Gsender do I have to connect to firmware manually every time?

Hello everyone,
Obviously this is not a big deal but the first thing I do when I turn on my cnc is to home. My current work flow requires I go into firmware, then manually click connect to firmware, then homing is enabled.

Is this the only work flow? Is there some setting where it can just do this on connection to the machine?

Thank you for any help.

@hendr1x That is not a normal workflow.
What machine are you running?
What version of gSender?
Can you post a screen cap of the screen in gSender that you are referring to? There is no “connect to firmware” box in any version that I have used.

Thank you for the response. I am running a Genmitsu 3030. gSender version 1.4.6. Happens every time I start up, very reproducible.

First screenshot is on initial start, I manually have to connect to the printer via dropdown (another step I am assuming can not be automated)…note that the homing is NOT present:

The only way for me to get it to appear is to click on firmware and then click the presented button :

Please let me know if you need any more information. My expectation is that this is all by design and can not be changed however I figured I would ask. Thanks for your time.

@hendr1x I am slow, but I think that I am starting to get it. :grinning:

You can set gSender to connect automatically to your machine so that you do not need to click on the “Connect to machine” button. Simply open settings and on the first page, you will see a slider “reconnect automatically”. Slide it on. If you are not connected when you do this, it will not connect for this session. You can either connect manually this one last time, or simply close gSender and re-start it.

Edited to remove nonsense. :upside_down_face:

I think this is more a long-standing issue with non-standard startup messages. You should be able to type ?? in the console to get it working correctly but it’ll require some changes to startup logic on our end for vanilla grbl long-term - basically we don’t send the $$ command until we see a startup message from the controller, and if that startup message is too different from what’s expected (IE doesn’t match regex) it won’t automatically send the command.

One helpful thing would be to share what startup message you get on connection. EG:


Ok…so “reconnect automatically” is working to connect to the usb controller automatically but the firmware issue is still occuring.

@gwilki : I am not attempting to do anything with my firmware other than have gsender recognize that I have endstops on my machine and allow me to use the homing functionality. Clicking the that firmware button is the only way I have found to do this.

@KGN : Please forgive me if I don’t understand your question. Below is the output of console on boot and after I enter $$. Entering $$ does indeed provide me with the homing button. However, if I shutdown gSender and restart I am connected to the controller automatically but again without a homing button. Please let me know if I can give you any more information.

client ?
client $$
$0=10 (step pulse,usec)
$1=255 (step idle delay,msec)
$2=0 (stepport invert mask)
$3=3 (dirport invert mask)
$4=0 (stepenable invert,bool)
$5=1 (lims pin invert,bool)
$6=1 (probe pin invert,bool)
$10=3 (status report mask)
$11=0.010 (junction deviation)
$12=0.002 (arc tolerance,mm)
$13=0 (report inches,bool)
$20=0 (soft limits,bool)
$21=1 (hard limits,bool)
$22=1 (home cycle,bool)
$23=0 (homing dir invert mask)
$24=100.000 (homing feed,mm/min)
$25=500.000 (homing seek,mm/min)
$26=250 (homing debounce,msec)
$27=1.000 (homing pull-off,mm)
$30=12000 (maximum spindle speed,rpm)
$31=0 (minimum spindle speed,rpm)
$32=0 (laser mode enable,bool)
$100=801.900 (X axis pulse:step/mm)
$101=796.250 (Y axis pulse:step/mm)
$102=800.000 (Z axis pulse:step/mm)
$103=177.777 (A axis pulse:step/mm)
$110=2000.000 (X axis max rata:mm/min)
$111=2000.000 (Y axis max rata:mm/min)
$112=2000.000 (Z axis max rata:mm/min)
$113=1000.000 (A axis max rata:mm/min)
$120=20.000 (X axis acceleration:mm/s^2)
$121=20.000 (Y axis acceleration:mm/s^2)
$122=20.000 (Z axis acceleration:mm/s^2)
$123=20.000 (A axis acceleration:mm/s^2)
$130=310.000 (X aixs max travel:mm)
$131=277.000 (Y aixs max travel:mm)
$132=80.000 (Z aixs max travel:mm)
$133=9999.000 (A aixs max travel:mm)

@hendr1x Understood. My apologies. I’ve edited and removed my misleading comment. Go with @KGN info

When you first connect, what is the message in the console? Don’t send anything. Just copy the “welcome message”, which is the first thing you’re controller reports to gSender.

This is what is present in the console after a fresh reboot of gSender with auto connect enabled

gSender - [Grbl]
Connected to COM3 with a baud rate of 115200
client ?

Huh, do you just not have a startup message at all? Even if you soft-reset? Interesting - we’ll see what we can do in that situation.

I’m working a little blind here…I don’t see anything that resembles a reset button. There is a reload icon on my offline controller…when I select that it sends the following…

client ?
Grbl 1.1f ['$' for help]
client $$
Grbl for ARM32
Version:ARM32 V3.0
$0=10 (step pulse,usec)

This reloading, resulted in me having a homing button…me not having to click “Connect to firmware”.

However, I tested again…once plugging the machine in first (usb), then starting gsender…this is my normal work flow and resulted in the original issue (manually having to connect to firmware). The second test, I started gsender first, then plugging in usb…in this scenerio I had to manually connect and it resulted in the same issue.

Let me know if I can provide more information.

Reset is a shortcut:


It might just be your grbl is compiled without a startup message which is an edge case we’ll need to handle - I see arm32 in your screenshot which leads me to believe you’re not running a vanilla GRBL/arduino setup.

I’m running the a stock controller that comes with the Genmitsu 3030. They do not have the product listed on their website. I actually asked them about it when I first got the machine and they confirmed it was a custom made board for them. I’m happy to ask their support any questions if you would like.

this in interesting, i am facing the same thing , not really a big deal, but i’m interested in the solution
i did use a genmitshu 3040 before and i had the lock icon at the start, i only had to click that to connect. but now since i use a generic grbl board the lock is gone.

How about a link to the source code for their firmware.

I just heard back from support. They will not be releasing the firmware code. I was told they were going to forward this thread to their engineering department.

I’m not a lawyer by any stretch but i think that if they started with GRBL source code they are required to provide the source code. The GRBL license is here if your interested.

The following quote is an excerpt from the GNU GPLv3 license.

To protect your rights, we need to prevent others from denying you
these rights or asking you to surrender the rights. Therefore, you have
certain responsibilities if you distribute copies of the software, or if
you modify it: responsibilities to respect the freedom of others.

For example, if you distribute copies of such a program, whether
gratis or for a fee, you must pass on to the recipients the same
freedoms that you received. You must make sure that they, too, receive
or can get the source code. And you must show them these terms so they
know their rights.


I was reading entries in this thread and wanted to share a similar case that I have experienced. I haved used open builds control for a couple of years with my now old cnc that has a arduino uno based standard grbl shield, all good. This winter I upgraded to a new and bigger machine and found fluidnc has wast range of feature that appealed to me. When it was time to begin using the machine, I found that my previous choice in gcode sender was challenged and far from stable in this combination.

I then stumbled over gsender by accident and gave that a try. First impression, very intuitive user interface, a bit slow to start but very stable.
I too have to clik on connect to machine but find that quite natural to do, so nothing I would change myself. But the missing home button and having to force it to read settings is something I would suggest getting addressed too…

From the thread, I can understand its the startup msg that is key here, can you share what gsender is looking for?
In that way I could try modify firmware or startup msg to mach this.

Also I have noticed that you can select between grbl and grblhal when connecting, I found that selecting grbl works best.

Happy to run test if that could be of help to you guys…


There is a setting to auto connect that worked for me. On the first page it says “reconnect automatically”.

Genmitsu developers have stated they will be offering no help on this matter.