USB Comm Speed

[gerald_martin]

I've been absorbing Gary's interesting black box control computer and that sure looks like a nice build. Gary, don't be surprised if others follow your lead.

I did buy a Link, and I need to get that set up and going. Gary, thanks for displaying the USB schematic, that makes sense.

My control computer is a Dell Optiplex 320 P4 3.0 with 2 GB RAM. (I know, that's not great...) Can I use this machine safely with 77% comm efficiency? I haven't had many comm errors, unless I'm pushing the limits. For instance, a JX 96 command will run at 25 inches per sec no problem. But try cutting a circle (CC, diameter 48, air cutting at say 8" per sec) and the machine will stall with comm errors.

I'm presently using the white USB hub connected to the Dell motherboard. Would I be better off to install, say, an Iogear USB 2.0 card? To use USB 3.0 the motherboard must support that speed, correct?

Or is it time to build a dedicated Bot controller? I could maybe be convinced. But the Dell is not that old, boots fast, and seems dependable yet.

Opinions, fellow Shopbotters?

Gerald

[Gary Campbell]

Gerald, first and foremost, the ShopBot controller card is NOT a USB 3.0 device. So, in my case, all ports are still operating under USB 2.0 specs. No USB 3.0 compatible board will work above the level of 2.0 on a 2.0 device

77% should be plenty, but then YOU say its not. Not to say your model is included, but there are known issues with Dell's USB architecture and SB use. Similar to Belkin hubs. Some work, but known issues none the less.

2 gigs of RAM is not enough to nest larger jobs with the link. Others have reported 25 to 30 minutes to nest jobs that I can in seconds. You do the math.

For many years, and especially prior to release of SB ver 3.6, any ol box would do just fine. Machines now can cut or jog at 10 times the speed of a few years back, therefore they will require close to 10 times the com rate.

WIth SB3 and the SB link open, not connected and not moving, their RAM total is 400meg. This win 7 box with them uses 2.58 gig idleing.

To put it short and not so sweet, you have a $20K to $40K CNC machine. Why would you ever want to SAVE a few hundred bucks on the computer that controls it?

One last thing.... I build my own so that I can select the components I want, by their specs. I dont do it to save money. Only way to save money is to buy cheaper parts.

[gerald_martin]

Gary, this is good information.

So, installing a PCI USB card does or does not eliminate the Dell usb architecture issues?

Also, are you running XP Pro on the control computer? 32 bit? Then max memory allocated is about 3.25 GB, right?

I'm ready to build a new "control console cabinet" for the bot. My original idea was to make a nearly dust free, fan ventilated enclosure for the current PC. Maybe I should follow your lead instead and build a new computer.

Thanks,

Gerald

[Gary Campbell]

Gerald...

"So, installing a PCI USB card does or does not eliminate the Dell usb architecture issues?"

In most cases adding the PCI card makes the Dell PC usable. Notice I did not say eliminate. Notice I said PC. One of the reasons I personally dont consider laptops is that we cant add a IO card, if needed.

"Also, are you running XP Pro on the control computer? 32 bit? Then max memory allocated is about 3.25 GB, right?"

Yes, XP pro, 32 bit. Ram shows on the system as 3GB

One of the reasons I like the rack case is that they have the air flow designed into the box. Some even are filtered. Few are cheap.

Dont forget, that as important (to me) as the components in the control computer are, there is an equal importance to stripping it of all background processes and applications. Known to Windows as services. DO NOT disable these services using msconfig (as I used to). Use Windows "services". I use Black Vipers "bare bones" settings and then remove a few more, as I also disable all that I can (network, etc) in BIOS

This is an unscientific guess, but about 80%+ of comm problems are due to the control computer, 10% to connections, bad parts (hubs or cables, etc) and the rest to static and/or ground loops. Most created by the installation.