Front Cover; Power Supply Unit (Psu); Operator Interface/ Fascia; Figure 2.5-1 7Sr224 With 12 Function Keys And 3 + 8 Leds In E10 Case - Siemens 7SR224 Technical Manual

2.3

Front Cover

With the transparent front cover in place the user only has access to the READ DOWN ▼ and TEST/RESET►
buttons, via blue push buttons, allowing all areas of the menu system to be viewed, but preventing setting
changes and control actions. The only 'action' that is permitted is to reset the Fault Data display, latched binary
outputs and LEDs by using the TEST/RESET
the case.
2.4

Power Supply Unit (PSU)

The relay PSU can be directly connected to any dc supply via a suitably rated fuse from 30V dc to 220V dc.
In the event of the supply voltage level falling below the relay minimum operate level the PSU will automatically
switch itself off and latch out – this prevents any PSU overload conditions occurring. The PSU is reset by
switching the auxiliary supply off and on.
2.5

Operator Interface/ Fascia

The operator interface is designed to provide a user-friendly method of controlling, entering settings and retrieving
data from the relay.

Figure 2.5-1 7SR224 with 12 Function Keys and 3 + 8 LEDs in E10 Case

NOTE: Transparent cover with pushbuttons not shown
The fascia is an integral part of the relay. Handles are located at each side of the relay which allow it to be
withdrawn from the relay case.
©2010 Siemens Protection Devices Limited
button. The front cover is used to secure the relay assembly in
7SR224 Argus Description of Operation
Chapter 1 Page 10 of 70