Parker AC890PX Series, Product Manual

Page: 96 / 517

Safe Torque Off
4-30
AC890PX AC Drive
may be present and must be resolved by the user before relying on the STO function. See “Fault Operation”
on page 4-16.
To start the drive:
Ensure the Safety Demand switch is reset (contacts closed). Press the RESET button to ensure the
Safety Control Unit is reset; its contacts to the 890 should close making the STO function inactive,
the 890 STO output should then turn OFF. Then press the DRIVE START button.
To perform operational stop (non STO):
Press the DRIVE STOP button.
Wait for the motor to come to rest.
To invoke STO:
Operate the Safety Demand (contacts open). This should cause the Safety Control Unit to open its
instantaneous output, shown here as a single channel. This causes the drive to decelerate to rest using
its own software which is not safety critical in this instance. Note: the drive’s block diagram must be
configured to provide this ramp to rest functionality.
After a time delay set in the Safety Control Unit, the pair of delayed OFF output contacts open
together. This time delay must be set longer than the worst case time for the motor to come to rest.
In response, the drive will confirm, by energising KA1 via X11/05, that STO has been invoked. The
user may wish / require that this is verified by mechanisms not shown on this drawing.