Hello

Look at

QUESTION:
Which types of interconnection can I use with S7-200?

ANSWER:
The S7-200 supports the following communications protocols and bus systems:

PPI
The S7-200 system protocol for communications between S7-200 components such as CPUs, TD200s, OPs and programmers is available to you. The PPI protocol permits you to operate several masters in the network simultaneously. You can program data communications between CPUs with just two statements. ....

About PPI connection look at How is data exchanged between two SIMATIC S7-200 devices in PPI mode?

I hope this will helps you.

regards