LG K7F-PIDA - Manual (Page 18)

Chapter 2. SPECIFICATIONS
2 - 11
6) Forward/Reverse Actions
(1) PID control has two kinds of action, forward action and reverse action.
a) Forward action makes PV reach SV by outputting MV when PV is less than SV.
b) Reverse action makes PV reach SV by outputting MV when PV is more than SV.
(2) A diagram in which forward and reverse actions are drawn using MV, PV and SV is shown as Fig. 2.9.
[Fig. 2.9] Forward and reverse action with MV, PV and SV
(3) Fig 2.10 shows examples of process control by forward and reverse actions, respectively.
[Fig. 2.9] Examples of process control by forward and reverse actions