Messages

1111

Modbus / Re: multiple serial modbus slaves

« on: December 20, 2011, 12:57:04 PM »

Success Peter - Thanks again for your help.

JFYI this was so I can run my THC alongside any other modbus devices such as pendants etc.

Cheers

Ian

1112

Modbus / Re: multiple serial modbus slaves

« on: December 20, 2011, 06:37:37 AM »

Thanks Peter

I'll take a look and get back

Cheers

Ian

1113

Modbus / Re: multiple serial modbus slaves

« on: December 20, 2011, 06:07:55 AM »

Hi Peter

Just tried checking "Modbus Plugin Supported" on the ports n pins dialog and I see now how you access the CFG# entries. I HAD been using vanilla Modbus WITHOUT plugin support which uses a different setup dialog which doesn't mention CFG# numbers. I hadn't checked plugin support because I'd assumed that referred to a 3rd party plugin i.e. the one you've said is broken.

AAAAGGGHHHH! All is clear now - I'll give it a go.

Many thanks for your help.

Ian

1114

Modbus / Re: multiple serial modbus slaves

« on: December 20, 2011, 05:10:22 AM »

Hi Peter - thanks for your reply and the docs.

Now I understand the hardware side of things but I'm still not sure about the software side because...

I have a plugin that was not written by me that allowed for multiple ModIOs to be set up. Unfortunately, something in Mach3 has changed that has broken the plugin when setting up more than one ModIO.

That said, it is not necessary to use the plugin, as Mach3 has its "Brains" that allow you to communicate with the ModIOs.

I've used Brains quite a bit with Modbus but I still don't see anywhere in the Brains interface to address a particular slave. When I first started playing with modbus brains I thought it was the (IMHO) rather poorly named field "Enter Modbus address to use" but that's actually the register number - not the slave address. I see the CFG# field but doesn't that refer to a configuration line in the plugin interface? I can see that would allow you to address multiple slaves via different CFG#'s but that's via the plugin - which you say is a) broken and b) you don't need.

Still confused...

Ian

1115

General Mach Discussion / Re: trying to improve motor speed

« on: December 20, 2011, 04:01:02 AM »

Hi Sheepdog

By the way Stirling, you lost the bet.  They're not little round things, they are Nema 23 construction.  

Just for the fun of it... I'm not paying up yet  

First I never mentioned little. Also, all Nema 23 means is the dimensions of the mounting flange and holes. You can get (old style) round can and (modern style) square can BOTH in Nema23 and all other nema sizes too. So are they round or sqaure section "cans"? - double or quits.

Ian

PS

You also have to realize that these motors are just turning and not driving anything, so there is no friction to drag the speed down

You can't "drag the speed down" of a stepper motor. It either moves at commanded speed or it stalls. There's no in between.

1116

General Mach Discussion / Re: Mach3 and THC Problem

« on: December 18, 2011, 05:26:17 AM »

Pleased it's all ok now and thanks for reporting back.

As you have sheetcam, I should say I editied the post a little for the puposes of my example code. You may want to look in function OnInit and change these vars to suit your system.

refdistance = 500 * scale
switchoffset = -0.08

Cheers

Ian

1117

FAQs / MOVED: Tangential arcs

« on: December 17, 2011, 12:42:07 PM »

This topic has been moved to General Mach Discussion.

http://www.machsupport.com/forum/index.php?topic=20251.0

1118

General Mach Discussion / Re: Tangential arcs

« on: December 17, 2011, 11:48:52 AM »

As you know - CV is a compromise. With Exact Stop you get the exact path you programmed but with a stop at "segment" junctions. With CV you get Mach's attempt at a constant feedrate (never sure why it's called CV as technically a constant velocity can only ever be a straight line - any whatever - I digress ). If you're happy with the "out of the box" CV for any particular job - then cool - it works very well. However there are times when you might want to tweak the way CV behaves.

So, when Mach needs to do (say) a corner, with CV it will cut (round) that corner as much as IT likes to keep as close to the commanded feedrate as it can. BUT - suppose you want to tighten that "rounding" a bit. There are a couple of ways you can do it and ONE is to set the CV Feedrate button ON. Then it effectively says to Mach - don't worry too much about keeping the feedrate up - I'm prepared to let you drop it to - whatever's in the CV Feedrate DRO. If you go with the default value in the DRO i.e. 1 you're saying to Mach - you can drop the feedrate to 1unit/min if you like. Which is about the same as turning OFF CV - i.e. just about exact stop.

So, instead of turning CV Feedrate OFF - which says "go as fast as you can round corners etc." you could set (say) 75% of your commanded feedrate in there. Now Mach will allow the blended feedrate to drop to 75% of the commanded feedrate if it needs to. It'll tighten your corners a tad but at the expense of dropping the feedrate a bit more than it would have done.

Hope that makes sense.

BTW - not sure why it's turning itself ON when you set it off - but it doesn't do that here. Checkout the <CVFeedOn> tag value in your XML after you've turned it off and closed Mach. It should be 0. If it is and when you restart Mach it's back on again then something's turning it on again - a macro maybe? guessing...

Ian

PS - I'm going to move this to general - FAQ's is not really the place for this.

1119

General Mach Discussion / Re: trying to improve motor speed

« on: December 17, 2011, 10:52:31 AM »

Voltage rating is 5.3v @ 1 amp.

This tells us straight away that these motors are not going to be good. 5.3V-rated is high and 1Amp-rated is low. As Gerry says - typically you need 15..20 * rated Voltage so you'd be looking at approx 80V..106V power supply to get the "best" out of them. Unlikely you'll get a driver for that voltage. Certainly your driver rated at 8..18V is not even close to the town the ballpark's in.

Even if you reverse the maths - to get anything close to speed/torque from your system the motors would have to have an inductance of 0.2mH for a 15V supply - and they'd be the first I'd have seen if they had anything close to that.

Couple this with the screws your using that demand a VERY high speed from your motors to get good linear speed and I'm afraid you're system is just all wrong. I'm betting your motors have a round can too rather than a square one?

I'm with Gerry - no way your speed problems have anything to do with software.

Ian

1120

General Mach Discussion / Re: first dirive

« on: December 17, 2011, 08:31:32 AM »

user banned