Parker Hannifin S.p.A. Divisione S.B.C. user’s manual TWIN-N and SPD-N
183
17 Appendix G: option “R” for safe disable function
17.1 Introduction
The drive ordered with “R” option are manufactured and validated to implement category 3
safety disable as described in EN 954-1 and EN 13849-1
By mean of this function it is possible to guarantee that unwanted restart of the motor
movements will not be allowed, even without using electromechanical switches between drive
and motor.
Drives labelled with “R” options are equipped of a electromechanical safety relay (certified
by TÜV institute). This relay, driven by user, turns off safely power semiconductor stage and
gives back a feedback though a free potential switch (normally closed).
The safe disable turns off the output power through an electromechanical action, independent
from drive firmware.
In TWIN-N drives both axes output power stages are switched off using a unique signal.
The safe disable function prevent from torque generation in an squirrel cage induction motor
connected to the drive even if a drive fault does occur.
If a permanent magnet synchronous motor (brushless) is connected, a short rotation may
occurs: 180° maximum, that becomes 90° maximum in case of salient poles technology
motors.
Machines risk assessment activity must take care of this fact.
The safe disable function do not provide an electrical shock prevention, so in case of service
activity on electrical connections, electrical power must be disconnected from drive and
operator must wait for the complete discharge of all internal capacitors (almost 6 minutes).
The safe disable function inhibit the power stage of the drive including dynamic brake power
stage: for this reason when the safe disable signal is activated a fast emergency stop will not
be allowed.
The safe disable function guarantees machine safety only if it is correctly applied in the whole
machine safety plant.
The machine have to be verified through a risk assessment activity to be sure that the residual
risk of a dangerous event is compatible with risk class of the machine itself.
W
W
A
A
N
N
I
I
N
N
G
G
W
W
A
A
N
N
I
I
N
N
G
G
W
W
A
A
N
N
I
I
N
N
G
G
W
W
A
A
N
N
I
I
N
N
G
G
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