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7.19.3 Detailed Functional Description
7.19.3.1 Activation and timing
SOS is activated if one of following request sources is active:
SOS request on safe fieldbus
SOS request on safe digital input
SOS request in SS2 sequence
SOS request as fault reaction
The SOS reaction time to a request over a safe digital input, safe fieldbus or as internal request is less than 10ms.
When SOS is activated, the safety module does the following monitoring:
Wait the SOS Activation Delay (UPID 47E1h)
The actual position is stored.
The SOS state becomes active and is displayed with the status signals.
The position monitoring is activated. If the position deviation is more than allowed by the parameter SOS Position
Tol/- (UPID 1A12h), the configured fault reaction will be initiated (configuration parameter SOS Fault
Reaction
UPID 47E3h)
7.19.3.2 Deactivation
SOS is only deactivated when no possible request sources is active.
7.19.3.3 Fault Reaction
If the supervision detects a failure, it will activate STO or SS1 depending on the parameter SOS Fault Reaction (UPID
47E3h).
7.19.4 Example for the Use
Example
Possible Solution
Opening a protective door must only be possible if the motors are
safely standstill. To guarantee, that the motors keep still, even
when some counterforce is active, SOS is requested.
Configure SOS over safe digital IO’s or PROFIsafe
The higher-level controller or PLC stops the motors and then
activates the configured SOS safety function.
Standstill is then safely monitored on the drive.
Table 82: SOS Example
2S Drive Systems / 0185-1174_E_1V1_SM_C1251-2S / NTI AG
0185-1174_E_1V1_SM_C1251-2S / 2021-11-26 16:43 (Rev. 12500)
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