Advantages Of Using The "Safe Torque Off" Safety Function - Parker Compax3 Series Operating Instructions Manual

Parker EME
3.11.1.3
Safety category 3 according to EN 954-1 and EN ISO 13849-1:
Requirements perfor- Use of the safe torque off function
mance feature
Reduced switching Simple wiring, certified application examples
overhead
Groupling of drive controllers on a mains contactor
is possible.
Use in th production Extremely high operating cycles thanks to almost
process wear-free technology (low-voltage relay and elec-
tronic switch). The "safe torque off" status is attai-
ned due to the use of wear-free electronic switches
High operating cycles,
(IGBTs).
high reliability, low wear
Use in th production Drive controller remains performance- and control-
process oriented in connectted state.
No significant waiting times due to restart.
High reaction speed, fast
restart
Emergency-stop function According to the german version of the standard:
Permitted without control of mechanical power
switching elements 1)

Advantages of using the "safe torque off" safety function.

1) According to the preface of the german version of the EN 60204-1/11.98, elec-
tronic equipment for emergency-stop devies are also permitted, if they comply with
the safety categories as described in EN954-1.
192-120114 N5 C3I22T11 June 2008
Compax3 device description
Conventional soution: Use of external switching
elements
Two safety-oriented power contactors in series connec-
tion are required.
This performance feature cannot be reached with
conventional technology.
When using power contactors in the supply, a long
waiting time for the energy discharge of the DC link
circuit is required.
When using two power contactors on the motor side,
the reaction times may increase, you must however
take into consideration other disadvantages:
a) Securing that switching takes only place in power-
less state (Direct current! Constant electric arcs must
be prevented).
b) Increased overhead for EMC conform wiring.
Switch-off via mechanical switching elements is requi-
red
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