Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 294

Processing details
■High high limit/high limit/low limit/low low limit check
This function block performs the high/low limit checks to the input value.
Input value
PVPI(%)
Input high high limit (HHA)
Input high limit (PHA)
Input low limit (PLA)
Input low low limit (LLA)
Item
Alarm (ALM)
HH: High high limit alarm value
PH_: High limit alarm value
PL: Low limit alarm value
LL: Low low limit alarm value
HH': High high limit alarm value (%)
PH': High limit alarm value (%)
PL': Low limit alarm value (%)
LL': Low low limit alarm value (%)
HS: High/low limit alarm hysteresis (%)
• The high high limit/high limit/low limit/low low limit alarm values are converted into values in percentage (%) in accordance
with the input (Inverse engineering value conversion)
HH-RL
HH'= ×100(%), PH'=
RH-RL
PL-RL
PL'= ×100(%), LL'=
RH-RL
RH: Engineering value high limit, RL: Engineering value low limit
10 LOOP CONTROL OPERATION
292
10.19 High/Low Limit Alarm Check (M+P_PHPL)
Occurred
Occurred
Input high high limit (HHA)
Input high limit (PHA)
Input low limit (PLA)
Input low low limit (LLA)
PH_-RL
×100(%)
RH-RL
LL-RL
×100(%)
RH-RL
HS
HS
HS
HS
Occurred
Occurred
Input condition of when an alarm occurs
TRUE (Detected)
Input value (%) > HH'
Input value (%) > PH'
Input value (%) < PL'
Input value (%) < LL'
HH'
PH'
PL'
LL'
t
t
t
t
FALSE (Reset)
Input value (%)  HH' - HS
Input value (%)  PH' - HS
Input value (%)  PL' - HS
Input value (%)  LL' - HS