Siemens SINAMICS S120 Function Manual page 285

Activation
The bypass without synchronization (p1260 = 3) can be activated using the follow-
ing signals (p1267):
S Bypass using the control signal (p1267.0 = 1):
The bypass is switched-in using a digital signal (p1266), e.g. from a higher-level
automation system. If the digital signal is withdrawn again after the debypass
delay time has expired (p1263), then a changeover is made to drive converter
operation.
S Bypass for speed threshold (p1267.1 = 1):
When a specific speed is reached, a changeover is made to bypass; this means
that the drive converter is used as starting converter. The prerequisite for
switching-in the bypass is that the speed setpoint is greater than the bypass
speed threshold (p1265).
Converter operation is re-selected when the setpoint (at the input of the
ramp-function generator, r1119) drops below the bypass speed threshold
(p1265). As a result of the condition – setpoint > comparison value, it is
prevented that the bypass is immediately re-activated if, after switching back to
converter operation, the actual speed is still above the bypass speed threshold
(p1265).
S Bypass for a fault condition (p1267.2 = 1):
The motor is used as "reserve" for direct online operation if the drive converter
fails. After the fault has been successfully acknowledged, and if the drive
converter on command is still present after the debypass delay time (p1263)
has expired, then it is automatically re-started and changed over to drive
converter operation.
Note
Selecting the activation "bypass for a fault condition" and the automatic restart
function can potentially influence one another. The fault that switches-in the
bypass is acknowledged when the automatic restart function is appropriately set
and when the fault is successfully acknowledged, the bypass is switched-out
again. There is no mutual interlocking of these two functions.
Parameters are used to set the quantities – bypass time, debypass time, bypass
speed and the command source for the changeover.
The following signal diagram shows the timing when the bypass switch is on when
activating "bypass for fault".
Example
After activating the bypass function without synchronization (p1260 = 3) the follow-
ing parameters still have to be set:
© Siemens AG 2006 All Rights Reserved
SINAMICS S120 Function Manual, 03/2006 Edition
Extended Functions
Bypass (vector)
4-285