CNC3018 and Serial Terminal Program

General CNC
1

Hi there!
I have recently assembled a DIY 3018 CNC Engraver and the machine and software are working fine. No issues. I tested Candle, G-Sender and LaserGRBL with my machine and sample CNC programs that work perfectly.
The question I have is if I try to connect and talk to the CNC3018 through serial terminal program, then the machine does not execute or respond to my commands, no motor moves, no spindle start.

I only receive the initial GRBL V1.1 welcome message. But if I type $ or “$” or ‘$’ nothing happens. I do not get the response from the CNC machine on my terminal program.

Also, if I type or send a ? command, then the machine responds with some message like IDLE … F0.0.

This means that there is no problem with the communication (software) or connections (hardware) settings. Then why I do not get any my machine or motors running when I send a G-Code command through serial terminal?

Is there any hand-shake between the PC side GUI software and the controller that these program use and that I also need to implement or follow that protocol in my sequence of commands?

Please help.
Thanks in advance.

2

That’s to be expected, try $$ then newline.

A single $ needs to be followed by a number and only shows/sets the value for a single parameter. Double dollar shows all the current settings.

Also sending [ctrl]X (ctrl key and capital X) should re-show the firmware line.

3

That eventually does not work. I tried as per your suggestion. But when first $ character itself is not recognized then there would be no question that its trailing character/s would be detected.

Also, there is no response or action from the CNC machine. Only sending ? works. Nothing else. No reply or error message received for other commands. That includes the Ctrl-X (or ^X) as per your suggestion.
Thanks any ways!

4

Your serial program needs to provide local echo. Eg grbl does not echo any characters it receives. So you will not see what you typed without local echo enabled.

Which serial program are you using?

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5

I recommend you use a G-Code sender application which also has a Console window which allows you to type commands like $100, $$, etc. Such a Console Window will already be setup for proper handshaking with your controller.

Otherwise, you need to start learning about things like local echo, carriage return, linefeed, carriage return+linefeed, etc.

6

Yeah I am aware of that and I tried that too. The console in those GUI Program offers me correct working. So no problem with that. I have tested that and found that it accepts those commands and the machine works properly.

But the question is why it is not possible to send the same commands through a Serial Terminal Program? I mean the machine does not respond or motors do not run with the same commands sent through the GUI Console mode.

Thanks!

7

Ok, it has the local echo (ON/OFF) settings. I shall try that and will come back to you.

Thanks!

8

The handshaking has to be setup correctly in the terminal program since they are created to connect to thousands of different devices.
Did you set the baud rate correctly? example: enable CR and NL at Baud 115200

9

Thanks a lot you all.
The baudrate was not a problem at all as I could receive the sign-on message from the machine when powered-up and also if I send a “?” command the message responded with showing status as etc.

After discussion and suggestions from you guys I found that I was only sending a Carriage Return (CR). The machine requires CR + Line Feed (LF). So when I tried this the machine started responding and I got “OK” message for the commands I sent.

So, thank you all once again for your kind help.
Regards,

  • Prasanna
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