Re: [CAD_CAM_EDM_DRO] How to replace Anilam controls with PC?

randolph.e.howard@... wrote:

> I have recently bought a manual Bridgeport mill which
> has been converted to ball screws and servo motors
> using Anilam Crusader II controls. It has 3 axis control
> with SEM servo motors (perm. magnet DC) on axis X, Y, and Z. The
> Anilam system is not working except for DRO functions
> so I am wondering, would it be possible to control
> this machine using a PC and inexpensive software and could I
> still retain the existing SEM motors? What would I
> need in the way of driver boards for the servo motors (they are
> missing)? The motors are SEM brand, MT30R4 and MT30E4, 135 and 75
> volts respectively. I probably should be asking other questions but
> I am pretty new to CNC control. Maybe someone can help me decide what
> is the best way to get this beast up and running. Thanks in advance.

Well, the first thing is to determine exactly what is there. If it
works as a DRO,
then the encoders must be working properly. As the encoders are still
hooked to
the anilam, you can use a voltmeter to determine which wires are encoder
power,
and what the voltage is, and which wires are the encoder signals. This
is a good
head start on a conversion, vs. the situation where the control is dead
or missing.

You need to see if the motors have DC tachs (which most of the SEM units
do
have), and what the motor and tach ratings are. I strongly suggest
keeping the
servos and getting servo amps of some kind. I have a semi-kit for servo
amps,
but you can also find a variety of good servo amps surplus, especially
for
brush motors.

Is the DC power supply still there, or did that go with the servo amps?

EMC is free from the National Institute of Standards and Technology, and

is very capable and getting better. It runs under a real-time version
of Linux,
not Windows. But, that is a nice, robust, capable, reliable system,
which is
what you need for controlling a machine that could kill you!

A 100 MHz Pentium with 32 MB of memory and a 1 GB disk is about
the minimum system requirements to bring up EMC. You can get by
with a smaller disk if you have another Linux machine to do compiling
and debugging on.

The last thing you need is an interface between the computer and the
encoders, servo amps, etc. Servo-to-Go has a board for ~ $800
that does everything, but that is a bit high. I am finishing up the
testing
of a set of low-cost boards to do the same functions when connected
to the computer's parallel port. I envision selling the complete
4-channel,
16-bit DAC board for $100, the complete 4-axis, 24-bit encoder counter
for $100, and (later) the digital input and output boards for maybe
$50 - 60 each. There will also be a backplane for these boards, for
maybe
$60 or so. Right now, there is a split in EMC between the things
controlled
by the real time section and the non-real time parts. So, this requires
the
parallel port used for motion (real time) to be different from the port
used
for auxilliaries, such as spindle motor, coolant, etc. I hope to bridge

that split with some interface code that passes the auxilliary info back
and
forth across the shared memory, so that everything can go on one
parallel
port.

But, right now, I have to write a C language driver under Linux and test

the boards with that. A quick and dirty test program under DOS/Windows
has demonstrated the boards work.

Jon