The power supply units supply the AS-Interface system with power via the yellow AS-Interface cable. Communications between the various slaves are modulated and are embedded in the power supply's output voltage. A special power supply is therefore required that does not filter out the data information.
The IR addressing mode is selectable via a switch on the front. When the IR mode is activated, communications are disconnected on the yellow AS-Interface cable. The slaves in the loop can then be simply readdressed without physical disconnection from the interface cable. Once programming is completed, the power supply unit is connected for communications mode and data communications is restarted.
Earth fault monitoring: SLA4 has earth fault monitoring between the AS-Interface cable and earth. In the event of short circuiting between +30.5 V dc or minus to earth, the power supply unit will indicate an alarm via a relay contact and a flashing LED. The power supply unit will continue to supply power to the connected slaves when a fault is detected. The fault is acknowledged by pressing a button on the front of the unit. If a separate earthis not installed between the machine and SLA4.100, we recommend earthing the Shield input via the primary side's earth. Do not leave the Shield connection open.
Fuse mode: SLA8 has a fuse mode. In the event of a short circuit, the power supply unit will produce a high short-circuit current for a few seconds (max. 5 s). The unit will then trip its electronic fuse. A tripped fuse is indicated by a flashing LED. To reset the unit, press the reset button at the front. This function entails that unintentional restarts are prevented and the connected units are protected from damage. For more technical information, see the general information section at the beginning of the power supply chapter.