In today's edition of “Insight's Inbox” we answer a reader's question about what we think would be the best PLC to use in a college course.
My professor reached out to me to ask which PLC I would recommend he purchase with some school funds he had left over, and I wanted to get your opinion?
Great to hear your professor is looking to add PLCs to his curriculum!
The first option is the ultimate budget option: The Allen-Bradley MicroLogix 1000.
I go into the gory details of why I recommend this Allen-Bradley PLC to beginners in the below article, but in short it programs like most other A-B PLCs, is inexpensive at ~$150, can be programmed with fee software, and even has a free emulator:
More information about the MicroLogix 1000 and its free software can be found in the below articles:
The $150 model has 6 inputs and 4 outputs and a Mini Din serial port for programming. Low cost programming cables for it can be found here:
I also know someone who sells a very affordable training course that would get your professor up to speed quickly:
The second option is like the first but with a more powerful Ethernet processor: The Allen-Bradley MicroLogix 1100
Upgrade from the 1000 to the 1100 and you will be spending roughly $500 per PLC, but you'll also be getting Ethernet communications, online editing, Floating Point and Long Integers, a well as expansion I/O capabilities.
They also program with the free software mentioned above, and more info about that can be found below:
Note before discussion some more expensive options:
Before going into the more expensive options, I would like to note that the more money you have, the more the Educational Program from Rockwell makes sense.
For around $200 you get a one year, one license toolkit of all their software along with 8-5 M-F tech support (for the instructor.)
But the best part is you get a crazy good hardware and software discount!
The down side? You have to call you local rep and fill in a form (i.e. no big deal!) It can also take a couple of weeks to process.
More info on this program can be found below:
For those with a larger budget, I would recommend the Allen-Bradley CompactLogix line
Specifically the CompactLogix L1 family, which likely will run you $1400 a unit, and the lowest cost software to program it (assuming you are not in the EDU program getting an 80% discount) is going to run around $900 per seat.
Your local distributor is likely to be able to order “Starter Packs” that combine the software and hardware for a reduced price.
More info below:
A word on Input and Output Devices
The hot new thing is Ethernet/IP, and everyone is putting VFD's, Valve Stacks, and all kinds of I/O devices on Ethernet, including remote racks of I/O.
So if you had a larger budget and are purchasing a CompactLogix, I would recommend also getting an A-B PowerFlex 525 VFD, Point I/O remote I/O, and an SMC valve stack.
As far as digital I/O, I recommend diffused and retro-reflective photo eyes, inductive proxes, 22mm push buttons and pilot lights, as well as assorted relays and contactors/motor starters.
For analog I/O, I would try and stay with 4-20ma in and out, with the most common devices having to do with speed, position, temperature and flow control.
Update: If you have your own question you'd like to ask, please post it as a comment on a related post here at TheAutomationBlog.com
Hope this helps!