WO2003005048A1

WO2003005048A1 - Establishing condition of connector and malfunction of couplings

Info

Publication number: WO2003005048A1
Application number: PCT/FI2002/000597
Authority: WO
Inventors: Erkki Lassila
Original assignee: Scanfil Oy
Priority date: 2001-07-03
Filing date: 2002-07-02
Publication date: 2003-01-16
Also published as: FI111104B; FI20011448A; FI20011448A0

Abstract

The connector (1) comprises n contact pins (2a to 2n). The secondary side of the connector (1) is coupled to a point, which also comprises a secondary side connector (3). Resistors (Ra to Rn) are arranged in the plurality of contact pins (2a to 2n) in the connector (1) such that a first end of each resistor is connected to a contact pin (2a to 2n), second ends of the resistors (Ra to Rn) being interconnected to a star point (6). The resistance between the secondary side connector (3) and the star point (6) is then calculated, and the resistance according to a real situation is then established. If the connector (1) is operational and the couplings intact, the resistance of the resistor network is equal to the calculated resistance. If the resistance exceeds this, it means that the coupling measured from the connector is faulty.

Description

Establishing condition of connector and malfunction of couplings

The invention relates to a method of establishing the condition of a connector and the intactness of couplings, which connector comprises contact pins, one side of the connector being connected to a point to which a secondary side connector is connected, in which method the condition of the connector and the intactness of the couplings are established based on resistance measurement.

The invention further relates to an arrangement for establishing the condition of a connector and the intactness of couplings, in which arrangement the connector comprises a plurality of contact pins, one side of the connector being connected to a point to which a secondary side connector is connected.

Electronic devices are typically composed of some type of electronics circuit cards installed in a cartridge. The cartridge comprises a back plate having connectors for cards to be coupled thereto, and, similarly, the card comprises a connector for coupling the card to the connector in the back plate of the cartridge. Typically, the connector in the black plate is what is called a male connector, comprising n pins for receiving the openings of a female connector in the card. It is essential to the reliable operation of a device that the connectors and couplings in the back plate are intact. Accordingly, before a device is taken into use, the condition of the connector and the intactness of the couplings have to be checked. Today, the condition of a connector and the intactness of couplings are typically established in the manner shown in Figure 1. A connector 1 comprises n contact pins 2a to 2n. The secondary side of the connector 1 is coupled to a point also comprising a secondary side connector 3. The condition of the connector 1 and the intactness of the couplings are measured with a measuring device 4 by measuring the resistance between each contact pin 2a to 2n and secondary side connector 3. If the resistance deviates from a normal value, the coupling measured from said contact pin 2a to 2n is faulty. The resistance is measured individually between each contact pin 2a to 2n and secondary side connector 3. For the measurement, the measurement arrangement comprises a switch 5, which enables the alternate selection of each contact pin 2a to 2n to be measured. Consequently, the es- tablishment of the condition of one connector 1 and the intactness of the couplings requires n measurements, making the arrangement quite difficult, labo- rious and time-consuming.

The object of the present invention is to provide a method and an arrangement for efficient establishment of the condition of a connector and the intactness of couplings. The method of the invention is characterized in that resistors are arranged in a plurality of contact pins in the connector, one end of the resistors being connected to a star point, the resistors being coupled to form a parallel coupling, the resistance between said star point and the secondary side connector is calculated, the resistance conforming to a real situation is specified, and the specified resistance is compared with the calculated resistance for establishing the condition of the connector and the intactness of the couplings.

The arrangement of the invention is further characterized in that resistors are arranged in a plurality of contact pins such that a first end of each resistor is coupled to a contact pin, seconds ends of the resistors being inter- connected to a star point, the arrangement comprising a measuring device for specifying the resistance between the star point and the secondary side connector.

An essential idea of the invention is to arrange resistors in several contact pins of the connector such that the first end of each resistor is con- nected to a contact pin and the second ends of the resistors are interconnected to a star point. The resistance between the secondary side connector and the star point of the resistors is calculated, followed by specification of the resistance according to a real situation by means of resistance measurement, for example. The resistance of a resistor network formed by the parallel- coupled resistors is thus specified. If the connector is operational and the couplings intact, the specified resistance of the resistor network is thus equal to the calculated resistance. If the specified resistance is higher than the calculated resistance, it means that the coupling measured from the connector is faulty. The idea of a preferred embodiment is that the values of the resistors to be coupled to the contact pins are unequal, whereby the magnitude of the determined resistance can be used to specify the resistor by which the coupling pin is located to which the fault is related.

An advantage of the invention is that the measurement can be implemented for the entire connector more rapidly than before. The resistors coupled to the contact pins being of different values allows very fast establishment of the point where the fault is located. The invention will be described in detail in the attached drawings, in which

Figure 1 schematically shows a prior art solution, and Figure 2 schematically shows a solution according to the invention. Figure 2 shows a connection block, i.e. a connector 1 , which is arranged for instance in the back plate of the cartridge in an electronics device. The connector 1 comprises n contact pins 2a to 2n. One side of the connector 1 is coupled to a point, to which a secondary side connector 3 is also connected. A resistor Ra to Rn is connected to each contact pin 2a to 2n. The second ends of the resistors Ra to Rn are interconnected to a star point 6. A measuring device 4 is used to specify the resistance between the star point 6 and the secondary side connector 3. Thus, said resistance is the resistance of a network wherein the resistors Ra to Rn are series-coupled with the connector 1 , the resistors Ra to Rn being coupled in parallel. If the coupling is operational, the resistance between the star point 6 and the secondary side connector 3 is substantially equal to the resistance of the parallel coupling formed by the parallel-coupled resistors Ra to Rn. If the measured resistance is higher, it may be concluded that there is a fault by at least one contact pin 2a to 2n, such as an inferior-quality solder or a point of discontinuity.

The resistance can be specified for instance by the measuring device 4 being a general meter that measures the resistance. If the measured total resistance is equal to a pre-calculated target value, it may thus be stated that the connector is operational and the couplings intact. If a resistor Ra to Rn is connected to each contact pin 2a to 2n, only one measurement is required, allowing rapid verification of the connector 1. If the total resistance deviates from the target value, measurements may then be continued for instance one by one to locate the fault. However, most preferably at this point, the resistors are arranged in half of the contact pins, the parallel coupling comprising this number of resistor having a special calculated resistance target value. If the measurement result corresponds to said resistance target value, it may be stated that the fault is not at said contact pins. The resistance is then measured at the remaining contact pins continuously decreasing the number of resistors in the parallel coupling in the resistor network, until information exists about each contact pin whether or not it is operational. In such a solution, the resistance of each resistor may be equal, whereby the total resistance is sim- pie to calculate, it being the magnitude of the resistance of one resistor divided by the number of parallel-coupled resistors.

Still more preferably, the value of each resistor Ra to Rn is unequal. In this case, the measurement result can be used to immediately conclude the resistor Ra to Rn at which coupling point the fault lies. When studying for instance a coupling comprising four contact pins, for instance resistor values Ra = 1 Ω, Rb = 2 Ω, Re = 4 Ω and Rd = 8 Ω can be used. The resistance formed from the coupling, in this example denoted by Rtot, is given by the formula

— 1 + —1 + —1 + —1 = 1 . ( .1. .)

Ra Rb Re Rd Rtot

Placing the values of Ra, Rb, Re and Rd in formula (1 ) yields

- 1 + —1 + —1 + —1 = - 1

1 2 4 8 Rtotl

whereby the reciprocal of the resistance corresponding to the coupling 1 /Rtotl = 15/8, once the denominators of the sum factors are expanded to be the same. Thus, in this example, 1 /Rtotl corresponds to the reciprocal of the target value of the resistance of the coupling. Should the joint corresponding to contact pin 2b be faulty, the value of resistor Rb corresponding to contact pin 2b is infinite, whereby the situation corresponding to the coupling is, expressed by formula (1 )

1 ■ + —1 + —1 + —1 = ■ 1

1 oo 4 8 Rtot2

The reciprocal of the resistance of the coupling corresponding to this fault situation 1/Rtot2 = 11/8, since, in practice, 1/∞ is zero. The subtraction 1/Rtot1 - 1/Rtot2 yields 15/8 - 11/8 = 4/8 = ^Λ , whose reciprocal shows that the joint of contact pin 2b corresponding to resistor Rb = 2 Ω is faulty. In the previous example, the values of resistors Ra, Rb, Re and Rd were selected using binary coding, i.e. Ra = 2° = 1 , Rb = 2¹ = 2, Re = 2² = 4 and Rd = 2³ = 8. When the values of the resistors are selected using binary coding, one measurement only is enough to directly find out all faulty joints, since only one resistor combination can correspond to the resistance value, by which the resistance of the coupling deviates from the target value of the resistance of the coupling. Naturally, the values of the resistors may be selected to be unequal also in another manner, but in this case one measurement only is not necessarily enough to find out which joints are faulty, should the same connector comprise several faulty joints at the same time.

The drawing and the related description are only intended to illustrate the inventive idea. The details of the invention may vary within the scope of the claims. Consequently, the resistance between the star point 6 and the secondary side connector 3 may be specified in many different ways. The mul- timeter measuring the resistance directly and shown in Figure 2 can thus be used. Furthermore, it is possible to introduce a known direct current into the above-described coupling and measure the voltage difference generated over the coupling. In this case, the resistance of the coupling being the resistance of the parallel coupling formed by the parallel-coupled resistors, a voltage prede- termined according to Ohm's law

U=RI (2), wherein U is voltage

R is resistance and I is current,

is generated over the coupling. If the voltage differs from this, it is due to the deviation of the value of the total resistance and a conclusion may be made that the coupling measured from the connection is faulty.

Claims

1. A method of establishing the condition of a connector and the intactness of couplings, which connector (1) comprises contact pins (2a to 2n), one side of the connector (1) being connected to a point to which a secondary side connector (3) is connected, in which method the condition of the connector and the intactness of the couplings are established based on resistance measurement, characterized in that resistors (Ra to Rn) are arranged in a plurality of contact pins (2a to 2n) in the connector (1), one end of the resistors (Ra to Rn) being connected to a star point (6), the resistors (Ra to Rn) being coupled to form a parallel coupling, the resistance between said star point (6) and the secondary side connector (3) is calculated, the resistance conforming to a real situation is specified, and the specified resistance is compared with the calculated resistance for establishing the condition of the connector (1) and the intactness of the couplings.

2. A method as claimed in claim 1, characterized by a resistor (Ra to Rn) being arranged in each contact pin (2a to 2n) in the connector

(1).

3. A method as claimed in claim 1 or 2, characterized by a resistor (Ra to Rn) having an equal resistance value being arranged in each contact pin (2a to 2n).

4. A method as claimed in claim 1 or 2, characterized by a resistor (Ra to Rn) having an unequally sized resistance being arranged in the different contact pins (2a to 2n), the resistance between the star point (6) and the secondary side connector (3) in a normal situation and in any malfunction is calculated, and the specified resistance value is used to conclude the contact pin (2a to 2n) in connection with which the fault lies in any malfunction.

5. An arrangement for establishing the condition of a connector and the intactness of couplings, in which arrangement the connector (1) comprises a plurality of contact pins (2a to 2n), one side of the connector (1) being con- nected to a point to which a secondary side connector (3) is connected, characterized in that resistors (Ra to Rn) are arranged in a plurality of contact pins (2a to 2n) such that a first end of each resistor (Ra to Rn) is coupled to a contact pin (2a to 2n), seconds ends of the resistors being interconnected to a star point (6), the arrangement comprising a measuring device (4) for specifying the resistance between the star point (6) and the secondary side connector (5).

6. An arrangement as claimed in claim 5, characterized in that a resistor (Ra to Rn) is arranged in each contact pin (2a to 2n).

7. An arrangement as claimed in claim 5 or 6, characterized in that the values of the resistances of the resistors (Ra to Rn) are equal.

8. An arrangement as claimed in claim 5 or 6, characterized in that the values of the resistances of the resistors (Ra to Rn) are unequal.