Input Parameters Pulsegen - Siemens SIMATIC S7-1200 Function Manual

9.4.3.6

Input parameters PULSEGEN

The values of the input parameters are not limited in the block. There is no parameter check.
Table 9- 17 Input parameters PULSEGEN
Parameters Data
type
INV REAL
PER_TM TIME
P_B_TM TIME
RATIOFAC REAL
STEP3_ON BOOL
ST2BI_ON BOOL
MAN_ON BOOL
POS_P_ON BOOL
NEG_P_ON BOOL
SYN_ON BOOL
COM_RST BOOL
CYCLE TIME
PID control
Function Manual, 03/2017, A5E35300227-AC
Default Description
0.0 At the input parameter "Input variable" an analog manipulated variable is con-
nected.
Values from -100 to 100 % are permitted.
T#1s At the parameter "Period duration" the constant period duration of the pulse
width modulation is entered. This corresponds to the s ampling time of the con-
troller. The ratio b etween the sampling time of the pulse s haper and the sam-
pling time of the c ontroller determines the accuracy of the p ulse width
modulation.
PER_TM >=20*CYCLE
T#50 ms You can assign a minimum pulse/break time at the parameter "Minimum
pulse/break time".
P_B_TM >= CYCLE
1.0 Using the "Ratio factor" input parameter the ratio of the duration of positive to
negative pulses can be changed. In a thermal p rocess, this would, for example,
allow d ifferent time constants for heating and c ooling to be compensated (for
example, in a process with electrical heating and water c ooling).
Values from 0.1 to 10.0 are permitted.
TRUE At the input parameter "Enable three-step control" the appropriate mode is
activated. In three-step control b oth output signals are active.
FALSE At the input parameter "Enable two-step control for bipolar manipulated value
range" you can select from the modes "Two-step control for bipolar manipulated
value range" and "Two-step control for unipolar manipulated value range".
STEP3_ON = FALSE is required.
FALSE Setting the input parameter "Enable manual mode" allows the output signals to
be set manually.
FALSE For manual mode three-step control, the output signal QPOS_P can be operat-
ed on the input parameter "Positive pulse on". In m anual mode with two-step
control, QNEG_P is always set inversely to QPOS_P.
FALSE For manual mode three-step control, the output signal QNEG_P can be operat-
ed on the input parameter "Negative pulse on". In m anual mode with two-step
control, QNEG_P is always set inversely to QPOS_P.
TRUE By setting the input parameter " Enable synchronization", it is possible to syn-
chronize the pulse output automatically with the block that updates the input
variable INV. This ensures that a change in the input variable is output as quick-
ly as possible as a pulse.
FALSE T he block has an initialization routine that is p rocessed when the input "Restart"
is set.
T#10ms The time between block calls must be constant. The "Sampling time" input
specifies the t ime between block calls.
CYCLE >= 1ms
Instructions
9.4 PID basic functions
469