Honeywell HC900 Reference Manual page 294

Function Blocks
PID Function Block
TUNING tab
ATTENTION
Use of Tune SET 1 or 2 can be selected via input (SWI) from the Loop Switch block output
(SWO) or, in the case of DUP_A or DUP_B, automatically depending on the value of the
previous output (≥ 50 % or < 50 %).
280 HC900 Hybrid Control Designer Function Block Reference Guide Revision 11
2/07