rs232 communication with (s7-1200 plc)

[adamlhadi 0]

Hi everyone

i have a vfd with db9 (RS232)as it's manual said ,so in order to make a communication with this VFD and (1200plc) i need CM1241(RS232) module or a signal board(RS232) 

but is't possible to use CM1241 (RS485) instead of CM1241(RS232)

technically  what's the difference between CM an SB in this case

kind regards

[a062549 5]

What VFD brand? Usually the DB9 is for programming only. I'd think the RS485 and even the Ethernet are used for the application. 

The 232 is only reliable at about 3 meters(?),