FRS500 AC Drive on Communication

[sid]

I am using 20nos. S500 AC drive and writing frequency through Rs485 Communication. My parameters are P.79 =0 n8 =1, inverter starts/stops from external terminals n9 =0, Frequency write via communication n10=1, Communication start Since the drive is in communication it always accepts frequency from communication, now in any case if computer communication cable fails, an auto/manual switch is moved to manual and drive should take frequency from internal POT or through external terminals. I have read the FRS500 Detailed instruction manual and found nothing about switching a mode. However i have attached a page of manual where it says if p79=0 & n10 =1, Computer link is Disabled when PU is selected &Enabled when external is selected, but there it is not mentioned that how to select PU or External. I have tried with X16 Signal but no results. Since Plant is continuous switch over should be fast. Parameter_Details.pdf

[Thorny]

Looks to me as though you have to set Pr 79 = 8 then then x16 signal switches between ext or pu Cheers

[sid]

I had set the P79=8 and tried to switch using X16 but there is no switching i.e drive remains in communication.