if an ap shows the RSSI value of a client is greater than 75dbm， which means signal very bad .
I dont know ruckus production very much , but i want to know how to kill the bad signal client offline , and then make sure that the client can connet the nearest ap when the movable client change its location .
How to set the ZD1200 , which can automatically implements the function .
I think you mean -75dbm of RSSI. That's still a good value for the signal, bad values would be -90 dbm or less but It would also depend on the noise and interference of the surrounding environment and even for the type of service (voice, video, data, etc.). A better measure is the Signal to Noise Ratio (SNR) which should be above 25 to have a good connection. On how to remove these clients, once they are offline they should be gone after some minutes when ZD refresh data.