Odd behavior...

[geneb]

I upgraded my system to the latest release of the SB control software for my PRT Alpha last week. I've been working on removing the plenum I burned up last Saturday and I recently noticed something odd with how the machine was working.

When I start the cutting file it "bangs" at each point where the spindle changes direction - that is to say instead of slowing down it just stops hard and then changes direction.

However, if I click the stop button and then resume the job, it will now decelerate into the direction changes like it used to. Any idea what is going on?

Here's the top snippet of the file I'm running - it basically pockets away the whole 4x8 plenum. :)

TR,15000

'Starting spindle
SO,1,1
PAUSE,2

MS,2.5,0.5

JZ,0.920000
J2,0.000000,0.000000
J3,0.000000,0.000000,0.920000
M3,0.000000,0.000000,0.000000

Thanks all!

g.

[ken_rychlik]

I don't know if this could be it, but did you upgrade the firmware with the new SB3?

[geneb]

I seem to recall it did do a firmware upgrade during the install. I distinctly recall checking within the software and it said no update was needed - this tells me that it probably did do the update.

tnx.

g.

[ken_rychlik]

The firmware update has nothing to do with the install.

After the install click on utilities and on the bottom is the firmware update button.

You have to cycle the controller off and back on after it is looking to do the update.

If you don't see the progress bars during the update, it didn't happen. It will tell you it did, but it didn't. :rolleyes:

[geneb]

I mentioned in my previous post that the host software said no update was required.

g.

[ken_rychlik]

I know that you mentioned it. I don't think you understand what I am suggesting. If you don't want to try it, thats fine with me.

If you call shopbot they can walk you through it. It will be one of the first things they suggest you do.

[ken_rychlik]

If it did the upgrade, you would have seen this screen.

[geneb]

I'm unable to understand the logic behind the suggestion though. :)

I did upgrade the firmware the last time I knew there was an update prior to 3.6.32 - and reading the release notes just now, the software didn't specifically mention an update was required. The "update" that I thought was going on was in fact a USB driver install.

I cannot see how a firmware update (that would simply re-layer the same version to the controller) would address this issue.

g.

[myxpykalix]

I don't think updating the firmware will address the problem you are havng but you do have to update the firmware with any new install.

Having siad that, I do recall myself when i upgraded (a version or 2 ago) that i noticed the same thing where it used to ramp down when coming to a end of a cut and although it doesn't "bang" like you say yours is, I noticed that it stops "harder" then it used to.

I have not had an issue where it fixes itself after a pause like yours though. What feeds/speeds are you running things?

[geneb]

As the snippet shows, 2.5in/sec @ 15k. :D

I don't suppose it's an _actual_ *BANG*, but it IS a lot harder than I'm used to seeing (which is the short-distance deceleration I get have the stop/resume).

g.

[srwtlc]

Check your ramp values (VR), it sounds like you may have some settings that are causing the abrupt acceleration/deceleration.

What Ken is getting at about the "Firmware" is the control box firmware and not the software on the computer. If your control box needs a firmware update, it can be done by going to "Utilities" then "Install Control Box Firmware". I think you have been there though from your last post. Not so sure that that would be the problem either as the machine shouldn't "get connected" then.

Check the ramp values next. Compare them with what should be for your machine. Should be something like this for the defaults... .4, .4, .4, .4, .4, .4, .4, .4, .2, .2, 100, .10, 65

[gerryv]

I was having some unexpected things happen in my learning curve. I got some good advise to try a firmware update. Even though I had received no warning window either, I thought, what the heck, they know a lot more than me so 30 seconds later my problem was gone. I guess I don't put all my faith in software never making a mistake - it's written by humans (chuckle).

[geneb]

Just for giggles I did a firmware update. The version number of the firmware as reported by the control software was the same before and after the update, so that is definitely not the issue.

It may indeed be the ramp values - I'll check those for sure when I get home this evening. Thanks for the suggestion Scott. Are those defaults for a PRT Alpha? If not, could someone point me to the correct defaults?

FYI, the definition of boring is watching a 'bot grind away a 4x8 vacuum plenum with a 1/2" bit. Even at 7.5in/sec it takes a looong time. :)

g.

[srwtlc]

Gene,

Yes, they were copied from the default setup file found in C:\Program Files\ShopBot\ShopBot 3\Settings\Settings for Older ShopBots\PRT_alpha Tools.

Start from there and adjust to your liking and also try some of the suggestions/guidelines found here....

http://www.shopbotblog.com/index.php/2008/03/a-ramping-the-vr-command-and-how-to-tune-your-tool-for-maximum-performance/

Scott

[geneb]

Scott, the VR values I've got match the defaults.

I also need to mention that it's no longer automatically starting the VFD controller interface software like it used to. TR commands are ignored unless I start it by hand (via Tools -> RPM Controller)

tnx.

g.

[srwtlc]

Gene,

Not sure where to go next on the accel/decel issue.

On the VFD interface, once you've started it with the tools menu, click on "RPM" in the little window and a fill-in sheet will come up. Check to see that you have a "1" in the "Start When SB3 Starts" line.

Scott

[dlcw]

Gene,

I once had a situation where Walle would come up to a turn and start crawling so slow that I was afraid that the material would start burning.

Somewhere, somehow Walle (my PRS Alpha) had a brain-fart and dorked up all my ramp values. I reset the ramp values and life was good again.

Might want to do a reset of the ramps and see if the problem fixes itself. Then adjust the ramps back to what you want them at.

[geneb]

During the cutting of my new vacuum plenum, I haven't noticed the hard cornering any longer. I'm not sure what the deal is, but I'm not going to complain about it. If it happens again, I'll take video of it and let the SB folks know about it.

Thnx all!

g.