Automation NTH

Over the past six years I’ve written posts about a lot of different companies; machine builders (Nalle Automation/NAS, Wright Industries/Doerfer, even my old company ACS), training companies (Automation Training and Udemy), and a whole bunch of controls manufacturers (check out the PLC tab). Today’s post is the first I think I’ve written on a systems integrator or “controls house” as they’re sometimes called.

Automation NTH is located in LaVergne, TN, close to Nashville. They do controls design and engineering, programming, system commissioning, contracting and have a large UL508A listed panel shop. They have been in operation since 1999 and like many controls companies and machine builders in the area, the principals (like myself) were at Wright Industries for a bit.

When I first moved here in 2006 to work for Wright, they were some of the first people I met, and my wife was hired into their panel shop, so I got to know them pretty well. After leaving Wright at the end of 2011 they were the first company I contracted for, doing programming and design work around the Southeast. I also got to know a lot of their engineers, many of whom also did a spell at Wright.

One thing that is a bit different about NTH is their emphasis on internal training. For several years they have had a program that takes local university engineering students on as interns. The four month program trains them in AutoCAD/electrical design, general controls and PLC programming, and working them in the panel shop. This allows Automation NTH to evaluate the interns and hire many of them when they graduate, ensuring that they are familiar with good controls practices and NTH’s way of doing things.

In addition they have expanded this into a “NTH University” program that provides ongoing training for employees, allowing them to gain experience in various disciplines.

This is a picture of their “PLC Trainer” wall. There are many different brands represented here, and most of the demo’s were built by the interns themselves as final projects. Platforms include Allen-Bradley, Siemens, Modicon, GE, Mitsubishi and more.

Interns and students have used several conveyors. machine vision and pneumatic components to do projects to enhance their skills. Recently Automation NTH has also expanded this program to allow customers from manufacturing facilities to take a one week “crash course” using the NTH University curriculum. Customers have given excellent reviews on this course since it allows technicians and engineers to use real world scenarios in their training.

I have been fortunate to become involved in this course myself recently as the course has been formalized. Both of my books are being used in the classes and new training equipment has been built for the conveyor labs.

A local university, Middle Tennessee State (MTSU) has also ordered 22 trainers for their engineering classes. They looked so good I simply had to order a couple for myself…

I will also be marketing these trainers and other similar ones on my website within the next few months. One thing that allows NTH to make trainers like this very economically is their CNC panel fab machine.

Oh, and did I mention they also have well-trained personnel, and interns? 😀

Posted in Engineering, Machine Builders and Integrators, Training Tagged with: , , , ,

Are Things too Complicated?

Today’s post is inspired by an ongoing adventure I have been having in the design and fabrication of My Little Factory. For those who haven’t been following my post since the beginning of this year, a great deal of my time has been spent building out my training facility, the centerpiece of which is a tabletop demo that students will eventually be able to play around with. I started calling this “My Little Factory” after my April post of the same name.

Part of this little automation demo is a cleated conveyor that I am using to re-create an automation project I did about eleven years ago. Rather than using an indexer or servo to move the pockets consistently, the mechanical designer on the project decided to use a standard VFD (Variable Frequency Drive) and AC motor, along with some photoeyes to detect the position of the cleats. While this might have been a less expensive hardware option than a servo with encoder feedback, the amount of time that it took to make it work correctly more than ate up the savings. Anyway, one of the reasons I decided to re-create this method is that it illustrates some really good points and makes for a fun programming project for students. The basic concept is that the conveyor run signal is applied until the next cleat is detected with a sensor, the conveyor is stopped, and a second sensor is used to verify that the cleat (and therefore the pocket) is in the right position for operations.

When I started this tabletop project I purchased several different fiber-optic amplifiers both to use in this system as well as to help show students some of the wide range of features that photoeyes have. I bought a couple of Keyence amplifiers with all kinds of programmable windows and a set of (very expensive) convergent beam fibers, a couple of Banner’s newest amplifiers (shown above), and a variety of used stuff from EBay.

As I worked on different parts of this project I was always thinking about how I would mount the fiber heads to make them easily adjustable, which amplifiers I might use to illustrate which point, and various other details. Each section of this demo has its own purpose behind it, and once something has been done one way, it can be difficult and time consuming to change. So yesterday I finally got around to building the adjustable sensor mounts and testing the sensors. I decided to use the new Banner sensors partially because they looked really cool and partially because I didn’t have cables for the Keyence amplifiers (which look really cool too…)

The mechanical mounting took longer than I thought it would. I had to make a lot of little brackets and drill/tap little pieces of aluminum, and then make do with whatever 80-20 extrusion pieces I had. Anyway I finally got everything mounted and powered on, and that’s when I was inspired to write this post. The instructions for the fiber amp is about 12 pages long! There are ways to program detection windows and tweak the timing, dynamically teach while the machine is running and set error thresholds, and change the response speed of the signal. What there didn’t seem to be was a simple on-off response to the cleat. As you can see in the picture, there is a number for the magnitude of the light signal and another for the setpoint. In addition the numbers will alternate with warning messages as shown in the leftmost amplifier. After getting it to operate yesterday before I went home, I took this picture this morning. The message “thr Alrt” was blinking, apparently meaning there was too MUCH light entering the receiving fiber. I know this because my green readout read 4000, the maximum magnitude for the amplifier.

Notice also that the fiber next to it has a yellow light at the top showing that it is ON. Not only did the fiber amplifier tell me that there was too much light, it also stopped working as far as I am concerned. When I misaligned the fiber heads a little bit bringing the magnitude down the amplifier output started operating correctly again.

The end result of all of this fun was that I replaced the amplifiers with the two shown above. Though not as sexy looking, these are some of the used fiber amps that I bought on EBay. They have a simple bar graph showing how much light is being received and of course the same type of little yellow light showing that the output is energized. Instead of having six wires there are only four, and if you want it to operate Dark On instead of Light On you have to connect the white wire instead of the black one. It is however a much simpler device.

This picture shows my high-tech test device for checking the input to the PLC, blocking the beam with my finger. While there is no warning or remote teach wiring, this sensor will probably do the job. I say probably because the signal is apparently much faster on the newer amplifier.

When I started in the industrial automation field some twenty-odd years ago, systems were much simpler. Emergency Stop circuits were single channel affairs and PLCs were also much less complicated. Sensors were generally pretty basic also, although Omron used to have a really cool convergent beam sensor that actually physically changed the angle of the lenses. I haven’t seen anything like that for twenty years or so.

Anyway, my solution to the complexity of this new fiber amp was to replace it with one that took less time to set up and would still work even if I set it up wrong. I wonder how many other people have done the same thing when confronted with amazing new products.

What do you think? Are things getting too complicated?

Posted in Automation Concepts, Conveyors, My Little Factory, Photoeyes, Sensors Tagged with: , , , ,

Super Vision!

As some of you may know, especially those of you who have known me since the 1990’s, machine vision used to be a major part of my career. I could conservatively say I was part of at least 40-50 vision projects with over 150 cameras and built many machines where vision was the core element of the system. While most of my projects used the now defunct DVT platform, I also used Cognex, Avalon, Keyence, Banner, Matrox and various others.

That being said, I have been out of it for a while. Other than a few integration projects and a sales call that turned into nothing, I really haven’t kept up with the technology and have mostly moved on to other endeavors.

About a month or so ago I received a call from someone who said they needed help with an issue that involved Allen-Bradley PLCs, and since that is something I know quite a bit about I said I would do what I could to help them. Usually I concentrate more on training and consulting, but I had a bit of time so I took this small job on short notice.

When we got to the plant after meeting with the technician Ross from MapVision, I was literally floored by what I saw. While I have integrated up to eight or ten cameras into a single machine, here was a self contained inspection station that literally created a 3D model of a complex part in real time that you could manipulate like you were using SolidWorks or ProE!

Beyond this door…

The part I was needed for is really not the point of this post. Yes, there was an Allen-Bradley PLC that controlled a servo that moved the part into the vision area, and yes, there was a problem, but this really had nothing to do with the vision system itself.

This system, the “Quality Gate”, has 35 cameras completely surrounding the part. The image can be rotated to any position and compared with any other image, including a hypothetical “Golden Part”. An algorithm even strobes between the two images, floating colored datum indicators over the part to show exactly where the problems may lie.

Control Screens

According to Ross, even if a camera or two were to be out of commission, there is quite a bit of overlap allowing full inspection to continue.

Now this system is in the range of a half million dollars, so it isn’t a lightly made decision to put one in, but wow! Things have really come a long way since my old ACS days.

Following are a few pictures from my trip. The basic layout is that an automotive part, in this case a welded dashboard assembly, is moved into a precise location and the system is triggered. One of the most important parts of a successful machine vision application is ensuring that the inspection area is completely under control as far as lighting and the visible environment. Because everything is inside of a dedicated vision enclosure, this is easy for the Quality Gate.

Cameras and Lighting

Datum Points

Part entering Quality Gate

As you can see, this isn’t just a few individual uncoordinated cameras looking at a specific small item, it is instead an overall inspection of the entire part. One of the things I learned very quickly is that this takes a tremendous amount of memory and processing horsepower. One of the reasons this wasn’t done when I was doing a lot of machine vision work is that the technology simply didn’t exist. In the last ten years the size and cost of available computer memory has changed immensely, and even the camera technology and resolution has evolved a lot.

Anyway, this is pretty much the most amazing machine vision system I have ever seen, and I attend at least one automation show with lots of machine vision vendors every year. Of course it would be difficult to justify setting up this full system for just a few days. I’m sure MapVision does have booths at trade shows, but they are probably either just showing videos or have a small demo with a few cameras. This would do no justice to what I saw. So if you are involved in automotive manufacturing and haven’t talked to MapVision, I would encourage to do so. You will be impressed!

Posted in Applications, gauging, Vendors and Manufacturers, vision Tagged with: ,


Today’s post, as promised last week, is written by Ryan McCarthy, a reader of this blog. While I always offer to place a reciprocal link to the website of whoever contributes guest posts to this site, amazingly Ryan is neither currently a blogger nor does he work for Unitronics. One plug I will give him though; he lives in Florida and is looking for work in the controls and automation field, so if any of you can help out, hit me up and I will put you in contact. We have corresponded a bit and he seems like he would be a great hire or automation partner, plus he writes quite well! Ryan, you really should start a blog yourself. Anyway, since I don’t know much about the subject other than that it is a PLC with built-in HMI (or vice-versa), I’ll let Ryan take it from here.


Unitronics is a younger company that started in 1989 and has since grown to be a more common name in the industry. Unitronics offers PLCs that are “All-in-One”, which means all their PLCs have a built-in HMI as well as communications. Based on my experience on other platforms, this really simplifies things. When I started out I had entire days spent getting a laptop set up to handle a project, from a communications software, an HMI software, perhaps two versions of a PLC platform when working to update a PLC. With Unitronics there are only three pieces of software total, the U90 Ladder, VisiLogic, or UniLogic.

The big upside of Unitronics is the very low cost of hardware. I/O modules are 100-300, whether discrete, analog, RTD and whatnot. Estimates I saw on their high-end processors that include the HMI are less than $1,500. However, depending on which platform you go with, the cost might be higher due to programming time. Their lower end runs in the few hundreds. Mind you, these still have touch screen displays around $400 included in that price. Development time is a bit higher in that environment, and there are several more constraints, however I’ve seen it have popularity with “copy-and-paste” applications for product lines.

I almost forgot this – they offer free support. Some of you might be thinking “free? Yeah you get what you pay for”. That may be true, but I’ve gotten to meet some of their technical support engineers and the guys are great! They have a forum on their website with both tech support and altruistic integrators helping answer questions. Personally, I’m a big fan of the company. They are strictly a hardware company and make no money on the software side.

You could look at their three-product series as tiers – low, middle, and high. The U90 series covers keyboard entry and text display type HMIs, current models being sold are the Jazz and M91, under 50 total I/O sort of range. Vision covers their base touchscreen models, the V130-V1210 and SAMBA processors, which have their varying HMI sizes, processing power, and memory. This covers projects up to 1000 I/O with snap-in expansions. UniStream covers their high-end product line, which comes with an improved ladder diagram and enhanced features all around. This line can expand to 2000 I/O.

Now that a general overview is covered I want to go into a little detail on each of those platforms – U90 Ladder, VisiLogic, and UniLogic.

U90 Ladder – The U90 ladder is for very simple inputs and displays. It is like VisiLogic except with the limitations of keyboard entry as opposed to touch screen, and strictly text display. As a result, the HMI and complexity of applications on this platform are limited. Going into detail about VisiLogic pretty well covers the logic functionalities of both the U90 Ladder and VisiLogic.


Shows easily accessible tabs for hardware, ladder and HMI “All-in-One”.

You would start by configuring your hardware, which is a very visual drag and drop process. This allows you to visualize exactly how you would build your snap in I/O and expansions on to the backplane. See the following for an example:

This shows IO expansion, snap-in I/O, the processor and its built-in HMI on the VisiLogic platform.

After configuring your hardware, you might setup your communications. The controller supports serial, TCP/IP, and OPLC communications. The ladder has a few drawbacks, it is an addressed (not tag-based) database without user-defined tags or add-on instructions, so you’ll be spending some time on your I/O upfront. There is a third-party simulator available for 30 euros to test your project and it’s strictly for certain VisiLogic configurations. Side note – I’ve heard it’s not so great (“sucks”) from an integrator, but I have no experience using it myself. You must connect every element in the ladder manually by placing them or connecting them with a line, it doesn’t do anything intuitively like most platforms. As long as you use the right communication protocol for your project, communications are nice and function blocked.

The HMI is nice, but different from the norm. Most applications I have made or seen involve a lot of stacking, which is disabled in VisiLogic. I can’t say that this is a bad thing, I think it makes the graphics much cleaner from the programming side, I just see it as a creative constraint. It’s all intuitive once you adjust, and I like the way things look afterwards, although it is generally a dated platform and lacks time saving functionalities.

Briefly – VisiLogic is extremely cost effective, great for most small jobs.

UniLogic – I’m going to cover features of UniLogic that are not included in VisiLogic. It’s their upgraded and most up-to-date platform. Apart from the list below I took from somewhere on their website, UniLogic has a WebServer for developing web pages within the HMI side of the PLC. It offers C programming for writing functions blocks to have on all your projects. UniLogic also allows communicating with the SQL database and querying it via IP address. This is one of the coolest features in my opinion, because it makes the bridge to IT more accessible than most platforms, and cost-free.

Data Tags

UniLogic is based on lexical data tags, not operands. The memory is dynamically allocated depending on the data tags you create, and the data type you link to your tags.

Data Tag Structs

These may be:

Automatically created: UniLogic creates data tag structs automatically where necessary, such as when you configure Hardware and communications, or use timers in your program.

User-defined: You set up structs according to the needs of your program.


Via Configuration, not Ladder. For example, if your application uses MODBUS, you set the desired operations/commands and operand areas in each slave configuration. You the set the frequency of data communication in the Properties Window for each slave.

User-defined Function Blocks (UDFBs). Take any UniLogic function (which are equal to VisiLogic subroutines), define input and output data tags, and then drag the function to any point in your program.

VNC–  Remote Access. You can use any VNC client to remotely access your controllers.

Customize the UniLogic interface. You can dock or unpin any window in the software. In addition, note that UniLogic will fit any PC screen without any degradation in quality. The main work window can be zoomed to suit your needs.

Overall I look forward to working with one of these. I see huge potential with IT integration and very minor capital expense.
That covers my light research on Unitronics PLCs. I hope this gives a decent overview of Unitronics, although it certainly is from a programmer’s perspective. If anyone knows hardware well I would appreciate a lengthy discussion with which to become more aware of the tradeoffs.


As you can tell, Ryan did his research and wrote up an excellent post discussing lots of good information on the Unitronics PLC platform. He certainly made it easy for me to add it to the blog’s resources page and it’s a good easy and informative read.

I am always looking for guest posts on automation-related topics. If anyone is interested in writing a post or contributing any other informative material, let me know! Oh, and if you are in Florida and need a controls guy who is always learning and curious, consider contacting Ryan!


Posted in PLCs, Vendors and Manufacturers Tagged with: , , , , , , ,

Automation Consulting, LLC Open House

When I started this blog back at the end of 2010 I really just did it for fun. At that time I wanted to make sure it contained useful information and was non-commercial in nature.

Then I went back into business for myself in 2012. Because I was mostly contracting to machine builders and integrators and had as much work as I wanted, most of the posts were based on the jobs I was doing or whatever technical things I thought of.

By 2014 I was spending a lot of my time teaching classes for Automation Training, so quite a few posts mentioned them and some of my travels.

Now that I’ve transitioned into providing training at my own facility, of course I am driven to mention more of my stuff on the blog. That certainly wasn’t the original intent when I started, but so be it. That is mostly what I am involved with at the moment.

So this is a pretty important week for me. My first student for my new course is doing two days this week, Monday and Tuesday. Because he gets random days off, he can’t take all 5 days consecutively. That’s one of the advantages of having my own facility, I can be flexible. Tuesday evening the owner of Automation Training is coming down from Canada, both for my open house and for a meeting with another important customer/client of mine, Automation NTH. We will be discussing some cooperative ventures that hopefully will benefit all three companies.

Then Thursday is my open house itself. If you live in the Nashville Tennessee area I’d love to have you visit! Of course there will be food, and several automation vendors will be here to answer questions. I wish I could say you could see “My Little Factory” in operation, but I’m afraid that’s still a few months down the road. I still don’t even have my pick and place cylinders. Actually I do have the gripper cylinders, but no gripper fingers to attach to them yet.

For those of you who were looking for some good technical content this week, again I apologize, but I do have a post on Unitronics, written by Ryan McCarthy, ready to go. I also will be writing a post on machine vision showing some of the cool stuff Mapvision does. I was fortunate enough to get to do a quick consulting job for them last week and got some great pictures.

The open house is Thursday, June 8 just off I-40 in Lebanon, Tennessee at my facility. It starts at 10 am and runs until about 3pm. If you can’t make it but want to visit some other time, let me know. Or come take a class! OK, so I’m done being self serving now. Carry on. 🙂

Posted in Me, My Little Factory, Sales and Marketing, Vendors and Manufacturers Tagged with: , , , , , ,

Fabricate – Panel Preparation

Today’s topic is on exactly what happens before you start wiring a control panel. It will also serve as an update on my progress on “My Little Factory”, which has drawn a lot of questions from my readers.

As I mentioned before, I don’t do a lot of panelbuilding, fabrication and wiring any more, most of my work now involves programming and training. In other words, old guy stuff. When I started the original Automation Consulting Services in 1996, much of our work was panelbuilding, and I learned a lot of the techniques as the company grew. Eventually most of the work was done by others, and my wife learned much more about it than I know. She ran the panel shop until we closed the business in 2006, then worked for two panel shops here in Nashville until a couple of years ago when she retired.

Anyway, with my new training facility I have dedicated the first part of this year to building things out, including this “Little Factory”. While my wife was kind enough to build and wire a couple of backplanes for me, most of the work is on me. So when I determined all of the components for my operator panel I decided to document the process of prepping the enclosure. Be prepared for a lot of pictures!

It all starts with figuring out what components you need in your panel or enclosure. In this case, since its purpose is to serve as an operator interface, I ordered a “consolet” type enclosure from Automation Direct. Many of the new components in my factory are ordered from them; they are easy to order from online and they ship for free in a day or two.

The Operator Interface itself is a “C-More” 7 inch diagonal touchscreen. I chose it because it is fairly inexpensive and has drivers for both Siemens S7 and Allen-Bradley. I’m not sure how it will talk to the Beckhoff 9020 PLC yet, but possibly Modbus or Ethernet IP.

The pushbuttons and fittings were a first guess at what I would use. I originally intended to use 3 buttons, but they didn’t fit so I used two. The green button serves two purposes: power on/reset for faults and the E-Stop circuit, and an index/cycle button for the cleated conveyor. The red button is of course an emergency stop. I have quite a few pushbuttons and pilot lights from old projects, so I just used those. I also had all of the fittings.

You can see the piece of graph paper underneath the touchscreen. After measuring the back of the HMI I used graph paper to outline the cutout.

These pictures show the process of transferring the cutout size to the face of the consolet. If I were doing this professionally, I would create a CAD drawing of all of the surfaces of the consolet, measure all of the components and provide a formal drawing to my panelbuilder. Since I am doing everything, I can just “wing it”. I have a pretty good eye for things being straight, and the graph paper helps, so I didn’t have to do much actual measuring.

The ultimate goal is to get a taped outline of your cutout onto the surface you need to cut out. The tape is a cutting guide, and also serves to protect the surface from the saw.

After taping the outline, I drilled holes in the four corners of the rectangle. The key here is to make sure that the holes don’t extend beyond the edge of the tape. I’ve found that a magnet is useful to pick up the big shavings from the drill. The holes should be big enough to allow the jigsaw blade to fit through them I also drilled small pilot holes before using the larger bit. The advantage of using a smaller jigsaw blade is that you can curve the cut slightly. The saw blade can then be run back and forth toward the corners of the rectangle to make the edges straight.

After finishing all of the cuts a magnet and vacuum cleaner was used to pick up all the loose metal. I used a flatt file to smooth all of the edges, removed all of the tape and cleaned the surfaces with WD-40 and “Goo-Gone”, the little bottle shown next to the open consolet. After that its good to check and ensure that the HMI fits in the hole, you’d hate to have to come back and file the opening any more!

I used the same graph paper to mark where the pushbutton holes would be drilled. Notice that I had originally marked for three buttons, but I found that they wouldn’t all fit when I looked at the inside of the consolet. This is again where, for a serious design project, you would want to draw everything ahead of time.

The item shown in the next frame that I used to mark the holes is affectionately know as a “pinger”, the technical name would be a spring-loaded center punch. This item is also commonly used to mark screw holes on an enclosure backplane. After marking the centers I used a small drill to make pilot holes.

The pushbuttons are both 30mm in size, and I happen to still have my Greenlee punches for several different sizes. You can see in the next frame that I also have a stepper bit that is a good size for the shaft of the 30mm punch.

I then used the stepper bit to drill the holes larger so that the shaft of my knockout would fit through the hole. I also had a picture of my old hydraulic knockout kit which I sold when I closed my company in 2006. As you can see it had a lot of different sized punches in it and was much quicker to use. I’m glad I kept my old wrench driven set though. As you can see the magnet also came in handy again.

When using the punch it is important to put the items together correctly; stud through the hole in the die and then through the front of the hole in the panel, then thread the cutting die onto the back. I once had a guy who worked for me put the die on backwards and he snapped the stud right in two. This is surprisingly easy when using the hydraulic punch.

I like to use vise grips to turn the stud. That way I can let go of them and turn the panel, and they stay connected.

After about 12-15 full turns of the stud the hole is ready to notch. As you can see in these pictures, there is an anti-rotation ring around the body of the pushbutton. The little stub on the ring fits into a notch that stops the device from rotating within the hole. The best tool to put this notch in is called a “nibbler”. I have one but forgot to take a picture of it, I’m sure you can find a picture online. If not, e-mail me and I’ll send you a picture. You can see what the ring looks like installed.

There are four fittings on the back of the consolet for cable entry. Two of then are 1/2″ fittings, which required another knockout, while two of them were drilled with a stepper bit. There are also three holes on the bottom used for mounting screws.

The tool shown in the lower left is known as a deburring tool. This is used to remove sharp edges from the holes. In the lower right you can then see the prepared consolet and associated components prior to assembly.

These pictures show the assembled consolet on a table, then bolted to the extrusion frame. After a bit of wiring there is the HMI powered up.

This picture is of the powered up consolet on the machine side of the frame. The picture below is of the left, or process side of the “Factory”.

As you can see, some progress has been made, but there is a long way to go. The disc on the right side is the dial table, and as you can see I have painted and mounted the process tanks. I am still waiting in delivery of the pneumatic components for the pick and places and the SMC dial table mechanism. Part of the escapements have been made. I had mentioned possibly needing to use a machine shop to finish out the escapements; I may now be able to do it myself if I can get hold of some of the proper sized aluminum angle. More updates to follow next month.

By the way, I will be having an open house at my new facility toward the end of the week of June 5. If you are in the Nashville area, stop in and say hi! I will announce the actual date next week when I have finalized things.

Posted in My Little Factory, Panelbuilding Tagged with: , , , , , , , ,

My Little Factory – Innovate

The week before last I talked about how I make some of the mechanical things for My Little Factory. A quick update on that: I have managed to make some progress on fabricating the escapements for the indexing conveyor, but I may have to turn some of the more delicate parts over to a machine shop. I have a prototype that works, but if I want it to be consistent and precise over all three of them I will need to leave it to the pros.

This week’s topic concerns some of the electronics and prototyping I want to do that honestly falls outside of the typical industrial arena. I took some liberties with the picture above; the “Innovate” sign is a bit up and to the right of the blue storage bins, but I wanted to get my workbench into the picture.

This area is where I do my prototyping and board-level stuff. As you can see there are lots of storage areas, an oscilloscope and function generator, soldering station, and a small library of electronics resources.

One of the things I am working on is converting the small millivolt-level load cell signals to a 0-10v input that can be used by a PLC. As I mentioned in my signal conditioning post a few weeks ago, this is done with summing boards and amplifiers, which are pretty standard methods in industry, but the equipment I have found online isn’t really suitable for a miniature factory. I am having cobble some things up and am revisiting some of my old Electrical Engineering and technician methods to fit everything in the way I want it.

A bit of history on how I ended up with this innovation area in the first place. As some of you may know, Radio Shack has fallen on hard times in recent years. I had heard they were bankrupt several years ago, but several stores had stayed open in my area of Tennessee, including one at a mall in Nashville. It turns out they were bought by Sprint. A couple of years ago I walked in to check it out and noticed a lot of “maker” stuff related to the popular STEM programs kids are getting involved in in school. There were various Arduino related gadgets along with the typical electronic components you usually find in their bins; pretty overpriced compared to the things you can find online. I bought some of it anyway, hoping to get around to playing with it in the future; this was before I moved my office to this bigger facility closer to home. I’m afraid it languished in my garage until the past few months.

Anyway, the last time I went to that mall there was a big sign on the door: Store Closing! Everything must Go! Long story short, I bought a LOT of their stuff, including some of their component bins. Then I went to all of the other local Radio Shacks and did the same thing.

I’ve also mentioned the Tibbo and Raspberry Pi components I’ve been interested in. These small board controllers remind me of some of the projects I did in college, but processors have come a long way since then. Electrical Engineering students were required to build circuits using the HC6811C chip, using LEDs and discrete components to build simple control circuits and illustrate the use of low-level programming languages like Assembly. Now with the Industrial Internet of Things (IIOT) these controllers are finding their way into applications everywhere. This opened the door for me to produce customized classes for people interested in prototyping and inventing.

It is difficult to make a lot of progress in this area until I have finished the industrial part of my classes, but I will soon be breadboarding some sensor circuits for demonstration purposes, and as I complete some of these microprojects they in turn will be making their way into more class materials. Until then, this area of my facility will be a fun place to try out some of the ideas I have had in the low voltage world. If you have been working with Arduino, Raspberry Pi or any circuit board level electronics projects, leave a comment!

Next week, stay tuned for an update on the Industrial side of My Little Factory with “Automate”

Posted in My Little Factory, Product Development Tagged with: , , , , , , , , , , ,

My Little Factory – Fabricate

A couple of weeks ago I started a series called “My Little Factory”, describing a system I am building for training purposes. I plan on updating the progress on this project monthly, but today’s topic is also related.

As those who follow this blog know, I have been involved in custom machine building for over twenty years. Even though I am nominally a “controls guy”, I have had to learn how to make mechanical things work and sometimes fabricate different items. From about 2002-2006 I did a lot of mechanical design for my own company, primarily using AutoCAD and drawing in 2D. Below is a collage of some of the tools in my old shop in Knoxville.

Now if I was the guy who had to make the thing I designed I wouldn’t have to draw as much detail, but if my machinist or an outside machine shop was making parts, everything had to be planned out very carefully. Dimensioning and spelling things out in great detail was very important.

The picture at the top of this post is most of what I have to work with now. My facility is primarily for training, and I am the only one here, so I have set up what I need to put together my project. I have to use the space that I have judiciously, and making things is not the main focus of my company.

I do have some tools at home also; recognize the toolbox? That is one of the few things I have left over from my old shop. The mill is much smaller than my old one, but it is still useful for making small widgets. I thought about bringing it to my shop, but it is pretty heavy and quite messy. Chips would get everywhere. I only live about 5 minutes from my shop though (~2 miles), so it’s not that big of a deal to go home if I need to make something. By the way, the table in front of the tool chest is actually a table saw with a board on top. It’s another messy thing that takes up a lot of space, so it’s better to leave that one in the garage also.

So what kind of things do I need to fabricate? Well, lately I’ve had to work with a lot of plastic.

If you look at the picture from my first “little factory” post, you’ll notice the plastic tanks on the left side; this is for my process control side of the project. Working with plastic is tricky. You have to go slow and use the right tools, such as plastic bits. It can also be very tricky fixturing small pieces while you are working with them. See the little blocks with the plastic fittings in them? I broke three of them because I didn’t have a good clean way to hold them in the mill. It’s hard to see from the picture, but the setup on the mill in my garage is what I used.  I also didn’t have a plastic bit for the hole that I needed to thread, so I used a wood bit.  I did finally manage to get them bored and threaded, but it took a lot longer than a pro would have.

The blocks are attached using a plastic cement that is applied with a needle, kind of like a syringe. The only reason the blocks have to be there at all is that the thin tank material wouldn’t hold a thread. The purpose of the boxes is to hold the tank on the three load cells in the picture. The screw holes are where the load cells are attached, and the square/rectangular holes in the boxes are to allow the blocks to extend through the surface. A 1/4″ hose then brings the water outside to the valves and pumps. I figured it would be easier to call the tanks “red tank, blue tank and yellow tank” rather than tank 1, 2 or three.

My Little Factory 7 May 2017

As you can see I’ve got all of the control panels mounted to the wall. Not everything is wired yet, but the Allen-Bradley and Siemens are both powered up and have the start of a program in them. The Beckhoff is against the back wall, I haven’t done anything with it yet. My wooden drive panel actually turned out ok.

It takes a lot of the same tools to make a little factory as it does to make a big one. Of course I don’t need millwrights to move things and since I am doing all of the work I don’t have to draw things in as much detail.

The next things I have to fabricate are the escapements for the little balls. This involves a whole lot of drilling and tapping aluminum as well as a bit of milling at home. I also have to go to Los Angeles week after next to teach a ControlLogix class, so I may not have them all done in time for my May update on this blog.

So why the word “Fabricate” over the tools? I’ve actually put a bunch of text over different areas of my shop, you’ll get to see more of that in my next post, “Innovate”. Of course the factory area has the word “Automate” over it. I even though about putting the word “Educate” in the training area, but that is probably too much. I even thought of a couple of words I could put over the bathroom, but I think not…

Posted in Machine Assembly and Fabrication, My Little Factory, Plastics

Sensors 102: Signal Conditioning

Today’s post is about what goes on between an actual detection device and the input of a control system.

In many control applications you don’t need to think about what goes on inside of a device. The signal is converted inside of the device to whatever your control system needs. Fortunately most industrial systems have standardized on certain voltage or current signals; 24vdc or 120vac for digital, 0-10vdc or 4-20mA for analog. In most cases the actual detecting element inside of the sensor is a low voltage device that requires somewhere from 1.5-5vdc, but for commonly used, mass produced devices all of the conversion happens inside of the sensor. You simply have to provide one of the standard industrial voltages mentioned previously and connect it to your input.

When I was in engineering school we built small digital circuits on bread boards using LEDs, resistors, transistors, bridge circuits, photodetectors and sometimes IC chips. Mechanical mockups of physical systems were made of cardboard, balsa wood or whatever a poor student could get their hands on. In general, everything was done at the 5-12 volt level and the signal didn’t have to travel very far.

With larger systems signals can’t be distributed at such low levels. Devices are often far away from the control enclosure, though communications-based distributed I/O blocks have all but eliminated the necessity of using 120vac signals. Still, it is certainly not realistic to transmit TTL (Transistor-Transistor Logic) signals from a sensor to the control cabinet.

But what happens when you have to convert a signal yourself? Well, there are a variety of commercially available devices that take in a signal of one type and convert or amplify it into a signal of a different type. Probably the simplest method of doing this with a digital signal is to use a relay. Relays are available with 5vdc, 12vdc, 24vdc, 120vac and even higher coils. Even with such a simple device, care must be taken not to corrupt the signal by introducing noise into the system. It wouldn’t do to tie-wrap your 5vdc wires to your motor cables or 480v supply!

Analog converters are available to convert 4-20mA to 0-10v and vice-versa, mV/V signals to standard analog, and various other special purpose of the problems that can occur is that shown at the top of this post. Not only do you have to worry about the aspects of the converter itself (where to put it, how to wire it, its cost etc.) but also how to provide power to it and the detection device.

In last week’s post I described my tabletop factory. In it I talked about using load cells on the process side to determine tank levels. The diagram above shows the layout of the devices that are required to do this; all of the components have been ordered and I have even received some of them. This has brought up some interesting decisions on where to put things and how to interface them. Since everything needs to fit in the space that I have, some of the signal processing devices will not be mounted the way they would be in the field. Though my “factory” is miniaturized, unfortunately the devices aren’t.

The fact that the load cells only have 24″ cables (a little over half a meter) gives you a clue that the mV/V signal isn’t meant to be run very far. My summing boards are also pretty huge, so it isn’t easy to figure out where to put them. Then there’s the fact that I need to run 5vdc to the board also; fortunately my control panel is close to the tanks so I do have a convenient place to put the power supplies.

The signal conditioner itself, which takes the mV signal and amplifies it to a 0-10vdc signal, uses a 12vdc power supply. Again, since the output from the summing board is a mV level signal, it needs to be close to the signal conditioner. In the field these devices might have been located underneath the thing being weighed, but my process tanks are only 12″ high.

In 2012 I described an application where I did this same thing for a batching system at Alcoa. In this case the hopper was MUCH bigger than the devices, and it was easy to locate a small enclosure underneath the hopper itself. Effectively, it was like building your own sensor and bringing the signal from the enclosure as a fully conditioned analog input.

Another option I would have had on this system was to use a pressure transducer at the bottom of the tank itself, similar to what I have described in some of my posts on ABD in Miami. The nice thing about doing this is that the transducer’s output would already be in a usable form such as 0-10vdc or 4-20mA. The problem is both space and the low volume (weight/pressure) of my tanks.

Anyway, some things to think about when planning your application: cost of the components, including the enclosures you may need to put things in; the distance a low voltage signal can travel without being degraded or corrupted; power supplies/voltages that may not be available in your control system, and cost of design/labor to put all of this stuff together. There is also the issue of how you are going to calibrate all of this when you are done putting it all together. Every time you pass through another conversion or device you introduce another variable into the system.


One of the areas in my new training center is an electronics bench. complete with oscilloscope, signal generator, bread boards and lots of components. The idea is to provide a development/innovation area for those interested in learning how sensors work at the component level or wish to learn basic electronics. Until I write up a formal class on it I don’t expect it will get used much, but it will be available for those taking my other custom classes. Hit me up for more information!

Posted in Load Cells, Process, Product Development, Sensing Tagged with: , , , , ,

My Little Factory – April 2017

This post is the first in a series I am writing about a project I am working on, hence the “April 2017” designation.

As most of my regular readers know, I have spent much of the past several years teaching PLC and HMI classes across North America for Automation Training. I recently moved my office from a small shared space facility in Nashville to a larger place only 5 minutes from home, and in January held my first class there for AT.

The class went really well. There was plenty of room for the eight students and it was kind of a “Grand Opening” for my new place.

Since then I have still been traveling and teaching, but I have also started building a hands-on section for advanced training classes. The idea is that rather than teaching instruction sets and specific platforms, I am creating a set of courses that allow students to interface with real equipment.

“My Little Factory” – April 23, 2017

This is what I’ve got so far. My wife builds control panels, so I am very fortunate to be able to do most of this in-house. I’m afraid my panel-building days are behind me, but I’m still pretty good at making parts and doing the field wiring.

The drawing at the top of this post shows what the system will eventually look like. There are two sides, a machine control side and a process control side. The machine control side starts with an indexing conveyor from QC Conveyors. Boxes will be place at the left end of the conveyor, indexed to the right where three escapements will drop different colored balls into the boxes. As the boxes arrive at the right end of the conveyor, a pick and place will move the box to a dial table. The dial will index the part under a machine vision station, which will inspect the boxes for the proper number and color of balls. Another pick and place will remove the box to the rear conveyor (also by QC) which will then move the box to different ends based on pass fail status.

This allows students to learn recipes, part tracking, pick and place sequences, and a host of other techniques needed in the machine control world. There will be dual channel safety circuits (good for troubleshooting), operator interfaces, and whatever else I come up with as I’m building it.

The process control side will have two ingredient tanks with load cells for volume/level, A mix tank (also with load cells), electric valves and pumps, and a flow meter. There are lots of opportunities here to train on calibration, PID control, configuration of flow switches and other techniques used in the process world. I am still considering doing some temperature loops also.

Notice that there is an Allen-Bradley CompactLogix and a Siemens S7-315.Originally I though I’d use the AB on the machine control side and the S7 on the process side. Mieko had already wired the CompactLogix when I thought what if a student wants to control the Machine side with the S7? This is when I came up with the idea of using cables to connect the PLCs to the different setups.

Its a good thing I did, because now I’ve added a Beckhoff 9020 to the mix. This will also be wired with cables and located behind the outfeed belt conveyor. I have a lot to learn about the Beckhoff, but I hope to create classes for it soon also. This allows me to get into the computer control and CodeSys world, which I believe will be popular in the future. Other platforms may appear later too.

Yup, that is a wood backplane. Obviously some of this stuff is expensive and I need to save money where I can. I will be painting it and mounting the conveyor drives next week and hopefully it will still look professional.

There are a lot of other things to show you in my shop; there is a fabrication area for making widgets, an “invention” area with Arduino, Raspberry Pi, Tibbo and lots of board level electronics stuff, a pneumatics area, a machine vision lab and of course the training area I showed in the beginning of this post. Altogether I have about 3500 square feet and I hope to make good use of it.

Other classes I hope to add that will complement the PLC, HMI and SCADA stuff I am already doing include AutoCAD, Machine Design, Electronics, Pneumatics/Fluid Power and Machine Vision. My business website hasn’t really caught up with all of this yet, but I am already accepting students for classes. The courses are very customizable and I expect most of my students to come from around Nashville at first.

Because this project will be taking quite a while, I will be updating progress in a series of posts titled “My Little Factory” with the month listed. There will be some useful stuff in these posts; one of the things a I am working on right now is interfacing the load cells through a summing board and into a signal conditioner. I am also designing the pick and places and will be building the escapements over the next couple of weeks.

If you are interest in knowing more or have any suggestions, leave a comment or shoot me an e-mail!

Posted in Applications, Conveyors, Load Cells, Material Handling, My Little Factory, PLCs, Pneumatics, Process, Sensors, The Course, Training, vision Tagged with: , , , , , , , , , , , , ,