PXI DAQ (RT) acquisition control

[alle]

hallo all,

I have an PCI-based data acquisition system which is working fine on the Mac. Due to the various resons we have to switch to the new, PXI-based real-time system.
The hardware is PXI-8175 controller and PXI-6031E DAQ.
The system has to continuously acquire the data from the 8 DAQ channels using external trigger and external scanclock. I would suppose that software part will be a control program on the host and executable program on the target.
so my questions are:
- how can I run and stop the acquisition on the target system from the host computer? I do not need it to be run at startup and user should gain a full control over it.
- how can I modify the target IP and its other network settings from the host machine via th
e control program, without MAX? (in case of deploying the system in the "guest" network)
- is it possible to use control program (as executable application with run-time engine) without any other LabView components installed on the host machine?

many thanks in advance.

[acoustics 2]

Hello alle,

sorry to disapoint you first, but I do not know any solution to the second part of your question, except perhaps modifying the *.ini files of the RT system, sending them through FTP and reset/reboot the RT system. The major problem with this will be to get an initial FTP session without corresponding netmask and IP address in a "guest" network. MAX seems to be quite tolerant to this, somehow ...

Now, to the other two parts of the question. I would recommend (i.e. that is, what I am currently doing) to set up a program for the RT computer and another one for the host. Both of them should communicate through TCP. The RT control program will have to do everything for you on the RT system and IT MUST BE ONE PROGRAM. In addition, your startup RT progr
am must definitely finish (it is the only RT program, which seems to be allowed to finish ...). Then, you can make your host program to start the RT program through an exec call with a -target option and a -quithost to be downloaded and started automatically from the host. Therefor, only the LV runtime engine is needed on the host. Now, your RT program is up and running on the RT engine and as a TCP server program it is waiting for your host commands, e.g. starting the acquisition.

For me, this seems/seemed to be the only way to have "everything" on the host side and all you have to do is to clean up the RT engine (remove startup program) and set up the IP/network stuff with MAX (sorry for that one ...)

Regards,

acoustics

[alle]

hello Acoustics,

thanks for your response. Yes, it seems that one has to carry a PC along, with all the Labview stuff installed, to be able to change network settings.
It is pretty disappointing.

To the second part - I'm still confused with the details. The general concept is clear - having target program for pure acquisition and host for storage, display etc. But the target program is always starting at startup - therefore there has to be some case structure in the very beginning of the program, that is awaiting for start granting from the host? And the established TCP connection is enough for all the data transfers?
Sorry for those probably lame questions, I'm totally new in RT, still confused with too general manuals and examples are not that selfsp
eaking to me.

regards

[acoustics 2]

Hello alle,

if you build a target program for the real time target, it will typically be installed on the target and you will configure it to start up automatically after boot time. In this case, you can create a tcp listener waiting for a host client to contact it and communicate any commands. Based on the commands, you can set up a case structure doing acquisition, calibration, etc., as needed. Typically you use a timeout for the listener in case of something goes wrong, but you should not do so in this time, as the RT engine really serves as an acquisition server. Be careful, anyway, as debugging, ... this beast might be quite difficult. In case, you might set up a ftp connection to the RT engine and change the ni-rt.ini file not to start u
p the program automatically.

The other alternative (which might be much more well suited for you) is to build the RT program with the windows target set. Then, you could start the program on the host with pointing to the RT target at start-up of the host-LV-program. Setting the "close host after RT startup" at the build options and calling the host program with the -target - option enables automatic download and start of the RT program from the host side. This can be done through the host client LV program through an os exe call at its startup. The RT server program will again have a tcp listen vi and a case structure as above, now with a suitable timeout (as it is started by the host). For this way of application, you should not have a startup program on the RT engine. This second way in addition has the benefit that you can update the RT server program by delivering a new host file only, so no need to download any files on the RT system at update time and no need to have an LV dev
elopment system for this.

Hope this helps. If you have additional questions, do not hesitate to ask. Unfortunately, I will not be available in this forum until mid of July.

Regards,

acoustics

[Vkumar]

Dear acoustics,

        I have Thermocouple data acquisition system. In which there are 2 chassis, (1) PXI 1002 with

PXI8176 controller with RT, PXI 6071E DAQ card (2) SCXI 1001 with  SCXI 1125 card  and SCXI1327 block.

PXI 6071E  connected to SCXI 1125 with SH1006868 cable and adapter SCXI1349.

I am using Labview 8.6 , DAQmx9.0

I have develop program for continuous thermocouple acquisition. Now i want to make program on trigger based data acquisition.  When trigger pulse comes system starts to acquire data ( and log in file) for userdefine time and stop acquisition. Again when trigger pulse comes   system again starts to acquire and stop at define time.

Can you guide me how i can develop such system.

Thank you.

--Vishnu