Reer ARGOLUX AU S3M2 - CONTROL UNIT THEORY OF OPERATION AND STATES; Test function

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CONTROL UNIT THEORY OF OPERATION AND STATESCONTROL UNIT THEORY OF OPERATION AND STATES
Test function.Test function.
A type 2 safety system maintains its protective function by checking correct
response to an external test command. The system must stop if the test
detects a fault that could impair safety.
At power-on or each time the light barrier is interrupted, if the area
controlled is free, the AU S3M2 unit switches to clear status with output
relays A and B de-energized. The test contact must be closed in order to
enable the next work cycle.
F
The test command must precede the start command of theThe test command must precede the start command of the
machine that initiates the next work cycle.machine that initiates the next work cycle.
F
The output relays of the AU S3M2 control unit are energizedThe output relays of the AU S3M2 control unit are energized
only if the test is positive.only if the test is positive.
The test function is always enabled at any point of the machine cycle
provided the light barrier is free. This means that correct system
functioning can be checked at any time without necessarily occupying the
protected area.
The first part of the test checks correct functioning of the light barrier.
Occupation of the sensitive area is simulated in this phase, checking the
response time and correct functioning of the output circuit.
Subsequently, the AU S3M2 checks the response time of its own output
circuit consisting of two guided contact safety relays.two guided contact safety relays.
The output chain is kept open during the entire test phase and this
condition is maintained also during checks on the response times of
internal relays A and B which are energized and checked in two separate
phases.
If the test is positive, the control unit causes energization of its output
relays A and B and, using a feedback circuit, checks the switching times of
any external auxiliary relays or contact blocks (K1 and K2). If this test is
also positive, the control unit switches to guard status guard status and enables the
next operating machine start command.
If no fault is detected, guard status is maintained until the area controlled
by the light barrier is intercepted.
Occupation of the area controlled causes immediate drop-out of output
relays A and B and the control unit switches to break status. break status. The test
command is not operative in this condition and the area controlled must
be freed in order to carry out a new test cycle.
If a test fails, the control unit switches to fail status fail status preventing energizing
of the output relays.
This error condition, characterized by blocking of the unit with the output
relays de-energized, is also sent towards the outside through switching of
the self-diagnosis output on the unit.