4 Connecting Multiple Sensors Per Sensor Circuit; Electrical Commissioning; 1 Prerequisites; 2 Electrical Connection - ASO Safety Solutions ISK 77 Manuel D'utilisation

ISK 77 / SPK 77 Inductive signal transmission system

9. Electrical commissioning

Connecting to the wrong terminals can destroy the switching unit.

9.1 Prerequisites

• When supplying with 24 V AC/DC, the voltage must comply with the requirements for Safety Low Voltage
(SELV).
• All applied voltages must comply with the requirements for Safety Low Voltage (SELV). With variant E,
the outputs are not galvanically separated from the supply voltage.
• Cables installed outdoors or outside of the switching cabinet must be protected appropriately.

9.2 Electrical connection

• Connect 24 V supply voltage to terminals B1 B2
• Connect stationary sensors to the SCE OPEN and SCE CLOSE connections.
• Connect the safety circuit to be monitored to the appropriate connections for safety outputs Open and
Close. The cables are to be laid so that it is impossible to bridge the safety contacts, e.g. by a short circuit
between the two connection wires (particularly with variant R).
Following successful commissioning, safety outputs are active. Actuation of a sensor causes the respective
safety output to switch to the inactive state.
Even while the safety outputs are being activated, their ability to turn off is constantly tested (not with variant
R). For this purpose, the semiconductor output is switched off several times per second for less than 1 ms and
the response at the output monitored. If the voltage at the output does not switch to the shut-down state,
the device deactivates permanently and can only be reset by switching the voltage supply off and back on
again. This permanent deactivation also occurs if, depending on the type of activation, the voltage cannot
break down (e.g. by means of capacitive elements).

9.3 Testing with connection options

For the design of the protection to conform to engineer standards (category 2 with external test request),
the protection must be tested prior to each dangerous movement or during the non-dangerous phase/
movement of the machine. The test is intended to ensure the proper function of the safety relay. After
applying the test signal, the control output must deactivate. This change in switching state must be evaluated
by the primary machine control. If the test result is correct, the machine control then initiates the movement
or the next work step. Otherwise, the controller must output an error message and prevent a dangerous
movement. If the machine control detects an error fault in the safety device, the machine control must
maintain a safe state until the error is rectified.
Test signal
Output (active)
(inactive)
28
< 10 ms >25 ms
< 50 ms