Collecting data with Arduino and Python

andypugh:

The Mesa 7i87 might have worked for you, plugged into the 7i77 smart-serial port.
........
I set up a UART on my Mesa card and have the Arduino talking 1Mb serial to a realtime HAL component. That was quite involved (custom Mesa firmware and changes to the Hostmot2 driver), but might also be an option.

Is the protocol between the Mesa card and the Arduino handled by firmware in the Mesa card ? If it so, could be implemented a modbus/etercath/devicenet or other protocol in the firmware ? (may be using a 7i44 not a 7i77)
Thanks you in advance,
VNR

Its also possible to make the Arduino speak LBP at 1 Mbps so it can be a standard sserial remote with "discovery" and all that, so it would need no special support on the LinuxCNC end. 1 Mbps is pretty decent for real time and should be fine with 1-2 KHz servo thread rates. We're looking at adding some autobaud code to SSLBP (for our newer 4 and 10 Mbps capable cards) so 1M baud could be added to the search list

I only need to read the spindle power in around 1 second intervals. I really don't care when I record a reading, as long as I know when a reading has been taken within .1 second, or so.

Sometimes, I will use a screwdriver for a pry-bar. I always keep a Crescent wrench handy, although I have SAE and metric wrenches from very small to quite large with extra copies. The trick is realizing when you really should use a pry-bar, a box end wrench, or a gas hatchet and sledge hammer.

This is the HAL I used:

A waitusr command would be superfluous.

Using M62 P00 followed by G1 X1 Y1 MDI commands (M62 doesn't take action until motion command), the signals change in the watch window, but datarecord pin values do not. (As seen in the attached watch window.

My Python script only writes the .csv header for the file, apparently h is never set to TRUE.

Thanks for all the input. I am still very much in the learning phase regarding linuxCNC, HAL, Python and C. I do plan to implement this as a comp later for a learning exercise. But, my summer is almost over, and I am behind schedule on my research. If I can't resolve these issues, I'll be out there with a clipboard and a stopwatch (think gas hatchet and sledge hammer).

Andy,

I think you are pointing me in the right direction. However, the code does not complete until LinuxCNC shuts down. In other words, the file opens when LinuxCNC begins, however it is not called again until shut down.

Mark

I don't know if posting it removed indentation and I have never seen the referencing you used for the pins before

What happens if you write it like this?

regards

ArcEye,

Yes, I think l the indents were stripped. And that is terribly important in Python.
The references are similar to how Jeff Epler did it in his arduino.py script.
My Python script works when executed outside LinuxCNC in conjunction with halrun.
But, I will try it the way you suggest. I think it is less confusing.

I will try to post my script again.

Mark

I am having problems posting my file. Maybe it will work this time.

Mark

Sorry, I should have read this before posting

www.linuxcnc.org/index.php/english/compo...&id=342&catid=29#342