[HawkJET]

I don't know that I'm technically a newbie, I have been automating machinery for years. But I have not used Linux at all and have only recently become interested in EMC2.

I have a Bridgeport Boss 3 Series I mill. I have read the articles in Home Shop Machinist that go through the steps of removing the old controls and preparing the machine for new electronics. I am at the stage where I am cleaning all the goo and grime from the machine.

I have Compumotor Zeta Stepper Motor drivers and have 'exercised' the axes using a single axis indexer. This way I have confirmed that I know how to wire the motors and they work.

A computer has been ordered and should be here in about a week.

I am wondering about a Break Out Board and how much 'extra' controls I can get. If this works well, I have another application that will need as many as six or eight relays (or equivalent) controlled with M codes.

I have seen the ModIO products at Homann Designs and I am confused as to what ModIO is and how it is connected to the computer.

Can someone give me a primer on controlling I/O with EMC2, BOBs, etc?

Oh, and a little background on me... I am a mechanical engineer, mold maker, owner of a small machine shop and sometimes an electronics technician. I understand stepper motors well (I used to design and build them when I worked for Compumotor about 30 years ago). I am fairly well versed in things computer (Windoze though) and am just ignorant in the realm of Linux, EMC2 and I/O control.

I appreciate any help you may have!

[kanton]

HawkJET.

Which issues of Home Shop Machinist have the articles that you referred to?

Thanks.

[HawkJET]

Which issues of Home Shop Machinist have the articles that you referred to?

HSM Sep - Oct 2004
HSM Nov - Dec 2004
HSM Jan - Feb 2004

You can get pdf copies of them at:

http://www.mgertech.com/cnc/cncmachining.htm

Under "-BRIDGEPORT CNC RECLAIM"

[samco]

Hello. Don't be afraid!

Depends on what you are looking at doing.. Are you planning on just using a printer port? Or 2 or 4? There are many ready made Bobs that work great with emc. (I don't know of any as I make my own when needed) You will be limited by step speed and such. Do you know what step frequency you are going to require? Most computers running emc can do anywhere from 20-40khz+.

there are also quite a few inexpensive interfaces that give you a lot more abillity - like Pico, mesa and such. They move the step generation/ encoder counting to the hardware so emc's load is reduced.

http://wiki.linuxcnc.org/cgi-bin/emc...orted_Hardware

(both mesa and pico are very involved in emc)

Also - as far as modbus - emc seems to support it through the classic ladder interface - but I have not played with it.
http://www.linuxcnc.org/docs/2.3/htm...der.html#r1_10

Classic ladder is integrated within emc allowing you to do ladder logic also.
http://www.linuxcnc.org/docs/2.3/htm...ic_ladder.html

read read read
http://www.linuxcnc.org/docs/2.3/html/

Are you planning also to be able to rigid tap?

sam

[HawkJET]

Are you planning on just using a printer port? Or 2 or 4?

Probably two at the most. I don't know what is available from just one.

There are many ready made Bobs that work great with emc. (I don't know of any as I make my own when needed)

I'm interested in what you have done. Do you have any build threads for building BOBs? Do you opto isolate? Buffer? Use relays? I'm interested in what you have done.

You will be limited by step speed and such. Do you know what step frequency you are going to require? Most computers running emc can do anywhere from 20-40khz+.

I haven't yet experimented with step resolution so I don't know for sure. I suspect 20-40khz should do it.

there are also quite a few inexpensive interfaces that give you a lot more abillity - like Pico, mesa and such. They move the step generation/ encoder counting to the hardware so emc's load is reduced.

I quickly glanced at one of these. They look very cool! I'll be looking into it further.

Are you planning also to be able to rigid tap?

No.

[BobWarfield]

Here is an introduction to Breakout Boards:

http://www.cnccookbook.com/CCBreakoutBoards.htm

The main reason to use a ModIO is the limit on the number of I/O lines available with a parallel port. If you can get by with what's available, you won't need one. You can also use a 2nd parallel port to increase the number of lines.

Alternatively, you could use a motion controller, like a Smoothstepper. Not familiar with what EMC supports or doesn't there.

Cheers,

BW

[HawkJET]

The main reason to use a ModIO is the limit on the number of I/O lines available with a parallel port. If you can get by with what's available, you won't need one. You can also use a 2nd parallel port to increase the number of lines.

This is basically what I had assumed. I guess I don't have the 'big picture' with I/O in general. What do people generally use? Does a control console with keypad and various control switches take the I/O from the parallel port? Does a second parallel port add a significant amount of capability? Is a second parallel port easy to get? (it has been years since I had to deal with printer port cards and parallel has given way to USB....)

Alternatively, you could use a motion controller, like a Smoothstepper. Not familiar with what EMC supports or doesn't there.

I understand Mach3 is the only software to support SS.

[BobWarfield]

The real bottleneck is inputs. With parallel, you generally get 11 outputs and 5 inputs. You can go through those inputs in a hurry by the time you've got home/limit switches and now want a bunch of control panel functions.

Another approach is to use a key simulator. This is a little box you can plug between your keyboard and your control panel. It adds a bunch of inputs. You close and input and it sends a keycode as though you had typed it on the keyboard. So, for example, you could use a game controller joystick to simulate pressing the arrow keys to jog.

This works pretty well, so long as the key pulses don't come to close together. You could do a lot of pushbuttons on a panel that way, for example.

So your choices would be one or more of:

- Add an additional parallel port card, pick up 11 outputs and 5 more inputs. I'd probably only do this if I wanted to run my MPG this way.

- Add a key emulator. Probably the cheapest and easiest way to get a bunch of buttons going on a panel.

- Use a touch screen. That works great for buttons too!

- Use a ModIO. BTW, Homann makes a real cool pendant that works via ModIO that I am building for my mill.

- Use a motion controller that has a lot of inputs like a Smoothstepper.

The input problem is what got me to buy an original GRex. It's a nuisance. These days I am inclined to go with a touch panel and a ModIO-based pendant with an MPG. Easy to set up and lots of bang for the buck.

Cheers,

BW

[HawkJET]

So your choices would be one or more of:

- Add an additional parallel port card, pick up 11 outputs and 5 more inputs. I'd probably only do this if I wanted to run my MPG this way.

I may do this too.

- Add a key emulator. Probably the cheapest and easiest way to get a bunch of buttons going on a panel.

This looks like the way to go.

- Use a touch screen. That works great for buttons too!

This could be really cool also.

- Use a ModIO. BTW, Homann makes a real cool pendant that works via ModIO that I am building for my mill.

This would be my second choice - only if I can't get the I/O I need from other methods.

- Use a motion controller that has a lot of inputs like a Smoothstepper.

Since SmoothStepper isn't supported by EMC2, I found this from one of the links in samco's post (above):
http://pico-systems.com/univstep.html

It looks like it is similar to SS, but for EMC2.

[HawkJET]

Does anybody have experience with Pico Systems Universal Stepper Controller?

[jmelson]

Does anybody have experience with Pico Systems Universal Stepper Controller?

You will find a lot more users on the EMC-users group on sourceforge than here. (see
[email protected] ) I've sold 99 of them so far, so it is a bit of a niche product, but has been on the market since 2002, so it was the first external step generator for EMC (back before there WAS an EMC2.)

Jon

[HawkJET]

Enough of my questions have been answered that I got enough background to understand what I have been finding from web searches. Thanks to all.

I am now planning on making my own BreakOut Board. Although I know just enough electronics to be dangerous, this is a fairly simple task for my electronics skills. I'll post the progress.

[gschoep]

On my Bridgeport Boss 5 I found enough inputs and outputs for the machine functions using one parallel port and a CNC4PC C11G card. The card is built with opto-isolators to protect the pc and has 2 relays to control high(er) voltage/current stuff. It is made for Geckos and the card was easy to use, it is built well, and tried and tested. The one problem I had with the card is that it has a cheap DB-25 connector.

Note that I have a Automation direct VFD that can work with a serial port and an EMC driver (which I have not hooked up yet). And I did have to wire up the limit switches in series.

But what I was missing was buttonology. I was demoed a HAAS mill and liked all the buttons for doing stuff rather than using the mouse and clicking on little icons on the screen. Then I discovered the EMC keyboard shortcuts and another thread on this forum for hacking a keyboard to make a controller. I started my own thread in EMC for a DIY button panel. Using a keyboard controller is the easiest solution IMO to satisfy my need for buttons although you can only get the functions there are keyboard shortcuts for (I guess).

But building a breakout board would be a fun task. I would make one that takes a few OPTO 22 modules. They are better than relays but probably would probably still need a darlington driver/etc to power.

[HawkJET]

On my Bridgeport Boss 5 I found enough inputs and outputs for the machine functions using one parallel port and a CNC4PC C11G card.

This is good to know. I am looking past my Boss 3 and to other machinery that I expect to do, so I expect I'll need more outputs controlled.

I was demoed a HAAS mill and liked all the buttons for doing stuff rather than using the mouse and clicking on little icons on the screen.

I am with you on this.

Then I discovered the EMC keyboard shortcuts and another thread on this forum for hacking a keyboard to make a controller. I started my own thread in EMC for a DIY button panel. Using a keyboard controller is the easiest solution IMO to satisfy my need for buttons although you can only get the functions there are keyboard shortcuts for (I guess).

THANKS! I will check this out!

But building a breakout board would be a fun task.

As I get into it some more, I am learning more about what I need and can tailor the board for that.

[HawkJET]

I am just putting the finishing touches on the PC Board layout for my BreakOut Board and will probably be ordering them tomorrow. But first, since I haven't yet gotten deep into EMC2, I have another question.

I have made an assumption that I want to confirm. I have been going on the assumption that I can define the parallel port any way I want (within reason). That is to say, I can define which output is used for say, the X axis step signal (for instance).

In other words, if my BreakOut Board expects pin 1 to have the charge pump signal, I can easily define that in EMC2, right? Or if I want it to be on pin 14, I can define it that way. Similarly, I can define which outputs are designated for the X axis Step and Direction signals.

I searched through several postings and have come to the conclusion that my assumption is correct, but I don't yet understand all the EMC2 terminology to be absolutely sure.

So please correct me if I'm wrong.

THANKS!

[chester88]

Yes and No.
You can changed any input pin to any input signal (or output pin to any output signal)
but cannot dictate if individual pins are input or output.
There are only a few choices:
maximum input pins, (13 inputs 4 outputs)
maximum output pins (12 outputs 5 inputs)
or X mode.
X mode is limited to some parports with open collector pins allowing 9 inputs and 8 outputs
see manual:
http://www.linuxcnc.org/docs/2.3/html/hal_drivers.html

[HawkJET]

You can change any input pin to any input signal (or output pin to any output signal)
but cannot dictate if individual pins are input or output.

Okay, GREAT! This is what I understood (only you explained it so much more succinctly and specifically than when I attempted).

THANKS Chester!

[HawkJET]

Okay, I'm almost done with my BreakOut Board. I have been distracted by other jobs at work so it took longer to get this far than I expected.

I designed this with flexibility in mind. One layout can be used for different needs depending on jumpers and what components are populated. I can set it up to have as many as eight outputs controlling relays or solenoid valves and use either five or twelve volts. They can be actuated by the eight data lines of the parport or if three are used, they can be controlled by the control lines of the parport. This makes it possible to easily use more than one parport and configure the BreakOut Boards differently.

There is a watchdog circuit (called the "charge pump" in these forums) and five opto-coupled inputs for such things as limit / home switches.

A sister board is used to direct various circuits to the limit switches, Compumotor ZETA driver inputs and outputs, and also connections for LEDs to indicate relay / solenoid actuation.

The ZETA drivers have various fault and safety circuits as well as reset inputs (along with the standard step / direction inputs). These are accessed through a DB25 connector on the driver. The sister board has ribbon cable headers for the necessary cables and another header for the individual reset switches (that will be installed on a small board mounted on the console).

I chose the ZETA drivers because I found a source of a bunch of them for about $55 each. They have several modes of electronic damping and the added advantage that they operate on line voltage so they don't require a separate power supply. I was never really sold on making a power supply to power stepper drivers (which are essentially switching power supplies themselves). It seems redundant to me.

The disadvantage with the ZETA drives is they are four amps maximum. I have overcome this by changing the power MOSFETs and current sense resistors to increase the current capability as well as reduce the heat generated (CAUTION, do not try this at home). An interesting aside, after some experimenting, there doesn't seem to be an advantage in going above six amps. The resonance characteristics change with current and the combination of these motors and mechanics get a little worse at seven and eight amps.

Also, these stepper motors were designed and built long before anyone knew what microstepping was. They are therefore optimized for maximum "full step" torque. The result is they don't microstep well and have a little more resonance.

The pictures show the BreakOut Board and sister board. I haven't yet installed the header for the parport ribbon cable (it goes in the right front of the BreakOut Board) or the headers for the ribbon cables to the Zeta Drives (right side of sister board).

[HawkJET]

Thank you to everyone that contributed here! I have had a heck of a time finding answers to my basic EMC2 questions in other EMC2 resources I have been pointed to. Subsequently, I have switched and installed Mach3. It was simple and painless (as opposed to my experience with EMC2).

Therefore this thread is no longer appropriate in this forum. I will post the rest of this retrofit in the appropriate place. Again, thanks for all your help.

[gschoep]

Too bad you found info on EMC2 lacking. What basic questions did you not get answered?

In my case with steppers and geckos EMC2 setup was easy. I used the config wizard which has gecko configuration already entered. I selected Mill, 3 axis, setup each axis and had movement. Well after I setup the geckos enables correctly.

Since then I have added to my configuration as I add equipment. I added VFD control and also coolant. I do agree that someone should make a step by step guide to EMC2.