souske

Hi all,

I am trying to set up communication between Met\Cal (Fluke's Metrology Softwre) and LabView. I've noticed that Met\Cal 7.2 has support for NI-VISA driver. I tried to use it but I can't force Met\Cal to use "TCPIP::127.0.0.1::<port>::SOCKET" syntax, instead it tries to connect to "TCPIP::127.0.0.1::inst0::INSTR" and generates an error. Has anyone used this, or know how to set up TCPIP connection with Met\Cal?

Regards

souske

QUOTE (crelf @ Apr 10 2008, 04:54 PM)

I don't know anything about your application, but have you considered doing your ultra-time-critical work in FPGA? Or maybe some of it and then stream data as needed to the RT host?

That's what I was planning to do. The thing is that right now I'm testing several different options and want to choose the best one for the system I am creating. I can see that with cRIO one has many possibilities to group the code according to its time priority. Not only by using loops with different priorities on the RT part but also by using the FPGA.

QUOTE (JFM @ Apr 14 2008, 08:35 AM)

I didn't know you can actually enable us support for cRIO. How do you do that?

Too much time with Windows, and I totally forgot that TimedLoops were made for RT targets. With TimedLoop on cRIO I also get nice 1.01 ms, but even cRIO can't squeeze 1ms from a standard "while" (with RT version of "wait until..." ).

Thanks for the reminder!

Hello,

I'm trying to get loop speed and I've got result that I have not expected.

I set "wait until next ms multiple" to values from 10ms to 0 ms and I want to check how fast the loop runs.

Can anyone explain why when I set 1ms I get 2ms? Is there something wrong with the vi structure?

I attach vi that I use (created in LV8.2).

Download File:post-1959-1207817923.vi

Is it possible to configure FPGA Compile Server in such a way that it would omit the tests at the end of the compiling process?

Regards

souske

QUOTE(Yen @ Feb 20 2008, 07:35 PM)

I'm not sure if you noticed Ton's original reply, but Wait Until Next MS Multiple is the wrong choice - it WILL wait until the next multiple, so if your code finished at xxxx36.001, it will wait an extra 2 ms until it will get to xxxx38. A better timing structure is the timed loop, but I'm not sure if it's available on the QNX.

Another alternative is to place a 0 ms wait. This should tell the OS to run this as fast as possible if nothing else needs the CPU. Additionally, playing with the VI priorities might get you better results.

Yes the are available and they "should work on QNX" (NI words). Setting the Period in the Timed Loop works (it is easy to see that), but I don't know

how to check if the loops are actually executed with the set priorities.

Is there any difference between 0 ms wait and not using wait at all?

Thanks for the clues.

The error number I get is 248, which seems not to be described anywhere. I found a flag that does not change the time itself but allows reuse of the port without

waiting. Well setting it doesn't help, but I'm still digging

Any ideas on the error?

Is anyone planning to visit the Embedded-World conference in Nürnberg?

Hi

I'm trying to run double loop program. One while loop acquires data the other transfers it via tcp/ip. Both loops are closed in a Flat Sequence Structure.

Before the the sequence I put TCP Listen and set the timeout to -1 (forever). After the FSS I close the TCP connection.

In client that receives the data I open the connection, while loop where I get the data and closing connection after.

It happens that the Listen doesn't wait for the incomming connection. From the observations I see that the source of the problem

might be not properly closed connection, because if I wait a moment I can run it again without a problem.

Does anyone has any idea what might be keeping the connection open eventhough I close it myself?

Is it possible that the error is somewhere else?

I tried to use various ports - the results are the same.

QUOTE(eaolson @ Feb 19 2008, 11:27 PM)

OK, that's a valid point. But because the ms timer is limited in resolution to 1 ms, I had to do a bunch of iterations and average. And this is for an empty loop. Since that's boring and you'll want to do something inside the loop, that will slow it down considerably.

And since the OP was talking about QNX, this is all probably a moot point.

Well maybe not so moot

Eventhough its QNX, when I run a loop similar to yours (without wait until next ms multiple) I get average execution time around 0.5ms. Which as you can see is not

useful information if I want to set the frequency for the loop. And the puzzling fact is that when I checked exactly what the times of specific cycles are, they ranged

from 0 to 3 ms. So it looks like in reality you actually take the largest value instead of an average.

Well then I deeply apologize for not specyfying that all those tests are executed on QNX RTOS

How do my assumptions and results look like now ?

Hi

I was trying to determine at what maximum frequency I can run my for loop.

To do that I set the "wait until next ms multiple" to some value and then calculated

the time it actually took the loop to execute and then compared them.

If they mached I assumed that the loop executed all comands inside without a problem.

I went from 6 ms to 1 ms and I got sth like this:

wait node time [ms] - calculated time [ms]

6 - 6.00

5 - 5.00

4 - 4.00

3 - 3.00

2 - 4.00

1 - 3.00

I suppose I can safely assume that 3ms is the minimal value I can use here.

Question 1. What exactly happens at 2ms that it takes 4ms to execute the code?

I suppose there is not enough time so some additional functions are being executed?

Question 2. Are there any other methods for determining how fast one cycle can be executed?

--

regards

souske

Now that is really strange. Maybe mondays are not that bad. Today the inline C nodes ARE supported

I really don't understand how is that possible, but I'm not going to agrue.

After including .o file (in console application properties) C code works like a miracle and there problem

with profibus drivers is no more

--

souske

Well I found the "C inline node" but this one is also "Not supported by current target". This structure is visible in functions palette only

if you writing software for a target that supports it so It took me some time to even find it, because if you're in qnx (or even blank vi without

a project) it won't be there and you won't be able to find it using search option. I don't know if it's a problem of a trial version of my MicroSDK

or is it just THAT limited? I find it hard to believe especially when you mention that NI treats CIN as a legacy.

I'll keep on hitting that wall

--

souske

Thanks for the reply.

As I wrote I'm using LabView Embedded Developmnet Module with some add-on that I found on ni.com that allows me to cross compile for QNX.

The standard C code node (I assume you mean Code Interface Node) is not supported by QNX target, at least that's what the error says:

"Code Interface Node: Node not supported in current target".

Right now I'm trying to use Call Library Function Node. I compiled the windows dll example for qnx (I used QNX Momentics) but I still get

some linking errors when I try to build it the project in LV:

C:\tmpo\sysexec\QNX_Console\QNX_Application\sysexectest.o: In function `sysexectest_BlockDiagram':

C:\tmpo\sysexec\QNX_Console\QNX_Application\sysexectest.o(.text+0x2b3): undefined reference to `avg_num'

cc: C:/QNX632/host/win32/x86/usr/bin/ntox86-ld caught signal 1

Any ideas what might cause the error?

Thanks for the idea client-server arch. here, but I will keep trying to use EDM.

--

souske

Hi,

This problem is a mix of several smaller ones but I suppose the RT is the common ground here.

Most of the drivers for a given OS are developed and copiled under given OS. How to solve the problem of software (and driver) development on a computer

with a different OS than the target machine? For example software development in LV on Windows and execution on QNX OS?

I know that it is possible to use EDM mod (Microprocessor SDK) to compile for other OS and architectures (I've done that and it works).

But where do hardware drivers compiled for QNX fit in? Even if you use MHDDK (if I understand correctly) one compiles the driver (which is written in C)

on the machine with QNX OS. How am I able to use it in a software that I'm developing under Windows?

Including external code is limited. CIN and System Exec are not supported by qnx target and CLFN will probably join that group too (I'm checking it now).

Does any one has any suggestions how to bite this problem? Or maybe my approach is wrong?

Just to clarify. I develop software under Windows with LV8.2 and want to communicate with Hilscher Profibus card on a machine with QNX Neutrino 6.3.2.

--

regards

souske