Siemens SIPART DR22 Manual page 44

1 Technical Description
1.5 Functional description of the structure switches
1.5.4 Controller types (S1, S49 to S53)
x-tracking in direction-dependent blocking operation is not possible because the P-step
produced by resetting the driving control error to blocking direction would immediately cancel
the blocking.
x-tracking takes place without the set setpoint ramp tS. By following up the setpoint to the
actual value (nominal ratio to actual ratio), the control difference xd = 0 and automatic opera-
tion starts absolutely bumplessly. Since one can usually assume in manual mode and DDC
mode that the actual value has been driven to the desired value, the followed up setpoint
corresponds to the rated value.
x-tracking only takes full effect if the follow-up of the inactive setpoint is locked onto the
active setpoint (S52 = 0) so that not only the active setpoint w but also the setpoint source
which is supplying after switching to automatic operation is followed up.
At S52 = 1 (without follow-up) the control difference is 0 during the A-operation but after
switching to the automatic mode the old non-followed up setpoint is immediately active
again. With the setpoint ramp tS this step-shaped setpoint change takes place via a time
ramp.
This combination is always useful when it is not guaranteed during A-operation (especially in
safety mode) that the actual value will be driven to the desired rated value by the actuating
manipulation and the follow-up variable would not be correct in full x-tracking.
-- Constants c1 to c7
In the individual controller types the process variables are partially linked with each other
whereby the constants c1 to c3 are used for the controlled variable links and constants c4
and c5 for the command variable links. The constants are set in the parameterization mode
onPA in the range from -1.999 to 9.999.
The constants c6, c7 serve to dose the disturbance variable connection to the controller out-
put yI or yII (see chapter 1.5.5.1, figure 1-50, page 90 and figure 1-51, page 91). They can
be set in the parameterization mode onPA in the range from -19.99 to 19.99.
-- Control signals for the setpoint switching
If available in the single controller types, the setpoint switching takes place depending on the
control signals Int (Internal/External key) and CB (Computer standby) as an AND function
RC = Int∧CB and its negation. The status of the control signal CB and the Internal key (2) is
indicated by the C LED (3) and the Internal LED (1).
With S49 the Internal/External key (2) can be set out of function and can block in the
positions Internal or External (see chapter 1.5.3, figure 1-17, page 38). The factory setting is
S49 = 0 only Internal. With S24 the CB signal can be set to Lo or Hi or a digital input
assigned, (see chapter 1.5.3, figure 1-16, page 37). The factory setting is S24 = -1, CB = 1.
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Manual
SIPART DR22 6DR2210
C79000-G7476-C154-03