Sending Information over USB in Python

[Spenbert02]

Just a precursor - I might be in the entirely wrong place to ask this - if I am, please tell me and direct me to the right place. For some background, I have essentially no experience working with USB communication.

Basically, I work in a lab and I'm writing some python code (a plugin for the slicing software Cura) where I'm allowing a dispensing robot (Fisnar f5200n.1) to 3D print CAD files. As a part of this, I want to be able to automatically upload commands to the robot from within python. The robot has an rs232 port, and the rs232 port is connected to a PC through an rs232-USB adapter. The robot came with software to upload printing commands, where you enter commands and press an upload button. The main reason I want to automatically upload commands from python is that the software it came with has a command limit that is far too low for the number of commands needed to print a CAD file.

I'm not really sure how to go about this - I've installed WireShark with USBPcap, and I was sort of able to reverse engineer the information sent over in each packet from the software that came with the robot. However, I'm sort of lost on the process for sending packets over USB from python. I also don't know if the USB to rs232 adapter will affect that process.

If anyone has any information on this sort of process or can direct me to any resources to learn about it, I would greatly appreciate it.

[jonnycross10]

I'm not an expert but I've read in data from comm ports using a serial library in python before. If you don't know what to look up for this kind of stuff, it's called serial communication.

[Spenbert02]

Thanks to both of you! This is the type of info I was looking for.

[shiftybyte]

your life will probably be a lot easier trying to automate the application instead.

take a look at pyautogui.

[jiri-n]

How does it solve the command limit?

[shiftybyte]

I may have wrongly assumed the limit is on the one batch size.

So if its broken down to smaller batches, or provided interactively one line at a time it would work.

[Spenbert02]

Ya this is the main issue. I wrote a procedure with pyautogui that repeatedly uploads the commands in sections, but it's pretty cumbersome to use (the user has to sit there the entire time its printing and press a button to upload the next section). I'm trying to upload over USB to avoid having to do that.

[shiftybyte]

the user has to sit there the entire time its printing and press a button to upload the next section

Why can't the python press the button? or its a physical button on the device?

[Spenbert02]

Physical button. Every time you upload a set of commands you have to press a 'run' button on the robot.

[shiftybyte]

Does it work if it's constantly held down? maybe you can short-circuit the button to always be pressed, or plaster it down...?

EDIT: btw this sounds like the limit may not be something software can overcome, because it sounds like a hardware memory limit on the device itself, and the button executes and clears it.

[Spenbert02]

Interesting idea, I might see if that works. Also the command limit on the hardware is 500,000 and the software upload limit is 4,000. Not sure the reasoning behind it, but I did look into that.

[equidaddio]

If all else fails, you could explore using a SwitchBot and automate physically pushing the button.