ABB FSO-21 - Configuring the FSO for FSE or Encoder Failure Situations; Encoder Diagnostics Failure Reaction

Configuration 317
Configuring the FSO for FSE or encoder failure situations
Always set this parameter to a suitable value:
• STO.14 Time to zero speed with STO and modoff
If the SBC function is in use, set also these parameters:
• SBC.13 SBC time to zero speed
• SBC.12 STO SBC delay*.
* Even if you use the speed limit activated SBC function (SBC.11 = Speed limit),
the FSO module starts to use the time controlled brake (SBC.11 = Delayed brake)
when it detects an FSE module or encoder fault. Then also the time defined by
SBC.12 is in effect.
 Encoder diagnostics failure reaction
You can configure how the FSO module reacts when motor speed data from FSE
module is lost due to e.g. failure in FSE module, safety encoder or its wiring. The
reaction is user-definable with parameter S_ENCGEN.11 FSE diagnostic failure
reaction and depends also on the status of safety functions.
Use parameter S_ENCGEN.11 to define the correct FSO reaction. There are three
alternatives: 1. STO, 2. no STO or 3. Est switch not active load. See the subsections
below.
Alternative 1: S_ENCGEN.11 = STO
The FSO module goes into the Fail-safe state and actives the FSO STO function
immediately when the encoder data is lost regardless of the status of the safety
functions.
For more information, see section FSO modes on page 60.
Alternative 2: S_ENCGEN.11 = No STO
FSO module does not react to encoder fault unless there are active safety functions
or some safety function is activated, while the encoder fault occurs. Thus, the
selection gives the user the possibility to fix the cause of the encoder data-related
failure before a safety function is activated.
If some safety function is active or activated when the encoder fault occurs, the FSO
module goes into the Fail-safe state. The SSM and POUS functions are exceptions:
They do not cause the Fail-safe state transition when an encoder fault occurs.
Also drive parameter 90.45 Motor feedback fault must be set to Warning to be able to
use this setting. Note: For a DCS880 drive, the equivalent parameter/setting is 31.35
Motor feedback fault = EMF/Warning.
Alternative 3: S_ENCGEN.11 = Est switch not active load
Note: This alternative is not applicable to a DCS880 drive.