Hi there,

Due to modification on an older S7-400 control system a related question to the Profibus IO qty. came up.

With S7-400 with CP master and non-Siemens slaves, 240 bytes can be read out per specified connection, or 236 bytes with unspecified access to the CP.

If I now want to transfer 300 bytes via a CP, can I only solve this if I specify at least two FDL connections?
It would be as shown below, the red option is for the case when unspecified FDL, broadcast or multicast with >236 bytes is possible.

thank you

stefan

Dear Stefan,

like mentoined in the other post im german forum, i think we need some more specific information what should be done exactly.

Because if we are talking about a PROFIBUS slave like an ET200S with I/O's, maybe a FLD connection is not the correct way to go in this case. And the screenshot looks like a standard slave for me. But in general the 240 byte is a limitation by PROFIBUS itself.

What properties, advantages and special features does the FDL protocol offer?

regards

sancruz

1. 2x CPU 417-4 H, V4.5,6ES7 417-4HT14-0AB0
2. CP 443-16GK7 443-1Ex20-0XE0V2.1
3. DP/PA-Link IM 1536ES7 153-2BA82-0XB0
4. 3rd party (irds)

Engineering done in: PCS7 V9.0 (SP3)

As I have learned, a slave can read only 244 Bytes, so if I want to read 300 bytes I have to use 2 Slaves

1. Slave: Bytes 1-244
2. Slave: Bytes 245 - 300

If a single device shall read those bytes it has to configure with multiple Profibus Slaves. Is it as simple as that?

I have sketched it, and that says more than a thousand words :), it would be Option 2, in that case.

thank you

stefan

is it answered in PCS7 V9.0 (SP3) - can a single device read 300 bytes? - 287541 - Industry Support Siemens

is it answered inPCS7 V9.0 (SP3) - can a single device read 300 bytes? - 287541 - Industry Support Siemens