Siemens Newbie

pressgrove

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Jun 2003
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3
I have a project I am working on that will be deployed at all of our sites (globally). Basically, we'll have a PLC that operates some fairly simple functions (basic I/O, some analog) with an HMI/SCADA console that will interface with it, in addition to some other systems in the same cell (primarily through Modbus).

Our plants have lots of German equipment in them (most with S7-xxx). Considering Siemens' global footprint and familiarity at other sites with Siemens and that seems like that's the direction we'll most likely go. The problem is, I don't speak Siemens. The only Siemens controls I've ever used were TI305 and TI405 (the AD versions). I have experience with AB, Automation Direct, etc. and have experience designing systems. That said, I have never done SCADA either.

I've done a little research and think I at least have an idea of what questions to ask, so here it goes (by all means correct me if I'm off base):

1. WINCC or TIA? I get the impression from what I read that Siemens is moving towards TIA being the do-all application that does PLC programming, HMI, and SCADA. The application I have will have data collection, but probably less than 1000 tags per area.
2. Which PLC platform? - One of our plants has installed some S7-1200s, and their local guy said we should start using S7-1500s. From what I read, they aren't really intended for the same purpose. That said, I would pay up for more connectivity options and longer life cycle (I don't want to replace this stuff in 5 years).
3. Can the HMI/SCADA talk ProfiNet and Modbus TCP/IP at the same time? Some of what we need to connect to is Modbus only, but I would assume the Siemens stuff is much easier with ProfiNet. The way I understand TIA, it has to run on ProfiNet (is this correct?).
4. We'll have 6-10 of these systems running in each plant. Does it make more sense to collect the data at each system, then back-up to a plant server, or should all of the data go directly to the plant server?
5. How much traffic does this put on the network? Our existing systems are on the same network with our office. Should they be on a separate network or does it matter (maybe a question for our IT folks)?
6. Any other words of wisdom?
7. (edit) I understand the S7 to use different programming methods. I have lots of ladder logic experience, but really nothing else. What is the best route to take? I'm not adverse to learning something new if it gets me additional functionality, etc. That said, one of the goals is to make it easy to troubleshoot and customize at the various sites.
 
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1. Since it is a new project, TIA is the way of the future.

2. It really depends of the system's complexity; S7-1500 will probably do in your application, however, for high volume of data processing (Process Industry) the S7-400 might be the way to go; the S7-300 and S7-1200 platforms look like are on their way to retirement.

3. It doesn't matter what SCADA uses for backbone protocol; if there is need for translation, there are available Gateways; again, since this is a new implementation, you could lay everything out on Profinet/Industrial Ethernet and translate upstream if required.

4. I'd try to keep everything in "one basket" with implemented redundancy; multiple data servers plus a convergent one will require quite a professional effort to operate and maintain.

5. Definitely create your own automation SCADA networking Level/Layer; IT involvement should be kept to a minimum and required only at Enterprise WAN connections level.

6. Keep an open mind and remember that you always get what you pay for; ensure availability and secure professional tech support before you need it.
 
7. Siemens programming is heavy on STL (Statement Logic) and FBD (Function Block Diagram); you could develop LAD (Ladder) programming where applicable, however, you will need to familiarize yourself with the Siemens professional approach to automation programming.
 
1. WINCC or TIA? I get the impression from what I read that Siemens is moving towards TIA being the do-all application that does PLC programming, HMI, and SCADA. The application I have will have data collection, but probably less than 1000 tags per area.

I assume you're talking about SCADA here. SCADA in TIA (WinCC Professional) is essentially a scaled down version of the WinCC V7 system. I've heard that it's actually built directly from it (with a new UI, of course). If you ask a Siemens SCADA person, they'll tell you that WinCC V7 is the primary SCADA package. It supports multi-server systems, whereas with WinCC Pro you're limited to one redundant pair. However, for small systems WinCC Pro might do the job. This is a place where your Siemens rep can help pull in a SCADA consultant to discuss your specific application.

2. Which PLC platform? - One of our plants has installed some S7-1200s, and their local guy said we should start using S7-1500s. From what I read, they aren't really intended for the same purpose. That said, I would pay up for more connectivity options and longer life cycle (I don't want to replace this stuff in 5 years).

The 1200's and 1500's are the primary lines going forwards. They'll be around for a long time. 1500's will be bigger, faster, better diagnostics, and with more communications options (recently got an optional OPC UA server loaded onboard). Code is mostly portable between the two platforms.

Honestly, though, especially with 1200F (F = failsafe) now available, you can do quite a lot with those small PLCs, including controlling remote IO/drives over PN.

3. Can the HMI/SCADA talk ProfiNet and Modbus TCP/IP at the same time? Some of what we need to connect to is Modbus only, but I would assume the Siemens stuff is much easier with ProfiNet. The way I understand TIA, it has to run on ProfiNet (is this correct?).

SCADA systems typically don't actually talk Profinet (PN) directly. They usually use S7 connections to get data out of the PLC. PN is designed for cyclic, low overhead, IO control, whereas S7 communication is intended for acyclic (as needed) data acquisition of potentially much larger data sources. PN is an open standard, whereas S7 communication is Siemens proprietary for their CPUs.

Yes, a SCADA system should be able to grab data from multiple sources over multiple protocols simultaneously, especially if everything is over Ethernet.

4. We'll have 6-10 of these systems running in each plant. Does it make more sense to collect the data at each system, then back-up to a plant server, or should all of the data go directly to the plant server?

It depends a lot on your application and process. Especially if you're new to SCADA, this is something where you're going to want to find a trusted partner to help you set up your system, and design it to match your needs.

Some systems would have a SCADA server local to each system, and then have all of them link back to a central point. In the Siemens world, that would probably be a server running Process Historian, and possibly some other options.

If the systems are relatively small, you could also have one central SCADA server that talks to all the PLCs, and then each system has a client that pulls data from the server.

5. How much traffic does this put on the network? Our existing systems are on the same network with our office. Should they be on a separate network or does it matter (maybe a question for our IT folks)?

Short version, it really depends what you're doing, but it shouldn't be a ton of traffic. You're more likely to see a bottleneck in the PLC or the SCADA system than in the ethernet infrastructure.

Definitely make sure your IT folks are onboard with what you're doing networking-wise, but also make sure they understand your requirements. If IT is responsible for your network, they also need to be able to show up at 3am if something breaks and stops production. I usually recommend separating the IT/enterprise network from the plant floor.

See the link below for one (old) commonly referenced data/communications model. For security purposes, every level should be on its own network, or at least isolated as much as possible. For the places interfaces between networks (SCADA getting data from PLC), any given communication should not cross more than one level (SCADA can get data from PLC but not communicate directly with IO). There should be firewalls in place where possible, to make sure that only specifically allowed communication occurs.

https://en.wikipedia.org/wiki/Purdue_Enterprise_Reference_Architecture

6. Any other words of wisdom?

Make sure you have an idea of what you need to learn, AND if you think you can, before you start the project.

Some things you can adjust to and become an expert in pretty fast. Others you might need to bring in an expert to assist. This might mean bringing in an integrator to do it for you, but it might also finding someone to use as a consultant to mentor you, point you in the right direction, and make sure you're doing things right. If you've made PLC platform transitions before, you'll probably handle this one OK. Learning SCADA from scratch is a bigger challenge. There is a big difference between UNDERSTANDING a scada system, and merely being able to put a button on a screen.

7. (edit) I understand the S7 to use different programming methods. I have lots of ladder logic experience, but really nothing else. What is the best route to take? I'm not adverse to learning something new if it gets me additional functionality, etc. That said, one of the goals is to make it easy to troubleshoot and customize at the various sites.

If you use the newer platforms (1200/1500), it won't be nearly as big an adjustment as if you use the older 300/400 platforms. There's really no need to use something complicated like STL anymore (although it is still supported in the 1500), you can do everything in LAD.

The main difference is the capabilities of modular programming FBs/FCs. If you used AOIs in the AB world, you should already be famaliar with the ideas. If not, your main hurdle will be understanding how to structure data/code to simplify your programming/troubleshooting efforts.
 
2. The 1500s are more powerful than the 1200 series. Depends on the project as to which PLC you will need, both will be supported for a long time. You can look in the Siemens site, they say when it will be phased out. https://support.industry.siemens.com/cs/pd/567215?pdti=pi&lc=en-WW

7. There is ladder, FBD, STL(kinda like assembly) and SCL (kinda like Pascal, sometimes referred to as STL)

Depends on what you want to program as to what is the best choice. Ladder/FBD is best for 'simple' programs and SCL is better for more advanced stuff.
 
2. Definitely S7-1500. S7-1200 are OK for the smaller need, but you with the bigger PLC you gain amongst other things more connection resources. And the way you describe it it sounds as it could be something you could need. Also, if you go for S7-1510SP or S7-1512SP, you have quite capable CPUs that are still very inexpensive.
edit: I advice to stick to one hardware platform, and avoid other hardware even if it is a little bit less expensive. So that means pick a hardware platform that can cover all your needs. In the long run it wont be more expensive anyway.

5. As others have said, the connection between HMI/SCADA and the S7 PLCs wont be Profinet but "only" ethernet.
If you go Siemens S7, then Profinet is going to be part of the equation.
Even if you can mix lower level Profinet with higher level HMI/SCADA etc. it is a bad idea. Just the handling of IP addresses, device names, topology ..., the mere thought of having to coordinate this with IT gives me the shivers.
What you should do is to split into separate networks. An extra Ethernet CM in an S7-1512SP PLC is inexpensive.

7. You are in luck, because with TIA you can now do everything in Ladder. In the past (with S7-300/400) you would have had to dabble with STL and pointers, but not any longer.
The other programming languages have thier strengths, but if you want to do everything in Ladder, then you can certainly do so.
 
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