Re: tool changer logic- mathematical challenge

Hey,
Thanks for the reply.
I have a pretty good idea of the overall logic required. My biggest
hang up now is the tiny detail of how to read the inputs. Whether
it's in a VBscript macro with Mach2 on a PC or a PLC or PIC. How do
I KNOW what the bit pattern is going to be for each distinct state
transition, on>off and off>on on each of the 4 sensors?

I'm guessing you are talking binary, IE 1000, 1100, 0100 etc...
How do you get from on>off to a distinct bit pattern?

What is a 'nibble'? :) Thanks for your help, I didn't do well in
comp sci class, but I still have my book!

> /* programming hints, regardless of whether a PLC or a

microcontroller

> is used:
>
> You should only need 4 sensor inputs - Just make an array of 8

nibbles

> with the proper sensor input bit pattern for each of the 8

positions.

> When a command comes to advance, just turn on the motor until the

input

> pattern matches the next one in the array.
>
> Have a timeout - if there are no state changes for some time period
> (like 1.5-2x the expected period), then shut off the motor, and

signal a

> fault if possible.
>
> */
>
> - Steve