Siemens SINAMICS G150 Operating Instructions Manual page 540

Functions, monitoring, and protective functions
9.2 Drive functions
If, when setting p3881 = 3 or 5, the setpoint is lost (e.g. cable break or fieldbus failure), then
the alternative setpoint that is set via p3882 is automatically switched to:
● p3882 = 0: Last known setpoint (r1078 smoothed) - factory setting
● p3882 = 1: Fixed speed setpoint 15 (p1015)
● p3882 = 2: Maximum speed (p1082)
Direction of rotation in essential service mode
Depending on your system, you may have to invert the setpoint locally for essential service
mode. To do this, parameter p3883 can be linked with a free digital input:
● Signal in p3883 = 0: The direction of rotation of the setpoint parameterized for essential
service mode is maintained
● Signal in p3883 = 1: Reversal of the direction of rotation of the setpoint parameterized for
essential service mode
Automatic restart
In essential service mode, if the automatic restart function is activated and the settings of
parameters p1206, 1210 and p1212 then have no effect. The settings in p1211 (automatic
restart, start attempts) and p1213 (automatic restart monitoring time) are still effective. The
setting of p1213 [0] = p1213 [1] = 0.0 s allows an unlimited number of startup attempts.
Bypass as a fallback strategy
If the converter fails due to an internal, non-acknowledgeable fault, essential service mode is
no longer possible. In this case, the motor can be operated via the controller in bypass mode
in the event of converter failure. For this purpose, bit 7 of the status word for the automatic
restart (r1214.7) must be interconnected with p1266.
The bypass function must also be activated without synchronization (p1260 ≠ 3), and the
changeover source for the bypass must be set to "Bypass via signal (BI: p1266)"
(p1267 = 1).
You must ensure that r1214.7 is also set, otherwise there will be no changeover to the line
supply. To end the bypass mode, the essential service mode must be deactivated. There is
no switchover to converter operation (drive coasts down).
Behavior in the event of an encoder error
When operating in vector control with encoder in the essential service mode, there is an
automatic switchover to sensorless operation and movement of the drive continues in the
event of an encoder error.
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Converter cabinet units
Operating Instructions, 07/2016, A5E03347396A