You may easily check continuity in wiring harnesses using CableEye.
You may either connect a model harness to CableEye and learn the
correct wiring, or enter the connections manually using the Netlist
Editor. The PinMap software lets you label each pin uniquely (for
example, "J1:1") You may then add descriptive notes
and label text, and store the wiring information on disk for future
reference. The wire list may be printed, and a wiring diagram
viewed on the screen as well as printed. Finally, a test harness
may be connected, measured, and directly compared against the
model. Differences in wiring will immediately be detected when
you use the COMPARE TEST TO MATCH function, and such differences
will either be graphically displayed or shown in a wire list.
These results may also be printed.
Because of the limited screen and page size, however, the many
connector graphics that would be required for a typical harness
cannot be displayed as individual connectors. Instead, you will
view groups of generic 64-pin dual-row headers corresponding to
each bank header on the equipment. Each pin may be custom-labeled
to obtain accurate identification of harness connector and pin
number. By carefully choosing how to wire your harness to CableEye's
test points, you will obtain easily readable drawings that will
allow you to quickly pinpoint wiring errors.
In a general production environment, the harness will be scanned
and compared to the model. If everything matches exactly, the
operator sees the green MATCH lamp come on and will know that
the harness passes the continuity test. No further action is necessary,
and the next harness may be tested.
If there is a mismatch, the red ERROR lamp comes on and the operator
may view the wiring on the PC's screen, or print the wiring, to
isolate the problem.
Once the basic continuity test is completed successfully, it may
be desirable to check for intermittent connections. In this case,
you would use CableEye's CONTINUOUS TEST function, which applies
test signals continuously to the harness. While this is occurring,
the operator would flex connectors, or any other location susceptible
to intermittent connections. Should a change in continuity occur,
the PC will produce a warning tone to alert the operator. The
intermittent connection will then be highlighted on the screen.
CableEye with expansion modules connected provides a maximum of
1048 test points. This means that in order to check a harness
in one pass, the total number of pins on all connectors of the
harness must total no more than 1048; one test point will be assigned
to each pin of every connector, leaving no pins unconnected. If
the harness contains more than 1048 test points, you will need
to check the harness in two or more steps, first measuring 1048
pins, and then checking the additional pins in subsequent steps.
Contact CAMI Research for our complete guide to wiring harness
guide testing.
When the harness under test terminates in bare wires without
connectors, you need a probe with which to hold each harness wire
while under test. CAMI Research supplies Minihook cables (Item
710) as an option for CableEye for just this purpose. Alternatively,
you may build your own using color-coded minihook grabbers (made
by ITT/Pomona and others). In this case, each test point terminates
in a minihook which is then clipped to one wire of the harness.
The Minihook cables supplied by CAMI Research consist of a set
of two cables, each of which has ten color-coded hooks (black,
brown, red, orange, yellow, green, blue, violet, gray, white).
Thus, a total of twenty test points can be accom-modated. Each
Minihook cable joins to CableEye via a DB9 male connector. When
wiring is scanned using the Minihooks, all standard CableEye features
are available. If you display wiring, ten discrete color-coded
hooks are shown on each side of the screen and wiring drawn between
them to depict the harness wiring (see below).
If the bare-wire harness under test requires more than 20 test
points, you may use multiple Mini-hook cables with a junction
box to transition the DB9 connectors to the 64-conductor flat
cable, and then display wiring using the dual-row headers as described
in the procedure for connectorized cables. Alternatively, you
may test 20 test points at a time with the same Minihook set until
all points are measured. Note that when you check a harness a
few test points at a time, you must choose the test points carefully
because of the inability to detect shorts across two group of
wires measured at different times.
End of Section
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