Samson 3730-5 - Page 117

4
Derivative component:
In controlled systems with long delay times, e.g. in temperature control loops, it is better
to use the derivative component RATE of the controller. Using the derivative component
RATE, the manipulated variable is calculated depending on the rate of change of the sys
-
tem deviation.
An output value OUT is formed from the calculated manipulated variable corresponding to
the OUT_SCALE, OUT_HI_LIM and OUT_LO_LIM parameters. This output value can be
passed on to a downstream connected function block.
The status of the output value OUT can be influenced by the STATUS_OPTS parameter de
-
pending on the status of the input variable of the PID Block. This allows, for example, the
fault state of a downstream connected output block to be activated.
The BYPASS parameter allows the internal set point to be directly transferred to the correc
-
tion value. Feedforward is possible over the FF_VAL input variable. TRK_IN_D and TRK_VAL
allow the output value to be directly tracked.
Refer to page 166 for the list of parameters.
EB 8384-5 EN 117
Appendix
Fig. 28 · PID Function Block
RCAS_IN
CAS
_I
N
FF_VAL
TRK_VAL
SP
TRK_IN_D
OUT
PV
IN
+–
SP
ON
OFFSP_HI_LIMSP_
LO_LIM
Sp_RATE_DN
Sp_RATE_UP
OUT_SCALE OUT_HI_LIMO
UP_LO_LIM
GAIN
RATE
RESET
PV_SCALE
PV_TIME PV_SCALE
FF_GAIN
FF_SCALE TRK_SCALE
Bypass
Set point
limitation
Set point
ramps
PID
algo-
rithm
Scaling
Output
limitation
PV scaling
Scaling
Gain
Scaling
Feedforward Tracking
Filter
Scaling