Schneider Electric PLC's vs. Allen Bradley

[scantime]

Does anyone have any experience with Schneider Electric PLC's? I am quite familiar with Allen-Bradley PLC's and programming software, however I had the opportunity to play around with a Schneider M340: my opinion, the program loading process was fairly easy, inherent features like function block locking is nice, but the programming (especially ladder) seemed a little clunky in places. I like Allen-Bradley (probably because I'm familiar with it), but would like to hear others opinions on this, especially functions that either manufacturer has endowed their PLC with that the other hasn't.

 

[grnick50]

I believe that M340 is a very nice PLC(PAC). I 've used it a lot in various projects and I never had any problems.
I like that it has all 5 IEC languages and my favourite is ST. I agree with you that Unity's Ladder is not its strongest point. I think an advantage is the integration of CanOpen in certain CPUs if you use it with Altivars or TesysU with CanOpen. In contrast, its Profibus solution I think is not good.
I have used it in several occasions with Modbus RTU and Modbus TCP/IP in multi-brand PLC networks (AC500, S7-1200) without any issues.
A very strong feature I think is that the program is downloaded with the comments so if it happens to lose your offline code you can always download it from the PLC.
Other nice features IMO is its Ethernet NOE card with the integraded Webserver, its timestamped DI modules, the visualisations in Unity that you can make for debugging and comissioning.

All in all it is a powerful and solid PLC that wont get you into trouble. I dare to say that if one is familiar with RSLogix5000 it is easy to understand Unity as I believe they have some features in common (contrary to Siemens).
For the AB guys, I think there is an EthernetIP functionality nowadays.

Generally for Schneider PLCs:
I would advise you to avoid Twido at all cost as it is a poorly featured PLC for its priced compared to S7-1200, Micrologix, AC500.
From the SoMachine series I used M238 which is nice and has a powerful Modbus Scanner feature that allows you to scan Modbus addresses from slaves with no code at all. On the Downside, M238 can only connect to ethernet via a gateway and only as Modbus TCP/IP server.
It is interesting to see how the Twidos replacement will be (Modicon 241) with onboard ethernet.
Lastly I would like to say that not in many occations I worked with Premium and in one occation with Quantum and I had no problems. However I have to say that in that level I prefer S7-300 / S7-400 instead.

 

[GeoffC]

I to am a fan of the M340 and Unity
All the IEC languages included. I do agree the ladder editor is a bit rough, but I almost never use ladder. The FB editor and language is excellent and would advise trying that.
There is a huge range of standard instructions, including a full process control library
If you need to set up communications the IO scanner makes this easy (when using NOE or NOC modules), just fill out the io scanner table and job done.
The simulation built into Unity is excellent
You will find using defined function blocks (DFB) or AOI in AB speak to be very powerful, they can even be edited online, and the logic inside can easily be monitored (right click select 'Refine')
To add to the above post it has native EthernetIP (using the NOC modules
The one programming package UnityPro is used for M340, Premium, Quantum and the new M580

 

[BobB]

I think it is relative - I am not an FB fan and do most in ladder so find it clunky for me. The reason I do not use FB is that many of my customers are in remote locations and I can talk them through ladder easily but they find FB difficult to understand. If there is ST inside the FB it is even more difficult.
The PLCs are OK and have some good features. Have not had one in for long enough to determine if there are any hardware problems or not. I find with many PLCs the power supply is the weak point and tends to fail in 3-5 years but do not know about these yet.
I find symbol programming to be a PITA and far too slow for me. I just like to get the job done, commissioned and out of there. I generally do not do maintenance so look for fast development and commissioning.
I came up in the old DOS days and program by keyboard and numbers - it is so fast it is not funny. Cannot do that with symbol based stuff.
That being said I notice that symbol based stuff is being pushed and forced on us by the Europeans. Doing a job with M340s at the moment and I reckon it is taking me twice as long to write the program due to the silly symbol based descriptions I have to use as defined by the client - switchboard/device allocation_wire number_terminal number_cable number_core number_switchboard/device allocation_terminal number_cable number_ etcetera - that becomes impossible to work with to be honest but I guess we are all going to have to get used to it. Not a huge fan of auto allocation either due to the way I program.
Appears to be a solid PLC and has a great variety of connecting cable combinations that make wiring life easier. AB is OK too but has too many file areas - good for somethings but I like a big internal memory may that I can allocate as I wish and then I know where everything is.
My main complaint with Schneider, Allan Bradley, Siemens and the like is the cost of annual support for software updates - it is horrific! I have to maintain 4 brands this way now and I can tell you the pockets are very empty when I have to pay them all!

 

[BobB]

I may add that AB, Siemens and many others take me longer to program too - not just Schneider.
Have only been doing PLC programming for about 28 years so probably know nothing!
Started with step controllers in the 80s! They were painful! And hand held programmers - so slow and hard to commission!
When the first DOS software came along it was wonderful - used to take a full DOS computer to site to commission. Yes, before laptops were useful and affordable - the laptops were nearly as hard to transport as a full computer.

 

[osmanmom]

it's not about which PLC is better,

its about where you to go for future,what type of industries you want involve.

its about how you deal the PLC.

 

[ganutenator]

For the price, the M340 is awesome.

Tons of memory, compared to the Premium plcs.

Plus, you can write code for something once, and then make it a function block and use it over and over again.

Yes, the ladder is sluggish. I have to hit alt + 1 every time I open a subroutine.

Ebool for rising edge instruction = stay away.

I hate the SFC language in this processor, much better in codesys, so I just make my own in structured text.

Wish they put line numbers in the st editor.

bloated software

other than that, not bad.

With AB seemed I would actually use my anomaly knowledge during a job interview.

 

[RheinhardtP]

Personally i would choose my hardware after assessing various different topics incl.

- Local Hardware Support
- Local Software Support
- Life cycle of Hardware
- Proficiency of local system integrator on the product
- Prices on hardware from local supplier
- Does hardware interface to well supported fieldbus system for drives , controllers ect. For example will you be running modbus/profibus/devicenet?

Give them a rating out of 5 or 10 and make your selection based on this. Depending what industry doing this assessment for i might add other fields.

You will find if you move across the world the assessment outcome would change. All PLCs can pretty much do the same thing. But you need to consider the equipment the PLC with interface to as well.

 

[GeoffC]

But you need to consider the equipment the PLC with interface to as well.

This is one of the real strengths of the M340, it can natively interface to Modbus, ModbusTCP, EthernetIP, CAN and Profibus

 

[Perrin]

I am also a unconditional fan of UNITY with M340 and now M580 .
I settled in since the beginning of its production either in Brazil in the sweltering heat of the Amazon, or in the Siberian cold RUSSIA, I have never encountered hardware problems and local spare parts stock.
I used CAN and Ethernet IP now. without the slightest problem.
I use 5 programming languages according to my needs, even if I have a weakness for the FBD language.
Never memory size problem, no more batteries to change, and competitive prices.
SIEMENS can go to the museum.
I do not even trying to change the type of controller.
SIEMENS can go to the museum.

 

[CapinWinky]

I like the PacDrive line for robotics, not really a big fan SoMachine and a lot of their libraries, so I would take B&R over their non-PacDrive lines simply for easier, more organized programming.

Twido is end of life 2016 and the M221 or M241 is the designated replacement. A few of their standard PLC lines will drop in favor of newer lines that are already out like the LMCs and the M258.

 

[V0N_hydro]

I have recently completed a project with 3 control logix and 2 compact logix PLCS, 6 Factory talk view SE HMI terminals (distributed network architecture, 3 PCs and 3 17" panelviews), factory talk SE historian, and 2 factory talk ME 15" panel views HMI terminals, coming from Schneider and wonderware/citect experience.


here are my biggest gripes with RSlogix:
Function Block Programming
1. I can't modify an add-on-instruction logic on-line or add a new one except by importing. modifying an AOI requires topping the PLC.
2. can't control layout of "wires" in function block - auto routing is brutal
3. Cut and paste is horrible in FBD editor - it always mangles the location of the blocks, puts them on top of existing blocks, etc
4. I got tripped up a few times by function blocks executing in unexpected order - left to right position takes priority over the top-left most block that is input to a net
5. Changed the sheet size or layout of one empty FBD routine and it actually changed the size of another that was the biggest size and had lots of organized bits to cut in to smaller 11x17 printable sections, but ended up with 4 11x17 sheets of logic all on top of eachother. I know I didn't select the wrong subroutine because the size was still set to the maximum in the one it resized!
6. I removed a pin from an and block and it is no longer shown but internally had the value of "0" on the input pin so it evaluated to 1 and 1 = 0. I prefer the schneider way of dragging boolean logic blocks to increase the number of inputs

Structured Text
7. can't use functions in structured text. eg checked_tag := max(0,min(100,user_input)); Have to say min.input1:=user_input; min.input2:=100; min(); max.in1:=min.OUT; etc
8. no breakpoints in ST

Sequential function chart
9. No jumps in SFC - have to connect with wires and then hide them - again no control over the layout of these branches

General gotchas
10. RSLogix programs can do type conversion on the fly, losing all the decimals if a tag is accidentally a DINT instead of a real
11. Factory talk SE: no easy way to save CSV files from a trend?! how is this not possible!
12. RSLogix 5000 v20 crashed multiple times. Luckily it is pretty good at recovering, don't think I lost any work in RSLogix.
13. Factory Talk SE studio crashed, just once, but I lost about 4 hours of work.


and the parts of the AB world I appreciated the most

14. Possibly the nicest thing was that the SE HMI (but not the MEs) just pick up every alarm block used in the PLC programs and the alarms are all configured in the PLC program.
15. The shared tag database between the HMI software and the PLC program was also nice, although I never did get it to work unless the PLC was online.
16. I also liked the produced/consumed tags and remote IO model with multiple CPUs listening to one module.
17. CTRL+mouse wheel zoom works in FBD editor. unity is really missing a usable shortcut for this

 

[GeoffC]

CTRL+mouse wheel zoom works in FBD editor. unity is really missing a usable shortcut for this

This works for me in Unity, just tried in Unity 8.1 and it works (have to make sure that you have clicked on the FBD screen to select before). But you are right it did not work in Unity 7.

 

[V0N_hydro]

Time to upgrade to unity 8 then, although I find I'm writing more smaller sections these days so probably won't be zooming as much. The CTRL+(number pad +) shortcut wasn't usable with laptop keyboards.

Allen Bradley's strength seems to be the ladder editor whereas that is probably unity's weakness. I have only ever seen one PL/7 schneider program that used ladder.

I started trying to use function block in RSLogix for everything like I do in unity and quickly found it was too cumbersome for boolean logic, and that the RSLogix ladder editor was pretty polished with great keyboard shortcuts and that ladder is pretty good for boolean logic.

I also liked how RSLogix had the concept of programs sections with local variables, so not everything was global.