Parker 638 series

9 Safe
Safe Safe
Safe Torque
TorqueTorque
Torque Off (STO)
Off (STO)Off (STO)
Off (STO)
84
07-02-12-02-EN-V1215.doc / Type: 638
● Applications in Accordance with the Regulations
The 638 Drive supports the safety function “Safe Torque Off”, in the sense of providing a definitive
stopping of the equipment, with protection against unanticipated start-up, in accordance with
regulations EN ISO 13849-1, Category 3, up to Performance Level e and EN 1037.
The motor must stopped controlled through the machine controller. However, it does not provide
for any verification of cessation of movement which may have been produced from some external
source. One must pay specific attention to the vertical axes, without a
mechanical self-inhibitor or balanced weight.
According to Machine Regulations 2006/42/EG, using. e.g. EN ISO 134849-1,
when considering the safety and risk analysis, the machine constructor is responsible to make
certain that the overall safety system for the whole machine takes all of the integrated components
into consideration. Note that the electrical drives must also be included in this consideration.
One must pay attention to and follow the instructions completely as stated in the validation report,
with regard to the initial start-up, service intervals, troubleshooting and repair of the equipment.
The STO conformance protocol outlines a suggestion for the documentation of the relevant safety
parameters in the validation report.
● Trained Personnel
Planning, installation and initial system commissioning require a detailed understanding of this
information.
Protective safety standards and risk mitigation issues which are connected to the specifics of the
installation must be recognized and taken into consideration, as well as appropriate actions to be
taken in the event of an emergency.
● Benefits with the Employment of the Safe Torque Off Function
Performance
Feature
Requirement
Application of the Safe
Torque Off Function
Conventional Solution : Utilization of
External Switching Components
Reduced
Switching Effort
Simple circuitry, certified application
examples
The grouping of multiple drives together
on a main contactor is possible.
Two safety-oriented performance protections in
series connections required.
Application in
Production Processes
High Switching
Frequency,
High Reliability,
Less Wear
Extremely high switching frequency
through the use of almost wear-free
technology (Low voltage relays and an
electronic switch). The condition
“Safe Torque Off” is achieved through
the use of a wear-free electronic
switches (IGBT’S).
This performance feature is not achievable through
the employment of conventional technology.
Application in
Production Processes
Faster Reaction Time,
Faster Re-Start
The drive remains power and control
related in a connected condition. No
significant wait time with re-start.
With the utilization of power contactors on the
incoming power line, a long wait time is required for
the energy discharge from the DC link.
With the use of two motor side power contactors, it
is possible to increase the reaction time, however
one must recognize the potential disadvantages::
a) Make certain that switching occurs only in a
power free condition, (DC Power! Prevent arcing).
b) Increased cost for EMC conforming cabling.
Emergency Stop
Function
Shutdown employing a mechanical switching
element is required.
This manual was downloaded on www.sdsdrives.com
+44 (0)117 938 1800 - info@sdsdrives.com