communication between two PLCs

We have two siemens s7 PLC on our network with four HMI.Last week PLC-1 went to stop mode and was not going to RUN mode.We decided for memory reset(MRESET).We downloaded hardware configuration and program again and PLC1 is now running.But now there is no communication between two plcs , although i can ping them from the HMI.
How should i proceed now.
We faced once same kind of problem on other system .We were suggested to download netpro but still it was not working.Later on someone told us to open netpro and download to current project connections and gateways and then the communication started.
Should we always do same when downloading netpro ?

It's tough coming in after the fact and not sounding like I told you so...

The first thing I'd have done was examine the diagnostic buffer of the CPU for the error message related to the Stop mode. To do this open PLC Module Information and go to Diagnostic Buffer tab. You can save this log to a text file for examination later.

If you thought downloading the program would fix the problem (not likely but worth a shot), here is a safe way to do it.

1. Go online with PLC and upload hardware configuration and all blocks. Save to your hard drive and now you have a backup of what was in the PLC.

2. Open the program you think is the right one, the one you are going to download to try and fix the problem.

3. Open hardware and go online - it will tell you if it is not equal or not equal but can still be used for diagnostics. This tells you if your hardware config matches or not.

4. Right click blocks folder and choose Compare Blocks. Select "time stamp only" so it doesn't flag data that has changed (numbers that have changed) and find out if your program blocks are equal or not.

Now you know whether you have current hardware configuration and program blocks. And you have the backup you just uploaded and saved to disk.

I strongly suspect you downloaded the wrong program or not the current program, the one that was running before PLC went to stop mode.

Forgot to add: When you download the hardware configuration you are sending everything in Netpro to the CPU - no need to do it separately from Netpro.

plc communication

yes paul
you are right that it is advisable to download the hardware setting before make reset.
where in hardware configuration do we configure the other PLC to communicate with.I think it is not there.
so it means its matter of program in different block .I should check all blocks if some missing .Because this plc alone is working perfectly without and problem.

What CPU: S7-400 or S7-300 and what model?
How are the plc's supposed to communicate?
With Profibus or Ethernet messaging?

I have not done much of this but I would investigate what blocks Siemens would use for messaging and look for them in the program. You can use the Reference Data to easily search for them.

I am sure there are people here who can tell you exactly how it works so post back.

Plc communication

Hi
It is S7-400 and communicating through ethernet.

(deleted - I thought the problem had to be with the flash card).

panthripu said:

Later on someone told us to open netpro and download to current project connections and gateways and then the communication started.

Click to expand...

It is not clear to me what you did differently between the two "downloads", but it confirms that it was missing connections that was the problem.

panthripu said:

Should we always do same when downloading netpro ?

Click to expand...

Like Paul B said, after compiling in NetPro, it ought to be enough to download the HW Configuration, because it normally already contains the connections from NetPro.
That it does not work now for the problem you refer to, could indicate that the connections are not saved in NetPro.

I think that one possible explanation can be that the HW Configuration has been reset at some time, without the connections from NetPro. Subsequently compiling in NetPro and downloading to the CPU should set things straight.

Can you confirm whether its profibus or ethernet you are using? if its ethernet then i think you should check the partner id's match the Ag_send/recv commands, then select each PLC one by one in netpro and click download. i believe the config is actually sent to the cp card in this instance, but maybe someone else could confirm this!
if using DP the config is all sent via hw configuration!

thanks

hi friends
first of all i would like to thank you all for your informationa and help as usual.
My problem is solved now.In netpro i found the ip address of partner was not correct.I just corrected it and download.
Now i have few questions,,,
Is it not possible to save all hardware configuration,netpro,program to flash memory , sothat in future if someone make same reset ,everything will get downloaded automatically when we restart the plc. If yes , then how ?