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Section 2: Hardware Description
2.1
General
The structure of the relay is based upon the Multi-function hardware platform. The relays are supplied in either
size E6 or size E8 cases (where 1 x E = width of approx. 26mm). The hardware design provides commonality
between products and components across the Multi-function range of relays.
Table 2-1
Summary of 7SR23 DAD Relay Configurations
Relay
Current
Inputs
7SR2302
4
7SR2303
4
Relays are assembled from the following modules:
1)
Front Fascia with three fixed function LEDs and ordering options of configurable LEDs.
2)
Processor module
3)
Analogue Input module 'A': 4 x Current + 6 x Binary Inputs + 2 x Binary Outputs
4)
Power Supply and basic Binary Input (BI) and Binary Output (BO).
5)
Optional Binary Input/Output module.
6)
Optional data comms module.
2.2
Case
The relays are housed in cases designed to fit directly into standard panel racks. The two case options have
widths of 156mm (E6) or 208mm (E8) , both have a height of 177 mm (4U). See Chapter 5 (Installation Guide) for
details of panel cut-out and internal clearance requirements.
The complete relay assembly is withdrawable from the front of the case. Contacts in the case ensure that the CT
circuits remain short-circuited when the relay is removed. Note that when the optional Ethernet comms module is
fitted to the relay the comms cables and the EN100 module rear securing screw must be removed before the
relay assembly is withdrawn.
The rear terminal blocks comprise M4 screw terminals for wire connections. Each terminal can accept two 90
degree ring tongue crimps.
Located at the top rear of the case is a screw clamp earthing point, this must be connected to the main panel
earth.
2.3
Front Cover
With the transparent front cover in place the user only has access to the
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
button.
The front cover is used to secure the relay assembly in the case.
©2013 Siemens Protection Devices Limited
Binary
Output
LEDs
Inputs
Relays
9
8
8
19
16
16
Chapter 1) 7SR23 DAD Description Of Operation
Case
E6
E8
and TEST/RESET
buttons, allowing
Chapter 1 Page 9 of 36
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