Patent GB-798571-A (GB)
Title: Apparatus for testing and controlling electrical circuits
IPC: G01R31/3193
Filed: 1954-12-17
Abstract: 798,571. Sequestial testing. SKILLMAN & CO., PTY., Ltd., T. S. Dec. 17, 1954 [Dec. 30, 1953; Feb. 22, 1954; Feb. 22, 1954; March 8, 1954; July 14, 1954], No. 36603/54. Class 37. [Also in Group XXXIX] A device for controlling the application of a number of tests in succession to a piece of apparatus and for applying one or more tests to a number of similar pieces of apparatus in successicn is adapted for use with a wide variety of tests on apparatus of different kinds by controlling its programme of operations by a record such as a punched or magnetic strip which is fed through the device during the progress of the tests. In the device described, a four-unit two-state code is used for selecting the various testing circuits and functions together with a "space" " signal in a fifth position on the tape operative to cancel any other signals in the same row and so to cancel punching errors. Each group of perforations or digit has any value from 1 to 15 and, in general, circuits and tests are selected by two- and three-digit groups. As shown, there are 8 groups of 15 terminals 1-1 to 8-15, Figs. 8, 9, to which the apparatus under test is connected and one terminal in one or more groups can be connected to any of 7 common test trunks TC1-TC7 to which test conditions in accordance with a further selection can be applied. All the terminals can be tested in turn for a ground connection by a uniselector US and further uniselectors can be controlled to test telephone channels in succession. Two testsets can be interconnected by a ten conductor line to enable a programme tape at one station to control the performance of tests at a remote station. Keys are provided to enable the four-unit code signals to be sent manually. Two tape-transmitters may be arranged so that one is concerned with the successive connection of the pieces of apparatus and the other with the succession of the tests. The terminals 1-1 to 8-15 can also be used for associating auxiliary apparatus with the routiner. For instance a group of uniselectors can have their wipers associated with the routiner over one set of terminals can be controlled over another set to connect the idle-channels of a group to the routiner for testing and to register, for subsequent testing, the channels found busy. Control of transmitter; selection of apparatus and tests. When the device is switched on, relay WX, Fig. 3, operates and locks up followed by WZ. On the momentary operation of a start key K2B, WR pulls up and locks releasing WX. WY then pulls up bringing down WZ, whereupon WX pulls up again WY falls and WZ pulls up. This action is repeated indefinitely, ground being applied to the tape feeler contacts XMA-XME, YMA-YME in the interval between the relapse of WX, WZ in each cycle and an impulse being given to the tape stepping magnet TMX, or TMY in the interval between the operation of WX and the relapse of WY. The first digit in each group operates a combination of register relays PAPE, Fig. 12, which lock up and energize one of the group selecting relays 1AG-13AG. When next WY falls, a first change-over relay PP is cut into the locking circuit of the register relays and switches the code wires to the 4-relay selector TA-TE, Figs. 14, 6 and 7, as selected by the operated AG relay..These relays are operated in accordance with the second digit and QP, which is operated over one or more of its windings in parallel with the selector relays unlocks a normally energized relay RY. Consequently, when QP falls, a second change-over relay RP is operated and locks up and switches the code wires to the third digit selector FAFY in the chosen group. The next signal is a space which operates PC only. This unlocks the first digit register and consequently the relay AG and also the change-over relays and RY pull up again. The circuit is thus ready for a new set of signals and assuming that one of the relays 1AG-8AG was operated, one of the terminals of the chosen group selected in accordance with the second digit is now connected to one of the common trunks TC1-TC7 selected in accordance with the third. Relay 9AG connects up a similar set of relay selectors, but these are concerned with the tests to be applied to the selected circuits. To substitute manual keys K3A1-K7A1 for the transmitters, K2A is operated to switch over the connection and release WR. Lamps A-E show the code-signals keyed or set up on the tape and lamps 1DL-3DL show the order of the digit in the sequence. Further functions are controlled by selectors 10TA-10TE and 13TA-13TE connected up by 10AG and 13AG, the latter group providing for the grounding of any one of the terminals 13-1 to 13-15. A single digit 11, energizes TOK, RZ to release all the selector relays. To release only the relays of one group, its relay AG is operated and then released by the transmission of a space signal. The routiner can be stopped by operating key K4B to hold WX. Digits may then be sent slowly by means of key K3A, each operation and release of which causes the transmission of a digit and the stepping on of the tape. The tape can be stepped on without transmitting a digit by means of key K5B. Key K7B disconnects battery from all parts of the routiner and from the apparatus under test. Testing for presence or absence of ground or battery and for an adequate A.C. path on a selected line. One of the 120 outlets is connected as described above to the test trunk TC7 which is jumpered to a wire which can be connected to battery or ground via relay TTR, Fig. 4, or to an A.C. source via relay TAC by the relays 9TA, 9TB of the test group selected by 9AG. If the expected condition is such as to energize TTR, the operation of that relay energizes TOK. If the expected condition should not energize TTR then its energization prevents the operation of TOK, the effect being looked after by the relays of the test selector. TAC exercises a similar control. If the second digit was such as to operate RZ, the operation of TOK by a successful test unlocks all the selectors of the groups 1 to 8. In other cases the effect is determined by the second digit received by the test group as registered by the relays 9FA-9FD. For digits from 1 to 6, the operation of TOK merely allows the test to proceed and for digit 7 causes the operation of XA, XC to switch on the second transmitter. If the relay TOK fails to operate and the digit was 1, WX is held to stop the test until K2B4 is operated to release it. With digit 2, DT operates and locks releasing the final selector relays. The transmitter continues to advance, acting now merely as a timer and the test condition is maintained. If TOK operates, DT is released at once. If it fails to operate, DT is released by the operation of RZ when the transmitter sends 98 to terminate the test. The test is indicated as a failure since TKL does not light. With digits 3 and 7 PCR is operated if the test fails and switches the tape signals to a printer on terminals EA-EE. With digits 4 and 5 relays 1ET, 2ET respectively are energized. These disconnect all the AG relays and so prevent the selection of any more tests until digit 14 (or 15) is transmitted, whereupon the first digit register relays unlock 1ET or 2ET and the test is resumed. Third digit 6 causes the operation of XA which holds in series with XC after the relapse of 9AG has released 9FB, 9FD, &c. Relay XC is disconnected by transmitting 13, 10 and then a space. XA is unlocked by XB and then XB, XC fall. Testing apparatus for short-circuits. This is done by connecting ground to one point in the apparatus, testing a number of other points for ground and counting the number of points at which ground is found. The existence of any short-circuit will give too high a value to this number. Transmission of 10, 14 energizes HU, Fig. 1, to home a uniselector US and 13, 12 grounds point 13-12 to operate SCR which locks up and energizes TTR. The sender now sends a 3-digit number to connect trunk TC5, which is grounded, via a jumper (not shown) to the selected point of the apparatus under test and also to extend one of the code pulses via SCR, Fig. 7, to magnet US to step on the uniselector. Off-normal relay SCT then operates and connects TTR to the wiper US2 which is on a grounded terminal so that TTR is held. SCT also arranges for the pulses provided by interaction of WX, WY, WZ to be delivered to the magnet US and makes the stepping of the transmitter dependent on the continued energization of TTR. US thus steps over the whole of its bank, but the transmitter only takes a step for each terminal, over which ground is found. When the transmitter has taken a number of steps equal to the correct number of grounded points, it sends the digit 11. If the apparatus is in order, US will be in its normal position and SCT will have fallen back by the time that the transmitted digit operates PA, PB, PE and in consequence, TOK, RZ are operated to indicate a successful test. If, however, the off-normal relay is still operated, the register relays hold WX to prevent further stepping and the test has to be restarted by the key K2B. Testing current consumption. The apparatus under test may receive its power supply from terminal B2. Test code 9, 4, 1 operates TY to remove a short from TZ which operates if the current is excessive and prevents the operation of TOK. The routiner then stops as with other tests. If TOK operates, the test proceeds. A marginal relay ZB, operated in the case of excessive current drain, inserts TZ in the circuit and gives visible and audible warning. Auxiliary controls for undescribed tests. The relay group connected up by 10AG in addition to the functions described above in connection with testing for short circuits can also be used to energize relays 1BR, 2BR, 3BR, 4BR for making connections, the effect of which is not described to various terminals AP1-AP14. With the aid of a slow-to-release relay BS, a fleeting connection between AP10 an