Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 190

Processing details
■Engineering value conversion
This function block performs engineering value conversion processing.
RMAX-RMIN
SPR= ×CASIN+RMIN
100
SPR: Setting value (%)
RMIN: Ratio low limit (%)
RMAX: Ratio high limit (%)
CASIN: Setting value (%) from primary loop
■Variation rate limiter
This function block performs variation rate limiter processing.
Condition
(SPR - Rn)  DR
(SPR - Rn)  DR
|SPR - Rn| < DR
SPR: Setting value (%)
DR: Variation rate limit value (%)
Rn: Ratio current value (%)
Rn-1: Last value of ratio current value
■Ratio calculation
This function block performs ratio calculation processing.
SPR,
Rn
Control cycle Control cycle
(CT) (CT)
Ratio operation value (MVP)(%)=
Rn: Ratio current value (%)
RMIN: Ratio low limit (%)
RMAX: Ratio high limit (%)
PVP: PV input value (%)
BIAS: Bias
10 LOOP CONTROL OPERATION
188
10.2 Ratio Control (Disable Tracking for primary loop) (M+P_R)
Setting value (SPR)
DR
Control cycle Control cycle
(CT) (CT)
Rn-RMIN
×PVP+BIAS
RMAX-RMIN
Variation rate limiter processing result (Rn)
Rn = Rn-1 + DR
Rn = Rn-1 - DR
Rn = SPR
Current ratio (Rn)
Control cycle Control cycle Control cycle
(CT) (CT) (CT)
DR: Variation rate
limit (DR)
t