Safety¶
jogpad is an operating aid. It is not a safety function and must not be relied on as one.
STOP is not an emergency stop¶
The STOP key sends the firmware's emergency stop command (for Klipper:
Moonraker's emergency_stop). That command travels over USB, the host
computer and the network, any of which can fail. Keep a wired emergency stop on
the machine. Do not label or build the STOP key like an emergency stop device
(red mushroom head on a yellow background).
While jogpad is switched off in Mainsail or Fluidd, STOP does nothing either, like every other key. If jogpad cannot read the switch, STOP still goes out.
No runaway moves¶
jogpad sends the next move only after the firmware has finished the previous one. Detents that arrive in the meantime are merged into a single move. Without this, fast turning queues moves in the firmware and the axis keeps travelling after you stop turning. A held key is the exception, see below.
Locks¶
jogpad refuses to move while a print or job is running or paused. Further conditions, such as a spindle or laser being on, can be added per machine in the configuration. A lock whose object or field the firmware does not know refuses as well, so a misspelt lock does not quietly stop working.
Holding a key¶
An axis key held for half a second keeps its axis moving until it is released. jogpad sends short moves and keeps only as many queued as Klipper needs to move without stuttering. Klipper cannot take back a move it has queued, so the axis runs on for 0.4 to 0.65 s after the release:
| Speed | Runs on for up to |
|---|---|
| 2 mm/s | 1.3 mm |
| 10 mm/s | 6.5 mm |
| 50 mm/s | 33 mm |
| 250 mm/s | 16 cm |
Choose the speeds with that in mind. jogpad refuses speeds above 250 mm/s, the reduced speed of robots moved by hand (ISO 10218-1); the machinery directive itself names no figure.
A pad unplugged while a key is held counts as released. A jogpad that crashes sends nothing more, so the axis stops after the moves already queued. Any other key of the pad ends the move as well.
Wireless pads¶
Wireless pads can drop or delay key presses and releases. Prefer a cable. If a release is lost on the way, a held key's axis keeps moving until you press another key, at most to the end of the axis.