Technical data

Table Of Contents
SFBs for Integrated Control
System Software for S7-300/400 System and Standard Functions - Volume 2/2
27-24
A5E00739858-01
Input Parameters
Parameter Data Type Range of Values Default Description
INV REAL -100.0...100.0 (%) 0.0 INPUT VARIABLE
An analog manipulated value is connected
to the input parameter "input variable."
PER_TM TIME >=20*CYCLE T#1s PERIOD TIME
The constant period of pulse duration
modulation is input with the "period time"
input parameter. This corresponds to the
sampling time of the controller. The ratio
between the sampling time of the pulse
generator and the sampling time of the
controller determines the accuracy of the
pulse duration modulation.
P_B_TM TIME >= CYCLE T#0ms MINIMUM PULSE/BREAK TIME
A minimum pulse or minimum break time
can be assigned at the input parameters
"minimum pulse or minimum break time."
RATIOFAC REAL 0.1 ...10.0 1.0 RATIO FACTOR
The input parameter "ratio factor" can be
used to change the ratio of the duration of
negative to positive pulses. In a thermal
process, this would, for example, allow
different time constants for heating and
cooling to be compensated (for example, in
a process with electrical heating and water
cooling).
STEP3_ON BOOL TRUE THREE STEP CONTROL ON
The "three-step control on" input parameter
activates this mode. In three-step control,
both output signals are active.
ST2BI_ON BOOL FALSE TWO STEP CONTROL FOR BIPOLAR
MANIPULATED VALUE RANGE ON
With the input parameter "two-step control
for bipolar manipulated value range on" you
can select between the modes "two-step
control for bipolar manipulated value" and
"two-step control for unipolar
manipulated value range." The parameter
STEP3_ON = FALSE must be set.
MAN_ON BOOL FALSE MANUAL MODE ON
By setting the input parameter "manual
mode on," the output signals can be set
manually.
POS_P_ON BOOL FALSE POSITIVE PULSE ON
In the manual mode with three-step control,
the output signal QPOS_P can be set at
the
input parameter "positive pulse on." In the
manual mode with two-step control,
QNEG_P is always set inversely to
QPOS_P.