Technically in school !:)

Hi,

Okay, just a few words Andrew:

Well, the schematics exist , you have to try to get hold of someone.
Some must have worked with these, and you know where you got the Beast,
- so you just have to do some detective work.

Here is a simple story about computers:

Most electronics is dumb circuits, but they do a specific job. With the
microprocessor and some code, this is different. In a normal PC, the
cpu can shut it self off from the main board, and let other processors
work with it. Another well known way it can do things, is to give
control of the bus system to a direct memory access unit. (DMA)
This is a software way of doing things, a "hardware" way of doing it,
would be to force it into some of these states. A "real hardware" way
of doing it, could be to remove the CPU, have another micro controller
put in it's place.
Then you could disassemble the software in the EPROM's, and write a new
software for the original CPU. Here is several ways to do things.

Here is a short story of what the best could do:

CPU, please check if there is any data from the RS232.
<There is >
Please read a string and place it in memory.
< Ok >
Split the string into data for the X,Y,Z axis, and the feed rate.
<OK>
For the X axis, store this data in the position registers, do the same
with the other axis.
< OK>
Place the federate in the DAC register.
<OK>
Now if <single step is pushed > then write to the enable port, and
output the command to the servos.

This little story says a few things:

First the local CPU, is the one that will read any data from an external
port,
then this one will know what to do, and where to store these data. All
these goes to output ports, like position registers,
DACs, screen, what ever. The main board in your machine have this bus,
and addresses, to all of these registers. It is just like the ServoToGo
card, but everything is already wired up, and the signals match, etc.

You could use a simple IO board in a CPU, change the addresses that EMC
has in the .ini files or wrapper code for the Stg boars, and talk
directly to your main board in the Beast. This is something that could
be done, but you need someone that knows how to do a task like this. (
Here is where I think some students could do some work, they would learn
a lot about EMC and control systems, and dig into the hardware of
things. This would be a very valuable work for a lot of people, if they
made the work public. This kind of retrofit could be done on all kinds
of systems. Okay some will reject to this, and say that the DACs on your
machine is just 8bit wide, or they say something else. The thing is
that you will get a system as good as the original one, - if that has
worked, so will this. To get a better result, than what was in the
original machine, - is just wasted energy in many cases. I really need a
lot of knowledge to do that. Let take a Mercedes Benz, and make it into
a hot street car. Add a root compressor stage, a turbo stage, a
sharper cam, wide tires, etc. How many do make a better car out of it,
and at what cost ?
90 % of all attempts, - is just a ruined good car. You really need a
lot of knowledge to make a success out of it. ( Well, if you want to
race Daytona 500, and have the money for it.... :)

Before I would cut any wires, I would evaluate what I got, what options
and to what cost. Or ship the piece to one of the others on this list,
that make a living out of retrofitting. Have a talk with them. The only
thing I attempted to do, was that you gave it some thought before you
start cutting wires. Have a chat with Jon, he knows what it takes. The
thing is that we often underestimate what it takes.

Best wishes

//ARNE