Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 187

■Ratio calculation
This function block performs ratio calculation processing.
SPR,
Rn
Control cycle Control cycle
(CT) (CT)
Ratio operation value (MVP)(%)=
RMAX-RMIN
Rn: Ratio current value (%)
RMIN: Ratio low limit (%)
RMAX: Ratio high limit (%)
PVP: PV input value (%)
BIAS: Bias
■Inverse engineering value conversion
This function block performs inverse engineering value conversion processing when the tracking flag (TRK) is 1.
SPR-RMIN
SV(%)= ×100(%)
RMAX-RMIN
SV: Tracking data (%) for primary loop
SPR: Setting value (%)
RMIN: Ratio low limit (%)
RMAX: Ratio high limit (%)
■Tracking processing
The following table shows whether tracking processing to the input variable CASIN_T is performed or not.
Condition
Tracking flag (TRK)
1
0
■Loop stop processing
When the stop alarm (SPA) of the alarm (ALM) is TRUE, this function block performs the following processing.
• Outputs (MVP) are held.
• The control mode is automatically switched to MANUAL.
■Processing operation
: Performed, : Not performed
Control mode Processing operation
Ratio calculation
MAN, CMV 

AUT, CAS, CSV
*1 Tracking is performed when the tracking flag (TRK) is 1.
Setting value (SPR)
DR
Control cycle Control cycle Control cycle
(CT) (CT) (CT)
Rn-RMIN
×PVP+BIAS
Setting value (SV) used (SVPTN_B0)
FALSE
TRUE
FALSE or TRUE
Variation rate limiter


Current ratio (Rn)
DR: Variation rate
limit (DR)
Control cycle Control cycle
(CT) (CT)
Result
The input variable CASIN_T is tracked.
The input variable CASIN_T is not tracked.
Engineering value
conversion


10 LOOP CONTROL OPERATION
10.1 Ratio Control (Enable Tracking for primary loop) (M+P_R_T)
t
Tracking
*1


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