Grex-G100

[in2steam]

I have been watching and reading about the GREX controlers and I am wondering a couple of things, and I should preface I understand its in development yet. And that not many people are running it yet, and these features may not be implemented or even planned.

#1 Is the controler capable of running in a network, thats to say can it be on a router, while doing live moves via MDI. Also is there or is there not USB support, either from Mach or the GREX
#2 can the controller run indenpendant of the host computer once a program is loaded, this is a assuming I have the proper inputs to rewind and start the cycle. So I can say shut down the computer, or unplug it from the network, or shutdown the Mach controller.
#3 If the above is true can Mach pickup midstream what the GREX is doing and interupt the cycle for say tool wear comp/offsets. Lets say the machine is running along and I re int Mach can it talk to the GREX and figure out what its doing on what program?
#4 Similiar to the aobve will the E-stop feature work from the host computer should the #2 happen then #3.
#5 Can the Mach support more then one GREX on a network. Say a lathe at one IP then a mill at anohter IP.
#6 I assume that this is available for the GREX but does it need mach running to use an MPG for offline movement, so the GREX has total control, without mach running, a JOG mode so to speak.
I am not an computer guru but I do have a basic understaning of ehternet and what the grex and mach can do.

chris

[JerryFlyGuy]

Chris, I'll see if I can't answer some of your questions for you..

Originally Posted by in2steam #1 Is the controler capable of running in a network, thats to say can it be on a router, while doing live moves via MDI. Also is there or is there not USB support, either from Mach or the GREX

Yes I run mine on a network which has two pc's as well as other equipment [wireless router, a pc connected via wireless, DSL router I'm adding a wireless bridge and a switch as well as a new PC just for games] on it and it doesn't seem to bother it [so far]. The USB part of the Grex seem's to be there mainly for use by independant programers and people who want to use it as a PLC [my understanding]

Originally Posted by in2steam #2 can the controller run indenpendant of the host computer once a program is loaded, this is a assuming I have the proper inputs to rewind and start the cycle. So I can say shut down the computer, or unplug it from the network, or shutdown the Mach controller.

Yes, Mariss designed it so that it could be used as a PLC of sorts to control systems which are self contained and repetative. This may require understanding the internal's of a Grex. This is in its documentation, however 99.9999% of it is over my head.

Originally Posted by in2steam #3 If the above is true can Mach pickup midstream what the GREX is doing and interupt the cycle for say tool wear comp/offsets. Lets say the machine is running along and I re int Mach can it talk to the GREX and figure out what its doing on what program?

Not sure, but at a guess I'd say no, either Mach is in control of the Grex, or its not, one or the other..

Originally Posted by in2steam #4 Similiar to the aobve will the E-stop feature work from the host computer should the #2 happen then #3.

The E-stop could be hard wired to the G100 which would give that ability to control it, it could be programed to stop on its own if certain perameter's weren't met, this ties w/ the answers to Q2 &3 as well.

Originally Posted by in2steam #5 Can the Mach support more then one GREX on a network. Say a lathe at one IP then a mill at anohter IP.

Yes and no, yes it could control several G100's w/ different address's and w/ differnt machine setup's but not at the same time, you'd need 1 pc for each g100 if they are run all at the same time, or 1 pc and only 1 Grex is run at a time. I think they could all be on the same network but..

Originally Posted by in2steam #6 I assume that this is available for the GREX but does it need mach running to use an MPG for offline movement, so the GREX has total control, without mach running, a JOG mode so to speak.

No the MPG would interface through Mach 3, which would tell the G100 to move the motors. Not to say that it couldn't be made to operate the G100 directly, but you'd have to program it to do that. [again see the documentation]

I'm sure others will jump in as well but for now, I hope that helps you understand some of its abilities. The G100 documentation is a free download from geckodrives website.. take a boo and see if its something you can work with.

Best
Jerry

[in2steam]

Thanks Jerry I have read some of the docs, and I agree most of its far out of the realm of what I know and I can program PLCs. Altough I have read up on jack rabbit computers so I may have to dust off that stuff. This would be a good case for a graphical user interface like most PLC's have.

I figured out the first two after I posted, the person that can be a programer and have good documentation that a non programer can understand will be a millionare.


In reference to #3 my big question is can mach hotswap with the grex, My ideal setup is to be running 2 machines on longer runs, of many parts, but I would have to use the computer for other things along with Mach. It would be a investment either way (new computer or extra Grex). This of course is a long term plan right now I am still in the discover phase of figuring out what I want to do with CNC. It would be nice to be running both at the same time, esp doing a setup one while the other is running on its own.

#4 really relates to #3 but I understand that the GREX has primary control of the machine. So yes a estop should be wired to the grex and, if properly done should be hard wired to the drives also, a true e stop(according to OSHA) would cut power to the grex and the drives but many don't do this. I was wondering if the feature would work from mach on a hotswap or would it automatically do that if mach reconnected. So for example I have the machine running along shooting out parts and I reconnect mach via the GREX, now mach is in e-stop would the machine now goto into e-stop also.

#5 has pretty much been answered from the above

#6 from what I gather this would be possible, my main concern would be using the machine if the computer was not avaliable at that moment, say it was running another machine, or not present. I would still like to be able to jog the machine to do some basic things. I would have to have a jog switch and MPG or switches. It would be a matter of programing from what I can see.

chris

[ger21]

#2) No, Mach can not load a program into the G100 and let it run on it's own. Mach has control over it at all times. The G100 can be run on it's own, but completely independant of Mach3, and you'd have to program it to do it.

So,
#3 - No
#4 - No

#5) I thought I read a long time ago that this might be possible at some time, but I'm pretty sure it's not possible now.

#6 You should be able to do some programming to do this, like you say. However, you can by a PC for half the price of a G100. Get a dedicated PC for each machine, it'll be much simpler.

[in2steam]

Thanks for the reply

So the grex is slaved to mach at this time? That does not completely make sense to me since the grex has such a low overhead how can it go faster??
does mach shoot lines(sorta like MDI) at the grex instead of a pulse command? I was under the impression that it was command via text.

chris

[ger21]

I couldn't tell you how Mach controls it. The G100 was not designed specifically to work with Mach3. Mach3 just happens to have a plugin to use it, and is the easiest way to use it at this time, imo. The Mach3 G100 plugin source code is available, if you want to see how it works (and you're a programmer so you can understand it). I'm pretty sure it's far more complicated than just sending text.

However, I think that programming the G100 by itself is basically some simple text commands, somewhat similar to g-code, although I think you need to have accel and velocity info in there as well. Still somewhat complicated, I think. All the documentation is on the Geckodrive Yahoo group as well as Geckos website.

[JerryFlyGuy]

Mach controls the G100 by sending message packets about 4 times a second. Each packet is a movement or series of movement commands which the G100 completes and then reports its completion back to mach, which sends more packets... etc..

The G100 will run one of two ways, either its under mach's control, or its not.. and there is no midway cross over for this [that I'm aware of] It's kinda like your printer, either the printer is connected to the PC and the PC operates as a print server, or you have a dedicated print server which the PC dump's to. There's no middle ground.

The reason that mach doesn't just dump everything to the G100 is because of control, in a machine tool environment, control is everything and is directly related to safety. You could argue that the G100 could report back to Mach what it's doing and what line its on etc.. but in the end you'd basically have the same system you do now, just in reverse. Having the G100 run on its own doing a repetative task is fine, when you get to machine tool operations and each is different, you need direct control w/ a proper interface.. which is the PC running Mach3.

Can you clarify the low overhead and need for speed comment? Currently the G100 will output 4Mhz of step & dir pulses per axis [thats 4 MILLION pulses on 12 pin's per second..] and will read an encoder count of 1Mhz as well. Thats pretty darn fast in my estimation... where would you like to see an improvement?

Jerry

[in2steam]

Originally Posted by JerryFlyGuy Mach controls the G100 by sending message packets about 4 times a second. Each packet is a movement or series of movement commands which the G100 completes and then reports its completion back to mach, which sends more packets... etc.. The G100 will run one of two ways, either its under mach's control, or its not.. and there is no midway cross over for this [that I'm aware of] It's kinda like your printer, either the printer is connected to the PC and the PC operates as a print server, or you have a dedicated print server which the PC dump's to. There's no middle ground. The reason that mach doesn't just dump everything to the G100 is because of control, in a machine tool environment, control is everything and is directly related to safety. You could argue that the G100 could report back to Mach what it's doing and what line its on etc.. but in the end you'd basically have the same system you do now, just in reverse. Having the G100 run on its own doing a repetative task is fine, when you get to machine tool operations and each is different, you need direct control w/ a proper interface.. which is the PC running Mach3. Can you clarify the low overhead and need for speed comment? Currently the G100 will output 4Mhz of step & dir pulses per axis [thats 4 MILLION pulses on 12 pin's per second..] and will read an encoder count of 1Mhz as well. Thats pretty darn fast in my estimation... where would you like to see an improvement? Jerry

Jerry
I should have stated that better, I was trying to say that the GREX supposedly moves quicker and better then a standard BOB setup, it would lead me to believe that its capable of more then the computer can through at it(in the more conventional pulse step setup). Low overhead means just that(the grex is not doing alot in comparison to the computer), the grex is far more capable of controling a cnc machine then the software of mach via a parallel port. This is of course assuming that there is not some sort of monster program in the memory with 1000s of lines to go through. So my assumption was that the GREX had code in its memory already, and from what you are saying it sorta does, but not a whole program only bits of it and as its completed it moves on to the next chunk after a status report.

I geuess what I am looking at is that I have a proven program, which I "could" dump into the memory/program of a grex and let it run with just simple inputs. Basicaly switches for program/online,estop, cycle start, feed hold, etc tied to the GREX. These should be from my estimation easy to do, the dumping of a whole program into the GREX is were I was gray/not sure. I am not great at modbus but I think I could do this with a PLC, I am not sure that it would be as fast as a computer with a BOB, and most likely not as fast as a GREX but would more then likely suit my needs.

At this point I am only planning on steppers, so acclerations are not as hard as servos. I am the type of person that likes to do it right and not go back and do it 4 times. I am in maintenance and I have to fix what people engineer all the time and its annoying, I would have rather done it myself in alot of cases. The servos question would most likely pop into your head, I also believe in simplicty when ever possible~KISS~ and I am not as concerned about speed and power.

BTW thank you for the replies.
chris

[JerryFlyGuy]

I don't think the Grex has enough memory to hold large programs [10mb rings a bell] how are you going to know where you are in your programing w/out some type of interface other than buttons?

I'm a bit confused, at first you want to use it because its faster better, then you say your not concerned about speed or acceleration... I'm missing something..

I would think for a simple system which has no concerns for acceleration and torque that you'd be more interested in a standard BOB. The Grex really only shines for two reason's, #1 it has more I/o and options in that regard [spindle control etc] and it can utilize a fantastic resolution [4Mhz step rate]

[well three if you can use the self program function of the unit and run it as an independant control]

If neither of these two are important, then faster, better, whatever aren't really a concern, as far as KISS, there isn't anything simpler than a $300PC and a $120BOB, the Grex is $400 PLUS the price of a PC, that or you program it yourself, now for each new function you want it to do, your going to have to write a new program.. in my books.. thats not KISS.

Some of these questions would probably be better address to Mariss on the Yahoo Geckodrive weblist. Mariss is the "Father" of the Grex and if he doesn't have the answer's.. ain't no-body got the answers

Best

Jerry

[in2steam]

Originally Posted by JerryFlyGuy I don't think the Grex has enough memory to hold large programs [10mb rings a bell] how are you going to know where you are in your programing w/out some type of interface other than buttons? I'm a bit confused, at first you want to use it because its faster better, then you say your not concerned about speed or acceleration... I'm missing something.. I would think for a simple system which has no concerns for acceleration and torque that you'd be more interested in a standard BOB. The Grex really only shines for two reason's, #1 it has more I/o and options in that regard [spindle control etc] and it can utilize a fantastic resolution [4Mhz step rate] [well three if you can use the self program function of the unit and run it as an independant control] If neither of these two are important, then faster, better, whatever aren't really a concern, as far as KISS, there isn't anything simpler than a $300PC and a $120BOB, the Grex is $400 PLUS the price of a PC, that or you program it yourself, now for each new function you want it to do, your going to have to write a new program.. in my books.. thats not KISS. Some of these questions would probably be better address to Mariss on the Yahoo Geckodrive weblist. Mariss is the "Father" of the Grex and if he doesn't have the answer's.. ain't no-body got the answers Best Jerry

In the end you are more then likely right, I was hopeful that I could do it that way. I have not put a ton of thought into this yet, I was more trying to get some basic answers first, see what it can do etc. I will more then likely stick my current plan and use a BOB and a PLC or just a PLC.

thanks for puttin me in the right direction.

Chris

[Richards]

You can download the GeckoMotion pdf file from GeckoDrive to get an understanding of the low-level commands that are available to control the G100 without using Mach or any other program. It is extremely powerful even though it is low level. By low level, I mean that in order to program a tool path to follow an arc, you would have to send the appropriate straight line segments to the G100. But, if you're willing to do your homework, you can probably make the G100 do whatever you would be able to do with Mach (not that I'm knocking Mach software. I have a license for it and am anxiously waiting the final few touches to be added that will allow me to use the G100 with Mach).

The G100 and G101 have interested me to the point that I have one of each on my test bench.

[in2steam]

I know that they work without mach, and they seem to do it very well from what I have read. My intentions were to be able to feed a program into the GREX and let it run on its own without Mach in a supervisor postion. Since this seems unlikely without mach or programing the GREX to do its moves internally, I have decided when I get to that point I will just use a PLC that I already own.
I have few obstacles to overcome, #1 I need to get the lathe I wanted to do this on, #2 convert it to CNC, #3 Add and then program the PLC into is controls. I am still only doing a very few parts at this point, maybe 4 this year so far, they are all simple moves, linear, one tool change. I wanted to free up the Mach for my mill, so I could do more complex moves on that and use CAD/CAM and not have another computer, I have limited space and amperage avaliable so every little bit counts.

I should probably state that I have not gotten the newest mill which I am converting to CNC, an X3, and still doing all my work manually on borrowed machines, so I have ALOT of work ahead of me before I get to this point. Thinking in advance I would rather intergrate now then try and retro fit and cause more problems. The reason I asked about 2 GREX's is my intentions are to outfit the mill with some sort of tool change for dedicated runs for the typical reasons, again saving me to program a plc and using modbus. In the end it will still be cheaper and easier for ME to do it with a PLC I am familiar with, others I cannot comment. Maybe by the time I get to point of install the controls I might still get it, but considering the PLC I use is nearly as fast, and about 3/4 the price outfitted similiar I willl stick with that(about 1/4 the price for the mill).
chris