Re: Re: 3 axis controller

[john s finnila <jsfinnila-at-juno.com>]

Ray, thank you for your input.  How I interfaced the PLC to the Mektronix
PC based control was quite simple.  The entire tool change logic was
contained in the PLC.  When a tool change command  is given from the
Mektronix PC, a T command TTL logic is outputted to the current sinking
input of the PLC (isolated input) along with a strobe command.  The PLC
instantly outputs a feed hold command to the PC (Mektronix board in the
PC) at which time the tool change commences.  When the tool change is
completed, the feed hold is removed and the program in the PC continues
to the subsequent blocks thus proceeding to machine until a new tool
change is called for.
This simply requires that the PC based control has provision for
outputting a tool (T) strobe command along with a BCD or binary tool
number command in TTL logic.  Then the complex logic of the tool changer
can be written in an external PLC.   Of course this same functioning can
be done internally in the PC, but it would require a fairly powerful and
user friendly software PLC.  A very nice feature of a PC based control
would allow for user friendly input/output commands such as these, and
also some spare M or miscellaneous output commands to do special machine
functions that may arise.  I hope this makes sense.  Does the emc allow
for these features.  Thank you for your input.

John Finnila