Hi guys

I have small plc S7-1211 CPU with analog board only. Without any communication module 

Quantity is 390 PLCs want to be connected to one SCADA computer.

However,  I saw that their is a limitation with the number of PLCs that can be connected to Wincc Professional 

I saw documentation to have up to 64 PLC what about 390 PLCs how can I conncte them can you help guys

Hi 

Hello;

Quite a project, I have never used so many CPUs to collect data on a single WinCC installation.

The only way I see to connect so many PLCs to a single WinCC Professional station would be to multiplex the CPUs. This implies organising the CPUs as "head stations", connected to WinCC and collecting data from "sub stations" in the field, But for tjis to work you have to consider the limitations of the equipment.

The CPU 1211c are the smallest of the S7-1200 family, with 50 kB of work memory (for both code and data).

https://support.industry.siemens.com/cs/pd/453019?pdti=td&dl=en&lc=en-WW

The S7-1211c can work both as Profinet IO controllers and IO devices,  but as IO controllers they can connect to max. 8 IO devices. And as you say WinCC can have maximum 64 connections.

Let's say you organize your PLCs as 50 IO controllers head stations connecting to 8 S7-1211c IO device sub stations each, that will give you a maximum 400 PLCs you could theoretically connect to your WinCC station through the IO controllers.

But remember the data memory limitation on the S7-1211c: you have to plan the amount of data written to WinCC to its bare minimum so as not to exceed the limit in the IO controllers collecting data for thw WinCC application.
Also the data you collect must be identified so you know from which IO device it comes from; I suggest that the tags transfered to the IO controllers have a prefix identifying them as belonging to the specific IO device that generates them.

Siemens automation microsets proposes a way to synchronize data between the IO controller head station and the IO device sub stations in such an application. It could possibly interest you for such a project:

https://support.industry.siemens.com/cs/ww/en/view/39040038

Hope this helps, 

Daniel Chartier 

 Great idea, Yes I can divide them up to 45 group,  I believe even S7-1212 with remote ET200SP IO will be a cheaper option

Luckily no real engineering will be required it is only reading data once a day.

Thanks

dchartier

Hello;

Quite a project, I have never used so many CPUs to collect data on a single WinCC installation.

The only way I see to connect so many PLCs to a single WinCC Professional station would be to multiplex the CPUs. This implies organising the CPUs as "head stations", connected to WinCC and collecting data from "sub stations" in the field, But for tjis to work you have to consider the limitations of the equipment.

The CPU 1211c are the smallest of the S7-1200 family, with 50 kB of work memory (for both code and data).

https://support.industry.siemens.com/cs/pd/453019?pdti=td&dl=en&lc=en-WW

The S7-1211c can work both as Profinet IO controllers and IO devices,  but as IO controllers they can connect to max. 8 IO devices. And as you say WinCC can have maximum 64 connections.

Let's say you organize your PLCs as 50 IO controllers head stations connecting to 8 S7-1211c IO device sub stations each, that will give you a maximum 400 PLCs you could theoretically connect to your WinCC station through the IO controllers.

But remember the data memory limitation on the S7-1211c: you have to plan the amount of data written to WinCC to its bare minimum so as not to exceed the limit in the IO controllers collecting data for thw WinCC application.
Also the data you collect must be identified so you know from which IO device it comes from; I suggest that the tags transfered to the IO controllers have a prefix identifying them as belonging to the specific IO device that generates them.

Siemens automation microsets proposes a way to synchronize data between the IO controller head station and the IO device sub stations in such an application. It could possibly interest you for such a project:

https://support.industry.siemens.com/cs/ww/en/view/39040038

Hope this helps, 

Daniel Chartier 

AutoGen_6753138

 Luckily no real engineering will be required it is only reading data once a day.

 If you only need to read data once a day an not continously, and you don't nee to write anything to a station, maybe you can change the IP address of the S7connection with a script:

https://support.industry.siemens.com/cs/de/en/view/89255950

I don't know if this is also working for the S7-1200 channel.

If it's working, then I'd create a set of internal tags for each station, loop through the list of station addresses, if the station is online, copy the external tag values to the internal data set, add a variable with a timestamp so the user can see how old the values are.