DE1287131B - Electronic pulse counter arrangement for displaying the displacement of a movable part with respect to a predetermined position - Google Patents

Description

The invention relates to an electronic meter arrangement for displaying the displacement of a movable part with respect to a given one Position in which a counting pulse generator is used to generate a sequence of each counting pulses representing a given increment of movement of the moving part, a counting device, reversibly responsive to the counting pulses, for generating the mentioned display and an error detection system electrically connected to the counter to detect errors in the pulse train received by the counter is provided.

In principle, it is already known to use in a counter arrangement Generating a particular display, a reversible one responsive to the counting pulses Provide counting device. In the case of the electronic counter arrangement for displaying the Displacement of a movable part with respect to a predetermined position of the above A proper working method should be guaranteed and if necessary occurring faults can be determined.

The invention provides for an electronic meter arrangement of the above Type for displaying the displacement of the movable part with respect to a given one Provided that the fault detection system has a test pulse generator to normally one directly or indirectly for each counting pulse generated by the counting pulse generator Generate test pulse that the fault detection system further includes first and second fault detection devices each of which has its first interconnected inputs for receiving the counting pulses and has second interconnected inputs for receiving the test pulses, wherein the first fault detection means generates an output signal when during the period between the arrival of any two consecutive Pulses at the first input no pulse is received at the second input, and where the second fault detection device then generates an output signal if during the length of time between the arrival of any two consecutive ones Pulses at the second input no pulse is received at the first input.

According to a preferred embodiment of the invention it is provided that in a counter arrangement in which the counting pulse generator and the test pulse generator are located away from the error detection system, the counting pulse generator with said first inputs of the first and second fault detection devices connected via a first connection device exposed to electrical interference is and that the test pulse generator is electrically connected to the mentioned second inputs of the first and second locking devices via a second, in the same electrical Environment as the first arranged electrical connection is connected and that between one of the electrical connections and the first and second locking devices a time delay device is connected to correspond between the arrival - Induced in the first and second connection by a common source of interference - Noise signals at the first and second detection devices have a time delay to create.

According to a further embodiment of the invention it is provided that that differentiating devices are provided between one of the first and second electrical connections and the first and second locking devices and serve to generate a double pulse as a result of each noise signal, which is generated in the mentioned connections by a normal source of interference.

Furthermore, it is provided according to the invention that the differentiating devices between the second electrical connection and the first and second locking devices and that the test pulse generator generates one or more pulse trains, the square wave pulses included, from their leading and trailing edges by differentiating devices the test pulses are derived.

According to a further embodiment of the invention it is provided that the test pulse generator has two pulse trains that can be transmitted in parallel on the second electrical one Connection produces that the pulse trains mentioned have unit duty cycle have that their frequencies are a quarter of that of the counting pulse train and that the phases are shifted by 90 ° with respect to one another.

Another embodiment of the invention provides that the time delay device connected to the first electrical connection and any impulse received delayed for the duration of the pulse.

According to a preferred embodiment of the invention it is provided that the reversible counter has a plurality of identical first in cascade has switched ring counter and each has a plurality of stages that are annularly connected and sequentially operable to a first count to effect the pulses picked up by the counter, for each first ring counter Another ring counter is provided, which is connected to receive the pulses to which the first ring counter is responsive and which has a plurality of stages, which can be operated in succession to count a second count from the first ring counter to form received pulses, the number of stages of the first and the further Ring counter either the same or a part of the other step number increasing without a remainder is and wherein a coincidence gate is also provided, which upon arrival of signals - coming from the first and further ring counters and their count indicate - an output signal which indicates the counter status in the first ring counter, only generated when the counter readings in the first and further ring counters either are the same or differ by a counter reading that is a whole Is a multiple of the smaller of the step numbers of the two counters, where is finally a display device is provided which responds to an output signal of the coincidence gate responds and as part of the mentioned, caused by the counter arrangement display causes the counter reading contained in the corresponding first ring counter to be displayed.

Further advantages and details of the invention emerge from the Description of an embodiment of an electronic counter arrangement for Display of the position of a machine tool mounting plate; this embodiment is described below with reference to the two related schematic figures.

The drawing (FIGS. 1 and 2) shows a rotating pulse generator 10 mechanically coupled to a bearing plate 9; The pulse generator 10 has four output lines 11 to 14 which are connected via a long cable 15 to a logic circuit, which is referred to as a whole as circuit 16.

A bidirectional counter (bidirectional counter) 17 is located near the logic circuit and takes from the pulse generator 10 on the logic circuit and on a short line 18 coming counting pulses and causes - as described below - a visual display of the (currently) present displacement of the bearing plate with respect to a given position of the same.

The counter is controlled by the logic circuit, namely for Counting in a forward direction of counting by a transmitted over line 20 Signal and for counting in a reverse direction of counting by one in the same Way via a line 21 transmitted signal. The counter is reset by a signal coming from the logic circuit via a line 22.

The logic circuit 16 has a sign selector 24 connected to the lines 11 and 12 for receiving input variables. This sign selector has additional inputs for a counter reading zero detector 25 connected to the counter 17 and, via lines 26 and 27, for a selector switch 28 for the given sign (sign selector switch).

The sign selector 24 emits its output variable via one of the two lines 30, 31 to a counting direction controller 32, to which the lines 20 and 21 are connected. Two further inputs of the controller 32 are connected to the time delay circuits 33 and 34 , which are connected to the output lines 12 and 11 of the pulse generator 20, respectively. An OR gate 35 has two inputs connected to lines 11 and 12 via time delay circuits 33 and 34 and emits the output variable via line 18 mentioned above.

Within the logic circuit, differentiating circuits 36 and 37 are connected to lines 13 and 14, respectively, coming from the pulse generator 10 and emit their own output variables via an OR gate 38 to two error detection circuits 40 and 41. These circuits are connected to the outputs of the OR gates 35 and 38, respectively, and generate outputs for a reset drive device 42. The outputs of the device 42 are forwarded to the counting direction controller 32 and the line 22 mentioned above.

The bidirectional counter 17 has six stages connected in cascade, only two of which are shown for clarity. Each level has one Bidirectional decade ring counter 44 and a bidirectional pentad counter 45; the outputs of the counters of each stage are through a coincidence gate 46 with a Visual display device 47 connected.

In operation, the operator measures the initial displacement of the machine tool mounting plate in the stationary state with respect to a predetermined one given position and leads to any of the six or all six display devices 47 through the setting switch 48 for a given size a given number, which represents this shift. At the same time, the operator operates the sign selector switch 28 corresponding to the sense of the shift, i.e. H. on plus or minus with respect to the given position. The sign selector switch 28 accordingly generated according to the sense of the displacement on the line 26 or 27 a pulse signal which the sign selector detects.

The machining process is then started and the bearing plate moves with respect to its predetermined position. This movement is transmitted to the pulse generator, which consequently emits a chain (sequence) of counting pulses to the line 11 or 12 , which depends on the direction of movement of the bearing plate, taking into account the predetermined position. Each counting pulse of the pulse chain represents a predetermined increase (increment) in the movement of the bearing plate; this increment also determines the size of the predetermined counter reading which was previously set on the counter 17 by the operator - as described above.

The counting pulses are transmitted from the pulse generator 10 via the cable 15, the associated time delay circuits 33 and 34, the OR gate 35 and the line 18 to the counter 17. In accordance with each received counting pulse, the count displayed by the display devices 47 is changed by one.

The counting direction of the counter 17, ie the decrease or increase in the count, is controlled by the sign selector 24 together with the counting direction controller 32.

The sign selector 24 - as already described above - noted on which of the two lines 26 and 27 a pulse signal from the sign selector 24, corresponding to the original direction of displacement of the bearing plate from its predetermined position, had been received. Correspondingly and depending on which of the two lines 11 and 12 a counting pulse is received, the sign selector generates an output signal on one of its output lines 30 and 31 corresponding to the counting pulse Zero detector 25, a signal which transmits the output signal of the sign selector 24 from one line to the other line of the two lines 30 and 31, ie, assuming the counting pulse remains on the same line 11 or 12.

The counting direction controller 32 receives the signal generated in this way on one of the lines 30 or 31, and depending on which of the two time delay circuits 33 and 34 the counting pulse comes from, the counting direction controller 32 generates an output signal on one of the lines 21 or 22 to cause the counter to count in the direction associated with this count pulse. If the bearing plate moves away from its predetermined position in one direction or the other, the counter is caused to count upwards, that is, when counting, the counter reading increases; if the bearing plate moves in one direction or the other towards its predetermined position, the counter is made to count downwards, that is, the counter reading decreases when counting.

The time delay circuits 33 and 34 are designed such that they generate an output signal as a result of the occurrence of the trailing edge of each received counting pulse. The sign selector 24 thus has the entire duration of each counting pulse available for generating its output signal along the line 30 or 31 in accordance with the counting pulse.

During normal operation, as described above, delivers the electronic counter assembly provides the operator with a visual indication of the displacement of the bearing plate with respect to the position specified for the bearing plate. Through this, that the operator - as described - a desired before the machining process given. Can bring the counter reading into the counter, which can be done by the counter when the bearing plate is moved, the counter readings displayed immediately correspond to the Dimensions of the drawing (according to which the operator works) made equivalent will.

The electronic counter arrangement, of which so far only the counting process is subject to various possible sources of error that cause can that the counter 17 indicates an incorrect count; such a one Operation would call the machining operation into question. For example, a Result in a malfunction in an electronic component of the pulse generator 10, that a pulse is missing in the pulse chain or that an additional pulse is added will.

The circuit, the mode of operation of which is described below, has the devices 36 to 38 and 40 to 42 and indicates when such a fault has occurred and automatically clears the counter display and prevents further counting. The operator must then determine the true position of the machine support plate before processing can continue.

The pulse generator 10 generates in addition to that on one of the lines 11 or 12 generated counting pulse chain (as described above) two more »test« pulse trains on lines 13 and 14. These test pulse trains have a pulse duty factor of one, its frequency is a quarter of that of the counting pulse chain, and they are mutually shifted in phase by 90 °. In addition, the leading ones and trailing edges of the test pulses forming the chains are arranged in such a way that they coincide with the leading edges of the counting pulses.

The test pulses of the pulse trains on the lines 13 and 14 are differentiated after their transmission through the cable 15 by the corresponding differentiating circuits 36 and 37 and fed to the two error detection circuits 40 and 41 via the OR gate 38. In this way, as a result of the pulse trains generated by the pulse generator 10 on the lines 13 and 14 , the circuits 40 and 41 receive a single pulse train which is formed from short pulses which are carried out simultaneously with the corresponding ones from the lines 11 or 12 via the associated delay circuits 33 or 34 received counting pulses are initiated (generated).

The counting pulses are in each case delayed by the circuits 33 or 34, as described, until the corresponding short pulses passed through the OR gate 38 have ended, so that the counter error detection circuits 40 and 41 normally alternate short pulses (»short pulse «) and should receive counting pulses.

The error detection circuit 40 is set to a "prepared" state by each pulse received from the OR gate 35, usually a count pulse; each pulse received by the OR gate 38, normally one of the abovementioned short pulses, resets the error detection circuit 40 from its prepared state. However, when circuit 40 receives a pulse from OR gate 35 when it is already in its "prepared" state, it generates an output signal which is fed to reset driver 42. As a result of this signal, the device 42 then generates a signal on line 22 for clearing the counter display and at the same time causes the counting direction controller 32 to prevent further counting.

Similarly, the failure detection circuit 41 is made by each pulse received from OR gate 38 is set to a "prepared" state and reset by each pulse received from OR gate 35 if they are is in its prepared state. The circuit 41 then generates an output signal for the reset drive device 42, if they are already in their "prepared" State and receives a pulse from OR gate 38.

So it can be seen that a failure of the pulse generator at Generating a counting pulse causes the error detection circuit 41 to output an output signal to generate as the circuit 41 two consecutive short pulses from the OR gate 38 receives without an intervening count pulse to reset it. In appropriate Way causes an additional counting pulse generated by the pulse generator that the Circuit 40 generates an output signal. Therefore, in either case, the return drive device becomes 42 energized to clear the counter display and prevent further counting.

Another possible source of error to which the meter arrangement is exposed consists in noise signals on the lines 11 and 12, in particular when the cable 15 is long and is arranged in a noisy environment. The noise signals can be of such a sufficient size for the counter that it regards them as counting pulses and accordingly gives an incorrect indication. If such a noise signal should occur, then, depending on the phase of the noise signal with respect to the generated signals, either the circuit 41 alone is effective to generate an output signal (as a result of the double pulse generated by the differentiating circuits 36 and 37) or, alternatively, the circuits 40 and 41 successively effective for generating output signals. Accordingly, the counter display is again cleared and further counting is prevented.

The devices 36 to 38 and 40 to 42 thus work together to detect counting errors due to failure of the pulse generator 10 and interference on the cable 15 . These circuits also detect most of the counting errors caused by disturbances in the logic circuit itself.

The pentad ring counters 45 form together with the coincidence gates 46 another institution, by which an imprecise counting can be determined is; this is described below.

The actual bidirectional counter 17 has a conventional counting arrangement which has decade ring counters 44 and visual display devices 47. The basic mode of operation of the actual counter, namely to count the pulses received from line 18 and to display the count value on visual display devices 47, is known to the person skilled in the art and is therefore not described. In each counter stage, the decade ring counter 44 is connected in parallel with a pentad ring counter 45, which accordingly rotates cyclically at twice the frequency of the decade counter. The associated coincidence gate 46 receives the output signals of the two counters and forwards the output signal of the decade counter to the associated display device 47 only when the counter readings in the counters are either the same or differ by a count of five.

If, for example, one of the decade counters 44 does not respond to a received counting pulse or carry pulse (which may be the case), the counter reading difference between this counter 44 and the associated pentad counter 45 will no longer be zero or five, and the associated coincidence gate 46 will be the display prevent by the corresponding display device 47, so that 'the operator is made aware that a counter malfunction has occurred.

It should be noted that the meter arrangement described and shown in the drawing is only an example and that various modifications are possible. For example, the rotating pulse generator 10 is a commonly available device having the four outputs shown. The two pulse trains generated on lines 13 and 14 provide a suitable pulse source for testing the operation of the generator generating the counting pulses and for detecting noise signals on cable 15 (as has been described). It should be noted, however, that only one test pulse train would suffice if the frequency of this pulse train is half the frequency of the counting pulse train.

The delay circuits 33 and 34 in the embodiment shown generate a time interval between the transmission of the corresponding noise signals via the OR gates 35 and 38 and also give the sign selector 24 sufficient time, as a result of a counting pulse received on one of the lines 11 or 12 , a counting pulse corresponding to this counting pulse To generate signal on line 30 or 3'1: It should be noted, however, that if interference is not a problem, there is no time delay between. the counting and test pulse generator (or generators) and "the" error Fcststelischältungen. inserted in, uss; -the required phase setting of the counting and test pulses is generated by the generator or generators themselves.

The differentiating circuits 36 and 37 @ s` "" tn of the described Counter arrangement for changing the test pulses provided in such a way that they make it suitable for a comparison with the counting pulses. They create one too Double pulse for each noise signal induced on their lanes 13 and 14 and thereby ensure that at least the detection circuit 41 for generating of an output signal as a result of a noise signal induced in the cable 15 will. However, a differentiating circuit between the pulse generator and the error detection circuitry in the or in each counting pulse line instead of, as shown, in the or in each test pulse line. One Such an arrangement would of course suitably generate counting and test pulses make necessary. In a further training in which the interference forms no problem, there is no differentiation effect in either the counting or the test pulses intended.

Although the described counter arrangement as a decade counter (with 10 Levels) trained "counting" counters and trained as pentad counters "with 5 levels" Has "checking" counters, it should be noted that each of the counting counters could have any desired number of stages greater than one; where the step numbers of counting counters and checking counters by any multiple (including one) connected; however, the multiple must be an integer. That everyone The coincidence gate assigned to the counting counter and the checking counter is designed in such a way that that signals from the counting counter can only pass through if those in the two Counters contained counter readings are either the same or different Step numbers of the counters, if the counter readings differ by a counter number, which is an integral multiple of the smaller number of stages in the two counters. If the counting counters are designed as decade counters, they have testing counter a count of five as described, or ten or twenty, etc. Stages.

In the embodiment shown in the drawing, for each Level-checking counters and coincidence gates provided. It should be noted, however, that it may also be sufficient to provide these devices only for those stages those with, for example, the last four identifying digits of the visual display are connected. The errors that occur with the identifying digits are usually for the operator through normal direct viewing of the machining process apparently.

The meter arrangement shown and described is not limited to generation a visual display of the position of a machine tool bearing plate limited, but can be used to 'generate a visual or' other indication of the position-of any movable or rotatable part and also to control such Partly be used.

Claims (7)

.:. "Paternity claims: 1. Electricity counter" Display of the displacement of a moving part with respect to a given position, in which a counting pulse generator for generating a sequence of one predetermined each Counting pulses representing the movement increment of the moving part, one reversible counting device responsive to the counting pulses for generating the mentioned display and an error detection system electrically connected to the counter Detection of errors in the pulse train received by the counter is provided, characterized in that the error detection system a test pulse generator to normally direct or indirect for each the counting pulse generated by the counting pulse generator to generate a test pulse that the Fault detection system further comprises first and second fault detection devices, whose first interconnected inputs for receiving the counting pulses and has second interconnected inputs for receiving the test pulses, wherein the first fault detection device then generates an output signal if during the length of time between the arrival of any two consecutive ones Pulses at the first input no pulse is received at the second input, and where the second fault detection device then generates an output signal if during the length of time between the arrival of any two consecutive ones Pulses at the second input no pulse is received at the first input. 2. Counter arrangement according to claim 1, characterized in that in a counting arrangement in which the counting pulse generator (10) and the test pulse generator (10) are arranged remotely from the error detection system, the counting pulse generator (10) with said first inputs of the first and second error detection devices ( 40, 41) is connected via a first connection device (11, 12) exposed to electrical interference and that the test pulse generator (10) is electrically connected to the mentioned second inputs of the first and second locking devices (40, 41) via a second; is connected in the same electrical environment as the first arranged, electrical connection (13,14), and that between one of the electrical connections (11,12; 13,14) and the first and second locking means (40, 41) a time delay means ( 33, 34) is connected in order to generate a time delay between the arrival of corresponding noise signals - induced in the first and second connection by a common source of interference - at the first and second detection devices. 3. Counter arrangement according to claim 2, characterized by differentiating means (36, 37) between one of the first and second electrical connections and the first and second locking device (40, 41) and serve to generate a double pulse as a result of each noise signal, which is generated in the mentioned connections by a normal source of interference. 4. Counter arrangement according to claim 3, characterized in that the differentiating devices are used (36, 37) between the second electrical connection (13, 14) and the first and second locking devices and that the test pulse generator (10) one or generated several pulse trains containing square wave pulses from their leading and trailing edges by differentiating devices (36, 37) the test pulses be derived. 5. counter arrangement according to claim 3, characterized in that the test pulse generator has two pulse trains that can be transmitted in parallel on the second electrical one Connection produces that the pulse trains mentioned have unit duty cycle have that their frequencies are a quarter of that of the counting pulse chain and that they are phase shifted by 90 ° with respect to one another. 6. Counter arrangement according to one of claims 2 to 5, characterized in that the time delay device (33, 34) is connected to the first electrical connection (11, 12) and each recorded impulse delayed for the duration of the impulse. 7. Counter arrangement according to one of the preceding claims, characterized in that the reversible counting device (17) has a plurality of identical first cascaded ring counters (44) and each has a plurality of stages which are connected in a ring and are operable in succession to a first To effect counting of the pulses received by the counter, a further ring counter is provided for each first ring counter, which is connected to receive the pulses to which the first ring counter responds and which has a plurality of stages which can be operated in succession to one To form a second count of the pulses received by the first ring counter, the number of stages of the first and the further ring counter either being the same or a part of the other number of stages rising without a remainder, and furthermore a coincidence gate (46) being provided which, when signals arrive - the from the first and further ring counters ko mmen and their counter reading - an output signal which indicates the counter reading in the first ring counter is only generated when the counter readings in the first and further ring counters are either the same or differ by a number that is a whole multiple of the smaller of the number of levels in the two counters is, finally a display device (47) is provided which responds to an output signal of the coincidence gate and, as part of the above-mentioned display effected by the counter arrangement, displays the counter reading contained in the corresponding first ring counter.