Sign in to follow this  
Followers 0
BobLfoot

Encountering my first Siemens PLC

11 posts in this topic

I've worked Automation for 35 years with Toshiba PLCs, Omron PLCs, Koyo PLCs, Allen Bradley PLCs, Automation Direct PLCs and Schneider Modicon PLCs.  But I now recently ran into my first Siemens PLC.  From what I've determine thus far it is a single rack S7-400 with a 414-2XL07-0AB0 CPU.  Allegedly it is sending data to a Controllogix PLC, a Wonderware Archestra 2017 Scada Node and another S7-400 within this machine.

There is supposedly a laptop with programming software on it in the electrical shop, but everyone swears the PLC is a Black Box and only the OEM when we Webex him in can access the machine code.  Right now were having a sporadic error and I'd like to know a little more about the PLC before I get into a Webex with the OEM.  

Can any point me to the Language Syntax and Basic Operation Manuals?  I found one on the Siemens site but it was mostly install and wiring.

Share this post


Link to post
Share on other sites

The S7-400s I worked with were programmed entirely in STL (Statement List) which is what the S5s used. That was a choice of the programmer. They also support ladder logic and (I believe, it's been a while) a form of function block.

I've attached a reference manual I saved way back in 2012. It says volume 1 on the cover, but both volumes are in there. I have a bunch of other material on CD but it's all at home since we don't have any Siemens stuff here.

I'm curious how they're exchanging info with a ControlLogix. I've done it with S7-300s before using gateway modules (ProSoft, Red Lion). I would "assume" without knowing that they're using Profibus to connect to the other S7-400 and probably to a gateway to get to the ControlLogix.

The software you will need is Step 7 for Simatic Manager. Be aware that minor revisions matter and that older licenses won't activate newer versions. Newer licenses *may* activate older versions, but I never tried it. If you convert the project to a newer version, you won't be able to get online without downloading to the PLC first.

I'd say keep hunting for the rumored maintenance PC. It may be a black box simply because no one there knows how to get into the software. You may also have to reach out to the OEM and ask them what version(s) of software the machine uses. Versioning with the Siemens software was always a pain in the neck, so do all you can to get the right version.

SIEMENS_S7-300,400_StandardFunctions_ReferenceManual_2006-03.PDF

1 person likes this

Share this post


Link to post
Share on other sites

Thank jrw.  I had heard rumor that versioning was a headache with siemens.

Would there be any benefit to me grabbing the free Step 7 Lite and learning my way around the software, before switching to the maintenance laptop and the live system?

Last thing I want to do is change something while trying to just monitor the system.

I am finding a 443-1EX30-0EX0 Communications Card, several 422-1BL00-0AA0 Output Cards and 421-1BL01-0AA0 Input Cards in the Rack with the CPU Card.

Share this post


Link to post
Share on other sites

well... Siemens software is synonym with headache. ;-)

if you have to use it, getting familiar with it is a good idea. it is slow so installing it in VM will make it even slower. but this used to be the way to go simply because we used to work with many brands and installing it on host could and did interfere with the other software products. so it is not a bad idea to use separate machine or at least make a system image... please note i have not used it in a while (except running some demos 2-3 years ago) and i am perfectly cool with that.

Share this post


Link to post
Share on other sites

 

7 minutes ago, panic mode said:

well... Siemens software is synonym with headache. 

Indeed...

I also strongly second the recommendation to use a VM for this. It does not play nicely with other software packages and only one version at a time can be installed.

 

I'm not sure about the Lite version; I've never used it so I don't know how useful it will be. A few tools to remember:

Simatic Manager has a copy of PKZip embedded inside that archives and retrieves their projects. You'll use File -> Retrieve to restore a zip archive and File -> Archive to back it up.

Cross Reference: Options menu -> Reference Data -> Display. There is a "Filter" button on the toolbar that you will definitely need to adjust from the default settings. At first, I would put a "*" in all of the fields so it shows everything. You can filter it down as you go. The x-ref will help you find most things...but not all.

If you find the proverbial maintenance laptop, the first thing I would do is archive a copy of the project. Then you can poke around as much as you want, and then delete it before retrieving your backup copy.

When you're ready to try to connect, go to Options -> Set PG/PC Interface. That will tell the software how you plan to connect.

I can send you a rough draft of an old work instruction I was working on before I left my last plant (it's WAY to big to post here because of all of the pictures and screenshots). We  started making machine-specific instructions. That's what this is a rough draft of, so some of it won't be perfectly helpful, but should get you started.

 

Share this post


Link to post
Share on other sites

Thanks so much everyone for the suggestions and hints.  This is a "back burner" project, but the SIemens Machine was upgraded from PLC5 to SIemens several years ago.  The two remaining clones are still PLC5 and slated to upgrade in 22/23.  We're pushing they go PLC5 to CLGX, but I want to be ready if some big hammer at the OEM or Corporate says "no It Must Be Siemens Now". 

Share this post


Link to post
Share on other sites
47 minutes ago, BobLfoot said:

...the SIemens Machine was upgraded from PLC5 to SIemens...

That phrase....does not compute...  I started in earnest with AB and Siemens at the same time and I would not consider that an upgrade.

Share this post


Link to post
Share on other sites

Posted (edited)

Bob

As you can see, there’s no shortage of opinions on this site. 
I think it’s human nature to dislike what they don’t know or are not familiar with. 
Or inherited from an Europe OEM. :)

While I do agree that S7400 is getting long in the tooth. An upgrade from AB to Siemens today would be to an S71500, not the S7400. 
 

also

find your original Step7 program and don’t go with Lite version


 

Edited by jrw

Share this post


Link to post
Share on other sites

The 414 was the smallest version I think. We are running 417's and 410's at my current employer. But we are using them with PCS7, not your plain Step-7.

If they were programmed in Europe, good chance it's all Statement List (think Machine language).

If in the USA usually mostly ladder with a few function blocks. 

We do have a LOT of S7-300's running around here, most have been migrated to TIA porta, but some are still at Step-7 classis. 

Bob, do you have a PC with a Siemens comm card in it? OR is it a Siemens PG (Siemens laptop for programming, has Profibus port built in)?

Based on the age, there is a good change the 443-1 comm card communicates with the program PC/laptop using ISO, not tcp/ip. ISO is a Siemens protocol that communicates over ethernet, but uses MAC addresses.  

The last/latest version of Step-7 classic is 5.6, but 5.5 was around for a long time. 

 

If you get on line, we can talk about Object Blocks (OB's) the difference between Functions and Function Blocks. And you will get you first exposure to Data Blocks.

Siemens is different, but allows a lot of customization, you can do almost anything with them, but they do not have as many built in instructions as the newer CLX's do.

Also, for standard machine control, with mostly discrete inputs/outputs and logic. The Siemens units are much faster than the PLC-5's.

 

Edit: Almost forgot, the S7-400's have an accumulator, so anytime you read or write data to another device, the bytes are swapped.   Also all addressing is in Bytes.

 

Share this post


Link to post
Share on other sites

Thanks Ken.  This SIemens project is on the middle or back burner right now, but that will only be for a while I suspect.

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