# Glossary

> For agents: start with the [agent guide](https://parol6.build/llms.txt). Every page is Markdown by default; add `Accept: text/html` for HTML.

## B

- [backlash](/lore/m2-one-joint) → The play in a drive before the output moves; the EG gearboxes have 15 to 20 arc-minutes of it.

## D

- [DIAG pins](/lore/m1-bench-it) → The two pins on a driver module that show its orientation; they must point at the red arrows in the official figure.

## G

- [GX16](/lore/m1-bench-it) → The 2-pin circular connector that takes 24 V DC into the robot's base; it has no fixed +24 V pin, so polarity is checked by meter.

## H

- [homing](/lore/m3-whole-arm) → Driving each joint to its switch or sensor, then a known number of steps to the after-homing pose; needed after every power-up, collision, stall or move by hand.

- [HP](/lore/skiff-target) → Horizontal pitch, the Eurorack panel width unit; 1 HP is 5.08 mm.

## I

- [inductive sensor](/lore/m2-one-joint) → The contactless sensor that homes joints 1, 4 and 6 by sensing a small steel screw.

## J

- [jogging](/lore/m3-whole-arm) → Moving one joint, or the tool along one axis, for as long as a button is held or a command repeats.

## L

- [limit switch](/lore/m3-whole-arm) → The mechanical switch that homes joints 2, 3 and 5.

## M

- [mastering](/lore/m3-whole-arm) → Correcting each joint's homed position in the firmware until a homed robot stands exactly at its witness marks.

- [microstep](/lore/m1-bench-it) → One of the 32 subdivisions of a full motor step that the drivers run at, so one motor turn is 6,400 microsteps.

## N

- [normally closed](/lore/m1-bench-it) → A contact that conducts until it is pressed; the E-stop must be one, so pressing it, unplugging it or cutting its wire all stop the robot.

## O

- [open loop](/lore/m1-bench-it) → Control without position feedback: the motors have no encoders, so the position is the count of steps commanded since homing.

## P

- [PETG](/lore/m2-one-joint) → The print material for PAROL6's parts; it softens around 80 °C, where PLA fails near the warm motors.

- [planetary gearbox](/lore/m2-one-joint) → A compact gearbox on the motor; PAROL6 uses the EG precision series, 20 to 1 on joints 2 and 3 and 10 to 1 on joint 6.

## S

- [set screw](/lore/m2-one-joint) → A headless screw that clamps a coupler to a motor or gearbox shaft.

- [ST-Link](/lore/m2-one-joint) → The STMicroelectronics programmer that uploads firmware to the board, through the PAROL6 programming adapter or the four named header pins only.

## T

- [TCP](/lore/m4-pick-and-place) → The tool centre point: the point on the tool that the software positions, set as a transform from the flange.

- [test firmware](/lore/m1-bench-it) → The bench firmware every board ships with: it checks the six drivers, turns every motor slowly and reports the inputs over USB.

- [threadlocker](/lore/m2-one-joint) → An adhesive for screw threads; blue goes on every metal-to-metal screw and on all set screws.

- [TMC5160](/lore/m1-bench-it) → The stepper driver module, in the StepStick format, that the PAROL6 control board takes six of; the firmware configures it over SPI.

- [transmission ratio](/lore/m2-one-joint) → Motor turns per joint turn; joint 6's 10 to 1 gearbox turns one motor revolution into 36 degrees at the joint.

## W

- [witness marks](/lore/m3-whole-arm) → Holes in neighbouring links that line up in the after-homing pose, so a pin pushed through them proves the pose.

## X

- [XT30](/lore/m1-bench-it) → The power connector on the control board that the base's GX16 socket is wired to.