GB2076165A

GB2076165A - Programmable Wiring Tester

Info

Publication number: GB2076165A
Application number: GB8109458A
Authority: GB
Original assignee: R Alkan et Cie
Current assignee: R Alkan et Cie
Priority date: 1980-03-28
Filing date: 1981-03-26
Publication date: 1981-11-25
Also published as: GB2076165B; FR2479500A1; DE3111549A1; FR2479500B1; DE3111549C2; IT1170848B; IT8148121A0

Abstract

A programmable wiring tester operable under high-voltage and high- current conditions comprises a microprocessor computer adapted to perform sequential testing, which is monitored by the microprocessor from data stored in a RAM of the computer by means of a digital keyboard; the ends P1-Pn of the wiring to be tested are each connected to one of a pair of relays r1 ,r'1 -rn,r'n connected to two poles of a Wheatstone bridge (Fig. 2 not shown) of which one side is the wire to be tested and the other sides are adjustable resistors adapted to keep the bridge in a stable condition. Continuity and insulation tests may be performed at high currents and high voltages respectively. <IMAGE>

Description

SPECIFICATION Programmable Wiring Tester This invention relates to programmable wiring testers.

Various wiring testers are already known, which may be classified as follows: non-programmable testers, self-programmable testers, and programmable testers.

Non-programmable testers, corresponding to the so-called low-range apparatus, compel the users to provide specific interfaces for each wiring to be tested.

Self-programmable testers imply the construction and exploitation of a wiring considered as a sound one. Moreover, this type of tester is objectionable because it refers to a wiring of which the position of its characteristic properties in relation to the requisite tolerance limits is unknown.

Hitherto known programmable testers correspond to high-capacity, high-range apparatus which, nevertheless, cannot be used for making high-voltage insulation tests or continuity tests under high-current conditions.

The present invention relates to a relatively economical apparatus which can be operated even by unskilled operators without any preliminary complicate teaching, and which, due to the combination of means such as relays, a microprocessor computer and a keyboard, takes advantage of the use of a computer while permitting insulation tests under high-voltage conditions and continuity tests under high-current conditions.

According to an essential feature characterising this invention, each end of the wiring to be tested is connected to a pair of change-over relays, whereby the end concerned can be connected to one or the other of the fault tracer poles.

According to a complementary feature of the present invention, the fault tracer or trouble shooter consists essentially of a Wheatstone bridge of which one side consists of the circuit to be tested, the state of balance of the bridge being determined by means of a comparator.

In order to afford a clearer understanding of the present invention, a typical form of embodiment thereof will now be described in detail with reference to the accompanying drawing.

In the drawing: Figure 1 is a wiring diagram of the circuit means interconnecting the test points, the relay means and the fault tracer; Figure 2 is a detailed diagram of the fault tracer; and Figure 3-is a block-diagram of the complete system.

Referring first to Figure 1 , the ends of a wiring system to be tested are designated by the symbols P1, P2, P3 ... Pn. Of course, the number of cable or wiring ends may differ from the number illustrated without departing from the basic principles of the invention. Each test point P 1 ... Pn is connected to a pair of reiays r1 -r' 1, r2-r'2,... rn-r' n, the energization of the first relay causing the corresponding test point to be connected to one pole A of the fault tracer and the energization of the second relay causes the corresponding test point to be connected to the second pole D of the fault tracer.

Thus, for instance, when it is desired to check the continuity of the connection P1-P4, it is only necessary to energize relays rl and r'4, and similarly, when it is desired to test the continuity of connection P4-P6, the operator simply energized relays r4 and r'6. It will be seen that the use of relay permits of testing the continuity of a line under a relatively high current.

In both cases, if the wiring continuity is broken, the tester will switch on a pilot light or any other sound or visual signal or tell-tale device.

The fault tracer consists of a Wheatstone bridge (Figure 2) of which one side AD actually consists of the wire to be tested, having a resistance R2. When current is fed to the bridge from S to A and B, the potential difference between C and D is zero if the ohmic resistance of resistors R 1, R2 and R4 of the four arms of the bridge are in the following relationship: R1 xR4=R2xR3. Since it is an easy matter to find the ohmic resistance R2 of the wire to be tested, the ohmic value of R1, R2 and R4 are set accordingly and the testing operation consists simply in checking the stability of the bridge by using a standard comparator Z which, in case of fault, will put on the pilot light V.

The insulation test may also be carried out by controlling the relays. Considering the above example concerning test points P1, P4 and P6, the insulation test consists simply in ascertaining whether this group of points P 1, P4 and P6 is insulated with respect to all the other test points, and this can be checked by simply energizing relays r1, r4 and r6, as well as relays r'2, r'3, r'5, r'7... r'n, and the high insulation resistance R'2 will be tested by inserting this connection in the Wheatstone bridge according to a procedure similar to that shown in Figure 2, but with ohmic resistance having adequate values, the bridge feed being capable of accommodating high voltage values.

The general arrangement of the system is illustrated in block form in Figure 3. The reference to the mains at 12; the microprocessor 1 3 is connected on the one hand to the control memory (RAM) 14 leading to the change-over relays 15 and on the other hand to the operating memory 16 (REPROM). The reference numeral 17 designates diagrammatically the input and output terminals, numeral 18 shows the digital control keyboard, and 19 the control board.

This control board 19 comprises essentially an ON/OFF switch 20, pilot lights 21 showing that a continuity test or an insulation test is in progress, digital display means 22 for the tested wire or wires, a printer output 23 and a printer ON/OFF switch 24, a sound alarm speaker 25 together with its switch 26, and a door 27 for access to the internal component elements of the apparatus.

With the digital keyboard 1 8 the operator can store in the control memory 14 of the computer all the data concerning the wiring to be tested.

Stored in the operating memory 16 is the internal program of the tester which permits a sequential scanning of the various points to be tested.

Claims

1. A programmable wiring tester operable under high-voltage and high-current conditions, which comprises a microprocessor computer capable of performing a sequential testing and to be monitored by said microprocessor from data stored in a random access memory of said computer by means of a digital keyboard, wherein each end of the wiring to be tested is connected to a pair of change-over relays connected to the two poles of a continuity or insulation detector, each testing operation being attended by the energization of at least one relay of each pole for connecting a fault tracer to the wiring ends corresponding to the energized relays.

2. The programmable wiring tester of Claim 1 wherein said fault tracer consists of a Wheatstone bridge of which one side consists of the circuit to be tested, and the other three sides consist of adjustable resistors adapted to maintain the bridge in a stable condition as checked by a comparator.