Siemens SIMATIC S5-100U, Системное руководство

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S5-100U Integrated Blocks and Their Functions
Table 9-7. Description of the Control Bits in Control Word “STEU”
Control
Bit
Name
Signal
State
Description
0 AUTO 0
1
Manual mode
The following variables are updated in Manual mode:
1)
X
K
, XW
K-1
and PW
K-1
2) XZ
K
, XZ
K-1
and PZ
K-1
, when STEU bit 1=1
3) Z
K
and Z
K-1
, when STEU bit 5=0
Variable dD
K-1
is set to 0: The algorithm is not computed.
Automatic mode
1 XZ EIN 0
1
XW
k
is forwarded to the derivative action element. The XZ input
is ignored. A variable other than XW
k
is forwarded to the derivative
action element .
2 REG AUS 0
1
Normal controller processing
When the controller is called up (OB251), all variables (DW18 to
DW 48 ) with the exception of K, R, TI, TD, BGOG, BGUG, YH
k
and W
k
are reset in the controller DB. The controller is
deactivated.
3 GESCHW 0
1 Positioning algorithm
Correction rate algorithm
4 HANDART 0
1
When GESCHW=0:
Following the transfer to Manual mode, the specified manipulated
variable value YA is adjusted exponentially to the manual value in
four sampling steps. Additional manual values are then forwarded
immediately to the controller output.
When GESCHW=1:
The manual values are forwarded immediately to the controller
output. The limiting values are in force in Manual mode.
When GESCHW=0:
The manipulated variable last output is retained.
When GESCHW=1:
Correction increment dY
K
is set to zero.
5 NO Z 0
1 With feedforward control
No feedforward control
6 and 7 - These bits are not assigned.
8 to 15 - The PID algorithm uses these bits as auxiliary flags.
The control program can be supplied with fixed values or parameters. Parameters are input via the
assigned data words. The controller is based on a PID algorithm. Its output signal can be either a
manipulated variable (positioning algorithm) or a manipulated variable modification (correction rate
algorithm).
EWA 4NEB 812 6120-02b
9-17