Operation Of The Sto Function And Diagnostics; Hardware Activation Of The Sto Function; Firmware Monitoring Of The Sto Function - ABB MicroFlex e190 User Manual

Operation of the STO function and diagnostics

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Hardware activation of the STO function

The drive contains two STO inputs. If both STO inputs are powered, the STO function
is in the standby state and the drive operates normally.

If power is removed from one or both of the STO inputs, the STO function is activated.
The drive motor output power stage is disabled. Enabling is possible only after both
STO inputs have been powered, and all the faults have been cleared.
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Firmware monitoring of the STO function

STO function activation
The firmware detects when the STO function is activated and will generates the 'STO
active' error (10033) if the drive is enabled. The drive can be enabled again only after
all the faults have been cleared.
STO input states
The state of the STO inputs are monitored by the firmware. The state of the STO
inputs are stored in a hardware register within the drive. The register is monitored by
the drive over a period specified by the STOINPUTMISMATCHTIME Mint keyword (the
default value is 100ms) . If the inputs are in different states after the specified period
has elapsed, the 'STO input mismatch' error (10035) is generated.
Appendix: Safe Torque Off (STO) 195