View Full Version : PRT-Alpha with Tool Changer, Anyone??

06-12-2006, 07:14 PM
My company just recently purchased the Shopbot PRT-Alpha with an ATC 6 tool changer. I'm looking for anyone else who may have this Shopbot or has used this machine to share experiences and techniques with. Since we have had problems getting this machine to operate properly.

06-12-2006, 10:24 PM
What seems to be the problem?

06-12-2006, 10:39 PM

I just got one of these -- it's been up and running for the last week or so. It's the coolest thing since sliced bread. What kind of challenges are you having?

06-13-2006, 07:13 PM
I do agree, the machine is very nice. I am glad that others are having success with this equipment, yet we still have some quirks:

We have had a very bumpy road. The first hour the machine ran perfect, then things began to happen. Shopbot was at our location when everything began to go, and they too were stumped. We were unable to change a tool for 2 weeks before Shopbot could get back to us with a modified code. Since the modification we are able to change tools during a file but with some conflicts.

The machine randomly sets it's VS limits to only .05 when we execute a file. If we try to change the values the consule won't let us.

The z-offset from table always gets replaced with unknown values after we zero a new tool, causing us to repeatedly run the table zero-offset command after a new tool has been inserted and digitized or else the tool is .5" below the table.

We get "&newtool" values for the current tool in the tool variables after a tool change and randomly when the consule is newly opened or after running the find prox. switch command.??? No idea what is causing this ??? It appears randomly...but causes great problems if we don't continuously check the tool.ini file.

Also, the machine has twice forgot where the tool holders are and tries to change tools either in the middle of the table or above the tool holders, plunging the tools to their death.

We have found that any possible interference on the computer running the consule could cause random behavior...We were dropping tools routinly during tool changes when it would tap off the z-prox. switch. Since pulling our ArtCam dongle and turning off the wireless connection this has not happened.

06-13-2006, 11:36 PM
You have my sympathy. Wish I could help.


06-14-2006, 12:43 AM

Gerald D. posted a optimization guide that might help with the P.C. side of things. After reading that guide, I removed all non-shopbot programs from the computer that runs the Shopbot. Another workstation handles all of my design work. In fact, I've set up the perameters so that I can't even edit a file on the Shopbot control computer. At first that was a nuisance, but it has saved me a lot of grief because I know that the lastest version of every file is on the design computer.

Anyway, this is the link to the file (http://www.talkshopbot.com/forum/show.cgi?tpc=26&post=36005#POST36005) that Gerald found.

06-14-2006, 01:54 AM
IMHO, I think that I would only buy a toolchanger if the supplier took total responsibility and supplied the whole controller (PC). And for such a critical controller, I wouldn't load anything else on to it. A dedicated PC controller for this job should be possible at around $1000 - surely this makes economic sense?

06-14-2006, 04:35 AM

For my ATC installation I have a dedicated machine (laptop, in fact) for the machine controller. All the ArtCam, etc. is done on a separate machine.

As part of the setup we have some very specific startup proceedures for zeroing. I do know we had some challenges during the setup process as there is an amazing amount to these ATC systems (pneumatics, proximity sensors, z-zero and tool zeroing, etc.).

So far, though, everything is working fine. Chris Burns at ShopBot was a superstar in getting it all working.

I hope you're able to get things sorted out -- it's an amazing setup when it's all working. I love to watch it go through it's paces changing tools for each phase of a job.

Now, if I could only make the darn vacuum hold down less noisy.

06-14-2006, 07:43 AM
I have the latest version of the windows control software on my design PC and the VS is set at .5. It can be reset to any number but when I preview the part made in PartsWizard it changes back to .5. If I preview a part made in Vector it does not change back. This has not been a problem for me because it is only on the design PC, but it has prevented me from using this control software on the shop PC. My machine is a PRT96 with no tool changer. I've tried changing the unit values but that did not help.
This is the first time that I've seen this speed setting problem and thought that someone could use this info and maybe help Micheal.

06-14-2006, 10:21 AM
We found that you really don't want the control computer doing anything except that to avoid problems and we don't even have a tool changer! "Sterilizing" our computer and keeping Artcam on another solved alot of early teething problems we had.

Even the big boys have headaches. I know a tech that was just installing a new piece of "big iron". First run was fine, second run it changed the tool and then ripped the entire changer off the frame! In the end it was RF noise that was tracked down as the culprit. An expensive problem for the manf! Sometimes we all pound our heads on the wall with CNC equipment but it's good to know we're not alone....

06-14-2006, 10:26 PM
We are in the process of converting an old laptop into the main control computer. It will have nothing but the control software on it. It is upsetting that ShopBot did not know better than to setup our machine with a fully loaded brand new computer that would knowingly cause interference. I too agree that for the price of this unit ShopBot should provide a PC to run it, just like the big boys do. I will keep you posted on any further complications that may develop. Thanks all.

06-14-2006, 11:20 PM
But that wouldn't be cheaper than looking for your best bargain around and doing a clean and lean install... that's what SB would do.

Here's a start (http://www.talkshopbot.com/forum/show.cgi?tpc=26&post=36005#POST36005)...

06-15-2006, 06:35 AM
I think the "supply your own PC" philosophy comes from the days of when a SB cost $4000 and a PC cost $2000.

06-15-2006, 08:18 AM



06-15-2006, 10:03 AM
Finding a supplier of PC components that is reliable might be a big part of the problem. I still install about 100 computers a year in my role as a consultant. Sometimes it seems that as I walk out of the computer parts store with the latest and greatest set of parts, a truck pulls up with parts that are even faster and cheaper.

The problem is not that better parts are available every few weeks; the problem is that I can't buy replacement parts, or even warranty replacement parts 60 days after installing a new machine. I can just imagine the headache that Shopbot would have trying to maintain computers that have a shelf life slightly shorter than a carton of milk.

One of my largest competitors in the process control world tried to get around the problem of to rapid technilogical advance by designing and building their own PC, from the chips up. Almost as soon as their design was finalized, some of their chip suppliers stopped making chips.

Perhaps specifying a computer from DELL (for those of us living in the U.S.) and specifying that ONLY Windows XP-PRO and Shopbot software could be loaded onto that computer might be a way to eliminate part of the problem. DELL has a good warranty, reasonable prices, and reasonable performance. Although I don't personally own any DELL products, I do recommend them regularly.

06-15-2006, 10:35 AM
Mike, sure there is a problem that things change very quickly, but why must this problem be passed to the customer? The customers don't want to be co-developers or guineau pigs anymore, they want a system to work straight out of the box.

There is a big difference in the type of PC you supply at the rate of about 2 a week, and the type of PC needed for a ShopBot. Your customers insist on the latest, freshest, model. SB's can run on 2 yr-old models. SB could buy up huge job-lots at low prices and warehouse them for a long time - reliability is the only issue.

06-15-2006, 11:41 AM
Hi Guys

Well here is my 2 cents to that .
I have an IBM 1.6 gig pentium 4 netVista hooked up to my PRT alpha 512 MB memory and it is hooked up to the net via 120 ft cat5 cable in to the house .I am crusing the web with it and do designs on it . There is also other stuff like anti virus etc. running while I run the bot and I have not had any problems with it crashing or so while running a cutt file . I do not have any games installed on that mashine or any other computer that I do work on with the bot , and all my cutt files are stored in the house on a computer via the network .
So the point to this story is that get a good IBM computer not them cheap clones and things will work out .

06-15-2006, 11:45 AM
I wonder whether anyone would buy a computer from Shopbot, assuming that Shopbot had to include the costs associated with buying a bunch of computers, warehousing them and then hiring additional people to service and repair those computers?

When we look at the CNC world outside of Shopbot, it seems to be divided between a camp that wants a turn-key solution - at any price - and the do-it-yourself camp that would be happiest if all parts were available free-of-charge, shipping included.

Maybe Shopbot could partner with a computer manufacturer, where the computer manufacturer would install and maintain the computer and Shopbot could do what they've traditionally done.

In addition, for those that wanted to use their own computer, it wouldn't hurt if Shopbot required that EITHER the purchaser have a recommended computer configured in a recommended way with only recommended software loaded onto the computer OR that the purchaser sign a waiver absolving Shopbot of liability if things didn't work.

Too many people think that their old Ford Model T engine should work perfectly in their new Lincoln Town Car. I always tell my computer customers that they need to replace their computers every 18 months - at the minimum. They can recycle the computers into a non-essential task, but they shouldn't run mission-critical tasks on old computers. In my shop, I replace the control computer every year - Power Supply, Motherboard, CPU, RAM, and Hard Disk at a typical cost of $450. The old computer takes its place in a non-critical part of the business, and the oldest computer in the business is given to a neighbor kid so that he can learn Linux.

06-15-2006, 12:02 PM
Mike, a stance that a company like SB could take is If you want after-sales support, buy our "controller". If you want to look after yourself, you can use your own "computer".

I would think that a half-decent computer has only reached the bottom of the bathtub curve (http://en.wikipedia.org/wiki/Bathtub_curve) by 18 months. ie. that it is only beginning its most reliable phase of life?

06-15-2006, 12:38 PM
Your idea of only offering support if a complete package is purchased might just work.

The 18 month figure is one that I use for mission-critical computers in an office environment. Some of those computers contain data that is worth hundreds of thousands of dollars. The time to reload that data (assuming that a customer that is too lazy to blow the dust out of a computer is going to follow a reliable back-up schedule), might cost the company $2,000 per hour. Looking at repair records showed that all computers either failed within the first week, while burning in, or after 18 months. Almost always the problem was a failed CPU fan (costing $5.00), but not one of my customers could be counted on to replace CPU fans every six months.

In a shop environment, with lots of MDF dust, excessive heat (compared to an office environment), and sloppy maintenence (come on now, how many of us blew the dust out of our computers before starting things up this morning?), replacing a computer's internals every 18 months is just insurance.

06-15-2006, 01:30 PM
I don't think that SB will ever be able to say "sorry, you are on your own" but at least they will know which calls to give the highest priority, and customers will have a clearer idea of where they stand.

Start every morning with a blow???

06-15-2006, 09:03 PM

We do not have a cheap computer running our Shopbot ATC controler. Our computer is brand new with Windows XP, 3.00 Ghz dual processors and 1GB dual Memory. The computer rocks, one thought is that the ShopBot computer can't handle the power. I have no idea what is inside the ShopBot computer? But if it was like putting a Shelby engine plugged into a Civic, it would not work well.

06-15-2006, 10:13 PM
I'm not at all familiar with the ATC controller, but from what you've just posted, it seems that the ATC requires its own computer. Is that right? So, basically, you have two computers controlling your Shopbot; one for the Shopbot itself and one for the ATC?

Has the Dual processor computer been tested to verify that it is compatible with the ATC? As strange as it seems, some programs will not run with a dual CPU system. (It's a constant problem in my other life as a computer programmer/supplier. Everyone wants the fastest possible machine, but sometimes that fire-breathing beast just isn't the best machine for the job.)

06-15-2006, 10:52 PM
I think I may have confused you. The Shopbot comes with a "computer" module and that is what I refer to as the Shopbot computer. I believe this just drives the servos and such. As for our "dual" CPU computer that currently runs Artcam Pro and the Shopbot control consule from which we execute files.

06-15-2006, 11:03 PM
I guess that I'm easy to confuse. Assuming that your Shopbot with ATC basically has an enhanced controller box that connects to a PC via a USB cable, I would encourage you to use two separate computers. A high powered workstation where you design your parts with Artcam Pro and a separate computer that ONLY runs the Shopbot SB3 software (and any software that may be additional that is required to control the automatic tool changer). Other than the possibility that programs on the workstation may interfere with the Shopbot, the main advantage of having more than one computer is that you can continue to design and simulate while the Shopbot is cutting.

06-16-2006, 12:24 AM
ArtCAM dongle are known to interfere with SB3 as it look every few minutes for it. I had the same problem... until I noticed. I remember that if I kept ArtCAM Insignia shut down while running the tool, it wouldn't create the problem... but I do think it's a good idea to have SB3 on it's own PC all alone. Anyway, you can't design while the machine run so if your business is just loaded enough, you'll just need another PC.

I don't have an ATC but do dream of it every once and a while... my idea of those devices is that it's just a matter of a routine and some input/output signals (from the controller) and that's it no need for any other PC?! Oh and compressed air right?

06-16-2006, 08:24 AM
I don't post here much but one reason I'm interested in Shopbot is because they don't stick you with the frills. Thanks SB for letting this DIY'er install my own computer. All CNC's have probs including 3/4 mil jobs I got the tee-shirt.

06-22-2006, 07:29 PM
M. Healey

So, How's it going now?


06-24-2006, 07:56 PM

We received new files from Shopbot this week and things have improved. We can now do tool changes and execute large files, yet we still encounter random errors.

We do have a completely dedicated computer that is now running the Shopbot. We still think that there may be a communication problem regarding the speed of a USB-2 port and the Shopbot control box. The random errors seem like the Shopbot is skipping lines in the code i.e. we did a tool change from tool 1 to tool 3 and it released tool 1 and then just sat there and thought it already had tool 3 in the spindle. The Shopbot never traveled to get the tool, but it registered in the .ini files that it had the new tool "tool 3".

Any ideas?

06-24-2006, 11:47 PM

I no longer have my PRT but had continual problems with the router not completing a job. During a routing function it would stop. The screen showed the gantry moving. It would scroll through all the code but nothing was hapening. I never figured it out. Hope you find a solution soon.



06-25-2006, 10:26 PM
We still have a problem with the communication being lost between our Shopbot and the PC. This usually appears when we open the Shopbot 3 software. It tries to locate the tool and then a yellow screen displays the communication was lost. Attempts to reconnect to the original port fail, and we are using the correctly assigned COM port. The only solution I found for this error was restarting the PC.

06-26-2006, 01:04 AM
Mike, have you explored getting an "approved" PC from SB?

06-26-2006, 03:34 AM

Did you set up the Shopbot on one USB port with the IO software and then at some point disconnect and plug into a different USB port?

I had a problem similar to yours and plugging back into the original USB port solved the dropped connection problem.

I have found that USB ports can be a little flakey, USB memory sticks that work on one USB port refuse to work on an other for no apparent reason.

In addition, make sure your motherboard firmware is up to date. There have been instances where Auto Assign for the COM ports does not work as it should. Same goes for any USB drivers.

06-26-2006, 08:35 AM
Gerald, We have not explored that option yet.

Dick, the updates are a good point and I will look into them. I did install the Software driver supplied by Shopbot and I have the USB cable plugged into the original port it was installed on. Plus, the Port assigned to it is the same that Shopbot points too.

06-26-2006, 11:52 AM
Good Morning Gentlemen,

I'm going to jump in here to make sure this post is focused and clear.

For several weeks now, Mike Healy and I have been diligently working to get the PRT Alpha ATC machine up and running.

Just as a point of reference, we are experienced router users (Onsrud 5'x12' for cabinet production) Epilog Laser, CorelDraw, Archicad, Autocad and Mastercam veterans...but admittedly Artcam and Shopbot newbies.

The ATC machine was set up on our site by a ShopBot technician.

We purchased a new computer and dedicated it to the Bot. It's an Intel Motherboard, Intel Processor, top end PC with 1 gig of ram.) The router did not tool change properly both during and after the factory setup.

The technician advised that the code would be revised soon to eliminate the tool changing errors.

Time to pause in this posting to put this communication on a level playing field: Mike and I purchased a ShopBot because of the tremendous user-group bank of knowledge that all of you have complied over the last several years. We could have purchased a more sophisticated machine, but chose not to because we knew that the learning curve to make carvings, 4 axis turnings and complicated parts was a steep one... and we wanted the support of this group to help us (in the future, we want to share, too) with the knowledge required to turn out first class finished products. Up to this point, we've hesitated to post... wanting ShopBot to figure this thing out on their own, but Mike felt that the group might have some suggestions. Clearly, we want to get off on a good footing with the ShopBot folks and want the use of this forum in a positive and proactive manner. We've all seen where emotion and opinion blurs facts and data! OK, back to the reason for this post!

At the moment, after running a half a dozen carving files over the weekend with the new ATC code, at appears as though most of the ATC errors are fixed. The remaining error on the ATC side is "Tool Not In Holder" and that occurs just after the former tool has been dropped off. The spindle moves upward a few inches in the Z above the former tool, freezes and the error message appears. (Upon closer examination of the the ATC software, the machine "Thinks" it has the new tool) The workaround for this is to erase all lines of code run up to the point of the error, C3 the machine and rerun the remaining code. It should be noted that this error occurs sporadically on tool changes... not always.

Ok, here's the punch-line. I believe that all of the errors we've gotten fall into 2 categories:

1) Machine Code

2) Hardware communication and handshaking between the ShopBot Controller and our computer.

I now believe (admittedly I'm guessing) that the majority of our remaining communication problems are hardware-handshaking occurring between the computer and ShopBot controller. We've installed all updates as advised by ShopBot.

I'm aware of the fact that there have been numerous posts on this site regarding communication. USB in particular. We understand that there have been documented situations where simultaneous computer operations on the same machine have affected router operation.

Just to be on the safe side... and eliminate any chance that our computer was the culprit, we purchased another brand new computer. This time, we stripped the new computer of all software except SB3. The computer is NOT on a lan. It's NOT on the net.

We continue to experience communication problems with the new computer/ShopBot. The USB port gets "disabled" The yellow Com not enabled SB3 screen appears. Software seems to at times skip over machine ATC move/tool commands.

Both of the computers we've used have fast busses and use USB 2.0 technology. Might the ShopBot controller be incompatible with USB 2.0? Should we try an old, slower USB 1.0 machine? Is there a way to skip the USB altogether? We're happy to use a serial or a parallel connection.

How can one perform a data communication test? How can one "ping" the ShopBot controller and verify that the packets of information are properly received on the SB controller end? We need to put some "facts and data" into this guessing game and make sure that we don't have any hardware issues as we're beating our software heads against the wall.

Thanks to everyone so far as they've helped us troubleshoot these issues. Mike and I appreciate the help of all of you.

Jim Hoffman

06-26-2006, 12:24 PM

It looks like you've followed a systematic approach to identifying the problem. USB has been an issue, particularly improper grounding of the USB connector. I couldn't find any photos on the forum that showed a grounding clip that many of us use. Bill Palumbo mentions Jim Z's 'fix' in his post of July 02, 2005 under the 'Timer Overrun' thread. You can search for it by using "USB pigtail" using the AND option. (Sorry, but the link isn't working for me this morning.) Hopefully, the description will help you to build the clip. (I use it on my Alpha - and it did stop most of the communcation failure errors; however, I also replaced the USB to Serial Bridge that Shopbot supplied with another brand purchased at BestBuy for $40.)

06-26-2006, 01:30 PM
Jim Zaccaro posted that USB grounding fix over here:

But Paco captured the pics over here:

06-27-2006, 12:10 AM

I'm glad you got back on the subject. I can discuss the computer issue with anyone that would like to offline. I think we have enough opinions on them and who should handle supplying them.

Jim and I have been in contact the last few days and we seem to have the software issues worked out, but we are continuing to test it at our shop for any possible situations that may not have been adressed to date. There was one major bug that took care of most of the issues and another smaller one that we are still working on that happens when the ATC is not allowed to finish its cycle by interrupting it.

The grounding solution is a good one to try but doesn't work for all controllers that are having issues communicating with a computer. Sometimes a different Serial-USB adapter is necessary as Mike pointed out and using the USB port that the adapter was set up on can be critical to it working correctly. We have sent Jim another type of adapter to try and will suggest the ground clip if that doesn't take care of the comm breaks.

Again, thanks to those that got this tread back on track and for all the suggests. In order to effectively address the subject of the thread at hand there needs to be a certain amount of focus maintained. We value the information sharing that happens on this forum and hope that it helps everyone.

06-28-2006, 07:59 AM
Other ATC owners,

Is there a specific routine you follow for starting-up your machine, both at power up and before running a file?

So far we discovered that it is helpful to always run a "bounce off prox." command to zero the x,y axises, or we get problems during a tool change where travel in the z exceeds the limits.

07-20-2006, 07:21 PM

Keeping on track, what's the status of Michael's tool changer. Is it up and running and how did you solve the problem?

Is there a way to attach a vacuum pick-up to the unit?

08-02-2006, 11:46 PM
I guess the answer is no.