Opinions about Siemens's industrial PCs ?

[Iner]

Hello,

For a project, a customer is asking for Siemens products and also wants a PC with WinCC rather than an HMI for databases purposes. I thought that a PCbox would suit its needs well because it would do both the PLC side and the WinCC Flex.

But my Siemens reseller advised me to use rather the new 1500 series (never used but it's tia portal only) or a S7 317, alongside with a PC with a WinCC Runtime licence, telling me that the PLCs would me more reliable than an PCbox.

Is there any known problems with siemens IPCs? I used it when I modified an existing machine and I did not encouter any problems but my experience on it is limited.

Thanks,

 

[BobB]

I gather the PCbox is a soft PLC? NEVER for me - he is right - the PLC will be far more reliable. By the way I would probably use an Advantech industrial PC for the HMI - very reliable for a PC and save some money.

 

[JesperMP]

[...] a PC with WinCC rather than an HMI for databases purposes.

A PC with WinCC is an HMI. What do you mean ?
Maybe you mean a PC based HMI rather than an operator panel HMI.
We use WinCC Flexible PC RT as our HMI. We will probably switch to TIA WinCC PC RT at some time in the future.

I thought that a PCbox would suit its needs well because it would do both the PLC side and the WinCC Flex.

It can do so. It requires a WinAC RTX runtime license to be able to do that.

But my Siemens reseller advised me to use rather the new 1500 series (never used but it's tia portal only) or a S7 317, alongside with a PC with a WinCC Runtime licence, telling me that the PLCs would me more reliable than an PCbox.

I think that if you go for a fanless and no rotating media PC, then it will be as reliable as a classic PLC.
The issue is that it is a different beast. You will have to learn how to set it up and use it. For example how will retentive data be handled. You may have to provide a UPS for it to handle retentive data like a classic PLC.
Also, as for any PC-based solution, users and security problems are risks that classic PLCs do not have.

From your description, the customer wants an IPC with the HMI software, so that he can also have a database on the PC (or a connection to a database from the PC). He dont ask for a PC-based PLC software.
So just give him what he wants and stick with what you are used to.

 

[Iner]

The customer just asks for a Siemens solution. I don't think he has any opinion past that thing except for the WinCC running on a PC.
I just wondered if a siemens IPC was reliable because it would do both the HMI and PLC. I have not digged the costs difference but I know a company who is using siemens PCbox as their standard for applications needing more than >200k of working memory so I was surprised by the answer of the reseller.

 

[JesperMP]

Siemens IPCs are really rugged, compared to some other "IPCs" that seems to be regular motherboards stuffed in a rugged-looking cabinet.

Even then, I would distinguish between IPCs with or without rotating parts (HDs, fans).
The latter are much more rugged.

 

[fasacrifice]

We once made a mistake and decided to use IPC (Siemens, the new generation and they are really good as a PC) to see how they are and what are the options. You get one PC and you can use that one as a soft PLC and HMI. You just connect any display and use as a HMI.

The problem is the concept of soft PLC and HMI not the Siemens itself. We are not happy at all. First of all it takes time to learn how to set them up. If it was a PLC, you just start programming right away but with these guys there is setup process involved.

The next thing is that the memory is not retentive on them if you shut the power of the IPC directly. If you want the memory retentive, you have the shut the IPC properly like shutting down a regular PC. It’s better to use UPS. The other option is that I think they have separate memory card (I don’t remember what kinda) to have retentive memory.

I can still not justify why one should use soft PLC and HMI. If you need immense data logging or high level calculation, just buy a powerful PLC and HMI and set up a PC beside that to pull the data from PLC and HMI and do all the required data logging and calculation.

 

[arlenjacobs]

I agree with the other comments as well. The PLC is more reliable by design, not because there is a problem with using an IPC.
Avoid the soft-PLC unless you have very specific reasons, and know, that it is better for your project.

Also think about Windows updates, patches, software changes. Operators (IT departments) like to mess around with that and it can be a support problem. One problem with the computer takes out two devices: HMI and PLC. If you customer has a good local IT department, then the updates are less of an issue.

Siemens IPCs are well built and excellent computers that will last. Don't worry about that.
If you want them to last longer, yes you need to have non-moving parts (solid state hard drive, no fans, etc.).

You must have a UPS battery backup for safe shutdown. Power losses can corrupt data and then you have to recover from that. Windows is not power safe.
Windows Embedded 7 can be setup to work with power loss, but that is not by default. It is something you need to enable (HORM and EWF) after you have configured your computer and software. But that still is not as good as a PLC for power loss.

 

[mk42]

For the posters mentioning shutdown concerns for WinAC, I think Siemens offers IPCs with NVRAM (NV = non-volotile), which I think is supposed to help with this. I think the soft PLC uses it for the retentive data.

For some applications, the soft PLC does make sense: if panel space is tight you can combine the PLC & HMI, for high speed data logging, for interacting with custom windows programs, or for REALLY large applications. The HW setup is a pinch different, but the programming is pretty much just like a 300 series PLC.

In general, though, I agree with the other posters. There is nothing wrong with the Siemens IPCs, and WinAC is a fine solution, but using a soft plc instead of a normal one tends to complicate things unnecessarily. IT issues affecting the HMI might stop production, but it would at least be a controlled stop, and the PLC can probably even work without it to some extent. To me, its just one more thing a maintenance guy has to learn, which makes it more likely to require engineering support for "simple" issues that they could probably solve themselves.

 

[Iner]

Thanks for the answers and your opinions, I wasn't aware that there were still these limitations about soft PLCs. It looked fine with a limited experience on it, but it's true that being PC based make it a lot less reliable with Windows, even its Realtime version and even it it's manageable, it's still more work . You are right if it isn't necessary, just stick with the simplier solution (S7-300 in this case).