op320-a communication

Hi,

I have a plc s7-200 (224xp) and a hmi op320-a, made the programs and download both, but the hmi don't connect with plc. the cable is correct like manual (op side pins 1-9 to plc pin 3, and op side pins 6-8 to plc pin 8) but the hmi just show CONNECTING... and never ends. 

someone could help me, need add some configuration to plc? or another pin configuration cable?

 thanks.