Jog speed slowly getting slower... Huh?

[jeffreymcgrew]

Hey everyone. Been having a strange issue with our Jog Speed.

After we upgraded to a 4G controller, we were running our PRT at about 8 Inches per second on the jog, and having a grand time doing it.

Then we started getting the occasional stall, so we went down to 6 IPS and no problems for over two years.

Now, we just moved to a new shop, and we're getting occasional stalling at 6 IPS, and have gone down to 4.

I just redid the USB connection, and we're getting a nice, happy 87% now.

I've got a new, better power supply on it's way to me now. Ours is the old style PRT one, we'll soon have the newer PRS style one that can supply a lot more voltages to the steppers.

We've got everything grounded, with a nice ground to the steel frame of our building (but not to the common ground that the shopbot is wired to... is that important?).

The computer it's hooked up to is old. Not OLD old, but not that new either. P4 1Ghz Shuttle with 512 megs ram and a dedicated USB 2.0 card running through a hub for the enhanced port.

The increased stalling happened when we moved. Shortly after we moved, I think we updated the Controller software as well.

The new power supply shows up tomorrow, and I'll report back if it makes a change, but I would love love love to hear what else I should look at!

[Gary Campbell]

Jeffrey...
Add RAM

[ken_rychlik]

Unhook the motors and make sure everything is free rolling and square also. I had issues with my prs a few weeks ago and the gantry was not running free and square. i changed that and am back to running fast again.

Kenneth

[jeffreymcgrew]

Kenneth, I'm certain it's running smooth and clear, we just redid it.

Looking at adding RAM or maybe getting a whole new computer to put on there instead.

Anything else to look into? We're (of course) in the middle of a huge production push, and so I'd like to get our machine running as fast as possible!

[ken_rychlik]

I would say 2 gig minumum on the ram.

I thought mine was dialed in too until I unhooked the motors and rolled it by itself. One motor was basically fighting the other one.

Another thing I did was to take the gearcase off and pack some fresh grease in it. They were pretty dry from the factory.

Kenneth

[jeffreymcgrew]

Swapped in the newer-style 64v power supply, and we're jogging again at faster speeds. Yay!

We've pushed the old one hard, and it's been hot here, so I'm not surprised that it might have been causing the problem if it was slowly failing. I'll try to test it now that it's out of the controller if I have a free moment. Which means I'll get to it sometime next year most likely.

The newer style power supply has much better heatsinks on it too, so that in combo with the added fans we put into our case has it running very well so far. I remember when we first installed our 4G upgrade we'd get some issues when it got really hot out until we put in more fans into our controller case.

The power supply in combo with the Spindle and it's like we just got a new machine! However if things keep up the way they have been, we might need to swap up to an alpha to keep up!

[ken_rychlik]

After you run most of a day how hot are your motors getting with the bigger power supply?

You have me thinking about one now. lol

Kenneth

[jeffreymcgrew]

Didn't notice much of a difference. It's the power supply they put into the PRS, and it was in the later model PRT4G's. Ours was an older PRT, with the older 44v power supply.

The swap wasn't hard, but it is wall voltage and there is real danger in wiring something wrong in it (or you) going boom. It did require me to pretty much disassemble most of my old controller box. With the included schematics and a call to Shopbot I was able to get it in there without much trouble. And so far it's been good, but we push our PRT4G at it's limits most of the time so your milage may vary as to what you'd get out of it.

It's a stop-gap for us until we can afford to swap to an Alpha setup. Finally getting to where our workload might need it to keep up!

[ken_rychlik]

Thanks for the extra info.

Mine is a prs set at 52 volts and I was considering alpha also. I don't want to fight all the lost comm issues though. They seem to be worse with alpha from everything I've read here.

64 volts may be enough to get me by for a while.

Kenneth

[wberminio]

Had to swap out my Shopbot Computer (older PC 1G RAM XP)
I'm temporarily using my laptop (VISTA 4 G RAM )

Wow! Jogging from 3-4 in/sec to 6-8 in/sec no lost steps
Interestingly my transmission efficiency went from 87.5% down to 77%

Will see what happens with my new computer (win7 6G Ram)!


Your right Gary-"Add Ram"

Thanks