[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