Serial Monitor error 10

I recently obtained a 【New Version】Upgrade CNC DIY 3018 Pro GRBL Control DIY Mini CNC Machine, and have it working fairly successfully. After adding X & Y limit switches, I've been trying to test them, but discovered that I need to set the firmware default $20 from 0 to 1.
I downloaded a free simple serial monitor that allows me to send commands and see results, which for $$ is the expected list of default settings.
However, when I send $20=1 I get 'error 10'
Is there a command that allows default changes that I must enter first, or is there something else I am doing wrong?

ALSO - when trying to test the limit switches, do they stop movement when the hand controller is used, and/or the software on a PC, or are they only effective during a running program?

I hope I have posted this query in the correct place (after seeing a query on the same machine) but I need a bit of help now as the knowledge of computing etc. built up over the last 80 years is starting to fade rapidly!

Don't use any third-party Serial Monitor, as they have many glitches and bugs. You should use Arduino's Serial Monitor. If you can't use that, then the safest one is PuTTY Serial Monitor. Try using that and then tell us that if it worked or not.

..Arnav

Thanks for responding so promptly, but there was no problem with the Serial Monitor itself, just what I was attempting. After some more extensive searching - relating to grbl this time - I found the answer. I was trying to enable Soft Limits without having previously activated Homing. As the info' stated - 'to use Soft Limits the machine needs to know where it is, which can only be achieved by a previous Homing function.' Since at the moment I just want to protect from damage, I can set $21 =1, to enable Hard Limits and use Reset to clear from any nasty excursions.

My GOTO for GRBL is here.
BTW thats for GRBL v1.1 which I reccomend anyone buying a chinese machine upgrade to.

Using a serial monotor is the hard way to change settings btw.
Most GRBL sender programs already have the ability to read the current settings and change them.

ArnavPawarAA:
Don't use any third-party Serial Monitor, as they have many glitches and bugs.

I personally think that that is nonsense.

ArnavPawarAA:
You should use Arduino's Serial Monitor. If you can't use that, then the safest one is PuTTY Serial Monitor.

The only advantage of serial monitor is that it's controlled by the IDE so during an upload it can be (and is) disconnected.

There are plenty good terminal programs (I use RealTerm under windows); there are also crappy ones :wink: