What is the difference between the Festo CP and the Festo CPI systems?
A CP extension string (CP bus node or CPV with CP extension string) allows you to connect a maximum of one output module with 16 outputs and one input module with 16 inputs. A CPI extension string (CPX-CPI or CPV with CPI extension string) allows you to connect a maximum of 4 modules (input or output) with up to 32 inputs and 32 outputs.