"Your Electronic Controller " Published by GraphicsPro I wanted to call this article "that magic box that runs your table", but I knew most of all of you already knew that. The controller might be magic, but it is not a hard mystery to uncover. The unit breaks down into several major areas – first, the straps or the cables that go to the table and from the PC (you see, this box is just an interface to get information from the PC and then code it into data to control your table) thus the name controller. Second, the driver section-- these are the boards that run the motors that push and pull the carriages on the table to engrave. Next is the power supply, this simply takes A/C (Alternating Current) from the wall and converts it into different levels of DC (Direct Current) voltages to supply energy to run the electronics (mainly to run the driver section in to today's controllers). Then there is an auxiliary spindle board to give juice to the spindle motor and accessories supported by the controller. This component mainly controls filtered A/C voltage. Next are the interface and/or motherboards. Sometimes this is one board or several. As in the case of the old Dahlgren SCU's, these controller's had EPROM font boards, Ram cards, CPU and Interface cards all mounted in a motherboard crib. Most of today's controllers have consolidated the functions of those expensive boards into software and one motherboard. Lastly is the Pendant, or the front control panel, it depends on which model you have. This is where the switches and/or buttons are that you use to control the table. What I will do now is talk about each area of the controller, touching on the differences between old and new and some most commonly used troubleshooting tips in each area. We will end up with a quick summary of what we have talked about as well as some maintenance tips. So let's begin. First we will discuss the cables or strapping that go to the controller from the PC, as well as the cables that go from the table to the controller. These are just a series of colored wires that pass energy and information to and from the unit. Problems you might experience here are wires breaking or getting cut. However, most of the broken and bent pins only occur in the connector side on older units. On the modern Controllers, when problems occur they are usually just a bad connection, so simply unscrewing and then re-attaching the cabling to their assigned connector can eliminate a bad or loose connection. Two notes here -- the number one thing a customer service person will have you do is to re-attach cabling with any signal loss problem. Second, this will also break static barriers. Static can confuse your controller -- especially with older models. It is like mis-tuning a radio, you know a signal is there and you can make out most of it, but not all of the information, in most cases, not enough to complete the job. Next the driver cards -- these cards take the signal that started in the software and relay information steps to the motors. The X and Y-axis driver cards are the same, so they put out the same signal or Amp level, usually 4.6 Amp as most of today's motors are that size. The Z-axis can be the same style of electronic board, but will have a different current output. Now, to explain how they work together, let's say we engrave a box. Once the carriages have traveled to the area where the box will be engraved, the Z-axis driver gets a signal to move down to the material via its driver card. Then the X-axis for the top of the box will move, then Y-axis for the right hand side of the box, then X-axis moves for bottom of the box, then the Y-axis for the left side to complete all sides of the box. When the box is done, the Z-axis is told to move up, then the carriages travel home. Now the movement of the axis is done when the X-axis (for example) get a series of pulses that the driver card sends to the motors to move a small amount. These pulses are steps, hence the title stepper motor or micro-steppers. The smaller the amount (length) of signal a driver card can send to a stepper motor, the smaller the movement of the motors, thus the more accurate an engraving system is. So a system that needs 6400 steps to move an inch is very accurate, in fact the only high use systems that I am aware of that are more accurate than 6400 SPI (Steps Per Inch), is a Servo system (we will talk more about these state of the art systems in the future). The next area is the spindle-auxiliary board. This board controls the signal voltage that goes to the spindle motor and whatever extra units you are running from the controller (like a vacuum chip removal system). The board will automatically turn these components on and off when the job starts and stops. This component basically just filters the noise from the your wall power (A/C) and lowers it, on many systems, to a level for that specific spindle motor that is on your system. There are adjusting points on this board to control the rate and balance of spin of your motor. The main troubleshooting tip here is to keep fuses on hand, and to never mess with these adjustment points -- most of you will just blow up the board, or the motor, or both. Next is the power supply. This component is called a shift-mode power supply, as it does shift into different modes. This thing simply takes A/C voltage from the wall and converts its to different levels of D/C voltage. For example, 5 volts for the logic circuits, this will be a different voltage for the driver cards, and so on. The best troubleshooting tool here is the have an Isobar surge protector, and an isolated line. That is, have nothing else on the same circuit breaker except the engraving system, and a surge protector box, not a strip. The strips do nothing; I say again the strips are worse than nothing at all. This is because they let you plug in more gadgets into the same circuit. Remember, the more things on the same breaker means you can lower the power and make the system work harder and endure more power surges. When the power is drawn down it does not come right back to normal, it goes high, then back down to its proper level. Isolate your line, and get an Isobar surge protector (they are $29.95 at most stores that carry them). The next component or components is the motherboard. On today's units this one board takes signal feeds from the PC, and uses this information to control the driver cards. In old controllers this can be done via several boards. Depending on the model, you may just need to check your connection if you are having problems. Re-seeding boards can work miracles. The last area of the controller is the pendant, or front panel, depending on the model. This has the buttons and switches that you use to start and stop your engraver (after a job as been downloaded). On the models with pendants that have switches, there are very few problems. However, the models with the front panels like the old Dahlgren SCU the run button tends to wear out, so put a "band-aid" over the run button to help with the wear and tear. Now, as I promised earlier, I will speak briefly on other controllers. These controllers are referred to as open-architecture units. In fact, they are designed to be used with a variety of different software. The biggest advantage is that you have the ability with these units to use software you already know. So you just get a new system and you are ready to go. Now, before I go on, let me say that there are a lot of people that use and love serial controllers. But this is an editorial, AND I think from an evolution stand point of a business, if I am going to purchase a new engraver to use with my same old software, (and 90% of today's new features are in the software), then what am I gaining by purchasing new serial controller to use with my old software. Heck, many of the manufacturers who are on the zenith, have technology like print drivers that would allow you to run their standard controller's from any software. But many clients do not use print drivers, as the features of new software designed for the engraving process, have just too many advantages. Additionally, I want the Engraver manufacturers to be responsible for software and hardware, Period. As a technician, I have seen clients who have been told from the hardware manufacturer that they have a software problem, and the software geeks tell them that it is a hardware problem. Thus my valued client is stuck in the middle. One other item, it is the opinion of many experts that a HPGL serial controller, though it does allow some flexibility with software, is not a true open architecture system, that only a print driver is truly open architecture. But as I have said, many have chosen just to use their old software or even new stuff with a serial controller for the process of engraving and are succeeding in this industry. The biggest troubleshooting tool with a controller is just to pay attention and think -- or if not, you may have to pay me (or someone like me) a large amount of money. That is, if it is smoking do not just keep turning it on and burning up more components. Now, one huge troubleshooting tip with your controller is to swap driver cards. This is done when you think that you are having a problem with just one of your axis's. Such as the spindle is not coming home and/or not being able to re-engrave a letter. So, if you get into your controller and swap the X-axis card into the Y-axis slot and vice a versa, and then discover the problem has moved to the Y-axis from the X-axis, for example; then the problem is that the driver card is bad and needs to be replaced. If not, you have a problem in the table -- maybe a motor. The last thing I want to leave you with is you need your engraver to run, and run well over a long period of time. Remember to keep the fans clean -- dust is a blanket that not only causes heat, but also keeps a fan from cooling off hot components. So, clean your fans and call for a technical tune-up once in awhile (once a year for older style units and once every 3-4 years or so for newer ones). OK, cables connected, unit plugged in, and controller on, (so power supply is working,) hit your homing switch, (driver cards are OK.) Send a plastic job, hit start, spindle board and pendent are OK. We are ready to go! |