Jermey,
I have done some commercial machines using ADC SureServos, ADC PLC's, and modbus, it is the primary products I use on commercial machines.
A few things:
1). I noticed that you were using the control reley range of address memory. You would be better off using the lower range stuff like 1400 for inputs and 6000 for outputs (in the PLC), you can use a work around for discrite bits by listing your address as 1400.0, 1401.0, 1402.0 etc. (currently you have to do this since the "Bit of Word" function in the Modbus config doesnt work (it is being worked on eventually, but currently it doesnt work). The reason I didnt list 1200 range is if your using a VFD controlled by an analog module then the analog module WILL conflict with that address range.
2). Using MWX, and MRX instructions, you can write via Modbus from the PLC to the SureServo's, that would include writing to the Index table for your ATC. Further you can read and write to the Drives parameters for high end stuff in where Mach can read advanced drive conditions, as well as write paramter changes on the fly for diagnostics or run time issues.
NOTE: You will have to have your PLC be your Modbus interface to the ADC drives, and then have Mach3 read/write to the PLC. It doesnt work well to try and have Mach directly talk to multiple modbus devices since the scan time is to slow, and you will get com errors.
3). SPEED: as you are aware you max RPM on 1kw's is 3k, on the 2ks it is around 2000k, having said those things, running the Parrallel port at 60K is fast engough to do what you want, and it currenly is fully developed. You final speed will end up being what your mechanical gearing will do. Further depending on what you do with your Encouder/gearing ratio, that will also affect your end speed and resolution. I would NOT push the PP past 60K even though it can. If you REALLY do need faster pulse rate than that, then go with the SS.
4). Motor sizing: "Copper Hill" makes a free servo motor sizing utility that uses SureServos (and a few others), for specing the machine. If your using a HEAVY Frame and Gantry like on commercial 5X10 tables then I would put 2Kw's on the X and Y, and a 1 Kw on the Z, UNLESS you gonna use a HEAVY Pensky MOTOR then I would go with a 2KW since that is a very heavy moter that has the ATC mechanism in it.
5). I would go with your Spindle motor being SEPERATE from your ATC Spindle, both from a future maintainace and cost stand point.
6). On the Machines I do currently, I drive PP's for ONLY Step/Dir and a second one for MPG/pendant readback. I use the Modbus for ALL other things.
7). If your gonna go with the Modbus, then go with the Ether Net TCP option, use a ECOM 100 module it is MUCH more robust from Mach to the PLC verses the serial system. The ADC PLC's are limited to speeds of 38,200 baud if you use standard serial, if your pushing alot of I/O then you will have problems.
. If you have more than 32 Inputs, and 32 Outputs (this assumes your using an Analog module to drive your VFD), also it assumes your using a combo Analog of 4 in, and 2 out, so you can also use feed, speed, and spindle overrides. Then use a PLC 205.
I used 2 DL06's in a drop net work with Mach3, it was a Pain in the butt to do the programing across two plcs. The client didn't want the cough up the extra 500 dollars that a single 205 would have done the job of 2 dl06's.
9). ATC: The M6 program will be the easiest thing to do on the machine. The modbus Coms between your PLC, and multiple SureServos will be the hardest. You will have to use a "Cyclic counter" method to cycle your coms between your servos, OR, you wll have to buy another serial com per servo drive DCM module, but in eighther case the config for eigther of these options is NOT, for the faint of heart. It is do-able, but there are alot of gotcha's you will have to over come.
10). I forgot to mention that you can also do a Modbus com from your PLC to the highend functions of your VFD as well, you can use it to drop DROS and messages onto your Mach screens as well.
11). To build a system "commercial level", you will need to use: Brains, the macropump, modbus, plc and screen designer, if you want to compete with the commercial boys, you will need to have a high end screen that will disply advanced diagnostic and control functions.
12). Not trying to discourage you, just wanted you to be aware of the issues. For a Commecial machine (that you plan to sell), I would wait till the SmoothStepper is stablized and does all the required functions that you will actually need on your machine.
13). If you hanging a computer on your physical machine frame, then I would use a SSD, or a vibration isolated HD. Also, I would recommend a CD Flash Drive as a secondary drive to have a "Ghost" of your Mach3 config, system, hard drive and OS set up. So when/if your primary drive dies, you can ghost a recovery profile and your customer is back up, with out you eating a service call.
14). BTW: If your using multiple vacuum zones on your table, I would recommend "Blick" manifolds, they also have options on Electro-solinoids to have your CNC control your zones or, turn then on/off from the screen, verses using manual ball valves.
15). On your ATC spindle, go with Air Control, unless your going to use a Cat40 or larger, then I would use a hydraulic system.
16). There is a Spindle Guy out in Oregon (cant think of the company at this moment), but he does HS metal/ceramic bearing spindles with Tool Claws, and Index Prox's. and options on water cooled jacket.
17). If you decide to take the pluge on the MWX/MRX coms to your drives, then "Scott" at ADC is the Big Dog on this subject at ADC. I spent many, many long calls with him on this very topic, it is NOT well covered in the manuals.
18). Make SURE, you are using the Latest DirectSoft5 software (with latest update), Also, make sure you have the LATEST firm ware in you PLC. The same is TRUE of the SureServo Programming software it has all the latest stuff that has gotten ride of many of the bugs that I hit origianally (some of the bug fixes was cause I was b!tching so much about them to ADC...........hehehehe).
Scott