21
The following figure shows an example of dual action PID (heating-
cooling) with
= 0 and
= 0.
ACTIVE
ACTIVE
COMMAND OUTPUT (HEAT)
ALARM OUTPUT (COOL)
SPV
PV
< 0
ACTIVE
ACTIVE
(HEAT)
*
(COOL)
SPV
PV
COMMAND OUTPUT (HEAT)
ALARM OUTPUT (COOL)
COMMAND OUTPUT (HEAT)
ALARM OUTPUT (COOL)
SPV
PV
ACTIVE
ACTIVE
< 0
(HEAT)
*
(COOL)
< 0
(HEAT)
*
(COOL)