Configure and calibrate¶
A machine needs this once, and again whenever its mechanics, drive or load cell change. Everything here is on the Settings screen, with the machine connected.
The order matters: the motor calibration moves the carriage using the limits you enter in step 1, and the load cell calibration uses the capacity and sensitivity you enter there.
Settings take effect after a restart
The machine reads its configuration when it starts. After Write to device, the app asks to reboot: click Reboot now before relying on the new values (or power-cycle the machine). Everywhere below, "write and reboot" means this.
1. Enter the machine configuration¶
Under Machine configuration, the values load from the machine. Fill them in from your hardware's datasheets, then click Write to device and Reboot now.
The ones that must be right before anything moves:
| Field | Where the value comes from |
|---|---|
| Encoder (step/mm) | Encoder counts per revolution ÷ millimetres of travel per revolution |
| Servo (step/mm) | Drive pulses per revolution ÷ millimetres of travel per revolution |
| Position Max (mm) | The carriage's usable travel |
| Velocity Max (mm/s), Acceleration Max (mm/s²) | Start conservative; the motion calibration tells you if the machine can deliver them |
| Tensile Force Max (N) | The lowest rated part in the load path (usually the load cell) |
| Load Cell Capacity (N), Load Cell Sensitivity (mV/V) | The load cell's datasheet |
| Drive enable | High enables for servo drives such as the DMM DYN4; Low enables for most stepper drivers |
Machine configuration describes every field.
If the carriage never moves
A wrong Drive enable leaves the drive switched off: motion enables, jogs are accepted, and nothing moves. Flip it, write and reboot.
2. Check the drive and encoder¶
Open Control, click Enable motion, and jog the carriage to the middle of its travel. Then go back to Settings → Motor calibration and click Run check.
It drives the carriage 5 mm out and back at 1 mm/s with the servo loop off and counts what the encoder sees.
- pass: the two steps/mm values match the hardware and the encoder counts the right way. Go to step 3.
-
error: read the Fix line. It gives the value to change, for either assumption:
Change the value you trust less, Write to device, reboot, and run the check again.
Every finding is explained in Motor calibration.
3. Run the motion calibration¶
Run motion calibration unlocks once the check has passed on the values saved on the machine. The panel says how far it will travel either side of the carriage's position: leave that much room.
It runs a short program closed loop and reports three things:
- Acceleration: pass means the carriage kept up with Acceleration Max at every speed. too high means lower Acceleration Max (or Velocity Max), write and reboot, and run it again.
- Tracking: how closely the servo follows its encoder.
- Suggested servo gains: starting values for Servo Kp and Servo Ki. Enter them in Machine configuration, write and reboot, and run the calibration again to compare.
Neither routine writes anything to the machine. You change the fields yourself.
4. Calibrate the load cell¶
Under Load cell calibration. Neither step moves the carriage.
Zero¶
Take any sample out of the grips so the load cell hangs free, and click Read zero. After 3 seconds it shows the zero balance and the noise:
Click Use this zero (it fills in Load Cell Zero Balance above), then Write to device and reboot. If the badge says still settling, wait and read again.
Sensitivity¶
With the load cell hanging vertically:
- Click 1. Read unloaded.
- Hang a known weight, enter its Mass (kg) including the hanger, and click 2. Read with weight.
- Repeat with more weights, up to at least 20% of the load cell's capacity if you can.
Click Use this sensitivity, then Write to device and reboot.
The flags (light, swinging, polarity) are explained in Load cell calibration.
5. Confirm¶
After the last reboot, check on Control that:
- with nothing in the grips, Machine Force reads close to zero;
- a known weight reads its weight;
- a 10 mm jog moves the carriage 10 mm.
Next: Run your first test.