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Hackaday readers don’t need an introduction to the Arduino. But in industrial control applications, programmable logic controllers or PLCs are far more common. These are small rugged devices that can do simple things like monitor switches and control actuators. Being ruggedized, they are typically reasonably expensive, especially compared to an Arduino. [Doug Reneker] decided to evaluate an Arduino versus a PLC in a relatively simple industrial-style application.

The application is a simple closed-loop control of flow generated by a pump. A sensor measures flow for the Arduino, which adjusts a control valve actuator to maintain the specified setpoint. The software uses proportional and integral control (the PI part of a PID loop).

Although the Arduino has a good selection of I/O pins, it doesn’t have common I/O capabilities you’d expect in an industrial controller. For example, the flow meter used in the demo produces a current proportional to flow ranging from 4 mA to 20 mA. That’s a very common set up in an industrial device since current loops are able to handle long wire runs, along with other reasons. [Doug] found he had to create a converter to get the data to the Arduino. He also needed a way to convert the Arduino’s PWM output to a 4-20 mA output, which was even more complicated.

Of course, the PLC had all of these options already, along with a user interface suitable to the task. From that [Doug] drew the conclusion that while the basic hardware was cheaper, it was a wash by the time you added the ancillary components. He also felt that the engineering time to build the Arduino version of the project swamped all the costs of using the PLC.

In general, we don’t disagree. However, it depends on what you are trying to accomplish. While a hammer is good at driving nails, it isn’t good with screws. You need the right tool for the job. If you really had 4-20 mA gear and needed a PLC-like user interface, then, of course, the PLC is probably the right choice. However, if you had started with the Arduino, you could have selected better flow monitoring and actuator choices, provided better power, and used a user interface more suited for the Arduino and gotten a better result.

Don’t get us wrong. PLCs have a place. So do Arduinos. So do ARM chips, Raspberry PIs, and 555 timers. For [Doug’s] project a PLC was clearly the right answer. That doesn’t mean it is always the right answer. However, we did think seeing the comparison between the two might help PLC experts understand the Arduino better and vice versa.

Although most PLCs are proprietary, we’ve covered OpenPLC before. Maybe the best idea isn’t to pick one or the other, but use both and play to their strengths.


Filed under: Arduino Hacks

When teaching Industrial Automation to students, you need to give them access to the things they will encounter in industry. Most subjects can be taught using computer programs or simulators — for example topics covering PLC, DCS, SCADA or HMI. But to teach many other concepts, you  need to have the actual hardware on hand to be able to understand the basics. For example, machine vision, conveyor belts, motor speed control, safety and interlock systems, sensors and peripherals all interface with the mentioned control systems and can be better understood by having hardware to play with. The team at [Absolutelyautomation] have published several projects that aim to help with this. One of these is the DIY conveyor belt with a motor speed control and display.

This is more of an initial, proof of concept project, and there is a lot of room for improvement. The build itself is straightforward. All the parts are standard, off the shelf items — stuff you can find in any store selling 3D printer parts. A few simple tools is all that’s required to put it together. The only tricky part of the build would likely be the conveyor belt itself. [Absolutelyautomation] offers a few suggestions, mentioning old car or truck tyres and elastic resistance bands used for therapy / exercise as options.

If you plan to replicate this, a few changes would be recommended. The 8 mm rollers could do with larger “drums” over them — about an inch or two in diameter. That helps prevent belt slippage and improves tension adjustment. It ought to be easy to 3D print the add-on drums. The belt might also need support plates between the rollers to prevent sag. The speed display needs to be in linear units — feet per minute or meters per minute, rather than motor rpm. And while the electronics includes a RS-485 interface, it would help to add RS-232, RS-422 and Ethernet in the mix.

While this is a simple build, it can form the basis for a series of add-ons and extensions to help students learn more about automation and control systems. Or maybe you want a conveyor belt in your basement, for some reason.


Filed under: Arduino Hacks, hardware

Industrial hardware needs to be reliable, tough, and interoperable. For this reason, there are a series of standards used for command & control connections between equipment. One of the more widespread standards is ModBus, an open protocol using a master-slave architecture, usually delivered over RS-485 serial. It’s readily found being used with PLCs, HMIs, VFDs, and all manner of other industrial equipment that comes with a TLA (three letter acronym).

[Absolutelyautomation] decided to leverage ModBus to control garden variety digital cameras, of the type found cluttering up drawers now that smartphones have come so far. This involves getting old-school, by simply soldering wires to the buttons of the camera, and using an Arduino Nano to control the camera while talking to the ModBus network.

This system could prove handy for integrating a camera into an industrial production process to monitor for faults or defective parts. The article demonstrates simple control of the camera with off-the-shelf commercial PLC hardware. Generally, industrial cameras are very expensive, so this hack may be useful where there isn’t the budget for a proper solution. Will it stand up to industrial conditions for 10 years without missing a beat? No, but it could definitely save the day in the short term for a throwaway price. One shortfall is that the camera as installed will only save pictures to its local memory card. There’s a lot to be said for serving the images right to the engineer’s desk over a network.

We’ve seen [Absolutelyautomation]’s work before – check out this implementation of Pong on an industrial controller.


Filed under: Arduino Hacks, digital cameras hacks

If you’ve spent any time on a factory or plant floor, it is a good bet you’ve run into PLCs (Programmable Logic Controllers). These are rugged computers that do simple control and monitoring functions, usually using ladder logic to set their programs. [plc4u] wanted to connect a smart card reader to an Allen Bradley PLC, so he turned to an Arduino to act as a go-between.

The Arduino talks to a USB card reader using a USB host shield. Then it communicates with the PLC using an RS232 link and the DF1 protocol that most Allen Bradley PLCs understand. You may not need a smart card, but once you know how to communicate between an Arduino and the PLC, you could do many different projects that leverage other I/O devices and code available on the Arduino and connects to existing PLC installations. Just remember that you’ll probably need to ruggedize the Arduino a bit to survive and be safe to the same level as a PLC (which might include a NEMA enclosure or even an explosion-proof box).

We’ve covered more than one open source PLC project before. If you want to learn more about the ladder logic PLCs use, there’s a good video on the subject. The video below, however, shows the smart card reader in action.

PLC Photo: By Cmarcante (Own work) [CC BY-SA 3.0], via Wikimedia Commons


Filed under: Arduino Hacks
Set
16

Arduino as a programmable logic controller (PLC)

arduino, plc Commenti disabilitati su Arduino as a programmable logic controller (PLC) 

SCHEMA-ELETTRICO-500x478

By Christian Granvillano @ open-electronics.org:

Today we’ll explain how to exploit the potential of Arduino as a programmable logic controller, connecting it to appropriate interfaces for I/O.

The PLC (Programmable Logic Controller) has been and still is the basic component of the industrial automation world. The Industrial application made the PLC systems being very expensive, both to buy and repair, and also because of the highly specific skills requested to software designers to extract the maximum potentials from controllers. Arduino is a kind of universal programmable controller, although it is only the “core” and in any case it has been built for general applications; with a little of external hardware (essentially interfaces capable of transferring signals from sensors and to actuators, reducing the EMI which may damage the microcontroller) and an appropriate software may, however, become something very similar to a PLC.

Arduino as a programmable logic controller (PLC) - [Link]

Set
16

Arduino as a programmable logic controller (PLC)

arduino, plc Commenti disabilitati su Arduino as a programmable logic controller (PLC) 

SCHEMA-ELETTRICO-500x478

By Christian Granvillano @ open-electronics.org:

Today we’ll explain how to exploit the potential of Arduino as a programmable logic controller, connecting it to appropriate interfaces for I/O.

The PLC (Programmable Logic Controller) has been and still is the basic component of the industrial automation world. The Industrial application made the PLC systems being very expensive, both to buy and repair, and also because of the highly specific skills requested to software designers to extract the maximum potentials from controllers. Arduino is a kind of universal programmable controller, although it is only the “core” and in any case it has been built for general applications; with a little of external hardware (essentially interfaces capable of transferring signals from sensors and to actuators, reducing the EMI which may damage the microcontroller) and an appropriate software may, however, become something very similar to a PLC.

Arduino as a programmable logic controller (PLC) - [Link]

Set
16

Arduino as a programmable logic controller (PLC)

arduino, plc Commenti disabilitati su Arduino as a programmable logic controller (PLC) 

SCHEMA-ELETTRICO-500x478

By Christian Granvillano @ open-electronics.org:

Today we’ll explain how to exploit the potential of Arduino as a programmable logic controller, connecting it to appropriate interfaces for I/O.

The PLC (Programmable Logic Controller) has been and still is the basic component of the industrial automation world. The Industrial application made the PLC systems being very expensive, both to buy and repair, and also because of the highly specific skills requested to software designers to extract the maximum potentials from controllers. Arduino is a kind of universal programmable controller, although it is only the “core” and in any case it has been built for general applications; with a little of external hardware (essentially interfaces capable of transferring signals from sensors and to actuators, reducing the EMI which may damage the microcontroller) and an appropriate software may, however, become something very similar to a PLC.

Arduino as a programmable logic controller (PLC) - [Link]

Ago
28

800 inches per minute at 0.00025″ Resolution

arduino hacks, chipkit, pic32, plc, PONTECH, quick240, velox slides Commenti disabilitati su 800 inches per minute at 0.00025″ Resolution 

800IPM Linear Slide Control

The folks over at PONTECH have just released a pretty impressive opensource PIC32 library for controlling a linear slide at speeds of 800 inches per minute!

PONTECH makes the Quick240 (Quick Universal Industrial Control Kard) which is based on the open source chipKIT platform. It was designed for industrial automation systems, where typically a ladder logic PLC might be used. The benefits to using a system like this is that because it is open, you are no longer stuck with proprietary hardware, and it is much more flexible to allow you to “do your own thing”. Did we mention it is also Arduino compatible?

Using this system they’ve successfully controlled two 8″ Velox slides at a whopping 800 inches per minute with a resolution of 0.00025″ — just take a look at the following video to appreciate how freaking fast that is.

The StepAndDirection library can be found over at GitHub for use with a PIC32 microcontroller.


Filed under: Arduino Hacks
Ago
28

800 inches per minute at 0.00025″ Resolution

arduino hacks, chipkit, pic32, plc, PONTECH, quick240, velox slides Commenti disabilitati su 800 inches per minute at 0.00025″ Resolution 

800IPM Linear Slide Control

The folks over at PONTECH have just released a pretty impressive opensource PIC32 library for controlling a linear slide at speeds of 800 inches per minute!

PONTECH makes the Quick240 (Quick Universal Industrial Control Kard) which is based on the open source chipKIT platform. It was designed for industrial automation systems, where typically a ladder logic PLC might be used. The benefits to using a system like this is that because it is open, you are no longer stuck with proprietary hardware, and it is much more flexible to allow you to “do your own thing”. Did we mention it is also Arduino compatible?

Using this system they’ve successfully controlled two 8″ Velox slides at a whopping 800 inches per minute with a resolution of 0.00025″ — just take a look at the following video to appreciate how freaking fast that is.

The StepAndDirection library can be found over at GitHub for use with a PIC32 microcontroller.


Filed under: Arduino Hacks
Lug
09

This is run by an Arduino

arduino hacks, industrial, plc Commenti disabilitati su This is run by an Arduino 

industrial-arduino-use

Let us be the first to say: Not a hack! Nonetheless this is an interesting read about how the Arduino movement has made hobby microcontroller boards attractive for industrial applications.

This is a digital printing machine which looks like it is used for industrial packaging. [Paul Furley] worked for the company which produces it, developing the software for the control interface. He recounts the story of how he helped guide the company away from choosing a microcontroller, and toward using an Arduino board. Actually, using three Arduino boards. We can already hear the flame war boiling up in the comments section. But before you rage, read the article and see if you don’t agree with [Paul's] reasoning.

The most compelling argument to us is that choosing Arduino is absolutely future proof. If the company goes out of business there are hundreds of clone devices already available. As the Arduino platform evolves it will keep pin compatibility in order to support the older shields. And if they choose a different microcontroller the Arduino IDE will still compile the same sketch for the new hardware.

One thing that pops into our minds is write protection. The machine uses a big PCB to which the three Arduinos mount. That can be produced anywhere without threat of having the source code leak as the PCB doesn’t include chips that need to be programmed. Arduino uses AVR chips that have write protection fuses which can be burnt in-house after they flash the control firmware.

[Thanks Thomas]

 


Filed under: Arduino Hacks


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