6-11 Safe Torque Off
AC30V series Variable Speed Drive
TRUTH TABLE
Overview
STO Input A
X10/01
STO Input B
X10/03
Drive Function
STO Status Output
X10/05, X10/06
STO Active
0V 0V
Drive cannot start or supply power to its motor. STO trip
reported.
This is the intended safe state of the product with correct
dual-channel operation.
ON
Abnormal one-
channel
operation
detection
24V 0V
Drive cannot start or supply power to its motor. STO trip
reported. If either of these conditions persists for more than
3.0 seconds (the maximum fault detection time), the STO
function will lock into a fault state. The drive cannot start until
the fault is rectified; all power is removed and reapplied (both
mains and any auxiliary 24V dc power).
This is single channel operation and thus deemed not as
intended for category 3 / PLe / SIL3 structure
implementation.
OFF
0V 24V
STO Inactive
24V 24V
Drive is enabled to run under software control. The drive can
supply power to its motor.
OFF
unpowered
Don’t care Don’t care Drive cannot start or supply power to its motor. OFF