Safe Torque Off
6-14
AC30V series Variable Speed Drive
FAULT OPERATION
A fault is always detected when X10/01 and X10/03 are in opposite states for more than 3.0 seconds.
States:
1 Both inputs are low. Drive is tripped and STO prevents the drive from starting. User output is ON. This is the “safe torque off” state of the drive.
3 One input is high and the other input is low. Drive is tripped and STO prevents the drive from starting. In this example, this state persists for more
than 3.0 seconds (being the maximum fault detection time), after which time the STO logic transitions to state 4 without further changes in input
state. The AC30V has detected a fault or single-channel operation.
4 The fault state (one input high, the other input low) has persisted for longer than 3.0 seconds (being the maximum fault detection time). The STO
hardware logic locks into state 4. The drive is tripped and the STO function prevents the drive from starting. User output is OFF. To exit from state 4,
the drive must be powered off (all power removed including any auxiliary 24Vdc) and back on.
DANGER
OPERATION OF THE AC30V UNIT SHOULD CEASE IMMEDIATELY AND THE UNIT SHOULD BE RETURNED TO A PARKER
AUTHORIZED REPAIR CENTRE FOR INVESTIGATION AND REPAIR.
FAILURE TO DO SO COULD RESULT IN INJURY, DEATH OR DAMAGE.
FURTHER OPERATION OF THE AC30V WITHOUT RESOLVING THIS FAILURE IS ENTIRELY AT THE USER’S OWN RISK.
SEE SAFETY CATEGORY DEFINITIONS AND LIMITATIONS, REFER TO EN ISO 13849-1:2008.
Channel A: X10/01
Channel B: X10/03
Output: X10/05, X10/06
STATE
24V
0V
24V
0V
ON
OFF
3.0s
1 3 4
