LOSING COM PORT

[frank134]

I have been having a problem with losing my com port connection. I have a new 2009 PRSAlpha. I found a bad usb cable that was bad two week ago. Replace and thing were fine till today. First part I cut was great. place the second part on the table and just about in the middle of the program the bot went nuts. So the first thing I did was check the com port. It could find it. So I shut everything and rebooted. Did a speed test set 79.9 . so I started the program again and it did the same thing, the bit dig into the board. set the com port and again it couldn't find it. the computer new, bot new and the cable are new. I have reloaded the software check all the ground and cable. everything seem to be fine. Did I miss something to check.

[phd1658]

Static electricity/grounding issues?

[fredtoo]

I'm having comm problems too and wonder if one should use an active or passive USB extension cable?

[steve4460]

Take a thin wire and hook it upi to the ground part of the USB cable where it goes in to the control box and then run it back to the computer and connect it directly to the metal case of the computer .That fixed it for me when I had that issue .
Bot on

[dlcw]

I ended up having to replace the USB hub that Shopbot sent because it was causing my system to lock up. I went to a powered hub from Radio Shack but through experimentation I found I had to loose the power cord. It is now passive/unpowered. I have not had a problem since.

I also have a 14 gauge ground wire from the controller box to the chassis of my computer. Every part on the Shopbot is grounded to a central point and that point is taken to the ground terminal inside the controller box with a 12 gauge wire. The VFD is included in all this grounded.

I have good comm speeds and no longer have lost comm problems. The important thing to remember is that every moving part of the bot needs to be grounded - spindle/router, z car, y-axis, gantry, airdrill, etc. Without this total grounding, you are going to have problems with this machine.

I spent 23 years in the Coast Guard in the radio communications field (electronics repair technician) and the most chased after problem involved proper grounding. In the Shopbot world it is no different. Grounding is king.

Don
www.dlwoodworks.com (http://www.dlwoodworks.com)

[bbrozo]

Frank -

I'm shootin' from the hip here but if other's suggestions don't help, check http://www.shopbottools.com/techposts.htm, the section titled "9/24/06 by Ted Hall, ShopBot Tools RE: Connection Issues, Communication Problems". It's dated but has some good suggestions in it such as trying to reproduce the problem with the part file using an air cut and other equipment switched off.

Bill

[fredtoo]

This is the USB hub that SB provided: http://www.amazon.com/IOGear-4-Port-USB-GUH285-Black/dp/B001GUY5PY/ref=sr_1_19?ie=UTF8&s=electronics&qid=1266720215&s r=8-19 Not very good reviews

Of interest: when I've plugged the hub into my pc with the SB and spindle control boxes plugged into the hub a speed test indicates about 70.4%. If I eliminate the hub and plug both control box USB plugs directly into my pc a speed test indicates only about 43%.

[frank134]

Bill thank that was some good info. The only thing I haven't grounded is the usb cable. I am also going to get a small ups for the computer. I figture it might be a noise problem and did a good ground on everything with #8 copper to a busbar right under the control cabinet to the building, water line, service and last 3 3/4 x 10 ground rod.

[ssflyer]

Another thing that I found helped with a lot of issues - use a UPS on the computer. Batteries are the best power filters there are...

[frank134]

ok grounded everything. problem is still their. I keep losing the usb port. I know now it the computer.I try and older one I have and it work fine. Why would this brand new hp computer keep losing the bot usb port? the only thing on it it the shopbot program.

[russ]

Frank
I have an HP as well and have had issues from day one. Finally I bought an usb pci card and bypassed all of the inter-graded usb ports. Solved some of my issues but still have to connect to a hub. Now it seems to connect at a speed between 82-84 would like to be higher but that's workable.

[frank134]

spoke to soon. the older computer did the same thing. I guess I call shopbot in the morning. I give up.

[ricky_spearman]

I would try reinstalling some new usb drivers and get them up to date- it worked for me and that's all it was... nothing wrong with the machine -- Thanks to Frank at Shop bot....