S7 300

Hi All,

I am new to Siemens PLC's.Could somebody please advice on which profibus IO units can be used along with S7300 PLC and if then

*)Is it possible to have a redundant HMI using Ifix using the S7300 and the Profibus distributed IO's.

*)How to configure and setup the profibus IO.................

*)Also is it possible to multidrop on profibus network-Siemens display panels and IO's


Kindly advice-Siemens Guru's.............

Hello krism;

Welcome to the forum; I hope we can get you information you can use for your projects.

From the nature of your questions, I believe you need to read up a bit on Profibus-DP networks and configuration. I suggest you look at www.profibus.com (especially the Technology and products tabs); you can also download the profn2_e.pdf file from Siemens' support website: it discusses topology and material elements for the bus.
http://support.automation.siemens.com/WW/llisapi.dll?func=cslib.csinfo&changelang=true&aktprim=0&siteid=cseus&lang=en

These are the 2 best introductions I know on Profibus-DP.

Now:
1) basically, you should be able to use any Profibus-DP slave with any Profibus-DP master. As long as you have the gsd file (configuration datasheet) for the slave, you can make it available to the master and configure it as part of the network. Look it up in the links proposed above.
2) redundant HMI? that depends on the software used. Look it up in iFix help files; if it can handle redundant comm links, you will requiere 2 seperate Profibus-DP communication cards in the PC (such as Siemens' CP5611, or Softing processors... Look at the Products tab in profibus.com) and the appropriate software drivers.
3)Each DP master comes with some kind of Profibus Configurator, through which you integrate the slave gsd files, and set up the bus (slave node addresses, individual slave data exchange [size and format], and bus parameters [speed, length, number of repeaters...]). For S7-300, this is integrated in the hardware config editor of Step7. The configuration must be downloaded to the CPU before comms can be established, and slaves must have their own configuration established (node address, bus parameters equal to those of the master).
4) Profibus-DP operator panels are available from various manufacturers. Siemens has a very diverse line of them, programmed through WinCC flexible (formerly ProTool). There is a limit on the number of such "masters class 2" (as they are refered to in the Profibus world)that a CPU can handle. For the S7-300, that can vary from a maximum of 3 to a maximum of 8 (check catalog values for HMI connections for your specific CPU).
Remember that you can have up to 125 participants in the bus, including at lest one master, your HMIs and your I/O modules [this includes simple I/O, drives, transmitters, other CPUs...].

Hope this helps,
Daniel Chartier

If you are going to use several local stations (S7-300 with Profibus io + possibly local HMI panels), then I would not tie everything together in ONE Profibus network.
There are many possible variants, but to cut it short I will recommend you to connect iFix via Ethernet, and keep the local io and HMI to each "station".
So S7 315-2 PN/DP CPUs (or the more powerful 317-2 PN/DP) in combination with Simatic Softnet Ethernet OPC server may be the simplest and best solution to you.

If you only have ONE S7 300 station, then maybe putting everything on one Profibus network could be OK.

Hi All,

Thanks for the answer's.I suppose the architecture of the system I intend to use would be beneficial in getting your expert opinions.

The system that is intended is one where there will be one S7-300 CPU ,distributed Profibus slave IO system and atleast 4 or 5 datapanels.This configuration with 2 PC HMI stations using Ifix running on redundancy.


*)was also wondering whether Siemens has the appropriate products on ethernet to realize the above architecture.

*)Could you also suggest which is the best in terms of reliability-Ethernet or Profibus control network.


Would really appreciate your expert opinions.


With Regards,

Siemens definitely have Ethernet products to match you stated requirements. Ethernet is part of their present and future policy.

I would say that Profibus is one notch more reliable than ethernet.
Even if you chose high quality Ethernet components, the segmented architecture with swithes mean that the reliability of the Ethernet network deponds on the swithces.
To minimize the risk with Ethernet you could consider a redundant Ethernet ring, with switches with dual power supplies.

Depending on your situation, you could split the system into Profibus for the io, and ethernet for the iFix HMIs and the "datapanels".

How big is the project ? How many io ? How many Profibus slaves ?

S7-300: I have a small question "What are the differences between DB and DI in Step7".

miamia,
dont be afraid to start a new thread. It is better than adding a new and unlinked question to an existing thread.

Anyway,
"DB" is for a regular (i.e. shared) Datablock.
"DI" is for an instance datablock. Instance datablock are always used in connection with FBs or SFBs.

It is possible to open and work with 2 datablock's at the same time. The first is opened in the DB-register and the second is opened in the DI-register.