hi all

in my factory one master-islave DP communication is used in one plant.(slave is s7-300 and master is s7-400).

this system works correctly and master reads information from slave without any problem.

i opened their projects and I was faced with a strange thing in configuration.

in slave ,configuration i/o addresses are different from i/o addresses in master..and program for transfering data that is writed in slave is corresponding with slave configuration and no corresponding with master configuration..

my ask is how does this system work correctly?

please see attached pictures .

thank you

thank you.

master: cpu414-3

slave: cpu315-2dp

suppose in "MASTER" project that is downloaded to  cpu414-3  i have this configuration for cp315-2dp:

partner dp addr.   partner addr.   local addr    length       consistency

            2                       I100                   Q0        2WORD           UNIT

and in " SLAVE" project that is downloaded to cpu315-2dp i have this configuration:

partner dp addr.    partner addr.        local addr     length     consistency

                                                                     Q10       2WORD      UNIT

now i want to read one channel of analog input (iw350) from i-slave and send it to master..in program in slave must i use Q0 or Q10?                                                                                                    

is this correct in slave program?   IW350 >>move>> Q10    or  IW350 >> MOVE>>Q0  ?

in this manual (Entry ID:6518822) https://support.industry.siemens.com/cs/document/6518822/dp-link-between-cpu-315-2dp-(slave)-and-s7-400-(master)-with-step-7-v5-3?dti=0&lc=en-WW

addresses in slave and master are same.

thank you

a.z.r

thank you.

master: cpu414-3

slave: cpu315-2dp

suppose in "MASTER" project that is downloaded to  cpu414-3  i have this configuration for cp315-2dp:

partner dp addr.   partner addr.   local addr    length       consistency

            2                       I100                   Q0        2WORD           UNIT

and in " SLAVE" project that is downloaded to cpu315-2dp i have this configuration:

partner dp addr.    partner addr.        local addr     length     consistency

                                                                     Q10       2WORD      UNIT

now i want to read one channel of analog input (iw350) from i-slave and send it to master..in program in slave must i use Q0 or Q10?                                                                                                    

is this correct in slave program?   IW350 >>move>> Q10    or  IW350 >> MOVE>>Q0  ?

in this manual (Entry ID:6518822) https://support.industry.siemens.com/cs/document/6518822/dp-link-between-cpu-315-2dp-(slave)-and-s7-400-(master)-with-step-7-v5-3?dti=0&lc=en-WW

addresses in slave and master are same.

thank you

Hi,

I think you should Move IW350 to Qw0

and read in master by iw100

HI MR YARAY

I'm with you opinion.

But as you can see in the figures in first post, in my factory different Q address are used in master and slave plcs..and program in slave is correspond with configuration in slave..also in master configuration Q addresses is different from slave..  but communications work correctly...while in siemens manual for master-islave communication Q addresses must be same in both master and slave.

 Hello a.z.r.;

In most exemples you will find on Siemens' support, the situation is simplified and input/output addresses are the same.

For example:

https://support.industry.siemens.com/cs/ww/en/view/6518822

But this similarity in addressing is not mandatory, you can select any addresses as available in your CPUs as long as they respect size and consistency requirements for your application.

Hope this helps, Daniel Chartier

a.z.r

HI MR YARAY

I'm with you opinion.

But as you can see in the figures in first post, in my factory different Q address are used in master and slave plcs..and program in slave is correspond with configuration in slave..also in master configuration Q addresses is different from slave..  but communications work correctly...while in siemens manual for master-islave communication Q addresses must be same in both master and slave.