problem connection between two CPU's in SIMATIC step 7

HI every one ,
I'm trying to connect two cpu's in siemens step 7
I followed all steps7 in this video https://www.youtube.com/watch?v=-qnvwz8nlRQ
but the problem I dn't get the same result , I have no connection and no transmission of the results
also I get one's in the STA I dn't know why
can any one help me

Hi

Let's start by asking can you go online to each cpu from the one point
This will test that your network cable is good to start with
Have you combined both projects in to one
Have you downloaded to both cpu
Can you post your project

Donnchadh

Hello and have a nice day to you.

I'm not sure if this is what you looking for, but just in case, then you can try.

I successfully established communication between two s7-300 cpu's. By PROFIBUS DP with Master CPU 315-2 DP / Slave CPU 315-2DP. You can follow this link if you like: (http://w3.siemens.com/mcms/sce/en/a...ments/field-bus-systems/d06_cpu315_cpu315.pdf).

Just pls. take note in no.35, Siemens have an error there. In OB1, it should be;
L IB 0
T QB 2
L IB 2
T QB 4

not the way it being shown. Anyway you can analyze it when you set up the profibus DP properties.

hi
thank you for ur reply
Donnchadh I did the simulation for the sender cpu it works but there is no sending of values to the slave
I dnt have the plc I only have the cpu 315-2DP in the lab and I dnt have access all time so I'm trying to send values for the cpu 315-2PN_DP to the cpu 315-2DP in step 7 and then download the value obtained to the plc .
is it possible ? could you help me I dn't have a big knowledge in the communication so for me if I do the communication within MPI that will be good for me

thank you jairus I'll try to follow steps , hope it will work I have question , is it the same thing if I change the cpu master to the cpu 315-2PN\DP ? what should I change in the configuration

rikita said:

thank you jairus I'll try to follow steps , hope it will work I have question , is it the same thing if I change the cpu master to the cpu 315-2PN\DP ? what should I change in the configuration

Click to expand...

Hello Rikita,

Yes you can replace it with CPU 315-2 PN/DP. You can follow step by step the procedures, except no.35, siemens have a little error there, so we need to replace the OB1 with.
L IB 0
T QB 2
L IB 2
T QB 4
:do not follow the one being shown in the manual for no.35 only.

hi jairus ,
I did all steps , I followed what u said I changed step 35
here is my work:
http://www.mediafire.com/download/2gg8rhw0ywh15u4/cpu315_c.rar
can you check if it is correct ?
I dn't see in the simulation a communication, where is the problm ??

rikita said:

hi jairus ,
I did all steps , I followed what u said I changed step 35
here is my work:
http://www.mediafire.com/download/2gg8rhw0ywh15u4/cpu315_c.rar
can you check if it is correct ?
I dn't see in the simulation a communication, where is the problm ??View attachment 36541

Click to expand...

Hello Rikita,

I can't simulate that project also in PLCSIM, but it work very fine in actual module. Just make sure you drag and drop the actual and correct module which you have to the hardware configuration. I apologize also to say that siemens have an error, i just forgot; for i used different modules, that's why the addressing is different. It's been a while since the last time i configure this. Now you can find my attachment file and you will notice i used different modules, just because that's what available here in the Lab. It is tested and working.

Base on the attached simatic S7-300 master/slave project.

Master CPU: OB1
L IB 0 // load input byte
T QB 40 // transfer into output communication (this is going to your slave)
L IB 40 // Load input communication (this is coming from your slave CPU)
T QB 0 // Display (this QB 0 because this is what being configured in the hardware configuration; pls. refer to the hardware configuration).

Slave CPU: OB1
L IB 0 // Load input byte
T QB 2 // transfer into output communication ( this is going to your master)
L IB 2 // load input communication (this is coming from your master)
T QB 4 // display (QB 4 because this is what being configured in the hardware configuration; pls. refer to the hardware configuration).

u know I did search and I have found out that when we send data via MPI using global data we cannot see the transfer of data withing the simulator ; they said that PLCsim is not real time so we cannot see what happens , really thank you for your helpI I'll try in lab and see result.