Re: [CAD_CAM_EDM_DRO] Pendant

Hi,

It seems from your replies that I have explained, what I am up to, quite
poorly.

The Pendant:

This is a device that connects to a motor driver and gives step and
direction out-puts. Sometimes referred to as a joystick. It is hardware and
totally independent of computer control. If fact you will be able to leave
the computer connected. In a CNC system the pendant/joystick is in software
and the pendant is just a switch-box feeding back into the CNC software but
in this case the pendant is intelligent and can drive the motor control
hardware directly. This not a replacement for full CNC as it will only
possible to move the machine slides in straight lines or, in the case of the
rotary axis, round in a circle.

The pendant has been designed to drive up to four axis, A through to Z, via
8 buttons 2 for each axis. There are 12 speed settings in groups of 4. A
Mode Switch to select which group of speeds is required and also a quick
Stop Button.

Out-put to the driver boards is in Step and Direction with a Dip Switch,
user set-able, so that the axis's moves in the correct direction. The
buttons are laid out as follows :

0 0 0
0 0
0 0 0

With the "A" axis on the left, the "X and Y" in the middle and the "Z" axis
on the right.

Speeds available are based on a lead-screw of 0.2" lead with a 3:1 reduction
gear and a stepper of 200 steps/rev. and are as follows:

1) Single step.
2) 1"/min. or approx 25mm/min which is 3000 pulses/min.
3) 2"/min. or approx 50mm/min which is 6000 pulses/min.
4) 4"/min. or approx 100mm/min which is 12000 pulses/min.
5) 8"/min. or approx 200mm/min which is 24000 pulses/min.
6) 12"/min. or approx 300mm/min which is 36000 pulses/min.
7) 18"/min. or approx 450mm/min which is 54000 pulses/min.
8) 25"/min. or approx 630mm/min which is 75000 pulses/min.
9) 50"/min. or approx 1200mm/min which is 150000 pulses/min.
10) 100"/min. or approx 2500mm/min which is 300000 pulses/min.
11) 150"/min. or approx 3800mm/min which is 450000 pulses/min.
12) 200"/min. or approx 5000mm/min which is 600000 pulses/min.

The speeds are selectable in groups of four, i.e. 1-4, 5-8 and 9-12. The
programming has not been started yet and it was these speeds that the
original question was aimed at. I am not sure at this point if the upper
speeds are attainable with the hardware, this will only become apparent when
testing is done.

While it is entirely possible to do the same as the above using two 555
timer chips and a resistor/cap network. Then feed the pulses-train though a
switch-box and strap the direction input to the driver board either logic
high or logic low, it is very messy. Only two speeds are obtainable. Single
Step and what ever speed equates to the timer out-put. I am hoping to bring
the pendant to market at a price that makes the 555 route too much trouble.

The pendant will be produced in three levels of kit form.

1) Bare PCB board with a programmed PIC. The end user find his/her parts.
2) All the components necessary to complete the pendant. The end user
solders it all together.
3) Completed PCB board. The end user puts it into the box and hooks it into
his/her driver boards.

All parts will be available as separate items.

I am also thinking of designing a second level pendant which is user
programmable. How this will work is speculation at this moment but it will
be a huge addition to the capabilities over the above. The product will
still only be able to move the machine slides in a straight/rotary movement
but in a programmable way with all the calculations taken care of.

Sorry this turned into a bit of a sales pitch.

Regards,

Terry