Is a PLC the right tool for the job?

[Jeffro67]

Hi All, I have a programming background but have never used a PLC. I have what I think is a simple automation project however Im not sure of the right type of controller to use. PLC or another type of controller such as ARDUINO.

The requirement is to measure the position of 3 levers. The levers have a travel of about 30mm. Depending on the position of the levers and rate of travel I need to fire a solenoid. The component must be analog so we can determine the position of the levers.

There would also be a dial/knob. This would act as an input to adjust the sensitivity of the solenoid firing.

The custom written program would be constantly monitoring the change of position of the levers and dial, then fire the solenoid as required.

Is a simple cheap PLC the right tool for the job?
What are the main components required?
Can I outsource the build and programming of the device?

Thanks is advance

 

[cardosocea]

Where is it to be installed? If it's in industry, Arduino is not the way forward. Look at Logo or S7-1200 or a Click.

 

[Puddle]

A Siemens Logo controller is about as simple as you can get and these support up to 4 analog inputs without any additional parts.

You'd just need an enclosure and most likely a 24v DC power supply for the sensors.

 

[BobB]

Arduino is a toy for fiddlers. Not industrially hardened.

 

[JesperMP]

If you need some of these requirements mentioned below, then the answer is that you need a PLC.

• Programming in a PLC language (i.e. LAD, FB, ST, GRAPH).
• Online view of the running program.
• Online change without shutdown.
• Diagnostics built-into the hardware and software.
• Industrially hardened, and approved to use in an industrial application.
• Reliability of the hardware.
• Reliability of the software. Both the OS and the runtime application.
• Proper support for both hardware and software.
• Availability of the hardware and software over 15+ years.

 

[busarider29]

If you need some of these requirements mentioned below, then the answer is that you need a PLC.

• Programming in a PLC language (i.e. LAD, FB, ST, GRAPH).
• Online view of the running program.
• Online change without shutdown.
• Diagnostics built-into the hardware and software.
• Industrially hardened, and approved to use in an industrial application.
• Reliability of the hardware.
• Reliability of the software. Both the OS and the runtime application.
• Proper support for both hardware and software.
• Availability of the hardware and software over 15+ years.

^This^

I would recommend Beckhoff (PC based solution). They have Windows, BSD, or Linux options for OS. Engineering software is free, the runtime can be endlessly renewed every 7 days with a captcha entry and mouse click. You can run the runtime on your laptop (just like on real PLC hardware) for testing and debugging your code. PM me if you want more info regarding this solution.

 

[Jeffro67]

Where is it to be installed? If it's in industry, Arduino is not the way forward. Look at Logo or S7-1200 or a Click.

It will be installed in the cabin of a race car. So it needs to withstand vibration etc

 

[Jeffro67]

A Siemens Logo controller is about as simple as you can get and these support up to 4 analog inputs without any additional parts.

You'd just need an enclosure and most likely a 24v DC power supply for the sensors.

Being installed in a car I only have 12V readily accessible. Are there 12V options?

 

[bkottaras]

I know Horner hardware works with skids/trucks as far as voltage goes.
Take a look at their line up and see if it covers your needs.
I'm sure other manufacturers may offer the "down to 12V" solution, I just haven't used any other than Horner.
Their pricing is also reasonable.

 

[bkottaras]

As far as vibration goes, you may need to do some rubber mounts to eliminate as much as possible. (with any hardware/brand chosen).

 

[robertmee]

Being installed in a car I only have 12V readily accessible. Are there 12V options?

You can convert 12vdc to 24vdc with a step up converter...theyre small and inexpensive. Would open more options for the PLC implementation.

 

[jds8086]

Do you require proportional control of your solenoids are will they either be on or off with no ramp. I ask because many automotive applications of solenoids utilize PWM outputs to smooth the action of whatever function the solenoid performs, or to control pressures, etc.

Do you have any experience soldering / working with electronic components (resistors/transistors/capacitors/etc)?

 

[IO_Rack]

You are asking for advice from a bunch of hammers in this forum, so this project certainly looks like a nail.

I wouldn't rule out using a microcontroller or Arduino. Since you already have programming experience and if you are crafty enough to build it with durability. You'll use less space and less power. It may get hairy if you need visualization other than LEDs. It would be more difficult to test and troubleshoot.

PLCs have a lot more plug n play options for analog devices, meaning you wouldn't need additional electronic components to apply your analog signals. Easy to troubleshoot and view online signals. As mentioned, finding a 12V PLC with your specs will be difficult but I've used DC to DC converter for this and it works well.

PLC or microcontroller, you'll need measurement devices if don't already have them. Linear encoders or potentiometers maybe?

 

[sigmadelta]

Siemens Logo has a 12/24VDC model with 8 digital inputs (of which 4 inputs could be analog) and 4 digital outputs (relay). Additional modules can be added if necessary.

https://mall.industry.siemens.com/mall/en/WW/Catalog/Product/6ED1052-1MD08-0BA1

 

[WhinnieThePooh]

If you need some of these requirements mentioned below, then the answer is that you need a PLC.

• Programming in a PLC language (i.e. LAD, FB, ST, GRAPH).
• Online view of the running program.
• Online change without shutdown.
• Diagnostics built-into the hardware and software.
• Industrially hardened, and approved to use in an industrial application.
• Reliability of the hardware.
• Reliability of the software. Both the OS and the runtime application.
• Proper support for both hardware and software.
• Availability of the hardware and software over 15+ years.

There's a lot of wisdom there. I used to try to install Arduinos in industrial applications, but abandoned it for those very reasons.

Go with a mainstream PLC brand that is well supported in your area, it will work out much better for you in the long run.