Lenze i700

Lenze · i700 servo inverter · reference manual · DMS 3.0 EN · 06/2016 · TD06 200
7 CiA402 device profile
7.4 Device control
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7.4.2.9 STO ("Safe Torque Off")
The status of "Safe Torque Off" is included in bit 15 as part of the CiA402 status word. Bit 15 contains
information whether STO is active or not.
This status information is required since the activation of STO causes all integral control parts to be
deleted. In case of hoists, for instance, the drive would be sagging without any corrective measures
after completing STO.
In order to prevent this unwanted state, the control has to be preloaded with a starting value after
completing STO:
• In case of a control type with encoder, the integral-action component of the speed controller has
to be preloaded.
• In case of the "VFC" control type, the slip frequency has to be preloaded.
 Note!
If STO is inhibited, a changeover to the "Switch on disabled" device status takes place and
a warning is transmitted.