gSender Workflow: Setting Zero, Running Jobs, and Recovery

What Is gSender? gSender is Sienci Labs' free, open-source CNC control software. It's the interface between your computer and your CNC machine — you jog the machine manually, set work coordinates (zero point), load G-code files, and run jobs from it. It runs on Windows, Mac, and Linux. This guide covers the complete workflow from power-on to finished cut. -- 1. Connecting to Your Machine 1. Launch gSender 2. Connect your CNC via USB 3. Select the correct COM port (Windows: Device Manager → Ports; Mac/Linux: /dev/ttyUSB0 or similar) 4. Select Baud Rate: 115200 for most GRBL machines 5. Click Connect — status bar shows "Connected" and machine position appears If connection fails: check USB cable, check that no other software (Candle, UGS) is using the same port, try a different USB cable. -- 2. Homing the Machine Most CNCs have limit switches that let the machine find a known reference position (home). Click Home in gSender. The machine will: 1. Move Z up to the limit switch (safe first move) 2. Move X to the limit switch 3. Move Y to the limit switch 4. Stop at machine home (usually back-left corner) After homing: machine coordinates (MPos) are now known. Work coordinates (WPos) are still wherever they were last set. If no limit switches: skip homing. You'll rely entirely on work coordinates you set manually. -- 3. Jogging the Machine Use the jog controls to move the machine manually: Arrows: X and Y movement Z+ / Z-: move the spindle up and down Step size: 0.1mm for fine, 1mm for normal, 10mm+ for fast travel Speed: how fast jog movements happen Move the machine to your desired work origin (the X0, Y0, Z0 point your G-code was programmed from). -- 4. Setting Work Zero (XYZ) Work zero is the reference point your G-code uses. It's separate from machine home — you can set it anywhere. Setting X0 Y0 (the corner of your workpiece): 1. Jog the bit directly over your desired XY origin (usually bottom-left corner of the workpiece) 2. Click Zero X and Zero Y (or Zero XY together) 3. The WPos display now reads X0.0 Y0.0 at this position Setting Z0 (the surface of the material): 1. With a paper feeler gauge method: jog Z down until a piece of paper just barely slides under the bit with slight resistance. Click Zero Z 2. With a touch plate / probe: place the touch plate on the material surface, connect the clip to the bit, click Probe Z in gSender. It auto-zeroes within 0.01mm accuracy. 3. Raise Z 5-10mm after zeroing so the bit isn't sitting on the surface -- 5. Loading and Visualizing Your G-code 1. Click Open and select your G-code file (.nc, .gcode, .tap) 2. The visualizer shows the toolpath in 3D — rotate with mouse drag, zoom with scroll 3. Check the toolpath makes sense — does it match your design? Are the cuts in the right places relative to origin? 4. Dimensions display shows how big the job is — verify it matches your expected part size Simulating the job: gSender can run through the file without moving the machine. Click Start with the spindle disabled (or use a dry run mode) to simulate. Watch for any path that goes outside your material boundary. -- 6. Pre-Flight Checklist Before pressing Start: [ ] Spindle/router is running (turn it on manually) [ ] Work zero is set correctly [ ] Workpiece is secured (tape, clamps, screws) [ ] Bit is correct for the job and tightened [ ] Collet is tight (should not spin by hand) [ ] Dust collection is running (if you have it) [ ] Bystanders are clear [ ] You know where the emergency stop is -- 7. Running the Job Click Start. The machine begins moving. During the cut: Watch the first pass carefully — does the bit engage material correctly? Listen: smooth machining sounds correct. Chatter, squealing, or excessive vibration = stop and investigate Check your first few cuts: are they at the right depth? Feed rate override: while running, you can adjust feed rate in real-time using the override slider. Reduce if something sounds wrong. Increase if cuts are going well and you want to speed up production. -- 8. Recovery: When Something Goes Wrong Machine alarms (limit switch triggered): 1. Don't panic — the machine stops safely 2. Click Unlock in gSender to clear the alarm 3. Jog away from the limit switch 4. Re-home if needed, reset work zero Power loss mid-job: 1. DO NOT re-home while the bit is in the material 2. Note the approximate position 3. gSender has a Start from Line feature — you can re-enter the job at a specific line number after re-establishing position Bit breaks mid-job: 1. E-stop or click Stop immediately 2. Raise Z 3. Replace bit (same type, same diameter) 4. Re-zero Z on the same surface reference point 5. Resume from approximately the line where the break occurred -- Useful gSender Features Outline: traces the XY boundary of your job at a safe Z height (not cutting). Verifies your material is large enough and positioned correctly. Macros: save sequences of G-code commands as buttons. Useful for going to a safe home position, turning on/off accessories, running a probe sequence. Start from Line: re-enter a job after a failure without re-running completed sections.

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