BECKHOFF AX5805 Installation - Manual (Page 88)

Product description
86 AX5805
3.6.6 Configuring the error reaction
This section describes the AX5805’s two error reactions in greater detail. The default error reaction is the
STO function. However, for some of the AX5805’s safety functions (SSR, SAR, SLI, SLP, SLS, SMA, and
SMS), it is possible to configure the error reaction to SS1.
3.6.6.1 Error reaction Safe Torque Off (STO 0x66400001)
This is the default error reaction. If this error reaction is configured, the AX5805 immediately switches all
torque off from the motors as soon as an error has been detected.
WARNING
Providing additional external safety measures for STO
When it is activated, STO initiates a coast-to-stop action. No braking is applied to the
connected motors; the torque applied to the motor is switched off and the motor coasts to
a stop. The time and distance it takes for the motor to stop depends on the mechanics and
kinetic energy present in the system. If there are loads suspended from the motor, the
motor may even be accelerated. The user must provide external safety mechanisms (e.g.
mechanical brakes) to prevent such inadvertent motion.
3.6.6.2 Error reaction Safe Stop 1 (SS1 0x66500001)
When the error reaction SS1 is activated, the AX5805 notifies the AX5000, that it should activate its
emergency stop ramp. The emergency stop ramp is purely functional and is not a safety function.
After the timespan set in the parameters 0x2030 and 0x2830 has elapsed, the AX5805 activates the STO
function, which removes all torque from the motor.
It is possible that the AX5000 fails to activate the emergency stop ramp. In this case, it is possible that the
motors will continue to rotate or even accelerate. Therefore, it is important to configure the timespan so that
an inadvertent acceleration during the configured time period does not lead to hazardous situation. On the
other hand, it is important to configure a timespan long enough so that the motors can be stopped.
DANGER
Choosing the timespan for SS1
The timespan for the error reaction SS1 should be configured so that no hazardous
situation arises if:
- the AX5000 fails to activate the emergency stop ramp, or
- if the motors continue to rotate or even accelerate.
After the configured timespan has elapsed, STO (Safe Torque Off) is activated. When it is
activated, STO initiates a coast-to-stop action. No braking is applied to the connected
motors; the torque applied to the motor is switched off and the motor coasts to a stop. The
time and distance it takes for the motor to stop depends on the mechanics and kinetic
energy present in the system. If there are loads suspended from the motor, the motor may
even be accelerated. The user must provide external safety mechanisms (e.g. mechanical
brakes) to prevent such inadvertent motion.