Hi everybody,

I use a C341 MODBUS RTU on a S7-300 CPU.  On documentation says that adress is a byte so I could have until 100 Modbus slaves, but on a document says that physical limit is 30 units.  Is it true?¿

(109474714_S300_ModbusRTU_DOC_v1d1_en.pdf)

How many stations MODBUS RTU slave could I have?¿

Many thanks for yours response,

          Guillem

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Split from S7-300 Modbus RTU -> Master - Slave.

Hi,

Slave Adress can be 1-255 (1 Byte).

Check manual-Link:

https://support.industry.siemens.com/cs/ww/en/view/1220184/17403971211

Regards,

Towome

Hello Willybong,
the number of slaves which can be connected depends on the used interface physic. With RS232 you can connect one slave, with RS485 up to 31 slaves. The Modbus slave addresses are 1 to 247.

I recommend to take a look at Smiffy's compendium to understand how Modbus works.

Regards,
Kaulquappe