Siemens SIMATIC S7 System Manual page 434

Hide thumbs Also See for SIMATIC S7:

Table of Contents

Communication

8.5 PROFIBUS

All of the output data (all 40 bytes) is treated as one buffer consistent block of data in the

EM DP01 and SMART CPU. The output data in the S7-300 is treated with different

consistencies depending on whether the user utilizes the I and Q areas or whether they use

the DPRD_DAT (Read consistent data for DP devices) and DPWR_DAT (Write consistent

data for DP devices) instructions. Even using the DPRD_DAT and DPWR_DAT instructions,

the data is only consistent within the 32 byte and 8 bytes blocks. The entire 40 bytes is

consistent only if the user manages this by not reading or writing the data in user interrupt

If you are working with a data unit (consistent data) greater than four bytes, you can use the

DPRD_DAT instruction to read the inputs of the DP device and the DPWR_DAT instruction

to address the outputs of the DP device. For further information, refer to "Data consistency"

You can configure the location of the input and output buffers to be anywhere in the

V memory of the S7-200 SMART CPU. The default address for the input and output buffers

is VB0. The location of the input and output buffers is part of the parameter assignment

information that the DP master writes to the S7-200 SMART CPU. You configure the

DP master to recognize its DP devices and to write the required parameters and I/O

configuration to each of its DP devices.

You configure SIMATIC S7 DP masters using STEP 7 programming software. For detailed

information about using this configuration and programming software package, refer to the

manuals for these devices. For detailed information about the PROFIBUS network and its

components, refer to the

Table of Contents

Troubleshooting

Simatic s7-200 smart