Sign in to follow this  
Followers 0
swimmy67

S7-200 Pros and Cons

16 posts in this topic

Hello all, My employer wishes for me to evaluate the Siemens S7-200 micro PLC. In our facility we currently use Mitsubishi FX PLC's. We have had a few customer requests for Allen Bradley PLC's. We are trying to find a solution that we will use for the next five years. This will be a move exclusivly to the product lines. What are the pros of the S7-200 system? What are the cons of the S7-200 system? I look forward to the responces. Thank you, swimmy67

Share this post


Link to post
Share on other sites
Hi, Please let me know what you really want. I think I can help you.

Share this post


Link to post
Share on other sites
I guess I really need some information about the S7-200 system. 1) Can the programming software program across a family line? i.e. S7-200, S7-300, S7,400? Do I need to purchase different programming software for the S7 family? 2) What is the advantage of having wizards in the programming software? 3) What are the advantages of using the Siemens vs. the AB MicroLogix PLC? 4) Can the S7-200 family use other HMI touch panels? i.e. IDEC, CTC, Maple? 5) Can the S7-200 Communicate to VFD's using Modbus/RTU? 6) How reliable is the PID loop in the S7-200? 7) Why so many wizards in the programming software? I just can't seem to get over the amount of wizards that are in the software and the amount of code that you can not see because it is Siemens Protocal. I hope you can answer some of these questions. Thank you, swimmy67 Edited by swimmy67

Share this post


Link to post
Share on other sites
Ans: 1)S7-200 family needs MICROWIN or MICRODOS softwares. Any versions of STEP7 can only handle the S7-300 and S7-400 systems. The family named LOGO uses the LOGOSOFT. 2)Wizards help us with default settings and default options. The ones who don't know much about the MENU/COMMANDS of the software can use wizard to set up a new project. 3)Some have merrit, some have demerrit. 4)Yes, you can but choose wisely. 5)Yes, use speciality modules if needed. 6)Based on program. 7)I'm not sure. But, do you hate wizards?

Share this post


Link to post
Share on other sites
Thank you for your response. I guess the wizards seem more cumbersome than helpful. For example, the PID wizard has over 7 pages that need to be "Next" through. The settings and parameters have to be set anyway, one page would work just fine. I have an evaluation copy of the MicroWin software and the programming seems very cumbersome. I have downloaded some programs to see how they function. I have to give an informed answer to my employeer reguarding the Siemens S7-200 product line. Thank you for all of your help in this matter. swimmy67

Share this post


Link to post
Share on other sites
Just wanted to clarify the wizard thing for you. You do not need to program via the wizards. They are their for you convenience. You could go and create your own high speed counter or pid controller in the plc but why when the wizard will create the code for you buy just answering a few simple questions. One thing you can do is talk freeport mode out of the programming port. This is the user mode for the AB guys. Out of the freeport there is code for Modbus ASCII and RTU Master/Slave. So yes, I can talk to a VFD or scale or else be a slave to a Modicon PLC. The PID loops work killer. I know a company that replaced an old system they sold that had 8 zones using Barber-Coleman temp controllers and put in a S7-226 w/ TC modules and are able to heat and cool better than the B-C system. To answer your question 3, all PLCs are good. Certain MicroLogix are not capable of online editing. The S7-224 and up are able but not the S7-221 or 222. The biggest difference is that Siemens does not FORCE you to pay a yearly maintenance contract. You can call the Siemens Hotline down in Johnson City, TN and they will help you with no other questions ask except for your name, number, company you're with and your problem. For free you would think the support sucks but no they are awesome. I just found out that Mitsu is going to a pay based support system also. I know a lot of people that have switched to Siemens S7-200 and have been very happy and successful. Especially if you are an OEM/Machine Builder. Good luck, Khek

Share this post


Link to post
Share on other sites
Khek Thanks for the informed answers. My company currently use the Mitsubishi FX family PLC for all of our equipnemt. We have had some of our customers request Allen Bradley PLC's and controls instead of the Mitsubishi PLC's. I have given the task of finding new automation controls for our machines and I have narrowed the list down to Siemens and Allen Bradley. My background with PLC's mostly was with Allen Bradley but I have used other PLC's such as: Reliance Electric Automate, PLC Direct, Toshiba, Mitsubishi, ATC, Telemecanique/Modocon, Allen Bradley SLC 500 and MicroLogix and PLC2 and PLC3 and PLC5, Siemens and Omron. I need to make an informed decision for the proper PLC and have the Platform work for a minimum of 5 years. Thank you in advance for your help. swimmy67

Share this post


Link to post
Share on other sites
Swim, No problem. I have had extensive history with the Mitsu PLCs all the way from K series to A series to F series to all the FXs. The last FX I used was the FX1N. I still feel one of the best micro PLCs is the FX2N but you are right there is not a world wide acceptance of Mitsu out there. Siemens is still #1 in the world so if you decide to sell your equipment in the global market Siemens would make sense. I graduated from Univ. Wisconsin so yes I was biased towards AB but that bias went away really quickly by the arrogance of the local distributor in Central Indiana and just the arrogance of Rockwell. Working with the S7-200 family has been a very good experience for me and the support line in Johnson City, TN has a bunch of great guys. They are willing and able to help you out. If you are looking for a good distributor in your area check and see if SE Automation/Standard Electric is in your area. They know the S7-200 platform very well and would be willing and able to help you out. Technical stuff I have noticed: 1. If you are doing floating point math the Mitsu stuff sucks in comparison to the Siemens and AB. 2. If you're doing ASCII by far Siemens kicks butt. 3. The wizards in the Siemens software is second to none. No one else has them. 4. The new AB MLogix 1100 looks cool w/ built in ethernet. Don't know how much availability there is on it. No one else has it built in. Siemens has a module you can add on and you can also get one w/ a web server. I don't think Mitsu has it for FXs. 5. Not all ABs can do online edits. FXs you can and S7-224 and above can. 6. Adding function modules in the Mitsu stinks because you have to add code to get it to configure. AB and Siemens you don't. 7. Through put is the same don't let the marketing crap fool you on how fast the PLC scans. 8. Rockwell software is keyed and cost a bunch. Mitsu software is serial number but I believe no key and moderately priced (GX developer). Siemens MicroWIN is inexpensive and no key even though legally it is a one site license. 9. Converting your program from Mitsu to Siemens wouldn't be hard, I've done it. Since Mitsu is octal based it is very easy since Siemens is byte based addressing. Change your Xs to Is, Ys to Qs, Ms to Ms and Ds to VWs. Of course there's a little more than that but truly it isn't that bad. Khek

Share this post


Link to post
Share on other sites
Actually KHEKD, Mitsubishi does offer Ethernet communication for the FX line. The FX1S, FX1N, FX2N. and FX2NC use the FX2NC-EnET-ADP, which is a serial to Ethernet converter. The FX3U uses the FX3U-ENET, which is a full-featured Ethernet module, which can be used for programming, data acquisition, and PLC to PLC communication. The FX3U-ENET also has capabilities to send and RECEIVE emails. You can actually email the PLC a CSV file of data (address and value) and it will read it in. Nobody else is receiving email yet, though some others can send. As for the 'built-in' Ethernet, what does it matter if it's on board or a module? I prefer the module. Means having to stock 3 CPUs and an Ethernet modules instead of 6 different CPUs. I've also programmed S7-200, and I still think Mitsubishi has a solid product and decent software.

Share this post


Link to post
Share on other sites
I agree with Crossbow. The programming software for the Mitsubishi PLC is very powerful. While I have been checking the Siemens Programming software, it feels cumbersome. The Siemens Representatives visited my facility and were touting their software as being user friendly and very easy to program. From what I saw the programming software is not very user friendly and not at all easy to program. Some people like the Wizards that are incorporated into the programming software, but I feel they are a waste of time. Granted, the Wizards generate the code required but some of the code can not be viewed beacuse it is Siemens Protocal. I like to know what is going on with my program. I do not want to rely on something that I can not see to run the program. Here are some things that I personally do not like about the Siemens Programming software: 1) The components can not be double clicked on to bring up a dialog box to be able to change or enter information. 2) There is a set number of "Networks" that are in the Ladder and when these are used then you have to insert new networks to be abld to continue with the program. 3) There are way to many Wizards in the programming enviroment. 4) The programming enviroment should be user friendly. Siemens MicroWin is far from user friendly. 5) There is a big learning curve invloved with the Siemens MicroWin software. 6) Drive communication is Siemens Protocal. USS. If you want to communicate Modbus/RTU there is required a separate module. 7) The RTD module only has two inputs. To get four RTD inputs, two RTD modules is required. The Siemens, I see, does have a Ethernet module and a Modem module. With sending our equipment around the world, it is a requirement that I be able to communicate with the PLC with either Ethernet or over a Phone line through the Modem or even a cell phone modem through serial or Ethernet. swimmy67

Share this post


Link to post
Share on other sites
can we discussed the comparision between S7-200,Micrologx and FX3G PLC Now mitsubishi is introducing FX3G as a successor of FX1N. since If we see that feature of FX3G is better the FX1N. My quection is FX3G is better then S7-200,Micrologx If yes why or if not why Regards Govind L. Lathkar

Share this post


Link to post
Share on other sites
Keep in mind Siemens has released a replacement for S7-200 now. The S7-1200 is their latest offering. If you're going to compare a new product like FX3G, you should compare to the new Siemens as well. Personally, I think the FX3G is a solid little PLC, it is more expandable and offers options the FX1N did not. When you get into the 40 and 60 I/O versions, you can add 2 serial boards onto the front of the PLC. It can also use the FX3U-ENET module and the left side adapter bus analog modules from the FX3U series.

Share this post


Link to post
Share on other sites
Buy the S7-1200 The S7-200 is better than Mitsi, the 1200 is even better, the 1200 is programmed with TIA Step7 Basic 10.5 and it does the HMI's as well, a bit slow at times but nice windows software GX Developer sucks I am biased, i really have a hate hate relationship with mitsi Its only my opinion which means nothing but Siemens wins hands down Edited by 504bloke

Share this post


Link to post
Share on other sites
In response to your post on s7-1200, If you find yourself working with Analog IO on the Siemens S7-1200 for the first time, you may wonder how and where to start as I did. I came up with a few basic tips for others working with Analog IO on this PLC platform. I was mainly focusing on implementing 4-20mA inputs and outputs, but the concepts should apply to other signal types as well. Here is a link to the blog with my function blocks and configurations: http://www.dmcinfo.com/blog.aspx/articleType/ArticleView/articleId/328/categoryId/10/Siemens-S7-1200-Analog-IO.aspx Hope this is helpful!

Share this post


Link to post
Share on other sites
This entire thread is like Budweiser vs Miller...the simple fact is, Siemens software is written in Germany, by Germans. And no one has mentioned that where Siemens truly shines is in using STL and FB programming. European programmers mostly write in STL, and most of the protected blocks in Siemens are written in it...for a reason. Whether you want to admit it or not, they (and I work with LOTS of them daily) have a different mind set than we do. American engineers (IMHO) still hold to the "Keep it simple stupid" or KISS mindset. Not so with our Bavarian brothers. For some reason, they value more complex choices in almost EVERYTHING they do. Now this thread is about "which is better"...to each his/her own. It took me nearly 5 years to get "really comfortable" with Siemens S7200 and 300. IMHO MicroWin was easier to learn than Step 7 v5.4 BUT, since ALL THE BIG THREE have now migrated to SIEMENS as their standard plc/hmi product (GM and Ford using the Transline 2000 Template) ANYONE wanting to stay current in programming better get onboard and learn Siemens...right away. AB has priced themselves right out the door. And that's the simple truth. We still use ControlLogix for some machinery, but when we explain the cost savings to most clients (siemens vs AB), siemens wins hands down. Now, I know you "ONLY AB" guys/gals out there are shaking in your pants...you don't want to learn a new package. But, don't say I didn't warn you. Siemens is here to stay, and since they are literally the LARGEST company in the world, I won't be surprised when they buy out Mitsu (automation) and Omron. I used to be one of those "only AB" guys, you fight it and fight it since you are scared of something new...but once you learn it *and learning takes failure* that can be a hard pill to swallow for some.

Share this post


Link to post
Share on other sites
We have AB, Idec, Mitsubishi, Omron, and Siemens PLCs where I work. Before I took any programming classes, I was able to teach myself basic programming on all of them except Siemens. I still get frustrated every time I look at one. Sorry, it's not really related to your question, but I had to vent.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0