ABB Symphony Harmony Series, Instruction, Page: 144 / 402

I/O Block
WBPEEUI240751C0 3 - 15
•
Circuit protection (surges, shorts, overvoltages, etc.).
Special Operations Switch (SW2)
The special operations switch (SW2) is used to enable normal
operation, to initialize the I/O module, and to select offline
diagnostics. Refer to Table
7-4 for normal operation and ini-
tialize switch settings. Refer to Diagnostics Diagnostics Diagnostics Diagnostics in Section 8 for a
description of the diagnostics.
Base
There are two types of I/O block bases (Fig. 3-5 ): screw termi-
nal and clamp terminal. There is a nonredundant and redun-
dant version of each base. In general, a block supports four
different base versions. The base has several purposes:
•
Field wiring termination.
•
I/O channel signal routing.
•
I/O module mounting.
•
Hardware keying of base to I/O module.
•
Shield (i.e., chassis ground) connection.
NOTE: The terminal strip can be removed from the clamp termination base for
cable connection applications. Refer to Cable Connection in this section.
The base attaches directly to a block mounting column. Align-
ment posts help locate the base on the mounting column. The
assembly is physically mounted using two captive screws (four
screws for a redundant base). Tabs on the base insert into slots
in the mounting column to help further secure the base in
place. I/O signals connect to the base and are routed internally
to I/O module connectors. Field connections remain undis-
turbed if the module is removed or replaced.
A nonredundant base provides mounting and connection for a
single I/O module. A redundant base is available to provide
mounting and connection for two I/O modules that operate
redundantly. The redundant base is wider than the nonredun-
dant base by the width of an I/O module and requires a redun-
dant block mounting column.
Screw and Clamp Termination Bases
A termination base supports either screw terminals (S type) or
clamp terminals (C type) for direct field wire connection. The