Problems / Bugs?


Having troubles with gSender or have suggestions to improve it?


As well, get additional insight into using gSender by looking at our Forum Category, YouTube Playlist, or Facebook Users Group

List of Common Problems & Fixes

gSender has not been static very long so not many standard questions have been asked yet. Nonetheless, we’ll continue keeping our ears out for common stumbling points while using gSender and ensure we address them here for quick reference.

Issues downloading or opening gSender

Since programs take a while before they’re recognized by Windows, Apple, and other virus protection programs as ‘safe’, if you find yourself running into problems downloading, installing, or running gSender on your computer you’ll want to check for any ‘virus protection’ that your computer is running to see if it’s making these blocks. An example of this is if you see “Windows cannot access the specified device, path, or file. You may not have the appropriate permissions to access the item.”

In cases like these, first find the source of the blocking and then either make an exception for gSender or disable the blocking temporarily during download and installation. For Windows-based computers you can read more here:

Connects but status says Disconnected

If your machine connects on a COM port successfully but the machine status still says “Disconnected” then this is not an issue with gSender. Connecting in the top-left only indicates a USB connection has been made successfully, meanwhile the machine status box indicates whether gSender has been able to recognize the CNC machine. Your control board may have a faulty connection: gSender looks for the standard GRBL response and boards that are loose or have become corrupted won’t emit this response, if this is the case you can contact our support if you have a CNC from Sienci Labs or contact your own manufacturer’s support for instructions on fixing your machine.

gSender connected to board but visualizer is displaying a disconnect

  1. Make sure the Arduino is fully seated by using a non-conductive tool, like a back of a plastic spoon, and push on the board through the vents in the back of the controller.
  2. Re-flash your machine by following the instructions here: gSender – Connected but No Controls
  3. Your machine isn’t supported yet by gSender: if your CNC isn’t GRBL-based or your manufacturer had edited GRBL too much or is using a different flavour from the standard version it’s likely that gSender won’t be able to recognize or control your machine

My CNC is not listed in the Machine Presets

Much of the information that gSender needs about your CNC actually comes from its built-in EEPROM values. This means that as long as your CNC is GRBL-based gSender should be able to control it just fine, even if it’s not listed in the presets. If some aspects of your machine don’t seem right, it’ll either be because your machine’s manufacturer didn’t flash your CNC with the appropriate EEPROM settings out of the box or they have some type of documentation which explains the values you need to change manually – if you find this information from your manufacturer then you should be ready to go in gSender. Select the “Generic” preset if you wish as well as send us a message if you’d like to see your particular CNC listed in gSender in the future!

Currently, presets are there to list common machines supported by gSender as well as to support firmware flashing and reset defaults for Sienci machines since we don’t have access to the exact build information needed for other CNCs.

The port is not detected for my 3018 CNC

The 3018 and similar variations have been tested to work with gSender. Sainsmart points out in their documentation that sometimes an additional driver is needed for your computer to recognize the CNC via the USB port. They make this driver available for download here:

In case this link stops working, the associated documentation can be referenced here:

For most of their machines they recommend using a 115200 baud rate, so double-check you’re using that value as well.

The port is not detected for my CNC

As long as you’re using an Arduino-based board with GRBL loaded onto it and you’ve selected the correct Baud rate in the settings then connection should be possible. Double-check that you’re not connected to your machine in another sending program at the same time as you’re trying to connect with gSender. As well, sometimes pendants or other forms of non-computer controllers can impeded on a g-code senders ability to connect to the machine.

We’re still working on making gSender work best across all devices and one aspect of this is port detection for a variety of CNCs. If your CNC still isn’t showing up on the port detector, we’d really like to hear from you.

One key bit of information that we need on our end is a picture or screenshot of your device information. You can get to this screen by:

  1. Make sure your CNC is plugged into your current computer via USB
  2. Open “Device Manager” in your Windows start menu
  3. Expand the “Ports (COM & LPT)” heading
  4. Find the listing related to your CNC. This will be the one that disappears and reappears if you unplug your CNC and plug it back in. It’ll also be the port you normally connect to on other g-code senders.
  5. Right click that device and open “Properties”
  6. Open the “Details” tab at the top
  7. In the “Property” dropdown, select the “Hardware Ids” option
  8. Send us a picture of the final view. An example of what that might look like would be:

We appreciate your feedback, and with your help we’ll make sure the next version of gSender recognizes your machine.

Jogging not working, I get an error

If you’re seeing a message in the ‘Console’ tab saying “error: Bad number format”, this is because you’re running an older GRBL machine (pre Grbl 1.1f). Contact your CNC manufacturer or look through their resources to see how you can upgrade your GRBL firmware so that your machine can be fully supported by gSender. If you have a Sienci Labs machine, this is as easy as using the ‘Flash GRBL’ option in the ‘Firmware’ tool in gSender.

Alternatively, you could be getting an error for ‘soft limits’. If this is the case then either your machine limits have been set incorrectly or you didn’t home your CNC when you first connected to it. Try homing your machine and trying again, and keep an eye out for if you’re only having this issue in certain parts of your cutting area.

Workspace is changing when a job is run

If your g-code includes any workspace commands from G54 to G59, G59.1 to G59.3, or has an M2 command at the end of the program this will alter your selected workspace either to the one specified or revert it to G54. These commands affect how GRBL stores the active workspace and so also affect the workspace stored by gSender. If you’re experiencing this issue then you’ll want to check your CAM post-processor and ensure that it stops inserting these commands when you export your g-code jobs.

Alternatively, gSender’s ‘Start/Stop G-code’ can also be equipped to sidestep problems with changing workspaces by saving the active workspace at the start of the program and then re-loading it at the end. This can be done with the commands %global.state.workspace=modal.wcs and [global.state.workspace] as shown in the picture below. Remember to ‘Update Event’ on both entries: