S7-300 <-> PC

Following one other thread I started regarding communication between PLC's (thank you for your help with that) I've found myself with a similar issue regarding communication with a PC.

I'm to develop a simple app that should send one byte (testing) to the PLC. Since I have Softnet v6.0 package available from a previous project I belive it should be used and so decided to test it and figure out how it works. I followed Jesper's guide (available from the download section) to set up the OPC Server except I use PROFIBUS DP protocol instead of MPI. Although everything looked ok, the PLC (S7-300 DP-master) keeps blinking the BF LED and using NetPro to check "Status Information" of the connection it shows that indeed the online connection to the module could not be set. The weird for me is that if I use OPC Scout the BF LED stops blinking and I'm able to read/write to/from the PLC.

I'm pretty sure that something is slipping me. Already tried following a FAQ/Example from Siemens site (20987358) but wasn't able to figure out where I'm screwing up.
I attached a couple of screenies in hope that it might help.

As usual, thanks in advance.
Best regards,
Nuno

Hello allstar

We cannot see how you have setup the connection in NetPro.

That the BF flashes may indicate that there is a Problem on Profibus, and that again may indicate that the Target Rotation Time has been exceeded.
On Profibus, it is imperative that you download the HW Config to the DP Master. This even if the connection is "unspecified". This is also what the warning messages in NetPro are telling you.

Apart from that, you can use the CPU Module Information to get the Diagnostics Buffer.
Also, you can also use the PLC HW Diagnostics to get info on the DP errors.

Hum.. I think the problem lies on the NetPro connection setup. When I select OPC Server (from the PC Station) and insert a new connection wasn't it supposed to be a 'Profibus' or 'DP' option for the connection type? There isn't anything remotely similar to it.. there's S7 (which I choosed given the other possible choices but no good), TCP, UDP, ISO-on-TCP, Point-to-Point, Email (?), and so on. I find it odd that there's no such type on the list especially since under OPC settings I selected it to work with DP protocol (thru the configuration console).
The other thing that boggles me is that when I choose to highlight the connection partner it correctly highlights the PLC's CPU (315-2DP) and the OPC Server but graphically the connection to the CPU is by MPI (this is 'graphically' since I'm only using the DP port) so I'm wondering if this isn't something else that I'm not fully understanding or maybe it's nothing.

I've pretty much pressed every download button that I could see, both for the PC Station and the PLC and (apparently) downloaded it sucessfully. Is this one of those things like the first time you configure the PLC where you have to connect the cable to the MPI port and then download the config?

I'll try to mess a bit more with the diagnostic support available. Done that already but going for a double check.

there's S7 (which I choosed given the other possible choices but no good), TCP, UDP, ISO-on-TCP, Point-to-Point, Email (?), and so on. I find it odd that there's no such type on the list especially since under OPC settings I selected it to work with DP protocol (thru the configuration console).

Click to expand...

It is most often the S7 protocol that you want to use. If there is more than one possible path from PC to PLC (i.e. Profibus AND ethernet) then you must specify it in the dialog that comes when you setup the connection. If there is only one possible path, STEP7 automatically selects that one. In your case the CP5611 via Profibus is allready selected.

The other thing that boggles me is that when I choose to highlight the connection partner it correctly highlights the PLC's CPU (315-2DP) and the OPC Server but graphically the connection to the CPU is by MPI

Click to expand...

Post a screenshot of that. It sounds strange.

is this one of those things like the first time you configure the PLC where you have to connect the cable to the MPI port and then download the config?

Click to expand...

This is a common myth. Actually, the only time that you have to download 1st time via MPI, is when you have a factory fresh CPU with MPI and DP interfaces. In that case the DP port is disabled, and can only be enabled by download from MPI or inserting a MMC card.

If you dont get it resolved, then zip and post your project. I can try to check it for you.

Hi Jesper,

Dont know how I missed this but the 'Hardware Diagnostics' showed that the inserted PC Station isn't identical to what I configured. I then checked to see what kind of nodes were present in the network and there I confirmed that the PC node has an active connection (like the node of the PLC master). So now I'm lost. I don't know another way to 'tell' Simatic Manager that this PC is supposed to be a DP-Slave.

I essencially followed your guide to add a PC Station to the project, then set it to match the Station Configuration and on the CP5611 choose the DP-Slave mode. Then on the Simatic Station HW, added a PC Station as a DP-Slave and configured it (in its properties established a connection to the configured slave on the list). If this is wrong (and it must be) plz share a correct way to do this.
I still dont understand the behaviour in the NetPro connections, even if everything was ok I would still get a warning when compiling and chekcing saying something along the lines of "you souldn't choose DP profile and use a s7 connection, make up your mind son!".

I attached a couple more screenshots and zipped the project aswell just in case.
Btw don't know if its relevant but the software I'm using is Softnet DP v6.0 SP5 + Step 7 v5.4 SP1 under Win2000.

Thanks for the support,
Nuno

Bump

Still haven't figured this out. Even following a siemens guide to add a PC as a DP-slave on a PB network this keeps showing me the same error over and over again. After trying everything I could think off I checked a compatibility table from Siemens only to find out that Simatic Softnet v6.0 SP5 ISN'T compatible with windows 2000 SP4 (required by Step 7 v5.4). So I'm hoping that this is the source of the problem and not my limited experience in these matters.

Anyone has a sugestion on another way to have a PC communicate with a PLC besides using OPC server?

You have chosen to use the DP protocol in stead of S7 protocol. This is OK, but it is not the most "normal" mode.

In the screenshot from the console it says that DP protocol is deactivated. It looks like S7 protocol has been selected in the configuration console. You probably copied the setup of the configuration console from my guide.
Remember that my guide is for an S7 connection, not a DP connection. When you do something different, you must adapt the settings accordingly. Select the DP protocol in the Configuration Console and see how it goes.

I dont think you are right about Softnet v6.0 SP5 does not work with Win2000. I use it with XP, no problems.

The screenshot you mentioned was wrongly attached since it was taken when I tried to set up a 'normal' config by selecting bus profile to be standard and using S7 connection. Same result though. Like I said, I followed your guide but of course I tried to adapt things to try to fit my case.
Regarding the compatibility issue I'm just mentioning what I saw at Siemens.

There's three things that bother me with this (besides the fact that it's not working properly):
1) The fact that when you try to set up a connection OPC Server <-> PLC you can't choose a "DP connection" from the list, even if you have DP profile selected in the bus and in the console config.
2) The fact that although I explicitly say that the PC is a DP-Slave it still shows (on the nodes chart at OPC settings in the console config) that it is "active" (same type as the PLC).
3) If I use OPC Scout to establish a connection between PC and PLC everything works like a charm (which should indicate that it's my config that is screwing up somewhere).

Btw thanks for your patience Jesper.
Best regards,
Nuno

Hello Nuno.

I have never tried to setup a PC Stationas a DP slave myself. So I dont know so much.
You are right that you can not select a "DP Connection" type. It looks like an S7 Connection is also used when the PC Station is a DP slave.

From what do you say that it does not work properly. Only the blinking BF LED ? What does it say in the HW Diagnostics ?
That you can get the OPC Scout test client to work, indicates that maybe it has to be like this and that the BF error is from something else. (The OPC Scout test client doesnt create any connections by itself. It uses the existing OPC Server connections, hence the term OPC test client.)

I have only two recommendations:
1. Integrate everything in STEP7 (which you allready do). This avoids the worst configuration errors.
2. Follow the official guide from Siemens as closely as possible.