System Manual HS3A-H21M4
7
Function
HS3A monitors the position of movable safety guards. The safety outputs are
switched on/off when the actuator moves into/out of the operating distance.
HS3A complies with the following safety requirements:
Category 4, PL e according to EN ISO 13849-1.
Redundant design of the circuit in the unit with self-monitoring.
This means that the safety system still functions even if an internal com-
ponent fails.
The switch state of the semiconductor outputs is continuously monitored
internally.
Short circuit detection at the safety outputs by pulse signals.
HS3A consists of the following components: coded actuator (transponder),
and switch.
Whether the complete actuator code of the device is taught in (unicode) or not
(multicode) depends on the respective version.
Devices with unicode evaluation (HS3A-H21U4): The actuator must be
assigned to the safety switch by a teach-in operation so that it is detected by
the system. This unambiguous assignment ensures a particularly high level
of protection against tampering. The system thereby possesses a high
coding level.
Devices with multicode evaluation (HS3A-H21M4): Unlike systems with
unique code detection, on multicode devices a specific code is not polled
but instead it is only checked whether the actuator is of a type that can be
detected by the system (multicode detection). There is no exact comparison
of the actuator code with the taught-in code in the safety switch (unique
code detection). The system possesses a low coding level.
When the safety guard is closed, the actuator is moved towards the safety
switch. When the switch-on distance is reached, power is supplied to the
actuator via the switch and data transfer takes place.
If a permissible code is detected, the safety outputs are switched on.
The safety outputs are switched off when the safety guard is opened.
In the event of a fault in the safety switch, the safety outputs are switched off
and the DIA LED illuminates red. Occurring faults are detected at the latest
on the next demand to close the safety outputs (e.g. on starting).
Door monitoring output
The door monitoring output is switched on as soon as a valid actuator is
detected in the operating distance.
Limit-range monitoring
If the safety guard with the actuator should settle over time, the actuator
can drift out of the read head operating distance. The device recognizes
this situation and indicates that the actuator is in the limit range by flash-
ing the STATE LED. This allows the safety guard to be readjusted in time.
Also see System status table on page 23.
