FUTABA 12Z Series Instruction Manual page 57

SUB-TRIM
The Sub-Trim function is used to set the servo
neutral position, and may be used to make fine
adjustments to the control surface after linkages
and pushrods are hooked up. When you begin to set
up a model, be sure that the digital trims are set to
their center position.
[Return Key]
Sub trim adjustment
(When the enter button is pushed for 1 second, sub trim is
reset to the initial value.)
*Before sub trim adjustment, adjustment of the linkage so that
control surfaces need not use sub trim as much as possible is
very important.
(The display screen is an example. The screen depends on the model type.)
[Cursor Lever]
[Data Input Dial]
PUSH
[Enter Button]
<Functions of Linkage Menu> 57