STEP7 online via Ethernet. Strange findings.

Hi,
i am in the progress of familiarising myself with my new 315-2PN/DP. It is going extremely well, almost too well.

Siemens manuals explain how to configure a programming PC in NetPro in order to be able to go online via Ethernet. So far so good.
But I find that if I change the PCs IP address to one that is NOT configured in NetPro, then I can STILL go online via Ethernet. It shouldnt be possible.

Its not a big problem, but it shatters my understanding on how the online connections work with S7.

Can anyone shed a bit of light on this ?

Jesper, I only have a minute and can't go into a ton of detail, but I can tell you that I never configure my PC in netpro. As long as my PC's static IP address in in the correct range as all of the PLCs at a particular site, I can go online with them all. If your PLC was configured to 192.168.40.100, for example, I could walk right in, change my laptop's address to 192.168.40.200 and go online immediately. I suspect that you are seeing something like this.

Just curious.

If I get one of those 315-2PN/DP do I have to upgrade my Step 7 5.1 to 5.3 or are there new drivers supplied with the 315-2PN/DP?

S7Guy,
you are right that I dont have to configure a programming PC in Netpro, but I forgot to tell that I also have an OPC server and Protool RT configured. And everything continues to work, regardless of the fact that the IP addresses set in NetPro and Windows Control panel doesnt match.

As for an explanation, it looks like you are right, there is a Siemens FAQ with a note like this:
"The IP address that is set in Microsoft Windows' control panel need not match the IP address configured in NetPro!".

(then WHY are we setting these IP addresses in NetPro, when it isnt really relevant ?)

Peter,
to be able to configure the new 315-2PN you will have to upgrade your STEP7 (v5.3+). This because the hardware catalog in v5.1 doesnt have the latest CPUs.
Previously, you would also have to get Simatic Net in order to program via Ethernet. But from v5.2 there are Ethernet drivers integrated with STEP7.

edit: To get the 315-2PN/DP in my hardware catalog, I had to install SP1 in addition to v5.3.

This is to Peter Nachtwey.

Peter,
I remember now that you had a defective PC adapter.
Just in case you wonder if you can go online with only an ethernet cable, then the answer is "no" !
Initially, you have to go online via MPI to enable the ethernet port. From then on you can do everything via ethernet - including changing the hardware configuration.

Jesper,

S7 uses in the first connection the IP adress, then the programm saves the MAC adress. For futher use, S7 search for the MAC adress and if not found, the IP adress.

Nak said:

S7 uses in the first connection the IP adress, then the programm saves the MAC adress. For futher use, S7 search for the MAC adress and if not found, the IP adress.

Click to expand...

Thats interesting, do you mean that STEP7 uses the MAC address of the PLC for the online connection ?
According to the manuals the MAC address is only used with ISO protocol. The MAC address of the PLC or CP cannot be set or viewed anywhere in the Hardware config or in NetPro (I cannot find it, I mean).

JesperMP said:

The MAC address of the PLC or CP cannot be set or viewed anywhere in the Hardware config or in NetPro (I cannot find it, I mean).

Click to expand...

In netpro, double click the CP to bring up the properties, in the 'general' tab, there is another properties button in the 'interface' box, click this and that will bring up the ethernet properties, here you can change the MAC address if you tick the box that says 'change MAC address / use ISO protocol'.

Is that what you was after?

Paul

Is that what you was after?

Click to expand...

Thanks, but I knew that allready. That is the MAC address of the PC, not the PLC. And I dont want to use ISO protocol.
I just dont understand what NaK is saying. Do you ?

That is the MAC address of the PC, not the PLC.

Click to expand...

No, that is the MAC address of the PLC, not PC. In fact, since I usually have multiple CPUs on a network, I have to make sure they are all unique, since Siemens uses the same MAC on each CP card.

Just in case you wonder if you can go online with only an ethernet cable, then the answer is "no" !
Initially, you have to go online via MPI to enable the ethernet port. From then on you can do everything via ethernet - including changing the hardware configuration.

Click to expand...

I haven't tried this with earlier versions of S7 CP cards, but during the last few years it has been possible to download the entire project (hardware config, connections, and code) via the Ethernet port, even if the PLC had no prior configuration. This is done using the default MAC address. So, it is possible do do everything you need to do without using an MPI adapter.

No, that is the MAC address of the PLC, not PC

Click to expand...

I really could not find that setting for neither an onboard Ethernet port (315-2PN) or a CP (343-1 LEAN).
However, on a "regular" CP 343-1 this setting IS available (just checked it).

.. during the last few years it has been possible to download the entire project (hardware config, connections, and code) via the Ethernet port, even if the PLC had no prior configuration. This is done using the default MAC address. So, it is possible do do everything you need to do without using an MPI adapter.

Click to expand...

There is no MAC address to set in NetPro for the 315-2PN. However, on the CPU itself is stamped a MAC address. So you may be right.
Then how do you go about downloading via this MAC address ?

Then how do you go about downloading via this MAC address ?

Click to expand...

I don't have a newer CP card right at this moment to verify the steps, but I got this from the Siemens manual. Basically, it allows you to set the IP address via the MAC address, at which time you can download the rest of the project. So, you can in effect commision a PLC without an MPI adapter, which is pretty nice.

From the Industrial Ethernet Manual:

1. Open the SIMATIC Manager.


​

2. Define the configuration of your S7 station with the appropriate components in​

HW Config in an existing or newly created project.​

3. When you create the CP, network it with an Industrial Ethernet subnet.​

When you create the CP in HW Config, the necessary dialog is displayed in​

which you can network the device and assign the IP address.​

4. Select the "Addressing" tab in the properties dialog of the CP you want to​

address.​

The tab displayed is identical to the dialogs illustrated in Section 3.4.1.​

5. Start a network search for available modules by selecting the "Browse..."​

button.​

6. Select the CP with the matching MAC address from the components listed.​

7. Assign the IP parameters taken from the networking to the CP by clicking the​

relevant button.​

Result:​

The CP is now accessible on Industrial Ethernet using the IP address.​

S7Guy,

It looks like you are right, but something may have thrown me off in the wrong direction.
Maybe Siemens has changed the menu structure of STEP7 and the HW Config, because it looks like you cannot assign the IP address via the MAC address in the HW Config dialog for the CP (or the onboard Ethernet port on a CPU for that matter). There is no "browse" button in the dialog for the CP setup.

However, there is an "Assign Ethernet Address" utility which is separate from the configuration of the CPs.
There you can indeed browse for available MAC addresses, and with these you can specify the IP address.
The utility can be found in the SIMATIC Manager under PLC .. Assign Ethernet Address..

So you dont need an MPI cable after all. Everything can be done via the Ethernet port.