S7-413 wont change MPI adress.

I have this problem with an S7-413-2 CPU.

The MPI adress of port X1 is set to 3. I want to change it to 2.

But no matter what I do, it stubbornly refuses to do my bidding .

I try to change the MPI adress in Step7 hardware config and then download it - no change.
I try to do an online CPU reset - no change.
I try to power down, remove the battery and the memory card, power up - no change.
I try to do a CPU reset with the keyswitch - no change.

Step7 "available nodes" tell me that the CPU is constantly MPI adress no. 3. Is this adress chiselled into the silicon or what ?

Please - ANY ideas or suggestions ?

JesperMP

The only thing that I can think of is that you have already an MPI module on your network assigned as MPI address 2, possibly your PC, which should be MPI 0.

That is the only way that I know that you will not be able to assign an address of your choice, try changing the MPI address to another number (126 or example) then see if the S7 400 will accept that change.

If it accepts that address then you must have another module already assigned address 2.

Hope this helps

Paul

Paul,

have tried to select another MPI adress (4) - no luck
My PC is adress 20. I can see both the PLC (3) and the PC (20) under "set PG/PC interface .. Diagnosics .. Read bus nodes".

Am I doing something wrong ? In Step7 hardware config I set the interface to type = MPI (fixed), Adress = 4, Networked = Yes.
When i choose download, I am prompted for the connected MPI adress, number 3 is allready highlighted, and i accept this whereafter the download goes thru.
Everything seems to go fine, but the MPI adress of the S7-413 stays the same.

JesperMP

I don't really know why you can't change the MPI address.

In the 'hardware configuration' screen, right click the CPU and select 'Object Properties'. On the 'interface' part select 'Properties' then change the address set in there. Click OK, then OK again, then 'save and compile' finally download. Then in 'simatic manager' click on PLC, Hardware Diagnostics, this will put the HW config screen online, check your settings in this.

If this is a new project that you have just started it might be worth checking that you have 'dragged and dropped' the correct CPU onto the rack, the firmware version is important because if this is incorrect you cannot talk to the PLC correctly.

Paul

Finally - it worked !

"Save and compile" were the magic words.

There is a button in the HW config that says "Saves and creates all system data in the current configuration". I thought that it did the same thing, but appearantly it does not.

Interestingly - it seems that the MPI adress is retained even after a reset with the keyswitch.
And - if you do not "save and compile", you can still download to the PLC. At least it should be interlocked with compiling of the changes.

Thanks Paul, it sure helps to have somebody else to talk to when having irritating problems like this. Without your input I would have fiddled around this for a long time.

JesperMP,

I am glad that you finally got to the bottom of your little problem, I was beginning to pull my hair out on this one as I could not see what you was doing wrong.

it sure helps to have somebody else to talk to when having irritating problems like this

Click to expand...

I do believe that's what Phil set this site up for.

Paul

To add something. If you look in the "Blocks" folder, you will see "System" blocks. That is what you created when you compiled the hardware config. When you copy the blocks to a Flash card or a MMC card, the hardware configuration is copied in the "system" block.