Technical data

Bit assignment of the control
word STEU (data word
DW 11 in the transfer DB)
DW 11
Bit no.
Name Meaning
11.0 AUTO = 1: Automatic operation
= 0: Manual operation
11.1 XZ_INP =1: Another variable (not XW
k
), is supplied to the derivate unit
by the input
= =: XW
k
is supplied to the derivate unit. The XZ input
is ignored.
11.2 DIS_CTR = 1: When the controller is called (OB 251) all variables (DW 20 to
DW 48) except K, R, TI, TD, BGOG, BGUG, STEU, YH
k
, W
k
,
Z
k
and Z
k-1
are cleared once in the DB RAM. The controller is
disabled. The historical value of the disturbance is
updated.
= 0: control
11.3 VELOC = 1: Velocity algorithm
= 0: Position algorithm
11.4
1)
MANTYPE = 1: If VELOC = 0 (position algorithm) the last manipulated variable
to be output is retained.
If VELOC is 1 (velocity algorithm) the control increment
dY
k
= 0 is set.
= 0: If VELOC = 0, then after switching to manual operation, the
value of the manipulated variable output YA is brought to the
selected manual value exponentially in four sampling steps.
Following this, other manual variables are accepted immediately
at the controller output.
If VELOC = 1, the manual values are switched through to the
controller ouptut immediately. In manual operation, the limits
are effective. In manual operation the following variables are
updated:
X
k
, SW
k-1
and PW
k-1
XZ
k
, XZ
k-1
and PZ
k-1
, if control bit 1 = 1
Z
k
and Z
k-1
, if control bit 5 = 0
The variable dD
k-1
is set to = 0. The algorithm is not calculated.
11.5 NO_Z = 1: no feedforward control
= 0: with feedforward control
11.6 PGDG = 1: W
k
, YH
k
input as floating point number
= 0: Input as normalized fixed point number
11.7 VAR_FLP = 1: The variables X
k
, XZ
k
and Z
k
are input as floating point numbers
= 0: Input of the variables as normalized fixed point numbers
Table 6-11 Control word in the transfer DB
6
OB 250/251: Closed-Loop Control/ PID Algorithm
CPU 928B Programming Guide
C79000-B8576-C898-01
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