Controls Retrofit to a Winding Machine:
Hopefully you have read the page about the Winding Machine Mechanical Refurbishment. Yes, winding machine controls can still be state of the art and not break the bank, OK!
It depends on knowledge of available options and ability to use that without emptying my customers pocketbooks. The fancy, ultra-complicated solutions of today are not really required to obtain consistent performance. They are a pain to program, and I would have to pass those costs to you, my customer. Since we run a business for profit we study our options carefully since we don't pass off excessive costs to customers while offering an unsurpassed experience.
In the present range of winding machines that we retrofit, we focus on ease of use, and providing capabilities that were not present at the time of the original build.The customer cannot make a profit without speed and consistency. We provide an ample helping of that stuff. And we will describe that in more detail following, as an overall thought and broken in to more detail as to the components of the system.
What follows is my overall thoughts, and how we did it without breaking the bank.
We provide capabilities that OEM's would charge extra for, and if your need is that unique it can also be provided. KR International has no hype in this area. A capacitor winding machine, no matter what brand, turns the winding arbors, and depending on type of machine sequences various mechanisms to complete the winding. With today's modern PLC's (Programmable Logic Controllers) it really doesn't take that much time and code to get the job done. Yes, it's that simple with experience for at least the basics.
Programmable Logic Controller:
We always have utilized Panasonic™ PLC's. Presently we are using the FPx series controls, of which Panasonic promotes as their best deal and is their second most powerful PLC. We have tried different demonstration Units from various manufacturers, and concluded they are not really suited for the ease of what we need, period. And price wise the Panasonic PLC's pack far more "punch" than their more expensive competitors. They are not a typical bargain unit with limited I/O and functions, costing just a medium percentage more than the bargain "no name" brands available online
So a good question is why? The Panasonic units have never died on us. The software utilized to program them is about as good as it gets. The programming software we use is the most advanced version out of the 3 offered, and uses every available CPU resource to do "Tricks" available to make a high speed program without excessive code. Most PLC programmers would pull their hair out using it, if they have never had experience with C++ Object Oriented programming in computers. The PLC's are also some of the industry's best performing, and all the tricks can be added without loss of performance.
Besides the programming and reliability, the internal hardware is ideal for a winding machine. In an event driven machine program, an ample amount of high-speed counters are there. Inputs can be utilized normally, or as interrupts, the list goes on. Specialty Modules are available to extend it's usefulness for the wild imagination.. And also for reference, single step execution time is 300 nanoseconds. Think about it, that's much faster than we can think. It runs machine programs much faster than a PC running a graphical operating system, since there is no "Graphical" overhead to deal with.
And it's not like we never learned from our mistakes. Our customers have always have given us their input on the "Wish List", as well as no hesitation to call us out if they find a quirk. Over the past 15 years we have corrected, improved and incorporated many customer's useful ideas. And we added some of our own. I have worked on the front lines of the capacitor industry. So we add tricks as standard, and we usually don't have to make a return trip to add features that should always have been there, and OEM's charge extra for.
The PLC is the conductor of the "Orchestra". Chosen to play a good game with the other members, let's describe the other members.
Operator Interface Unit:
Illustration taken from the design software. Dummy data is shown during design. This is the main operating screen that would normally be seen and is for film/foil.
This is one of the most important parts of the system! Why you ask? So we can tell that fancy PLC what you need to do! Besides that, it tells you what to do, and displays all necessary operational data..
Don't you wish your winding machine would store all your setups? Ours do. Does it wake up from a previous day with all setup info intact? Ours do. Would you like it to have uncanny control over the active materials? Since it uses a PLC, we use variables, not constants. You have to tell the controller what to do anyway! Some of the antiquated machines don't have control over how much dielectric material is wound before and after the active materials. Ours do.
Illustration taken from the design software. Dummy data is shown during design. This is one of the data change screens that could change and save operating parameters. The actual opening, saving and deleting operating date is handled by the MS Windows® CE operating system dialogs, and cannot be shown statically, becuase it is dynamically created.
OOPS, you thought I got off the operator interface subject, NO NO. The operator interface is utilized to do this. The Operator Interface Unit is capable of "Recipe" storage. It is a Microsoft Windows CE© based unit. It is made in Sweden by Beijer Electronics. It has no resemblance to units made by PLC manufacturers and other aftermarket units, period. What you see is Windows©. You can recall, modify and save "Recipes" files, just like a computer, since it is a computer. It is not designed to replace the PLC, rather is supplements it's usefulness to take care of the graphics and file storage and unload the overhead on the PLC to maintain 100% accuracy. We might add it is a full color, high resolution display.
By simply setting internal relays and registers in the PLC while running, this operator interface can explain in detail what is going on in the process, entirely in your language. By using the function keys and a built in keyboard, winding settings are easily changed. This is not a "touch screen" unit, which easily breaks down over time. For reference, a "Recipe" is a starting point, after loading parameters, they are changeable to suit the variation in materials. Even upon power loss, the PLC has retentive capability to start again using the same data.
And what good is a winding machine without self diagnostics? Just for reference, the machine might as well think for itself. Except for the rarest of cases, the failure and adjustment warnings utilize the graphical capabilities to tell you there is a problem and details, even suggested course of action. You save time, money and frustration in this case. Call us with the error code and description and we'll get you back up and running as fast as anybody in the industry. "Failure" in most cases means that operations have slowed down, as we program operation timers in process, and could mean that air pressure has dropped, there is mechanical binding for some reason or a connection problem. Adjustment might be necessary. The machine is normally running like a rattlesnake. Lazy doesn't make profit.
Illustration taken from the design software. Dummy data is shown during design. This is one of the Error screens that could be shown during operation. The error screen shown depends on the many operational monitoring checks during normal operation.
Winding Machine Drives:
AC VFD's
Winding
Orbit Gear Motor
We have always utilized AC Inverter Drives, with AC Inverter duty motors. However, they are not all created equally in suitability, capability, speed range or price.
As a general rule, we use Eaton® Sensorless Vector AC Drives, with Bodine® AC Inverter Duty Motors. Why? Gobs of torque at very low speed, very high speed capability with a good torque curve and extremely well behaved acceleration and deceleration. After careful testing the best overall and in budget with a speed range of 150:1. Servos just are simply out of the budget range, and really in the scheme of things are far more complicated, after careful testing no real advantage was realized. Our setups can start and stop much faster that the actual winding can take and remain intact.
The interface to the drive is serial communication to the PLC. All aspects can be controlled, speed, acceleration, deceleration, s-curve, etc. Without any trimpots or fiddling, the parameters for different capacitor materials can be changed from the operator interface. Delicate or heavy materials, and difficult materials can be profiled and the settings saved in a "Recipe".
A new practice coming into play with the old E W Barton capacitor winders is we add a separate drive for the winding head indexing. An advantage to machine control, the winding drive is completely independent of the winding head indexing drive for much better independent performance characteristics.
If you are considering upgrading your machine, the sensorless vector controls spend a much greater time in high speed winding, and are dynamically braked. That means it doesn't take forever to coast to a low speed. This shortens the winding time considerably, you might just make a profit if we keep this up.
Sensors, Encoders and other Detection Devices:
General rule of thumb here is a preference for inductive proximity sensors with connectors and a replaceable cable for direct detection of metallic assemblies. Rotary Sensing (counting) use is detected with optical encoders, sealed with connectors and a replaceable cable. Sensing actuator cylinder position is accomplished by using magnetic pistons combined with hall effect sensors, position adjustable of course. We avoid as much as possible the use of contact switches, for obvious reasons.
Controller Output Scheme for Inductive Loads:
This is applicable to the antiquated E W Barton machines or any other old low tech electromechanical relay designs. In these cases, clutches, brakes and any actuator containing a solenoid could be very sluggish. The old school of thought just switched AC on and off with physical relay contacts. Rectification (typically half wave) was utilized with a RC snubber network to increase contact switching life, at the expense of snappy reaction time.
In my experience I run into 3 typical cases. Conversion to 90VDC, conversion to 24VDC and lastly direct switching of line voltage. In the cases of DC converted switching, the RC snubber network drastically affects the turn on and turn off times, charging the capacitor through the resistor. An added variation with switching could vary up to 8 - 16ms depending on timing with the peak to peak voltage of the line AC waveform.
With the modern controls, we can make the inductive loads "Snappy" yielding less cycle time per winding. If possible, for example we change the air valve solenoids to 24VDC, and the output circuits of the PLC are designed to deal with the low level inductive "kickback". There are no AC switching delays.
As for the industry standard 90VDC coils in the clutches and brakes, the source is AC line voltage, and they are switched and isolated from the PLC's 24VDC output by use of a zero crossover switching, fused AC Output module. The internal circuitry is designed to absorb the inductive load kickback voltage by nature. The DC output portion is now just using a simple rectifier bridge, full wave, which is the industry standard way of determining the "90VDC" rating of the actuators. No capacitors are utilized in the circuit to delay switching, and to the naked eye it's so fast there is no discernable delay.
Oh yes, I am aware there is a small electromechanical time delay present in switching electromagnetic inductive devices. But a relay sequencer can cause is some cases up to a 0.25sec delay before switching a load, now the electromagnetic switching time delay is at a maximum of 8ms to saturation with the inherent small inductance in the winding machine actuators. When the old delays added up versus the new system, we can shave off several seconds off winding alone.
The larger solenoids present in the E W Barton Foil/Film perforators use the same method as above, with a voltage dividing power resistor for the 24VDC coils. Other enhancements provide deadly accurate consistency, which is not inherent in the OEM scheme.
Direct switching, for example an Orbit Solenoid or Seal Heater (120VAC) uses an AC Output Module. In all cases both the PLC and Load are protected, along with easy troubleshooting protecting your bottom line budget.
Temperature Control of Sealing:
Closed Loop temperature control is accomplished by adding a thermocouple input mode to the PLC, and using either a PID loop or an IPD loop in the PLC's program. The heater in the sealer assembly is pulse width modulated by an AC output module. Temperature variation control is possible within ±3% over a day's time. The PLC is programmed to make windings while the sealing temperature is within range, avoiding unraveling windings which are simply scrap. Temperature setting can be set on the operator interface terminal, and the setting is also stored in "Recipes". Set and forget.
Interconnects and Wiring Terminations:
Wago Cage Clamp®
We are proud to use Wago Cage Clamp® terminal blocks. Once the wire is in place it will not become disconnected under any circumstance. They can of course be removed manually by opening the cage. Without going into extreme detail, our terminations are fairly dense and well organized. If it is within our control there are no exposed wiring points such as screw heads to present a shorting or electrical shock hazard. To prevent stray strands of wire, we use ferrules on all wiring, with printed shrink sleeving as a strain relief. Wago® makes such a variety of products, we use whenever possible, an example would be an insulated fuse block, with a LED indicator for fuse failure, that plugs into a terminal block. We also use indicating terminal blocks. The wiring is identified, neat and organized.
The Visual Experience of Control Operation:
We take care to present a visual confirmation of most of our controls operation. Why? It may look impressive, but the real aim is for visual operation confirmation without the need to chase electronic test equipment. All commercial sensors that we install have operation indicators built in. The optical rotary encoders pass through interconnect terminal blocks with indicators, indicating phases A, B and Z. All air valves indicate operation at the solenoid connectors. All solid state relays and output modules have built in indicators. It ends up being a light show, but very handy if anything is in question. Besides that, the PLC indicates all inputs and outputs on the face. If the PLC picks up an operational fault, it indicates that in the operator interface terminal. I detest machines that require hours of troubleshooting with voltmeters.
Mains and Control Power:
The Mains are determined at time of order. However, at my facility there is only 120VAC and 240VAC 60hz single phase. The workaround is to build and test with my source, and install the proper voltage control items at shipping. Many components we use are dual voltage and frequency tolerant. But in some instances this may add a smaller, reasonable cost to your order.
Control Power is the de facto universal standard 24VDC, as this provides the greatest selection of peripherals available.
Power to provide for demetallization burnoff (Metallized Only) is an isolated ground unregulated DC power supply, The voltage is human safe, between 40 - 50 VDC current limited and adjustable current, the lower the current the lower the voltage at the electrodes. The advantages of using an unregulated DC supply is a more consistent removal rate, as well as easier arc starting. Common grounding burnoff will cause arcing virtually anywhere in the machine, as well as contribute to catastrophic controls failure.
How are We Saving You Money, and giving you a HIGH TECH PRODUCT?
Simply put, we have been doing this for over 15 years, and realize that tested products save on the bottom line. We are not using 15 year old technology. We constantly order demonstration units and test them for usability, and return at least 99% of them. We study which manufacturers are gaining and losing in the technology world. Quite frankly, the dazzling array of products that we use doesn't cost an arm and a leg. We are not lured by smoke and mirrors into buying more expensive technology than what it takes to get the job done. We are not influenced by so called experts (sales people paid to promote useless technology to us anyway) with an eloquent twist on speech and writing. We simply have to consider our customer's bottom line which involves a great deal of study of utilizing things that are inherent in what we purchase. I doubt the so called experts could wring out the power that we do without experience, the demonstrations that we see are not related to capacitor winding. We do consult with technical engineering of the manufacturer to make sure what we need to do can get done. And after that first 15 years, our costs of developing the programming necessary to accomplish the goals has been amortized over the lifetime to offer quick solutions without reinventing the wheel. If we were just starting from scratch, what we buy doesn't come programmed, and it would take forever to get there. This is certainly not the case at present. A good example is buying a $200 PLC then spending $25,000 dollars of man time to program it.
Guess what? We don't buy $200 PLC's and our entire control systems cost far less than that fully programmed!