Technical data
25
Integrated safety thanks to Safe Torque Off
Agile drives incorporate redundant functional
logic and hardware architecture to disconnect
the motor safely and stop it in the minimum time
possible.
The simultaneous activation of two digital inputs,
STOA and STOB, corresponding to two identical
but distinct electrical paths, causes the software
to recognise an external emergency condition,
suspendthegenerationofPWMpulsesand
physically disable the optoisolators that transmit
signals to the IGBT drivers, all in less than 10ms.
This brings the motor to a controlled stop,
followed by total isolation from the inverter.
Any alarm condition arising inside the drive also
generates an emergency stop in the same way,
irrespective of STOA and STOB signals.
Suggestive block diagram
STOA
STOB
M
Diagnostics and
monitoring
Control unit Power unit
PWMμC
STOA STOB Effect
0
0
Safe Torque Off active; motor stopped and isolated
0
1
Safe Torque Off in stand-by; the software awaits a second signal:
after 5-s wait time with no signal, the drive generates an alarm
1
0
1
1 Safe Torque Off not activated; the motor functions conventionally