Messages

131

General Mach Discussion / Re: How to use stepper motors with position encoders

« on: August 12, 2015, 01:02:09 PM »

What kind of encoders, and what do you want to do with the position encoders?

If you're referring to the newer closed loop stepper/driver combination (i.e. Leadshine ES/Easy Servo series), then you just run them like a standard servo, using the fault/out of position outputs to stop motion/e-stop if there's a problem.

But if you're referring to closing the loop outwith the stepper driver (i.e. by adding encoders to a standard stepper motor), then with Mach 3 alone, all you could use them for is to display the actual position. Mach 3 has not got the capability to use them to close the loop. If you wanted to run closed loop with such motors/encoders, you would have to use an external motion controller that's capable of closing the loop (only one I'm personally aware of is the Dynomotion KFlop, but I'm sure there are others)

132

General Mach Discussion / Re: Mach3 Calibration with GearBox

« on: August 12, 2015, 12:56:25 PM »

You've not provided enough information, as we need to know either your Z screw pitch, or Z axis tooth spacing/pitch (you say pinion, so I'm going to assume you're using a rack?)

If you want to understand how to calculate the steps, have a read of this article - http://www.uk-cnc.com/2015/07/25/calculating-steps/

133

Show"N"Tell ( Your Machines) / Re: My Shizouka AN-S

« on: August 12, 2015, 12:44:43 PM »

Looking good.

How are you controlling the toolchanger?
Interfacing to and using the original control boards, or have you replaced the boards with additional Inputs/Outputs(relays) via the Galil/Mach?

I'm in the process of removing all the original control boards from my Shizouka, so I can move the control to the KFlop.
I've been working my way through the Summit manual/wiring diagrams to work out the actual tool cycles (I'm very impressed by how it's managed with minimal components!), and I think I've got it figured out, but would be interested to hear what sequence you're using.

134

Building or Buying a Wood routing table.. Beginnners guide.. / Re: Future upgrade of first build

« on: August 09, 2015, 04:40:30 PM »

CNC4You sells pretty decent stuff at good prices.

The ballscrews, being C7, aren't the best of quality, however they're more than good enough for most machines. They'll certainly be a major improvement over any non-ball type screw. C7 will make them a rolled screw with not the best of tolerances, but perfectly good enough unless you're striving for the ultimate in precision.
The stepper motors are well recommended, so no issues there, and the drivers are pretty generic but good quality.

135

General Mach Discussion / Re: boxford vmc190 conversion costs

« on: July 29, 2015, 06:16:59 PM »

It depends how competent you are with electronics.
I'm fairly sure you could re-use the original stepper drives by connecting them to a new break out board (BOB), for about £30 plus time to trace the required terminals/pins. Spindle control may be more involved and add more expense (I can't remember what kind of spindle are on these)

However, I'd personally suggest some more modern stepper drives, as modern drives would give you a good performance increase, and eliminate having to work out the existing stepper driver connections. Good quality drives can be had for around £40 each (some form of Leadshine are the recommended go to brand in the UK), and combine them with a BOB (less £30 for something basic).

That's if you want to run from a parallel port. If you want to use and external motion controller, there are a few options starting from about £40 upwards.

Also, you may need to allow for various consumables (wire/connectors), replacing anything that may be broken, and an actual computer if you don't already have one.
It's certainly doable for sub £50 if you have the electronic ability and only want basic performance, if you want better performance and less hassle probably around £150, but I'd probably budget for £300 to allow for any additional purchase that may spring up along the way and adding an external motion controller.

136

General Mach Discussion / Re: IF you wanted to UPGRADE to MACH4 ??

« on: July 22, 2015, 07:50:49 AM »

I personally think the biggest issue with Mach4 is communication. No body seems to know the current status, or where the various plugins are at.

If you only ever post here on the forum, you only ever see the problems being discussed with very little if any input from any of the Mach guys. At least over the Yahoo group you get some input from Brian. Running my own business I understand you have to prioritise where time is spent, but I'm sure they could at least spare an hour or two a week to post on here and provide some idea of what's been going in the background.
Even just a thread only Mach guys can post in to act like an informal blog, and give a brief roundup of what's been happening over the past week.

As for the plugins, it would be good if details were a bit easier to find. USS/ESS I keep hearing about, but unless you dig into their forum, details don't really exist. As has been mentioned CS do have a plugin, but all the public details point to it being well out of date. The only person who seems to be keeping on top of things is Steve@PMDX giving updates when required.

137

General Mach Discussion / Re: Arduino Gurus ??

« on: May 08, 2015, 01:52:29 PM »

It has given me an idea, but my free time for the next couple months is pretty limited, and I'm trying to avoid new projects until I get some existing ones finished!

As for posting elsewhere, I suspect the main groups that it would interest, would be Mach and LinuxCNC users. Arduino  have their own motion controller libraries but it won't have the ability to handle a hand controller due to lack of resources, and I'm not sure what other PC based machine controllers have the ability to handle customised serial interfaced inputs.

138

General Mach Discussion / Re: Arduino Gurus ??

« on: May 08, 2015, 01:30:28 PM »

I'd think you'd be looking at a custom PCB to keep within size constraints. Standard Arduino's are pretty large, although some of the smaller mini boards could probably be squeezed in, although you do lose some of the pins depending on the exact model.

Provided you're not in a rush, custom PCBs from China aren't that expensive, although assembling them can be a bit time consuming, as I very much doubt you'd be able to justify full production run costs/quantities.

139

General Mach Discussion / Re: Arduino Gurus ??

« on: May 08, 2015, 12:52:20 PM »

I've kind of strayed away from Arduino's, however I have used them quite a bit.

It's probably doable with one of the newer ARM based arduinos, as I'd think you'd be pushing an Uno to manage all the above, and Mega's are not the cheapest of things to use (I built a fairly complex system using a Mega, but the cost of the AVR chip means it'll remain as a proto, and someday I'll probably port it over to something ARM based).

RS485 just needs a serial port along with a suitable driver chip.
If you opt for a serial based LCD display, it'll cost a couple bucks more, but greatly simplify code/chip resources.
4x4 matrix is easy, but you'll need 8 pins to use the Arduino library.
Rotary encoders should be realtively easy, as the ARM chips should handle the interrupts reasonably well (Uno only has 2, and Mega 3or4 Interrupt pins IIRC and some are shared, hence my suggestion for ARM as it's got far better interrupt configuration although I've never checked to see what Arduino has implemented). Off course you could go fro polling the pins instead of interrupts, it all depends on if you're happy to miss the odd pulse.
LEDS are pretty easy. Can either go for direct connected if you have enough pins left, or go for a hex output chip (they have a proper name, but my mind has gone blank!)

Ardiuno libraries are available for all of the above, but you'd need to check that they're compatible with the ARM based boards.

140

General Mach Discussion / Re: E-Stop: Latching or Momentary?

« on: May 01, 2015, 06:51:25 PM »

Depending on where you are in the world, from a safety regulation point, all e-stops should be of a non-self resetting type i.e. a twist to reset type.

I know in Europe there is also a requirement for all user buttons to work on low voltage (defined as 48V or less), and a reset must be required after any e-stop i.e. the system can't start working again just by resetting the e-stop button.

Now the regs are over, for the size of machine you're using, I'd apply some common sense, as it will be capable of doing plenty damage if things go wrong.
Personally, I'd recommend you use latching E-stop buttons, that control the power supply(s), with Mach being notified of an E-stop having occurred. I would never recommend that you rely on any computer to handle the E-stop, as if the computer happens to be the cause the of the problem, then you run the risk of the E-stop being ignored. By killing the power supplies, even if the computer is doing something it shouldn't, the machine will stop, and remain stopped until you reset the E-stop button.