Siemens or Omron?

I'm on the opinion, that if you know what you want to acheive, you should be able to do it, independant of the platform that you are using. Sure, every manufacturer does things differently, and the different models have different features / strenghts / weaknesses.

I think it is like any type of software, once you understand it, the rest falls into place.
 
Silly question to ask really, everyone will answer the one they use, We even had a Mitsibushi here, as most posters are American it a wonder we didn't get a load of Allen Bradley suggestions.

At the end of the day, all the top end PLC's will do what you want, whether people suggest on or the other is based entirely on their personal comfort zone.

By the way, Siemens hands down :ROFLMAO:
 
Silly question to ask really, everyone will answer the one they use, We even had a Mitsibushi here, as most posters are American it a wonder we didn't get a load of Allen Bradley suggestions.

At the end of the day, all the top end PLC's will do what you want, whether people suggest one or the other is based entirely on their personal comfort zone.

By the way, Siemens hands down :ROFLMAO:
 
Silly question to ask really, everyone will answer the one they use, We even had a Mitsibushi here, as most posters are American it a wonder we didn't get a load of Allen Bradley suggestions.

At the end of the day, all the top end PLC's will do what you want, whether people suggest one or the other is based entirely on their personal comfort zone.

By the way, Siemens hands down :ROFLMAO:
 
I am at present using my first Siemens PLC for about 5 years. I normally use Omron. I program in ladder as this is usually specified to allow maintenance personel to view the ladder and facilitate quick trouble shooting on a system. The job is for a client who exclusively uses Siemens and at present has a Citect SCADA system with over 100,000 tags in the database. They have many Siemens PLCs networked throuhg the premises. Their engineer has been working with Siemens for over 15 years now and really knows the whole system back the front. He also writes drivers for everything, manufactures his own RTD transmitters and other transmitters of varying types, interfaces etc etc. A very smart man.

He has actually complemented me on getting on top of Siemens as well as I have in the short time that I have had to do the project and described Siemens ans "not very friendly".

I would make the following comments on both PLCs and software and note where the opinions are those of my client:-

1. Having to set absolutely everything up in hardware in Siemens is an absolute pain and there are no easy to use tools to make life easy. With Omron, using CX-Programmer V6.2, you just upload the I/O table from the PLC. To set up various cards there are many tools available to set up all cards just by double clicking on the card in the I/O table.
2. It is very easy to structure the program in both PLCs.
3. Both PLCs offer FB programming and STL is available in FBs for both brands.
4. You can protect FBs with passwords in both PLCs.
5. My client uses ladder almost exclusively but uses STL from time to time when he requires to use it only. He claims that ladder scans faster and I am not in a position to argue that point.
6. Serial communications are extremely easy with Omron to any serial device using a very inexpensive serial card and CX-Protocol software to write the protocol. The serial card even has a trace function on each serial port in Omron where one can trace what is sent and received without the need for an outside analyser. Siemens is absolutely not friendly and far more expensive to achieve the same result. My client has avoided serial communications at all costs with Siemens until I was recently given some excellent assistance on this site as to a far more reasonably priced Modbus interface from Siemens that even my local Siemens rep was unaware of. However it is far more difficult than with Omron and other serial protocols are not easy either.
7. Omron programming software is far more friendly and easy to use that is for sure. Omron also offer a huge number of shortcut keys that can be programmed to work how you want to work. Siemens is very limited, as are most manufacturers. I miss masses of shortcut keys more than anything.
8. Even the very powerfull Siemens 318-2 processor only has 256 timers and then you have to make your own. This is really very few for a large project.
9. The S5 timers are an absolute pain! Many here make their own timers, as does my client, to get away from the S5 timers. Fancy having to program words just to see the PV of the timer! Siemens really should have fixed the timers with the S7 PLC.
10. If anyone thinks that the Omron PLCs are "toys" and not very powerfull, think again. The high end CJ1 and CS1 PLCs have exteremly fast scan rates and a huge number of functions that are vewry easy to use and monitor in ladder. It is my understanding that these PLCs have amongst the very fastest scan rates of all PLCs, if speed is an issue. The CJ1 has 64 bit input and output cards that are the size of a cigarette packet and the CS1 is smaller than the S7-400 and has 96 bit input and output cards. Extremely space saving. Siemens have limited the I/O cards to 32 bits although they are all screw connections rather than plug in. I do find this a bit of a pain and prefer the Omron offering here but many would not. I make my own flying leads away from the plugs but many would not be bothered. The Omron transister output cards are limited to 100ma whereas Siemsns run at 500ma. That does not really bother me either as I only use transistors to drive protected LED indicators and relays with flywheel diodes for either brand.
11. Siemens hardware is generally quite a bit more expensive than Omron.
12. Omron software is far more easy to use and intuitive than Siemens. I hate software that I cannot start to use intuitively straight away these days, although the full software package takes a lot of time to use properly of course. Siemens is definately not in that category but is very powerful as one dicovers what it can do.
13. I absolutely object to the huge folder and file structure that S7 Pro produces. Why? It just fills up hard drives at a million miles an hour. I have a large Omron project for a power station job using 9 PLCs and many remote I/O and the whole file for the project only takes up about 500k on the hard drive and that includes all comments. The printouts use a full box of US fanfold paper so it is not a small project.
14. Omron do have a very good monitoring table function but Siemens is really very good here and better than Omron I feel. However, having to make one of these tables up to force I/O for testing wiring before loading the software is a pain. To force outputs with Omron one can simply call up a 64 bit word in binary and toggle the output with a single keystroke. With Siemens one has to make the table and then write 1's and 0's to the bits.
15. The cost of software is a huge issue for me. I work for myself and struggle to justify huge software prices. This is one of my biggest issues with PLC manufacturers. I Ozz, Siemens charge big money for S7 basic software. I can purchase a full set of software from Omron that includes the programming software to suit ALL current PLCs, Simulator, NC card software, screen software, Device Net and Profibus configurator and much more for less than it costs for the Siemens S7 basic. I really find that discusting quite frankly but Siemens are no worse than AB, Modicon etc. Omron were not good either until recent times (last 2 years) where they have suddenly realised that a good complete software package at a reasonable price is the way to go. Just have to educate evryone else now. I have absolutely no objection to paying for software tools but it is not reasonable in my view to place the software virtually out of reach of people like myself who work for themselves and find that software that costs several months salary is definately off my purchase list. I also find it strange that many people who pay these exhorbitant prices then run around looking for free software to use for word processing etc. Is this because they cannot afford these other packages after paying for PLC software?
16. It has taken me far longer tp program my current project in Siemens than it would have using Omron. Part of this is due to me being unfamiliar with the software but I have had the assistance of a guy that knows Siemens back the front and I estimate it would have taken twice as long even if I knew Siemens back the front.

Now to comment on a few others posts here
Simple, what is the total price? Structure etc. are secondary questions..
Watch out as time is very expensive. I find that I do not have much time and a speedy software package is very important. It not only means that one takes longer to program a job but another one is waiting in the wings and not getting done either.
Siemens is good."
They all have their strengths and weaknesses.
People do seem to have a "Siemens = STL" mentality. I have frequently written FCs and FBs using Structured Text (so easy from a development point of view), and then, protect them and call them from LAD. No-one need ever know what's going on inside these blocks if they don't want to.
You can do this with Omron if you so choose. I do not.
I've programmed both (and at least 7 other brands / 20 totally diff plcs) and I'll never do a Siemens again. Debug / actual programming time is at least 3x any other brand.
I would say about double not 3X if using ladder. The ladder tools are not good. The Europeans use a lot of STL and I believe that would, at the end of the day, be quicker and about the same time in both brands. I just do not like STL!!!
Also, in large and complex applications you must buy more Omron PLC's because you will overflow memory.
You have to be kidding!!! I would rather break a system down into small chunks and use multiple PLCs than use a "monster" any day!!! The PLC dies and you lose the whole plant. Distributed systems allow far more flexibility. Also, how do you define memory? All manufacturers define memory differently. I have seen one PLC (no names) that alledgedly had 250k memory. An Omron PLC with 20k memory did the same job. It all depends how it is defined. The 250k referred to RAM, the 20k referred to instructions.
I'm on the opinion, that if you know what you want to acheive, you should be able to do it, independant of the platform that you are using. Sure, every manufacturer does things differently, and the different models have different features / strenghts / weaknesses.
So true. Time can be a killer though.

Generally, I will work with what I have to work with but as I get older I find I am generally restricting myself down to packages that are reasonably priced and fast and easy to program and install in a control panel. Reasonably priced includes hardware, software and installation and commissioning time.

By the way Peter, I have GX-Developer here and it is a bit ordinary quite frankly. Mitsubishi do have 2 good things going for them, definable register areas for retentive/non retentive registers and "drop in" notes in the software, although I have seen programs where this feature was over utilised and was, quite frankly, a mess. I have found the hardware a bit "fragile" over the years.
 
A little more on the subject of structure. Structured programming if often referenced here, in specifications etc. I would like to comment on PLC memory structure and usage.

1. I am quite puzzled why Siemens have stuck to byte structure. Although there may be a good reason, I suspect it is to be backward compatible with Siemens users although I do hear complaints from their users from time to time about it.
2. Too many PLCs have too many memory areas for my liking. I do like the Omron notion of CIO (common I/O) area. This includes all I/O and a huge area (a blank sheet if you like) that can be used for anything - this area is non-retentive. There are a few other areas such as data memory (register) that is memory retentive (word address only), extended memory (like data memory), holding relay that is memory retentive and can be used as bit and/or word area, work area (new to Omron - like M bits in other PLCs) that can be used as word and/or bit area, timers and counters and that is about it.
3. I absolutely dislike having to type in I, Q etc for inputs and outputs - often with % in front of the I or Q. This reflects my notion of too many memory areas where QW, IW, MW etc etc (different in different brands) etc have to be typed in. Takes too much time. In Omron the CIO area is so flexible that if one selects BOOL and types in 101 this is immediately interpreted as 1.01. Further, when an I/O table has been created and this channel is, say, an input card, an I is automatically placed in front of the address. If a word type is selected (integer, BCD) the address 101 is automatically interpreted as a word address channel 101 in the CIO area.
4. Quick and easy entry of functions etc are also appreciated by me. I use F8 in Omron for calling a function. This raises a text box where I can type MOV #327 D2000 which moves the BCD value 327 to data memory (register) 2000. Very easy. If I wish to move an integer I type MOV &327 D2000 - if I wish to have the move happen only on a rising edge I type @MOV &327 D2000. No need to drop in a function block by drag and drop and then have to move around and fill in a heap of entries.
5. This type of memory structure removes a lot of confusion, except for a regular user, of whether one has used the right memory area such as IW, MW, F file etc (different areas in different brands). I like the structure to be simple and configurable.
6. The disadvantage of this type of structure is that if one is not accustomed to it and organised, the whole thing can finish up a mess. I normally organise the CIO area, for example, in to sections (structure the memory area to suit the program/project) and then work within that structure. The beauty of this is that I am in control of how I structure the memory usage. With the latest Omron PLCs one can even specify the start address of the I/O cards with respect to the CIO area. For example, the first input card defaults to start at CIO memory address channel 0 - however one can change that to start the input card address at channel 3000, or 5000 etc. Device Net modules can also be programmed to use memory anywhere within the CIO area.

I guess my comments will probably cause a bit of a stir but I guess evryone sees the world from a different perspective depending on one's upbringing. I first started with Texas Instruments PLCs (re-badged Hitachi), then Hitachi, then Toshiba, then AB and then Omron. I have worked with those and many other brands since - GE-Fanuc and Mitsubishi quite a bit - but still prefer the blanket memory area approach where I can basically use the whole memory area as I wish. I do find the restricted use of the many different memory areas in most PLCs an absolute pain. I like to organise memory usage to my own liking and to suit the project at hand.
 
BobB said:
5. My client uses ladder almost exclusively but uses STL from time to time when he requires to use it only. He claims that ladder scans faster and I am not in a position to argue that point.

Tell him he's wrong. He's obvioulsy got some duff info there.

Try writing a line of code in ladder, with some parallel branches and something like a timer or counter. Then convert to STL and see how much of the baggage needed by the system to 'view' in ladder can be removed. All those bits wasted scan time,

I wouldn't say writing in STL turns your code into a turbo charged system, but its definately quicker.


BobB said:
8. Even the very powerfull Siemens 318-2 processor only has 256 timers and then you have to make your own. This is really very few for a large project.

The 300 PLC's are medium range PLC's for 'powerful' PLC's move to the 400 range. You wouldn't use S7 300 for a large project. As for timers they do have the SFB timers which means limitless timers, with these you use the TIME format instead of S5TIME, which is in DINT format and a lot longer than 9990 seconds.

I agree with the serial comms statement, S5 was worse believe me. Nowadays though most equipment have profibus. can't remember the last time i used serial with an Seimens PLC.
 
Last edited:
I am lead to believe the 318 and recently released 319 are really 412 (at least) processors in a 300 case. However, my client tells me that there are a mixture of "bits" if you like where some 400 OBs are required but also 300 OBs to suit the I/O. A bit of a hybrid it appears.

I have never used Profibus but have used Device Net extensively. Will have to have a good look at Profibus the next time a long run and/or faster communications are required. It is my understanding that Profibus is also far less particular than Device Net with respect to the specification of cable type. This would be a huge bonus as Device Net cable is very expensive.

I am still finding that Modbus is the most common interface available at a reasonable price for generator controllers, power monitors etc. Not much Profibus or Device Net on the gear I normally use. It is very cost effective though.

Caterpillar were rumoured to have a Device Net interface on the way for their generator controllers but it has never surfaced. They used to charge an arm and a leg for Modbus RTU interface, as do Cummins, but prices have started to come down. I think the only reason they charge the prices they do is that they can. Would hate to see what they would charge for Device Net and/or Profibus. Most of the US manufacturers in this area usually use Lonworks as their network and a Lonworks/Modbus RTU converter is required quite often for communications to PLCs.
 
BobB said:
It is my understanding that Profibus is also far less particular than Device Net with respect to the specification of cable type.

I've not used Device Net, came across Control Net with a redundant network once for remote I/O stations.

Asi I am impressed, you can run that cable in with your power cables to no adverse effect.
 
Thick Device Net cable is about 3/4 inch thick but both comms and DC power supply run through the cable. It is very well screened.

One has to be careful with Device Net with respect to power supply for comms modules. If the voltage drops over a certain range over the network there can be big troubles. If you ever use it I would suggest paying particular attention to recommened installation procedures. One is that the 24VDC power supply be connected in the middle of the run. It is quite tolerant of voltage range but not of voltage drop over the length of the run.
 
BobB said:
I am lead to believe the 318 and recently released 319 are really 412 (at least) processors in a 300 case.


The S7-318 2DP CPU is very similar to an older S7-414 CPU (not the current).
The S7-319 3 CPU is a Type 3xx CPU and not like the 318 or 4xx!!!
 
Gromit said:
Hello,

Which of those two PLC manufacturers do you find more usefull.
I used to program Omron PLCs for about an year. Then I had to jump to the Siemens brand. Comparing them I find the Siemens programming more professional and heavy, in respect to Omron, which is more user friendly and intuitive.
For Siemens we have structures, arrays and the data memory can be very large (Mbytes).
Omron has a data memory max 512 kwords, no structures, no arrays. But you can program all your stuff in LAD only. No need to mix LAD and STL.
I can not decide which conception is smarter?

Regards
Hi, I very urgently need an OMRON CPM1A MAD-01 and they have run out of in in their European stock. Can you or anyone possibly help me?
 
heloo
I have omron c200hg which soft can I use to make ,modification
on program .
thank alots

marinko said:
Both are smart:)
You must be familiar with both conceptions (Siemens and Omron):(
Omron is very good in a relatively small applications, i.e. to rewrite relay scheme in the plc program. Also, Omron PLC's are cheaper and are more cost effective.
But, if you deal with reletively complex problem where you have large amount of data and make complex operations, using Omron PLC will be more time costing because Siemens has powerfull and simple modular concept of programming. This saves time and nerves. Also, in large and complex applications you must buy more Omron PLC's because you will overflow memory. Also Siemens has some more advanced hardware that greatly simplifies develloping and commiting of project.

Price is most important, so use Omron in common applications, and Siemens in complex applications.
 

Similar Topics

I want to connect a S7-315 cpu to an Omron CJ2M via Ethernet I/P and transfer mainly bit data ie. turn an Omron output on from the S7-315 or turn...
Replies
2
Views
2,466
We recently created a channel on YouTube about PLC Onron Training and the others . I am very happy to Share to the community...
Replies
0
Views
1,921
I am looking for addressing difference between Omron and SIEMENS. In this Ladder netwoks has W10.00 address.This is a Omron ladder. I want to know...
Replies
15
Views
9,220
Hello Experts, Anyone can help me how to configure the CX-Programmer to link a communication into Siemens MP277 touch screen. Any help is...
Replies
2
Views
1,922
Hi, I want to make a communication between CJ1M si Siemens PLC through ethernet network. It's that possible? What setup must i make in Omron...
Replies
0
Views
1,110
Back
Top Bottom