Cargo 211091, Руководство пользователя

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211091
7
Vedpak 113_Version 2_201109
211091
6
Vedpak 113_Version 2_201109
Characteristics of the Short/Grounded Circuit Signal
1. Strongest when flowing exclusively through one
wire.
When the signal is conducting through only one wire, the
signal strength is at its maximum because 100 % of the
signal is traveling through that wire exclusively to return
back to the negative side of the battery. If the signal
branches out to parallel circuits, its strength divides and
of course is weaker in each branch of the divided circuit.
But when the signal recollects through the single nega-
tive cable to return to the battery, the signal strength is
at its maximum again because 100 % of the signal is
concentrated through the single negative battery cable.
(See "Isolate the Circuit You are Tracing").
2. Travels the path of least resistance.
In case of a short circuit that blows its fuse reliably, you
can sometimes get away with not having to isolate the
circuit. The majority of the signal will follow the path of
least resistance through the short and then back to the
battery. In fig. 1, you can see the majority of the signal
travels right to the short circuit. You can also see only a
small portion of the signal running through parallel wires.
3. A 4 KHz Polarized Signal.
The fact that the Grounded Circuit signal is a 4 KHz
polarized signal provides directional information for the
receiver to pick up. This capability to indicate the direc-
tion to the short or ground takes the guesswork out of
tracing grounded circuits. (See "Direction to the Short")
4. Carries a current of only 100 mA.
When generating a Short/Grounded Circuit signal, a
maximum of 100 milliamp flows from the signal lead.
This keeps you safe from damaging sensitive computer
circuits.
Path of least resistance
Major portion of signal goes
into short (Ground)
Lights have resistance
and limit signal flow
Very small traces of
signal branch into parallel
circuits
Characteristics of the Open Circuit Signal are:
1. Transmits through NON Conductive Materials.
The signal that the tester transmits when tracing open
circuits, radiates what is called an E-field. For the sake
of simplicity we will refer to an E-field in this manual as
an "Open Circuit Signal".
The open circuit signal radiates from wires and passes
through non conductive material such as dry carpet,
plastic panels or plastic molding. The receiver is used
to detect these signals so you can trace and locate the
open or break in the circuit. (See "Locking the
Sensitivity".)
2. Easily Shielded by Conductive Materials.
The open circuit signal is however easily shielded by
conductive materials such as metal, wet carpet, neigh-
boring wires in harness and even your hand. This means
that if conductive materials are between the transmitting
wire and the receiver, the open circuit signal will not
penetrate through and therefore not be detected by the
receiver. So it is necessary to be aware of
possible shielding issues and try to avoid them as much
as possible.
A great alternative to the receiver in detecting open
circuit signals is to use the tester by direct contact.
(See "Verify an Open Circuit").
Open signal passes through
dry non-conductive material
Dry carpet / plastic panels and molding
Holding the receiver by this corner, pre-
vents your hand from shielding the open
circuit signal
Wet carpet / metal / shielding wire harness
Fig.1