____________________________________________________
>>
>> Yours is a very common way of thinking about the operation of a handwheel.
>> It is more like the notion of the joystick. From a service standpoint, I
>>want the wheel to move 0.0100 when I command it to so that I can see axis
>> problems.
>>Ray,
>Ray, in incremental mode it can do that, but in continious mode
>it should stop when the wheel stops turning.
>Bill
Bill,I have never seen a wheel on a machine tool that opreates in "continious mode". The purpose of a wheel is to quickly move to positions without having to issue g-code commands, or to easily find the edge of a part without having to (in EMC's case) press a key a bunch of times to jog in .001 steps. If you want a continious mode, or feed mode aren't there keys for that already, that continue to move as long as they are pressed? Having used machine tools day in and day out for years, I guarantee you, that a wheel that you have to keep spinning as long as you want the machine to move, will quickly get tiring. Keys are much better for that kind of motion.
I am more interested in how the machine will figure what speed it is supposed to be moving at while the wheel is spinning? What kind of out of position errors will be generated when it can't keep up with the commanded position of the wheel? I have a feeling that current controllers actually do two different things when keeping up with machine position, while using wheels.
1. They keep track of the number of pulses, and move at a maximum (fixed) rate.
2. They Immediately stop when the wheel stops, and ignore all stored pulses. However, I think for this to work effectively you would need feedback from encoders, to keep from losing track of position, unless someone can think of a way.
Lamar
IncrediMail - Email has finally evolved - Click Here