I'm starting to work with PLC S7 214. I would like to be able to communicate my PC with this PLC and vice versa. Firstly, I'm interested in monitoring my PLC memory by programming the communication link (without using any existing software like MicroWin). Does anybody know how the S7 214 communication protocol works?
Does anybody know or have some example of how to programme this protocol? Any information well be of great interest.
Thanks in advance.

Pau Marti
Automatic Control Department.
Politechnical University of Catalonia.

 

Dear List'
For monitoring the PLC S7 214, you would require some type of HMI software like Protool or WinCC. It has built in drivers through which you can communicate as much as you need. If you need to built your own driver, you would need some interface software which work as server mean you can call the functions of that package in a simple C++ writen software, like Prodave of Siemens. I don't exactly know what version of
Prodave you should use.

Imran Shabbir,
[email protected]

 

Siemens do a package called Prodave S7 which is a set of DLL's which will interface to C/C++ Delphi and VB to enable you to communicate with S7
devices under win95. I have used it and it works fine, if your Siemens rep cant find it I can dig up a part number.

Regards

Martin

 

Why not use the built in RS232 capability in Freeport mode to connect to a pc serial input, you can write code to transfer the information
you want. you can use the PC programming lead to connect.

there are plenty of examples on the tips and tricks CDRom and the siemens website

 

I am currently working on a project where I am connecting 24 Siemens S7-214's & S7-216's to a SCADA PC using an MPI network. The PC is actually
connected through a S7-414 because it also communicates with S7-300's and M7's at a faster baud rate, but it can operate directly onto the MPI network if required.

A Siemens CP5412(A2) communications processor card is installed in the PC (ISA card) and the S7 communications software (part no. 6GK1 702 5CW51-3AA0) is used as the driver. This software provides diagnostic tools and can also be used with the Step7 programming software. In my application, the driver is used with a FactoryLink SCADA system, although I believe there are other interfaces available from Siemens for OLE/DDE and OPC.

The maximum baud rate of the PLC's is 19.2Kbps using Profibus cabling, and the maximum length between segments is 50m without repeaters. No additional programming is required for the PLC's except to modify the node address. The maximum node address is 126 but I am not sure if you can have more than 31 nodes. Can anybody advise?

Regards

Colin Jones
[email protected]
CISE Ltd.
Trident House, Trident Industrial Estate, Warrington Road, Risley,
Warrington, Cheshire. WA3 6AX United Kingdom
Phone: +44(0)1925 826500 Fax: +44(0)1925 826550 Mobile: 07968
297906

 

Dear Pau:
By default S7-214 uses a protocol called PPI, but if you want to connect this CPU to your PC and monitor I/O with other software packages than
protool or Win CC (Siemens), one choiceis to use the Freeport mode of the interface and use MODBUS protocol. Details of that implementation you can find in S7-200 tips and trick CD. If you cant
find that CD contact me and I will send you the program. In a very very simple aproach you can send I/O status using ASCII and read them with Hiperterminal (use it as simple exercise ).

Rodrigo Pinto

 

I don't recall what the *electrical* limit for the number of nodes in a segment is (probably 31), but whatever it is, that may not be your
practical limitation. Depending upon your application, the practical limit may actually be determined by communications load on the network.
I have been told, that even with an S7-300, and MPI network is not normally suited to systems of larger than 10 nodes. There is an explanation in the S7-200 manual of how to calculate network load and how it affects the
response time, but I am not sure that it explains your exact situation. I would suggest you investigate this aspect in some detail before you finalise your design.
The networking on the newer S7-22x (which replaced the S7-21x) series is supposed to have been much improved for exactly this type of
application.


While we are on the subject of Siemens, I read in the news this evening that Siemens is trying to take over Milltronics (who make ultrasonic sensors for process industry use). They are offering a very big premium over the last share price on the TSE, so I suspect they will succeed.

**********************
Michael Griffin
London, Ont. Canada
[email protected]
**********************

 

It is not adviceable to have more than 31-32 nodes on the same segment. This is due to the signal loss you get for connecting each additional node. You may try and it may work but there is no guarantees.


/Johan Bengtsson

----------------------------------------
P&L, the Academy of Automation
Box 252, S-281 23 H{ssleholm SWEDEN
Tel: +46 451 49 460, Fax: +46 451 89 833
E-mail: [email protected]
Internet: http://www.pol.se/
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-----Original Message-----
From: Colin Jones <[email protected]>

I am currently working on a project where I am connecting 24 Siemens
S7-214's & S7-216's to a SCADA PC using an MPI network. The PC is actually
connected through a S7-414 because it also communicates with S7-300's and
M7's at a faster baud rate, but it can operate directly onto the MPI network
if required. ...<clip>

 

WinCC for monitoring a 214? Quite expensive! For short monitoring and testing you can use step7 micro win. Otherwise perhaps protool pro (also expensive)..

 

Dear Rodrigo,

This is exactly what I am trying to do; interface an s7 214 with a SCADA system via Modbus RTU and Freeport mode.
At the moment I am sending the info. as ASCII strings but the data doesn't always get interpreted correctly, leading to poor quality trend graphs on the SCADA.

I would be very grateful if you would mail me the program required for the PLC.

Best Regards,

Paul Darby,

Ireland