Thank you all, I'll do tests Best regards,
Pierre 2016-05-22 5:09 GMT+02:00 Chris Albertson <albertson.ch...@gmail.com>: > On Thu, May 19, 2016 at 12:37 AM, Erik Christiansen < > dva...@internode.on.net > > wrote: > > > On 18.05.16 08:30, Chris Albertson wrote: > > > This is a general problem that applies not just to CNC machines. What > > > to do if the human interface allows a human to tell a machine to do > > > something it can't do? In this case the interface allows you to > > > command the axis to move faster then it can. The best design is to > > > prevent this. You'd need to have some kind of force feedback, a > > > torque or brake applied to the command wheel to prevent you from > > > turning it to fast. Cheaper solution is a big red LED that lights up > > > as you approach 90% of the maximum speed. Or in place of the LED a > > > vibrator motor to shake the wheel. > > > > I like the big red LED, especially together with a little mobile phone > > vibrator motor or a complaining squawker, but what about just limiting > > the joystick/knob output to MAX_VEL? > > > If it is a joystick then yes that would work. A joystick is a "jog" > command that says to the machine "go left" and you can't enter a bad > command because pushing it hard to the stop always means "go as fast as you > can". > > But the user interface device we that started this discussion was a dial. A > dial says "move a distance proportionate to how many degrees I turn the > dial". It is intended to by an analog of the dial that turns a lead screw > on a manual machine. The problem is the user can turn the dial as fast as > he likes and the only feedback that he is turning it to fast is lag in the > control. In other words the "feedback" is that the machine no longer moves > proportionate to how many degrees I turn the dial. > > The first is a velocity control and the second is a position control. > > To make a joystick always work you all you ned to do is able the hard stop > "max speed", just like you said. > > The dial could too if you could limit what a user could do with it, > > My point was not really HOW to fix this just to point out that user > interfaces can have theoretical issues a designer must address. They > either need to logically not allow invalid input (like a joystick) or the > designer needs to specify what happens when the user makes an invalid > input. This applies to software, toasters and cars not just CNC tools > > > > Within LinuxCNC that ought to be > > possible, maybe using a hal limit component? If it had to be done in the > > arduino, then the limit would also not need to be hard-coded into the > > program if means to increase/decrease the value via the user interface > > were provided, as the result could then instead be saved in on-chip > EEPROM. > > > > The latter method would permit scaling of the joystick travel to match > > MAX_VEL, whereas the former would result in the last bit of joystick > > travel doing nothing, which is suboptimal. > > > > If an operator is likely to jerk the joystick instantly to full travel, > > then it might be an idea to limit output to e.g. 95% of MAX_VEL, so that > > LinuxCNC can catch up despite limited MAX_ACCEL. > > > > Erik > > > > > > > ------------------------------------------------------------------------------ > > Mobile security can be enabling, not merely restricting. Employees who > > bring their own devices (BYOD) to work are irked by the imposition of MDM > > restrictions. Mobile Device Manager Plus allows you to control only the > > apps on BYO-devices by containerizing them, leaving personal data > > untouched! > > https://ad.doubleclick.net/ddm/clk/304595813;131938128;j > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > > > -- > > Chris Albertson > Redondo Beach, California > > ------------------------------------------------------------------------------ > Mobile security can be enabling, not merely restricting. Employees who > bring their own devices (BYOD) to work are irked by the imposition of MDM > restrictions. Mobile Device Manager Plus allows you to control only the > apps on BYO-devices by containerizing them, leaving personal data > untouched! > https://ad.doubleclick.net/ddm/clk/304595813;131938128;j > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Mobile security can be enabling, not merely restricting. Employees who bring their own devices (BYOD) to work are irked by the imposition of MDM restrictions. Mobile Device Manager Plus allows you to control only the apps on BYO-devices by containerizing them, leaving personal data untouched! https://ad.doubleclick.net/ddm/clk/304595813;131938128;j _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
