Barcrest MPU6 - I.D.C Connectors

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4.6 I.D.C connectors
Wires to the MPU6 Barbus are terminated in female housings, normally using I.D.C.
(insulation displacement connection) or alternatively, crimped connections. I.D.C.
termination offers the advantages of reliability and economy; the wire is forced into a “U”
groove in the terminal which displaces the insulation and makes contact with the conductor
underneath.
The colour of the nylon housing indicates for which gauge of wire the “U” groove is designed.
In the case of MPU6 systems most wires are 7/02 and therefore most of the I.D.C. housings
are coloured white.
4.6.1 Identification
The in-line I.D.C. connectors are identified in three ways: -
• The number of ways (Varies from 7 to 17).
• The colour of the cap (Colour coded cover clips into each housing and holds
the wires into their location).
• Position of the polarising key (Matches a missing male pin on the header).
• Crimped in-line connectors are identified in a similar way, except the colour
coding is applied to the body of the housing rather than to the cap.
4.6.2 Connector orientation
Correct orientation of the connectors is clearly determined by physical constraints and
polarising key location, so the cable harness is handed and can only be physically connected
in one direction. Pin number identification is moulded onto the side of the housing. For
example, in the case of 5-way connectors, the inter-connector wiring is: -
1 - 5
2 - 4
3 - 3
key key
5 - 1
4.6.3 I.D.C. lamp connections
All connections to I.D.C. lamp holders use green and blue wiring, which is connected from
lamp to lamp as a matrix.
Each lamp is connected between a green "lamp drive" line and a blue "lamp select" line.
The green or blue wire is inserted to catch under the barbs of the moulding on the lamp
holder. Should the wire become loose, move it sideways before pressing it down into the
contact so that the connection is made in a new position (see Fig. 3).
The green and blue wiring from lamp holders on the top or bottom glass is routed to I.D.C.
connectors on the MUX5/MUX5E board(s). The connector caps are coloured green for
identification. In general, the lamp holders in the top glass are supplied from the
MUX5/MUX5E board(s).