ladder logic (PLC) vs Labview

[joejoe666]

hello, i am wanting to know what the difference is between ladder logic and labview in a manufacturing plant environment? To clarify, why would a company go with ladder or labview? From what i read, i see that both can control and do the same things. Is the only difference price and amount of people who know the each of the programming language? My whole company has 4 manufacturing plants and everything is PLC based.

Assumptions:
Please put C++ and other languages aside in this comparison.
i am very new the progamming world so please explain in simple (for 10 yr old kids) verbiage. i am a senior mechanical / design engineer. I am thinking about learning ladder or labview for personal development.

 

[jackofalltrades]

ladder logic is not a program it is the method of thought for the language. there are many languages micrologix, for certain allen bradley plc's
automation direct has it's own language and every maker has it's own and none work with another.
I write plc programs and know nothing about labview.
but it is probibly just another plc program from another maker.
automation direct sells the most cost effective plc's and the cheapest software to write the program with.
Hope that helps your question.

 

[jackofalltrades]

try logixpro it is where I started cheap and has simulations to test your programs. It is a good basic to intermediate starting point.

 

[CycloWizard]

Ladder programming is very similar to LabView overall. LabView has a more flexible UI than the ladder tools that I've used but it's also rather expensive whereas there are many ladder tools that are free. I think it might be a little easier to learn with ladder first then move on to LabView later on if you have need of it.

 

[rhoffman21]

JoeJoe,
My company is a National Instruments Alliance Partner company specializing in using LabVIEW based systems in industrial and automation environments where PLC's are the norm. I have seen a number of pros and cons for both traditional PLC's and NI based platforms. If you are going to go with LabVIEW, it is important that you fully understand the system requirements and commit to doing it right, especially out on the plant floor. I have run into a number of plant controls engineers who have a bad impression of LabVIEW because someone in the past hacked something together that didn't work reliably. In short, it is tough to overcome the ubiquitous PLC and its inherent flexibility, but we are making serious inroads in places where a PLC just can't cut it. High speed data acquisition, data analysis, user interface design are areas where LabVIEW can excel. Here is a case study that I wrote on this type of application.

http://sine.ni.com/cs/app/doc/p/id/cs-13823

We are working on technology that combines the flexibility of ladder logic programming with the power of LabVIEW. If you have an application where this makes sense, please feel free to contact me.

Thanks,
Rob

 

[natenut]

I'm writing a PLC program as we speak. I have also written Labview in the past, i used version 6.0, i know they have a few more recent additions. I actually taught a class on Labview that introduced automation control theory like PID loops, motor drives and coordinated motion.

Comparing labview to PLC's is an apples to oranges comparison. They have much different niches. I wouldn't' even consider Labview for a manufacturing environment. PLC vendors have libraries and pre-canned stuff like PID loop, remote IO, drive interfaces ect, redundant communication protocols, interoperability between communication protocol ect... that you would have to re-invent from a very different perspective with Labview.

Labview is great for data acquisition on a small time scale. Like sampling an audio transducer and cross correlating it with another to find patterns. If i needed to do testing on a hall effect ion thruster, i would use labview exclusively for measuring things like fuel flow, temperature, thrust, strain, ect. getting sampling speeds high enough to asses physical properties and their interaction is much simpler. However, if i needed to control a production line that incorporate drives, motion and logic that was spread out over a large area, i would use a PLC all the way. I'm not saying you couldn't use labview to do it, its just that it would be a lot more work.

Take that with a grain of salt, i haven't used labview in about 8 years. Dont know what they have out now, but i do know that their I/O cost per point is much higher than PLC's as well.

 

[natenut]

let me clarify, i wouldn't use Labview to run a manufacturing environment. but if i needed to do some quality testing, i would totally integrate it into a testing station. It makes things like talking to database servers a bit easier if your logging test data results and the like.

 

[rhoffman21]

I can certainly understand some hesitation in using LabVIEW in a manufacturing environment if your experience is several years old. However, we do it everyday, and have become critical links in manufacturing processes in the automotive sector in everything from over the road commercial trucks to electric vehicle production. When done right, LabVIEW is capable of incredible reliability and robustness, and we have made it our business since 2004 to work in the most demanding environments where we are compared every day against PLC's and win. There certainly are caveats to this, and if not done right it can lead to disaster, but that is no different than any controls system out there. Feel free to contact me if you would like more information, and look us up at www.signalxtech.com or ni.com/signalx.

 

[CycloWizard]

I'm writing a PLC program as we speak. I have also written Labview in the past, i used version 6.0, i know they have a few more recent additions. I actually taught a class on Labview that introduced automation control theory like PID loops, motor drives and coordinated motion.

Comparing labview to PLC's is an apples to oranges comparison. They have much different niches. I wouldn't' even consider Labview for a manufacturing environment. PLC vendors have libraries and pre-canned stuff like PID loop, remote IO, drive interfaces ect, redundant communication protocols, interoperability between communication protocol ect... that you would have to re-invent from a very different perspective with Labview.

Labview is great for data acquisition on a small time scale. Like sampling an audio transducer and cross correlating it with another to find patterns. If i needed to do testing on a hall effect ion thruster, i would use labview exclusively for measuring things like fuel flow, temperature, thrust, strain, ect. getting sampling speeds high enough to asses physical properties and their interaction is much simpler. However, if i needed to control a production line that incorporate drives, motion and logic that was spread out over a large area, i would use a PLC all the way. I'm not saying you couldn't use labview to do it, its just that it would be a lot more work.

Take that with a grain of salt, i haven't used labview in about 8 years. Dont know what they have out now, but i do know that their I/O cost per point is much higher than PLC's as well.

It's true that PLC libraries can do a lot of the heavy lifting for you but it's also pretty easy to build your own controller in LabView. In fact, that was the first thing I ever did in LabView. Of course, you have to know a bit about how controllers work and how to tune them to pull it off. I guess another consideration is the type of hardware you have available and what your budget might be. LabView has APIs for lots of different hardware at this point though some hardware vendors will charge extra for these APIs.