Messages

21

General Mach Discussion / Re: What motor size and driver should I use

« on: November 19, 2009, 02:59:40 PM »

Hi John,

I have a Gorton 1-22 mill, a little bigger than the bridgeport.  It has really old NEMA 42 Pacific Scientific motors with Geckos on X and Y and a big DC servo on the knee, Gecko drives all-around.  I would avoid going with a knee-drive, it is slow, heavy, and it was pretty difficult retro-fitting a ball screw in there....  I run 80IPM rapids all around and can take heavy cuts at 30IPM no problem.  Gecko's are superb stepper drives, I have a small preference for Vipers for servo (the preference gets bigger as the motor gets bigger :-))

Hope that helps,
Dustin

P.S-  Direct drive on the steppers, .2in pitch ballscrews.

22

General Mach Discussion / Re: Lathe turret, VB, PLC, MODBUS, Position

« on: November 18, 2009, 12:43:07 AM »

Peter, Hood,

Thanks so much for the help, I've got Mach talking nicely to the PLC now using the start address 16384.  Ive even managed to trigger a mini-ladder test program that toggles real outputs on the PLC from a VB script, progress!! 

Peter, the ModIP sounds really great, this is pretty confusing and I've got a fair bit of experience with electronics, and micro-controllers.  I'd hate to jump into this without any background....

I'm still not totally clear on the bit-packing options, but I may just stick with it the way it is, things seem to be working and if the CLICK will not unpack them properly anyway I'm OK with the inefficiency.

Thanks again, I'm going to experiment more with the script tomorrow.

Dustin

23

General Mach Discussion / Re: Lathe turret, VB, PLC, MODBUS, Position

« on: November 17, 2009, 06:07:51 PM »

Hood,  Normal, I am pretty sure.  I don;t think I am using a plug-in, but I am not sure what that is.

Dustin

24

General Mach Discussion / Re: Lathe turret, VB, PLC, MODBUS, Position

« on: November 17, 2009, 12:31:15 PM »

OK, I'm getting there, but am having trouble getting the PLC to talk to Mach, I think mainly because I'm confused about terminology.  I have input FROM the PLC to Mach working but activating input auto-polling and setting it to "coils" (whatever that means :-))  In the PLC the inputs are called X and the address starts at hex 0000, so that is where I started the addressing in mach, seems to work fine, I told mach to look for Y home on port 0, pin 0 and if I activate the first input on the PLC the DRO lights up in Mach, everything is OK-Dokey.

The other way is where I am confused.  The PLC outputs are labeled Y, but I don't think that is what I want.  There is also a "thing" in the PLC called "C" which seem to be internal registers and I figured they would be what I need to write to, as they are the only other thing that seems to make sense.  Their Modbus addresses start at 4000 HEX.  If I enter 4000 hex into Mach it says that is an invalid address depending on where it is set.  I've tried what seems like every combo of Holding, Coils, Input, and Discrete in the test page and while some seem to write values into the PLC somewhere, they don;t seem to change the "C" state....

Does that make any sense :-)?  Thanks so much for all the help so-far, I appreciate it!
Dustin

25

General Mach Discussion / Re: Lathe turret, VB, PLC, MODBUS, Position

« on: November 16, 2009, 05:21:28 PM »

Hood, Thanks for the ladder snippets, I think that will be really helpful.  The big picture is becoming clearer...

Dustin

26

General Mach Discussion / Re: Lathe turret, VB, PLC, MODBUS, Position

« on: November 16, 2009, 05:18:29 PM »

Hood, Yeah, I am hoping rigidity is not an issue here, I think that would be a bad sign :-)

Hmm, Hopefully the home switches that are on there are good enough, they are the stock Takisawa ones so I am assuming they are fairly accurate, as long as I go at them with the same feedrate.

Dustin

27

General Mach Discussion / Re: Lathe turret, VB, PLC, MODBUS, Position

« on: November 16, 2009, 04:56:05 PM »

Thanks for the snippet Hood, I've found that on other posts and it is helpful.  Is SetModOutput a subroutine?  Or is that a command?  Where would I find info on the syntax of that (what the (9,1) means, etc)?  I am assuming it is toggling bit "9" in the PLC but I am fuzzy on how to address the PLC.

Dustin

28

General Mach Discussion / Re: Lathe turret, VB, PLC, MODBUS, Position

« on: November 16, 2009, 04:47:22 PM »

Hood, Thanks for the information, I need to look into the G54 and tool offsets a bit....  I guess I don't care if the home switches are accurate, I don;t think I would trust them for actual cutting anyway.  I was more thinking of a tool change reference point that would not change every time the machine was turned on.  I may still be slightly confused on the sequence of things, need to work with it a little more...

Thanks for the input,
Dustin

29

General Mach Discussion / Re: Lathe turret, VB, PLC, MODBUS, Position

« on: November 16, 2009, 04:43:50 PM »

Hi Peter, Hood,

Thanks Peter, I think it is clear, I need to spend some hours with it and get in further.  What I think you are saying is that I will need to use brains to allocate PLC addresses to Mach inputs, or something similar....

Hood, the CLICK I have is hooked up with a serial cable.  It is the DB 9 pin at the computer and a phone cord at the PLC.

Thank you,
Dustin

30

General Mach Discussion / Lathe turret, VB, PLC, MODBUS, Position

« on: November 16, 2009, 11:42:04 AM »

Hi all,

Thanks to everyone's help I am making good progress on the Takisawa turret.  I've got all the I-O wired and have a CLICK PLC wired up and communicating with MACH.  Also the power side is up and running, the motor relays are happy....  I have a few questions that maybe some folks could help with, any comments would be appreciated :-)

1-  I am having trouble with the idea of home switches and separate coordinate systems.  This may expose some ignorance on my part, but on my other machines I have no home switches and never change between coordinate systems, just zero the machine on the part and go.  Now I want the tool change to take place at the same spot all the time without having to zero off anything but the home switches, I think....  Anybody have a good explanation of this?

2- Another conceptual issue I am having is with communication between Mach and the PLC via VB scripts.  What it looks like others have done is write a ladder in the PLC and have Mach write a bit to the PLC to initiate that ladder program.  In other words Mach communicates with the PLC with single bits like I-O instead of sending some sort of commands?  I've read through a lot of posts on here and that seems like the idea but I wanted to see what folks think before assuming that is how it works. 

3-I think I want to avoid Brains for this one, is that a good idea?

4- When setting up the MODBUS, the dialogue box will not go away.  If you hit OK it just goes to the bottom left of the screen and stays there?  Is this abnormal?

OK, hope that's not too much stuff....  I will post some more images in show and tell one of these days, it is looking good.
Thanks so much,
Dustin