CamBam
News:
 
*
Welcome, Guest. Please login or register.
Did you miss your activation email?
August 15, 2018, 21:07:54 pm


Login with username, password and session length


Pages: [1]
  Print  
Author Topic: I had an interesting experience on the bed-router...  (Read 439 times)
lloydsp
CNC Jedi
*****
Offline Offline

Posts: 7586



View Profile
« on: July 23, 2018, 19:33:46 pm »

We had a stepper driver fail in the 'loaned' bed-router.  I called the company for advice.

They don't supply replacements for 'that old' of a machine, but recommended a Gecko drive that would work.

Only, when I looked, the drive they recommended used ground-referenced step and direction signals, instead of the +5V-referenced signals of the old board.

So I called them again, and suggested that the pulse directions would be wrong, and they said 'no'.  Just change the 'd#' value in the initialization file to change the directions.

So, I went to the manual (again!).  It says that the 'd#' value only changes the direction of travel of the axis, not the signal polarity.  Fortunately, they DO have a value ('e#') that changes the polarity from negative-going to positive-going.  It is assumed to be zero if not included in the config line.  And it's not, so I must add it.

It's AMAZING to me that tech-support folks don't know their own machines!  This thing is only 11 years old (I checked).  That's not 'out of support' for most companies, but certainly is for them, both in the parts support they provide, but also in 'product knowledge' of the machine.

That sort-of scares me.  I was IN tech support for many years (for medical computers).  I cannot imagine a primary tech-support contact not knowing the characteristics of a machine that young!

Lloyd
Logged

"Pyro for Fun and Profit for More Than Fifty Years"
Bob La Londe
CNC Jedi
*****
Offline Offline

Posts: 3303


^ 8.5 pounds on my own hand poured bait.


View Profile WWW
« Reply #1 on: July 23, 2018, 20:15:37 pm »

It's AMAZING to me that tech-support folks don't know their own machines!  This thing is only 11 years old (I checked).

Nope, but federal guidelines only mandate support for upto ten years in those industries where its required (except for recalls) at all.  Some companies even prohibit their franchisees from working on older equipment.  

Quote
That sort-of scares me.  I was IN tech support for many years (for medical computers).  I cannot imagine a primary tech-support contact not knowing the characteristics of a machine that young!

Lloyd

With the combination of tech advancements in CNC and the relatively high average employee turnover in any industry you should not be surprise at all.  


Ummmm….  Lloyd.  I thought you were going to have a complete duplicate set of everything for this machine.  
Logged

Getting started on CNC?  In or passing through my area?
If I have the time I'll be glad to show you a little in my shop. 

Some Stuff I Make with CamBam
http://www.CNCMOLDS.com
lloydsp
CNC Jedi
*****
Offline Offline

Posts: 7586



View Profile
« Reply #2 on: July 23, 2018, 20:25:23 pm »

"Ummmm….  Lloyd.  I thought you were going to have a complete duplicate set of everything for this machine."

----------------
Heh!  'Working on it', Bob! <grin>  I have almost everything, except for spare steppers and stepper drivers.  (actually, I have one spare stepper that will suit, but it's not a 'spare', it's 'mine'!)  I do have all the major failure nodes covered (spare vacuum blower, spare spindle, and spare bearings for the rails.)

So long as we're not 'down' for three or more business days, it's not an emergency -- YET!

But you're right.  I need to get onto ALL the replacements, just in case.  Maybe even a spare rail, or two!

Lloyd
Logged

"Pyro for Fun and Profit for More Than Fifty Years"
Dragonfly
CNC Jedi
*****
Offline Offline

Posts: 1979



View Profile
« Reply #3 on: July 24, 2018, 15:33:13 pm »

Quote
So, I went to the manual (again!).  It says that the 'd#' value only changes the direction of travel of the axis, not the signal polarity.  Fortunately, they DO have a value ('e#') that changes the polarity from negative-going to positive-going.  It is assumed to be zero if not included in the config line.  And it's not, so I must add it.
AFAIK direction is determined by level, not edge. Therefore d# parameter should work.
Falling or rising edge is important for the clock pulse input.  Most commercial drivers I've seen have their inputs electrically isolated by optocouplers. Each optocoupler's LED pins go to a two wire terminal which provides a very flexible wiring to the controller board - either with common ground or with common plus.
Logged

Before asking a question do some effort and walk through all menus and options in CamBam.  Maybe the answer is there. Please.
lloydsp
CNC Jedi
*****
Offline Offline

Posts: 7586



View Profile
« Reply #4 on: July 24, 2018, 16:13:42 pm »

Fly,
If one does not invert the pulses, the 'active' edges will be in the wrong places, and timing will be off (perhaps even 'fatally' off).

I've done quite a bit of stepper designs.  The relative timings of the active edges of the s & d pulses are critical. (not 'difficult', just important)

Just changing the axis direction does nothing for the pulse edge relationships.  But since this controller anticipated boards with either negative-going or positive-going pulses, there's a setting for inverting them.  The manufacturer of the interface board goes to fair lengths to explain the purposes there.

And, yeah... I'm real familiar with opto-isolators, both common cathode and common anode varieties.  I use them in almost all my designs.  Have-done since they were first available in the early '80s.

My 'problem' is that the vendor of the router didn't even know such a setting existed!

Lloyd
« Last Edit: July 24, 2018, 16:16:05 pm by lloydsp » Logged

"Pyro for Fun and Profit for More Than Fifty Years"
lloydsp
CNC Jedi
*****
Offline Offline

Posts: 7586



View Profile
« Reply #5 on: July 24, 2018, 16:45:45 pm »

I'm sorry, I shouldn't be so 'didactic' in my diatribes about electronics, but it was my living for almost 50 years.

SOME controls issue the step pulse close-enough to a change in the dir signal that any particular driver might end up with a timing violation if the active states are inverted.  My goal is to set the control and drives up the way the manufacturers intended, not just what 'might work'.

I've been working with robotics since late 1982, when I began a nationwide lecture tour, explaining to professional groups (physicians and medical business managers) all the amazing things coming in the new field of Personal Computing.

Me and my 'pet' robot, "Reginald Smythe-Byte" did a show together.  We had about a 50'-long table display of every "personal computing" device ever invented, from the abacus to mechanical adding machines, to calculators, and on to the TI-99A, Commodore-64 and the new IBM PC.  He was hidden under a skirted table, so the audience did not know of his presence.

I gave about a half-hour lecture on the great things coming, then we had a short comedy routine where he came out from under a table, interrupted my lecture, and explained the 'real art of personal computing' -- from a robot's perspective.  He danced, played music, talked, and told them just how terribly I treated him on airplane flights around the country.  It was fun!

Lloyd
« Last Edit: July 24, 2018, 16:53:40 pm by lloydsp » Logged

"Pyro for Fun and Profit for More Than Fifty Years"
Dragonfly
CNC Jedi
*****
Offline Offline

Posts: 1979



View Profile
« Reply #6 on: July 24, 2018, 20:13:23 pm »

I never put a shadow of a doubt over your knowledge, Lloyd.

But unless there are drivers whose direction is triggered by a short pulse instead of a steady logical level at the pin I do not understand what you are talking about. There is a configurable (usually) time interval to be held (to let the logic level settle) after a 'dir' change and before the first step pulse is sent. From then on it's either 0 or 1 at that pin until next change of direction.
Logged

Before asking a question do some effort and walk through all menus and options in CamBam.  Maybe the answer is there. Please.
lloydsp
CNC Jedi
*****
Offline Offline

Posts: 7586



View Profile
« Reply #7 on: July 24, 2018, 20:26:03 pm »

But Fly, if you don't KNOW the timing of the step pulse relative to the dir change, you don't know if you're violating the timing of any particular driver board.  My only point in the whole discourse was that there is a prescribed way to change the polarity of the signals to match +5-referenced or Ground-referenced s & d signals.  Given any scenario, I'd rather use the method the manufacturer of the control prescribed, than some 'half measure' that might or might not work.  I'm not going to take the time to drag out the oscilloscope and actually time the pulses.  The software vendor already provided for my scenario.

And my only 'complaint' was that the router vendor didn't even know that setting exists! <grin>

Lloyd
Logged

"Pyro for Fun and Profit for More Than Fifty Years"
lloydsp
CNC Jedi
*****
Offline Offline

Posts: 7586



View Profile
« Reply #8 on: July 25, 2018, 15:43:21 pm »

The part (Gecko board) came in this morning's mail.  Seven minutes later, the machine was running an exerciser!

Yahoo!

Lloyd
Logged

"Pyro for Fun and Profit for More Than Fifty Years"
Bubba
CNC Jedi
*****
Offline Offline

Posts: 2471



View Profile
« Reply #9 on: July 26, 2018, 00:47:01 am »

I know you could do it Grin Grin Grin. Good luck.
Logged

My 2¢
lloydsp
CNC Jedi
*****
Offline Offline

Posts: 7586



View Profile
« Reply #10 on: July 27, 2018, 17:59:29 pm »

Well... things are getting better!  Some of you may recall that I had a real 'run-in' with the ShopSabre folks a few months ago.  Because my machine is "obsolete", they didn't want to talk to me at all.

I raised heck, going all the way to the owner. 

Well, they must've 'flagged' my account, because now when I call, they greet me by name even before I identify myself.  They've even gone to extra lengths to make sure I had some proprietary spare parts quickly.

But most-amazing --  They've altered their web site to state on the front pages that they now "offer free technical support on any ShopSabre machine, no matter how old."  Neat!

I ordered a new X-axis ball nut.  They don't even use those THK nuts and screws on any machine newer than about 8 years.  But they had the part in-stock, and even taped a new grease brush (for the mounting block end) to the package.

Sometimes - and certainly not always - raising a little "hell" has beneficial results!   Grin

Lloyd
Logged

"Pyro for Fun and Profit for More Than Fifty Years"
lloydsp
CNC Jedi
*****
Offline Offline

Posts: 7586



View Profile
« Reply #11 on: July 28, 2018, 19:22:02 pm »

And... I just finished 775 (of 2025 pc) 5-shot fireworks plates for Sea World and Disney.  The machine ended up 'dead-on' at the end of a three 4x8 sheet run.  To be safe, I drilled an 'index hole' in each new sheet, so I could re-position to that place and check the head alignment.

That 'move it by hand' tip from the ShopSabre service rep is a good test.  It's all working again!  

I had to completely refurbish the X-axis (could not move it at all, with all my strength), but Z was already good, and I tested Y today, and it moves easily by 'hand' also, so we're good!

Lloyd
Logged

"Pyro for Fun and Profit for More Than Fifty Years"
Pages: [1]
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.21 | SMF © 2015, Simple Machines

Valid XHTML 1.0! Valid CSS! Dilber MC Theme by HarzeM
Page created in 0.141 seconds with 19 queries.

Copyright © 2018 HexRay Ltd. | Sitemap