Hi Sir :

I have a profinet IO device and I use S7-300 CPU-15 PN/DP to control IO device.

I use STEP 7 to program my PLC program.

The input/output start address of IO device is 256 and I extend process image size from 128 to 600.

Since the end address of IO device is 575.

I get the same error code 80b1 when using SFC14 and SFC15 and the length exceed 4 bytes.

Below is my code.

CALL “DPRD_DAT”

LADDR :=W#16#100

RET_VAL:=MW52

RECORD:=P#M 40.0 BYTE 4(If the length exceed 4, RET_VAL is 0x80b1)

CALL “DPWR_DAT”

LADDR :=W#16#100

RET_VAL:=MW50

RECORD:=P#M 20.0 BYTE 4(If the length exceed 4, RET_VAL is 0x80b1)

The expert in this thread said that maybe the slave device does not support consistent read/write.

My question is that how to confirm if my slave device does not support consistent read/write?

If my slave device does not support consistent read/write, what SFC should I used?

Best regards,

Marcus

------------------------------------------------------------------------------------------
Split from SFC14 returns 80B1.

Hello,

so you have defined your I/O area only as 4 BYTE long, mean from definition not from your code where you have defined pointer? In this case I see possibility to define like 4 BYTES as units or complete block. Another solution can be probably 2 WORDS as unit or as complete block. I see probably missunderstanding how long I/O area you have defined. Look again to cfg, or give us some Picture how you did it.

hi Alumi,

please show us a screenshot of the HW-config with the module you want to read data from.

The area where the pointer is on has to be as big as the projected slot of the specified LADDR.

hope this helps,

regards,

Hi Sir :

I appreciate your reply.

Actually, I am a beginner with STEP 7 and PLC program of Siemens.

Maybe I misunderstand your suggestion, if so, please correct.

The attached file shows  my PLC setting which includes hardware configuration.

I am sorry for that I am new to the forum and it seems can only attach one file, am I right?

I do not know Duris_I's question about "how long I/O area you have defined".

Is there some settings I miss?

According your suggestion, it seems like it is not related with if my slave device does not support consistent read/write, am I right?

Best regards,

Marcus

hi Alumi,

your specified module IN/OUT is 320 Byte long. This is too long for consistent reading/writing with SFC14/15(max. consistent userdata of an IO-device is 255byte) and I don´t think that this adress-area is projected consistent.

The size of the process-image is not relevant when you want to read out with this functions.

But if you have increased the process image to a size that includes the adresses you can access the adresses over the process-image with EBx/EWx/EDx Ex.0-Ex.7(X=256-575) and the same with outputs. You don´t need a function for this.

hope this helps,

regards,