PROline Prosonic Flow 93 FOUNDATION Fieldbus 6 PID function block (PID controller)
Endress+Hauser 191
6 PID function block (PID controller)
A PID function block contains the input channel processing, the proportional integral-
differential control (PID) and the analog output channel processing. The configuration
of the PID function block depends on the automation task. The following can be
realised: basic closed-control loops, feedforward control, cascade control, cascade
control with limiting.
The possibilities available for data processing within the PID function block include:
signal scaling and limiting, operating mode control, feedforward control, limiting control,
alarm detection, signal status propagation.
6.1 Signal processing
Fig. 5: Internal structure of the PID function block
• IN = Input of the controlled variable from another function block.
• CAS_IN = Input of the remote setpoint value from another function block.
• BKCAL_IN = Input of the feedback value and status from the BKCAL_OUT output of the downstream
function block which ensures bumpless switching of the operating mode.
• TRK_IN_D = Discrete input for activating the external output tracking function.
• TRK_VAL = Input for the external value for tracking from another function block.
• FF_VAL = Input for the disturbance variable from another function block.
• OUT = Output value and status (manipulated variable) of the PID function block.
• BKCAL_OUT = Output for the feedback value and status transferred to the BKCAL_IN input of the
upstream function block to ensure bumpless switching of the operating mode.
F06-53xFFxxx-16-xx-xx-en-003
PID Block
PV_SCALE
PV_FILTER
Scaling and
filtering
TRK_VAL
FF_VAL
CAS_IN
MODE
TRK_IN_D
BKCAL_IN
IN
SP
FF_GAIN
FF_SCALE
RCAS_OUT ROUT_OUT
PV
SP_HI_LIM
SP_LO_LIM
SP_RATE_DN
SP_RATE_UP
GAIN
RATE
RESET
OUT_HI_LIM
OUT_LO_LIM
OUT_SCALE
HI_HI_LIM / HI_LIM
LO_LO_LIM / LO_LIM
DV_HI_LIM / DV_LO_LIM
TRK_SCALE
OUT_SCALE
Converter
Feed forward
calculation
BCAL_OUT
OUT
Setpoint
limiting
PID
Equation
Output
limiting
Alarm
detection
Bypass
Output from super-
visory host system
ROUT_IN
Calculated
actuating
variable
Setpoint from super-
visory host system
RCAS_IN
F06-53xFFxxx-16-xx-xx-en-004
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