S7 300/400 MPI-PROFIBUS Comunication

Hi,
I've got to connect to an S7 300/400 plc, and I`m wondering if there is any possibility to connect, configure and program the PLC using a simple RS232/RS485 converter, instead of buying the Siemens PC-ADAPTER. I would appreciate any information on this subject.

Thanks in advance!

Good luck in this regard

I would like to know the very same thing, so hope there is somebody out ther that knows

Checked this out myself recently...
No you cannot roll your own without knowing Siemen's secrets, which are not in the public domain.
However, if you are using S7 5.3 and your PLC has an ethernet port, or a pre-configured ethernet card, you can easily connect via ethernet and program away. This is what I often do now.

Doug

or a pre-configured ethernet card

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Just a small correction:
The ethernet card or the onboard ethernet port doesnt have to be preconfigured.
There is a utility inside STEP7 to initialise the card or onboard port with an IP address. When that is done you can access the CPU for programming.

So, if I use STEP 7 5.2 instead of 5.3, Can I use the Ethernet card for programming a brand new PLC from scratch?

Thanks in advance,
IO

Yes.
Actually I think that the ability to program via ethernet came with v5.2
If you have v5.2, then check if there is an option to select a TCP or ISO protocol in the Set PG/PC Interface utility.

Also, look in the STEP7 manager if there is an Assign Ethernet Address function under PLC. That is the utility you need to set up the card or onboard port.

Hi,
Actually i've got a simular question.
I'm working right now with a serial adapter and Simatic manager v5.1 with SP6. The slowness is making me nerveous!!! My notebook is a P4 Centrino 1.8GHz with 512Mb RAM, so it should be fast enough. I guess the new v5.3 with Ethernet will be faster, so i'd like to upgrade.
- how can i add a ethernet-card when my rack is full?
- I have a cell with 3 S7/300 PLC's all profibus-master, they communicate thru DI/DO. I'd like to bring them all in one network, can i bring several profibus-masters in a ethernet-network?
- Are there other possibilities? I'd like to keep all 3 PLC's as profibus-master.
Thanks in advance
Heino

I'm working right now with a serial adapter and Simatic manager v5.1 with SP6. The slowness is making me nerveous!!!

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The PC adapter is horrible. The PC Adapter USB is much faster. On a S7-300 with MPI at 187.5k it runs acceptably.

how can i add a ethernet-card when my rack is full?

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You can expand the rack with IM modules and then install an ethernet CP.
Or you can exchange the CPU with a 315-2 PN/DP with an onboard ethernet port.

I have a cell with 3 S7/300 PLC's all profibus-master, they communicate thru DI/DO. I'd like to bring them all in one network,..

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Yes, it is possible to have several masters in the same Profibus network, you should then integrate all CPUs in the same project file in STEP7.
But why do you want to do that ?
The update of the Profibus io will be much slower.
The only advantage is that you could transmit data between the CPUs on Profibus (but then only if they use CPs and not the onboard DP ports).
If you have another network where all CPUs are connected (MPI or Ethernet), then they can transmit data that way.

.. can i bring several profibus-masters in a ethernet-network?

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I am not sure what you want to do. You can certainly connect several CPUs to the same Ethernet network.

Are there other possibilities? I'd like to keep all 3 PLC's as profibus-master.

Click to expand...

What is it that you want to achieve ?