Using SFC 14 and 15 with multiple slaves

Hello everyone,

nbut using SFC 14 and 15 will not specify which profibus slave to read/write from based on it's slave number, how can I use those blocks with multiple slaves since there is no parameter in the fucntion for the slave number?!

Thank you 

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Split from use a SFC 14 & 15 block to read and write data in a DP slave.

AUTOMOTO21

Hello everyone,

nbut using SFC 14 and 15 will not specify which profibus slave to read/write from based on it's slave number, how can I use those blocks with multiple slaves since there is no parameter in the fucntion for the slave number?!

Thank you 

DP slave is addressed. Please check this application example. May be useful. 

Hello Piscean,

I know that the slaves are addressed, but SFC, the function itself does not have a parameter for the slave address (which slave to read from) , it only has the register number parameter, error code parameter and datablock parameter.

Please read page 41 of attached document in earlier post.

SFC15 „DPWR_DAT“

Fig. 4-6

Using SFC 15 "DPWR_DAT" you transfer the data RECORD consistent to the addressed DP standard slave. Data transfer is synchronous, i.e., after completing the SFC, the write procedure is finished. The source area must have the same length which has been configured by you with STEP 7 for the selected module.

The SFC 15 "DPWR_DAT" is necessary because the transfer commands which access the I/Os or the process image of the outputs can only be used to consistently write a maximum four bytes. 

Parameters:

LADDR Configured start address of the PAA area of the module to be written to.

Note: The address must be hexadecimal, for example, start address 100 means: LADDR:=W#16#64.

RECORD Source for the user data to be written. It must be equally long as configured for the selected module with STEP7. Only the data type BYTE is permitted.

RET_VAL If an error occurs during processing of the function, the returned value will contain a hexadecimal error code. 

Hello Piscean, 

I would like to thank you first for your continuous support.

One thing I am still not getting. please find attached the picture of the function, where in this function do you put the profibus slave number? how does the function know which slave I want to read/write from and on??

 "LADDR is for the logical address, the address of the first register and does not correspond to the profibus address"

LADDR: 

-it identifies the slave module I wand to address with my function.

-does not correspond to the profibus address .   

how can you identify which module I want to address when you are not putting any parameter for the slave profibus address!!!!?

if I want to address slave 1 (has the profibus address 1) and I want to read register number 300 to 400 from it, I will put the following parameters in the function

LADDR = 12C (which is hexa for 300)

RECORD = DB1.DBX0.0 (The DB I want to store the data that I read from profibus in) or should it be in another format?

RETURN = any integer memory to sore the execution error code in.

then where the hell is the parameter that specifies which slave I want the data from?

If I have 2 slaves, 1 and 2

for slave 1 I am reading register 300 to 400, for slave 2 I am reading register 500 to 600 what will you put in your function to specify that for 500 to 600 I am reading from slave 2 not slave 1???

dchartier

Hello Automoto;

See if the attachment provides enough information. Note that it simply confirms the text that was already in the help file you copied.

Hope this helps,

Daniel Chartier

AUTOMOTO21

 "LADDR is for the logical address, the address of the first register and does not correspond to the profibus address"

LADDR: 

-it identifies the slave module I wand to address with my function.

-does not correspond to the profibus address .   

how can you identify which module I want to address when you are not putting any parameter for the slave number

if I want to address slave 1 (has the profibus address 1) and I want to read register number 300 to 400 from it, I will put the following parameters in the function

LADDR = 12C (which is hexa for 300)

RECORD = DB1.DBX0.0 (The DB I want to store the data that I read from profibus in) or should it be in another format?

RETURN = any integer memory to sore the execution error code in.

then where the hell is the parameter that specifies which slave I want the data from?

If I have 2 slaves, 1 and 2

for slave 1 I am reading register 300 to 400, for slave 2 I am reading register 500 to 600 what will you put in your function to specify that for 500 to 600 I am reading from slave 2 not slave 1???

dchartier

Hello Automoto;

Daniel Chartier

 

Slave address 1 OK.

Why you want to read register 300 to 400. For 300 - simply put address. e.g. W#16#12C.

Slave 2 for 500 -  W#16#1F4 

my god

but 1F4 = 500 !!!!! how can slave 1 know that I am not requesting 500 from it but I am requesting it from slave 2??

and I want to read for example 10 or 100 registers after 500 for example from 500 to 510 , if I put 1F4 in the laddr parameter I only read only 500 ? no?