I am converting a mid-sized mill from an old Dynapath System 10 to Mach with a Galil 2200 board.  I have a pretty good idea of how to do everything except the tool changer.  It has a 12 tool carousel with an arm. Currently, it uses an old Omron PLC to handle the M functions and tool change.  Communication between the Dynapath and PLC is basically a parallel interface using the CNC outs to PLC inputs. It uses six lines for data (tool or M number), one line to signal an M code, and an final line to signal a tool number.  I have a Siemens S7/200 PLC that I have pretty much duplicated the Omron programming on, so I'm not worried about having to buy a PLC or software.  The PLC is fairly complex with 22 ins and 16 outs.  As I see it, my options are:

1) Emulate the current setup by writing some VB code to duplicate the current interface (should be fairly easy, but kind of a crude method)

2) Keep the PLC functions the same, but communicate with the PLC over Modbus (I am not fluent in Modbus, is it worth the trouble?)

3) Drop the PLC and do all of the tool changer functions in Mach using the extra IO on the Galil (one less programming langauge to mess with)

Any thoughts?

Mike

Modbus is the way to go I think, its the way I do it anyway and it is fairly straightforward, must be, I managed it
 You still need some VB obviously but you are just using that to turn on and off outputs from Mach to the PLC via Modbus.
Hood

I am going to use S7 200 for tool change. What are the things i will need for this? Does it needs really complex programming?

Depends what you are meaning, if its VB programming then if the majority of the toolchange is handled in the PLC then the VB side will be relatively simple.
Hood

What you suggest? I also thinking to use PLC for most of the job

Can you provide any simple example for tool changer?

Sorry if i am asking too much but i am new to this field. Is there any training program available for this software?

I do not know anything about the Siemens PLC but I can give you examples of my PLC and Modbus setup if you think that may help. I use the Koo DL06 PLC.

Hood

Ok thanks in advance

Can you mail me at my mail id vithanidevesh@gmail.com

I have attached an image showing the modbus setup for my PLC and a small portion of the ladder.
Hood