond?

Thanks for your help in advance.

[Doug_L._Bear]

Hello,

The synchronization method should be the same as listed in the post from a year ago above.

In regard to the delay, it should just be the time that the controller on the card takes to react to the sample clock and should be easily on the order of microseconds, and possible nanoseconds.  Regardless the delay should be constant and can be removed in post processing of the signal.

[pchemjjang]

Thank you for your reply.

I have another question. According to what other people are saying, I cannot use the max timebase, 80MHz, but 20MHz because of the RTSI cable. If that's the case, how do I choose 20MHz from the block diagram instead of the max timebase, which is 80MHz.

I know it is a basic question, but I would appreciate your help.

pchemjjang

[Doug_L._Bear]

The timebase used can be specified with a DAQmx Timing Property Node.  More»MasterTimebase»Source and set this to the 20Mhz sample clock on the card.

Hope this helps and let me know if you have any more questions.

[pchemjjang]

Thank you, Doug.

I have Traditional NI-DAQ, however.

Could you show me an example of how to use the property node with the Traditional NI-DAQ instead of NI-DAQmx?

pchemjjang

[pchemjjang]

Doug,

I would like to ask you one more question.

Going back to my original question in the first message, I thought I couldn't use Traditional NI-DAQ and NI-DAQmx together (incompatible). But I am not sure now.

I appreciate it if you could tell me if I can use those two versions together.

BTW, I am using LabView 7.1 and the current program is written in the Traditional NI-DAQ version.

Basically my question is:

Can I add a DAQmx version subVI or some property nodes (DAQmx) to the existing Traditional NI-DAQ version program?

Thank you very much.

pchemjjang

[Doug_L._Bear]

Unfortunately you cannot use DAQmx and Traditional DAQ in the same tasks.  You could run simultaneous data acquisitions though, one written in each.  You are correct you cannot use property nodes with Traditional DAQ.

In Traditional DAQ the timebase can be set in the AI Clock Config VI, the LabVIEW help will have more information about specifically what to wire to specify various sample clock sources and rates.