EMC2 - PyVcp - ClassicLadder

[wazjebk]

Hi guys,

i have a little problem. I'm building a cnc lathe which will be(is) running with EMC2. I want to integrate device on to it which will place raw material into lathe head and take out finished parts. Also i want this device to count finished parts and show number of parts on custom PyVcp panel and there i found a problem. I can set output type s32 in ClassicLadder, but PyVcp vidgets can take just float numbers. Is there a solution i check a few web pages and manuals, but i didn't found the solution.

Best regards

[chester88]

Yes there is a solution.
you need to convert the signals from float to s32.
there are HAL components to do conversions.
The one you want is conv_float_s32 .
you then connect the pyvcp to the convert component and the convert component to classicladder.
Don't forget to add the component to a thread.
There are other conversion components too.
Look in the EMC manual or type man conv_float_s32 for more info.

BTW in the upcoming release of EMC 2.3 classicladder will be able to read and write floats though internally they are converted to s32 (CL doesn't handle floats internally yet)

Chris M

[chester88]

oops I read your post wrong - you wanted to send from CL to pyvcp.
To do that use conv_s32_float
Otherwise same deal.

Chris M

[wazjebk]

Many thanks. I'm looking forward to try emc 2.3. Thanks again.

[chester88]

When you get this done It sounds like an interesting example to add to classicladder's
example page in the wiki:
http://wiki.linuxcnc.org/cgi-bin/emc...LadderExamples
Feel free to add it or send me info and I will add it.

Cheers
Chris M

[wazjebk]

hi,

i converted those nubers succesfully, when the project will be finished i'll upload whole project. Thanks again.

[Big John T]

Originally Posted by wazjebk Many thanks. I'm looking forward to try emc 2.3. Thanks again.

In 2.3 (when it comes out) you can display a float, s32, and u32.

http://www.linuxcnc.org/docs/devel/h...cp.html#r1_5_4

I don't have a full example yet in the manual, but I'm working on it...

John

[wazjebk]

I have one more question, is there any possibility to minimize delays in pyvcp?

Best regards.

[chester88]

Pyvcp is a user space program- meaning not realtime. realtime guarantees response time-user space does not. If you raise your base period that will help user space program response time. If your are using software stepping then raising the base period will lower the max speed. Servo systems are much more forgiving.

If your pyvcp is sluggish then is the rest of the desktop too?
What ws your max jitter from your latency test? (you did do one right?)

[wazjebk]

Hi,

i didn't run my pyvcp with axis jet, i'm running it just like standalone window with classicladder. Does pyvcp runing slower like standalone application(window)?

Best regards

[chester88]

I'm not sure what you are asking. Pyvcp, AXIS and even the GUI for classicladder are all userspace so if one is sluggish then they all are probably. what thread speed did you choose for your stand alone programs? Explain how sluggish pyvcp is.

[wazjebk]

hi,

when sending a signal from classicladder(counter) to pyvcp panel it updates my number immediately. But when i click a button on my pyvcp panel clssicladder sometimes doesn't even register my click, so i must press the button for a while(0,5s) to classicladder register my click. I'm not by my linux computer now, but my periods are defenitelj shorter as 0,5s.

best regards