Xenus Plus Compact STO Manual
16-01553 Rev 00
Page 21 of 31
Copley Controls
7.1.6 Example STO Timing
Power
+24 VDC supplied to the safety relay
Reset/Start
Momentary push-button that causes the K1~K2 relay contacts to close, supplying power
to the STO inputs of the drive, and de-activating the STO function.
This allows the drive to produce torque/force in the motor when it is enabled.
E-Stop
The latching push-button switch inputs to the safety relay. The HI level of this indicates
that the button has been released, opening the NC (Normally Closed) contacts.
K1, K2
The instantaneous contacts in the relay. A HI level indicates that the contacts are closed,
supplying power to an Enable input of the drive to place it in an enabled state.
K3, K4
Relay contacts that will open after a pre-set time delay. This allows time for the drive
to remain in an enabled state while it performs a controlled deceleration that brings
the motor to a standstill before the STO function is activated,
preventing any torque/force production in the motor.
t1
Switch-on delay. If the E-Stop button is out, this is the delay after the Reset/Start button is
pressed in and the K1~K4 relay contacts close, deactivating the STO function and
enabling the drive (1).
t2
Delay-on de-energization. When the E-Stop button is pressed in (E-Stop), this is the delay to
the opening of the K1~K2 contacts which disables the drive, initiating a controlled
deceleration of the motor (2).
t3
Waiting period. This is the time-delay that allows for the controlled deceleration of the motor.
When the E-Stop button is pressed in, this is the time delay to the K3~K4 contact opening
which will activate the STO (3).
t4
STO response time. This is the time between the de-energizing of the drive STO inputs
(K3~K4 contacts open) and the entry into the safe-state.
Fig. 6
