I have written another post about this issue but the main title typed wrong and i couldn't edit .
So i decided post new discussion .
Actually AD5412 works apparently correct ( I mean I send the command and proportionate voltage/current is on the output ).
But when I connect my voltmeter or oscilloscope to the output the output drop to the clear value( Zero or middle depend on setting) .
it happen even when i connect a screw driver(metal object) to the ground .
But when voltmeter or oscilloscope is connected before power up every things is ok .
Fault Pin is not active before or after voltage drop.
after output dropped if i write new value it's appear on the output.
after output dropped data register is dropped too.
"Clear Select " and "clear" pins are connected to the ground just in case .
and here is my spi bus
i am be very happy if analog device support help me .