Siemens Simatic S7 Series System Manual page 469

Offset Field
48 Hysteresis (HYS)
52 Initial Output Step
(STEP)
56 Watchdog Time (WDOG) REAL
60 Suggested Gain (AT_K
64 Suggested Integral Time
(AT_T )
I
68 Suggested Derivative
Time (AT_T )
D
72 Actual Step size
(ASTEP)
76 Actual Hysteresis
(AHYS)
S7-200 SMART
System Manual, 09/2015, A5E03822230-AC
Format Type
REAL In
REAL In
In
) REAL Out
C
REAL Out
REAL Out
REAL Out
REAL Out
11.1 PID loop definition table
Description
Normalized value of the PV hysteresis used to deter-
mine zero crossings (range: 0.005 to 0.1). If the ratio of
DEV to HYS is less than 4, a warning will be indicated
during auto-tune.
Normalized size of the step change in the output value
used to induce oscillations in the PV (range: 0.05 to
0.4).
Maximum time allowed between zero crossings in sec-
onds (range: 60 to 7200).
Suggested loop gain as determined by the auto-tune
process.
Suggested integral time as determined by the auto-tune
process.
Suggested derivative time as determined by the auto-
tune process.
Normalized output step size value as determined by the
auto-tune process.
Normalized PV hysteresis value as determined by the
auto-tune process.
PID loops and tuning
469