3. Architecture, configuration and applications
3.1. Architecture (actuator sizing)
For actuator architecture (actuator sizing) the maximum torques, run torques and
operating times are taken into consideration.
Incorrect actuator architecture can lead to device damage within the safety-
related system!
Possible consequences can be valve damage, motor overheating, contactor jamming,
defective thyristors, heating up or damage to cables.
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The actuator technical data must imperatively be observed when selecting the
actuator.
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Sufficient reserves have to be provided to ensure that actuators are capable of
reliably opening or closing the valve even in the event of an accident or under-
voltage.
Information
For the “Safe end position feedback” safety function, heed that signalling is made
via mechanical switches. Since these elements have an unavoidable hysteresis, the
actuator slightly leaves the end position before the end position signal is deleted.
Consequently, there is a marginal range of actuator positions to the safety position,
for which the end position is still signalled although the actuator has already left the
end position during operation from safety position. If the range in question is ap-
proached from the opposite direction, this limitation does not apply. In general this
range is relatively small. However, for unfavourable configurations (low number of
turns per stroke), this range can amount to more than 10 % of the total stroke.
Should, within the framework of unfavourable conditions, the effect described above
represent an unacceptable limitation for the safety function, we recommend evaluating
both limit and torque switches for the end position feedback.
Power supply
Information
The plant operator is responsible for power supply.
3.2. Configuration (setting)
Configuration (setting) of the safety-related functions is performed as described in
the operation instructions or in the present manual (functional safety).
Information
An exact setting of torque and end position switches for the end positions is imperat-
ively required to ensure correct function of “Safe end position feedback”. For setting
details related to the respective switches, please refer to operation instructions.
Configuration of reaction monitoring diagnostics and Partial Valve Stroke Test
(PVST)
Depending on the type of diagnostics required, the reaction monitoring or Partial
Valve Stroke Test configurations have to be checked and adapted, if required.
For detailed configuration options on reaction monitoring as well as detailed
information on the Partial Valve Stroke Test (PVST), refer to Manual (Operation and
setting) AUMATIC AC 01.2.
3.3. Protection against uncontrolled operation (self-locking/brake)
For self-locking AUMA actuators, it can be assumed that a load up to maximum
torque will not result in uncontrolled valve operation from standstill due to valve torque
load. Consequently, in these cases, further protection against uncontrolled operation
is not imperatively required. However, certain applications may require active position
locking, for example by using a brake.There are user-specific standards demanding
this type of protection.Therefore, each project must be subject to individual verification
if any further protection is required. In any case, this protection is required for
actuators without self-locking.
7
Multi-turn actuators
SA .2 with AC(V) 01.2/AC(V)ExC 01.2 Architecture, configuration and applications
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