Now, because you’ve gotten the board parallel to the X axis, the short (Y) edge is square to the X. You can move the carriage down to one end of the sheet and move the tip of the cutter along the short edge, moving the YZ Car. By observing the tip of the cutter as it moves along the short edge, you will be able to evaluate the square of the two axes on the tool.
Relaxed Alignment vs Powered AlignmentSquare is maintained on your tool by the 2, X-axis motors. The motors always move absolutely identically and they keep the X Car perfectly square when they are powered. The X Car itself, when not locked into position by the motors, is not designed to be capable of maintaining the alignment on its own. In the ideal world, the X axis will always ‘relax’ into a square position when powered off. But in practice, because the motors and gearboxes have a lot of friction, there may not be an exact, relaxed alignment position of the carriage and it will be possible to push one or the other end out of alignment. To get the tool square with the motors installed and engaged, start powered off, push the carriage back and forth a few times from the center and let it take as natural an alignment position as possible. Do this over the edge of your sheet so you can check square. Your relaxed alignment should be within about 1/8” of square across the table, as indicated by your cutter tip moving up and down the Y edge of the sheet. If you are further out of alignment than this, visit the “Making Adjustment” section below. Once the alignment is close and continuing with the motors powered off, push the one end of the car slightly to bring the whole gantry into perfect square with the board. You may need to lock one or both ends with clamps to manage this. Then, when you’ve got it square, turn the power to on to the Control Box, and if a PRSalpha, hit the Reset Button. The motors will power on and lock into position. Your tool is now square in X and Y, and it will remain square whenever it moves until the power is removed. Setting the End Stops So Your Tool Will Always be SquareBecause the X car is not intended to be able to physically maintain alignment when the power is off, after a period of being powered down you cannot be certain that in a busy shop the carriage has not been bumped a little out of square. So, you need a system for guaranteeing square each time you restart the tool. The mechanical End Stops do this for you. First let’s get the End Stops installed perfectly square at the bottom end of your tool. Do this by driving the X Car, using the KeyPad mode in the software, down to the bottom (X = 0) end of the tool. Slow down when you get close, and move the car to the point that each wheel bearing is about ¼” from the end of the rail. Slide the End Stop on Each side into the Table Side and up against the motor pinion. Then back the X Car off and tighten the End Stops securely into place. You now have End Stops that you can use to square the car. When you turn the tool off, park the X Car near the bottom end of the tool. Whenever you are ready to power up again, first gently/slowly pull the X car into the stops to square it, and then turn the power on. The car is square and will stay square for the duration of your work session. Cutting Forces (a question that may arise)
Making an Adjustment for Wheel Bearing Alignment or SquareThe X Car of your PRS ShopBot is the primary structural component of the tool. We build the X Car in a precision fixture that exactly spaces the wheel bearings and that assures a perfectly square and true gantry. After assembly, we handle and pack the gantry in a way that is intended to assure it stays square. However, we recognize that in the process of trucking the tool to your location, considerable stresses can be put on it and that a small amount of on-site adjustment could be necessary. The following is a general procedure for dealing with a wheel bearing that rides high or to one side, or with finding that in its relaxed condition the X Car is more than the 1/8” out of square (see above for discussion of relaxed vs powered alignment). First, make sure that if you are experiencing a problem with the ‘ride’ of one of the wheel bearings or with square, you have ruled out problems with the rails not being parallel. Make sure the rails are level. Then test the ride of the wheel bearings up and down the rails and re-measure the spacing of the rails. If the rail spacing is right, and you have the same ‘ride’ problem up and down the axis, then proceed to make the following adjustment. Use clamps to lock the X Car in position. This will take 4 clamps, one at the front and back of each End Plate of the car. If the car is square, the clamps will keep it locked square.
The Gussets under the beam are designed to define the orientation and position of the end plates. You’ll loosen them to correct the orientation. There are 4 bolts on the Gusset at the End Plate and 6 bolts on under the beam. Make sure all bolts are loose. The ones under the beam sometimes bind after you loosen one of the others, so keep going around and make sure all are free, but try not to let them come out of the t-nuts in the beam. For the situation where you are adjusting a wheel: with Gussets loose, if the wheel bearing has not dropped onto the rail, give the End Plate a downward tap with a rubber mallet to get the wheel bearing into position. For the situation where you are adjusting square: with Gussets loose, use the clamps to move one side of the car the distance required to make it square, and check to see that all the wheels are correctly re-seat themselves, a tap with a rubber mallet may be necessary. Now you are ready to re-tighten the Gussets. First, tighten the lower 4 bolts on each Gusset, then draw up the 6 top bolts tightening each a little at a time.
9/24/06 by Ted Hall, ShopBot ToolsRE: Connection Issues, Communication Problems
What about those Connection Problems? We recently went through a period with the ShopBot Control System and Control System Software in which we had a spate of “connection” issues. It started shortly after we introduced the PRTalpha and probably had some relationship to the enhanced communications speeds and modified protocols used by the new controller. I believe we now have these problems resolved, and in this message I’d like to provide a little information about ShopBot “connections” to help clarify what goes on when your PC communicates with your ShopBot and why this is even an issue.
First I’d also like to make a bit of a plea: If you are having any kind of “connection” problem, please let us know about it. We want to get your tool working right and we want to make sure we’ve really gotten all issues resolved. If there is something we’re still missing, let us know by calling or e-mailing tech support so that we can get it cleared up. We need to know about problems that may reflect software or hardware issues that we have not encountered on our development tools here in our shop. Tech support is available by phone and email throughout the workday, and we monitor phone messages and email during the evenings and on weekends and holidays. [Just click Send Tech Support Message from your ShopBot software if you are connected to the internet, use the form on this website, or send an email to support.]
OK. Now for some of that information: But first, let me say that I am not talking about getting your initial PC link to the tool established. Your PC communicates with the ShopBot Control box through the PC’s serial or USB port, in the case of PRTs, or through a high-speed serial card or USB, in the case of PRTalphas. Getting the correct drivers configured for the port or for the USB bridge can sometimes be a hassle because of the incredibly varied way that Windows and PCs may be configured. We’re always looking for ways to make this process go smoother. But my focus here is not about establishing the initial link to your control box. Rather, it’s about after you’ve gotten all the Windows drivers set up right. It is with the integrity of the relationship between the PC and the Control Box. We want a robust and consistent “connection” through which the PC and the Control Box function reliably together. This relationship is normally established by continuous communications between the software in the Control Box and the ShopBot software running on the PC. Our occasional problem has been the occurrence of a break in this back-and-forth communications -- a “connection break” or “communications break” that brings up the yellow, Connection Problem screen. When the problem happens it can be tough to track down why because there are 3 potential causes:
When we moved to our current location about 6 years ago, I was excited by the fact that it was a real factory with a heavy duty industrial electrical system (230 and 460, 3-phase available) with lots of heavy-draw, electrically-powered equipment around. I thought it would give us a very realistic industrial environment to test our controls against ambient electrical noise, and I’m sure has helped us. But there are still a variety of ways that electrical noise can be introduced into the shop environment and we certainly aren’t sampling them all. Our controls systems, particularly those on the PRTalphas, have electronics and drivers that are well protected against noise. But there can certainly be situations where radiated noise or noise transmitted over common grounds systems can become problematic. On the positive side, there are some standard procedures for cleaning up noise in industrial settings that usually clears up things for ShopBots. The document that I’ve copied below discusses reducing electrical noise, and can be found as well in your ShopBot software by going to HELP > Troubleshooting & Maintenance > “Electrical Noise…”.
Why Does the Software Even Care When the ShopBot software is running, there is a continuous exchange of data. The PC sends motion info to the Control Box, and the Control Box replies with a report of its status and the state of the input switches. Thus there is a continuous test of the integrity of the communication stream, the functioning of the Control Box, and the input it might be receiving. When the tool is in motion, the returned information additionally confirms that each step has been taken, and reports on the location of the tool in the event of a Stop or Pause. In the process of a fast move, 10,000-30,000 step pulses might be transmitted each second. The PC actually knows that the outboard controller correctly received and processed each step and that the driver transmitted the step to the motor (and in the case of PRTalphas, that the motor actually moved the exact distance it was supposed to). It is this tight communications link between the PC and Control Box that assures that your ShopBot receives and carries out the required motion, and only the required motion.
The Protective Feature of Serial Communications Because our stepper motor instructions are sent serially, they are inherently encoded. This encoding is a form of protection. That is, the step command is not related in a simple way to the electrical pattern in the cable (for example, stepping is not a simple stream of pulses). It is embedded in relatively complex batches (bytes) of electrical information that need to be de-coded by the Control Box before being turned into steps. Electrical disruption (such as that produced by electrical noise) can potentially disrupt the reception of the bytes so that communications fails. But, even though noise can disrupt reception, noise is unlikely, in and of itself, to produce errant behavior of the motors or tool. Industrial controls can communicate using serial or parallel communications. Serial communication is recognized for being inherently more noise resistant due of its encoded nature. In contrast, parallel communications can be very fast. But, unless it is additionally encoded, the data lines essentially provide open access to trigger steps from a motor driver. Because of the openness of parallel data lines they can become effective antennas for translating electrical noise into aberrant behavior. So the kind of electrical noise that might disrupt communication with a serial connection, with a parallel connection could result in a motor taking errant steps. Getting a “connection error” message is frustrating we know, but it also alerts you that there is a noise issue somewhere that needs to be dealt with. A parallel connection to a tool with the same noise problem could just go on generating extra steps in all your files, without you ever knowing. The first 50 or so ShopBots had a parallel interface to the tool, but since that time we’ve exclusively used serial communications for the protection provided by its encoded nature. This may make us somewhat prone to communications disruptions, but we view it to be a conservative approach.
The Connection … For those who have had trouble with connection issues, I hope this information helps clarify the kinds of things that may have been going on. I also hope we have been helpful in getting them sorted out. We are working hard to continually improve the robustness of communications between your PC and ShopBot, and to improve the diagnostics for problem situations.
*As a note: WindowsXP Home version has been especially problematic for us. We’re working on understanding why it is different. We do not recommend using it at the moment. Please use WindowsXP Pro version.
TROUBLE SHOOTING ATTACHMENT (also see: HELP > Troubleshooting & Maintenance, in the ShopBot Control Software) 1) Software or Operating System Functions that May Interfere with Normal Operation of your ShopBot Because ShopBot continuously streams information between the PC and the Control Box, Windows Operating System distractions are able to disrupt the smooth motion and operation of your tool, and can cause communications problems. There are two symptoms of communications problems: stuttering in the smooth motion of your tool, which results from the information stream being choked; and connection losses, which results from the communication stream being distorted or fully blocked. In general, reasonably fast (800+ MHz) computers with adequate memory (250+ Meg) available for buffering operations should have plenty of reserve capacity for running a ShopBot smoothly. But there are some things that can interfere. Here is a partial list. In Windows itself: - Screen Savers (ShopBot disables basic screen savers, but there are numerous types of software that can load screen savers and these may remain operational and potentially problematic for ShopBot). All screen savers should be disabled. - Power Save functions such as turning off hard drives and reducing the CPU speed. All Power Save functions should be disabled or set to "none" because you don't want your computer slowing down in the middle of a large cutting file because you have not hit the keyboard recently. You do not want powersave functions reducing power to the CPU or allowing it to go into a slower speed mode under any conditions. SPECIAL NOTE for LAPTOPS: If you are running on batteries ... as the battery gets lower your computer will go into powersave mode and will reduce power to the CPU, USB and serial ports, disrupting your connection to ShopBot. Only run your ShopBot with a laptop that is plugged into power. - Turn OFF Windows automatic Update. Windows can spend a lot of time checking and downloading the most recent Windows stuff from the web and you don't want it to disrupt your cutting file. You can still Update, just set it up for manual and do it when you are not cutting a file. Some other types of programs will also do automatic checks of sites on the web (such as updating anti-virus software), all this automatic checking needs to be disabled or it will interfere with your tools movement. Other Hardware: - Watch out for Palm devices, cell phones, or any other device you may have set up to hook up to your computer and synchronize. Once these devices have been installed to automatically connect to your computer, the computer constantly dedicates time to testing each serial and USB port for them, and can mistake ShopBot communications for a Palm Pilot or other device and disrupt your cutting session. If you have an older computer that was used by others, be suspicious of what it may be trying to do. It is easy to set the devices to non-automatic mode so that you hit a button when you are ready to connect to them. - In particular be alert to the possibility that a “dongle” for a particular piece of software may interfere with ShopBot communications because of continuous communications with the dongle. The parallel port dongle for ArtCAM Insignia and Pro are know to interfere with ShopBot movement if the software is left open during cutting. - Wireless and LAN networks are usually OK. And running Part Files over a network is usually fine. BUT, if you are having connection problems consider testing without network connection to rule out network activity as a source of interference. More importantly, if you are not close enough to a wireless transmitter that your computer “sees” and if the computer is going in and out of range, it will waste large amounts of computational resources trying to re-establish the connection. And, it will do this over and over again as your tool is trying to work. If you do not have a good signal, turn your wireless off so that it does not distract your computer from running your ShopBot. Other Software: - It goes without saying that you should not start other resource-consuming software running before starting ShopBot running. - But there is a lot of software that may be being started on your computer, but of which you are not aware. Look out for programs that are running in the background and can trigger high resource demands. This would include any kind of program that occasionally goes to the web and checks for an update (Such as anti-virus software ... set it up to check only when you first connect to web). It would also include any active mail monitoring or messaging software (this means no Instant Messaging while you are cutting). Look and see what programs are started by windows at start-up, and disable all you do not need. Try running "MSCONFIG" from the Start > Run and have a look to see if you should modify something in the start-up, if you think competing programs may be a problem.
2) Electrical Noise from other Equipment Running in the Environment of your ShopBot Extraneous electrical noise can disrupt your connection by interfering with communication between your computer and the ShopBot Control Box. Noise can be radiated from some component of the wiring, it can sneak in over the ground system, or it can back feed into one of the power inputs. Electrical noise can usually be ruled out pretty straightforwardly. Use a long Part File of the type in which you are getting the Communication/Connection problem. First run it air-cutting with all other electrical equipment turned off (ie. No router, vacuum hold-down, or dustcollector). Then run the same file actually cutting with all the electrical equipment on. If the problem only arises with full cutting and all accessories and equipment running, then it is very likely the Communication/Connection problem is a result of electrical noise. Sometimes it may be as obvious as getting the dropped connection at the point the spindle or vacuum is turned on. Other times, there may be a cumulative build up of noise signals so that there is no obvious, instantaneous link to turning something on or off. But the problem still only happens with accessories active. If your problem appears to be electrical noise: a. First make a complete check of grounding. All components in the ShopBot system including accessories, computer, Control Box and tool should be grounded to a common system ground with all grounds leading to a single point (typically the electrical system ground). The USB communication uses ground on the communication line and for shielding, so it is important that there are no floating grounds in the system. Grounding the USB Connector’s metal sleeve has been found to be helpful in some situations. b. Don’t panic … most noise problems that have cropped up with high power accessories such as spindles and vacuum pumps have been remedied by just altering the runs of incoming power lines to the Control Box or the run of cables going to the tool. Make sure to keep the USB cable (or serial cable) as clear of all other electrical cables as possible. Sometimes, being too neat and carefully tying all cables tightly together can cause problems. Try not to run the incoming power lines together or parallel to each other. Try to keep the motor and data lines (proximity switch, zzero plate, etc.) apart from the power line to the spindle or router (run them on opposite side of the wire guide and bundle them separately after they leave the tool). If you have lengths of extra motor cable, do not arrange it in tight coils, and do not put extra cable inside the control box. c. If you have installed any additional elements in the system, such as relays, solenoids, etc, these can be a source of electrical noise that is sometimes difficult to track down. You’ll need to test run the system without this equipment connected, but with other accessories operational to try and isolate the source of the noise.
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