DE1209196B - Arrangement for determining the coincidence and the sign of the difference between a predetermined nominal value and an existing actual value - Google Patents

Description

Arrangement for determining the coincidence and the sign of the Difference between a specified target value and an existing actual value In The U.eßtechnik occurs very often the task of a certain element in the course to bring the measuring process into predetermined positions. It can be predetermined Acting positions of displacement or rotation of such an element.

For this purpose, the element to be moved or rotated expediently provided with a device that its respective position, the so-called Actual value, displayed digitally. The existing element is then used to move the element Compare the actual value with the specified target value (reference variable), and it is from this comparison, which results in the so-called control deviation, a variable derive which moves the element into the specified position. Once this is reached, the control deviation becomes zero, i.e. i.e., there is coincidence between Actual and target value.

There are various methods known with the help of such a Position control can be made. It is known, for example, the system deviation to be determined in a computing circuit by forming the difference according to amount and sign. With this method, the actuating speed is dependent on the amount of Control deviation regulated so that the coincidence position is reached quickly and not is overrun. However, this method has the disadvantage that it is a very laborious one Switching presupposes.

It is also known that only this is the case with simpler position controls Sign of the difference between the target value and the actual value as well as the coincidence ascertain. Since nothing is said about the size of the control deviation, it is not possible to adjust the control speed before reaching the coincidence position to change. In this case, one speaks of a shutdown control, since when it is reached the coincidence position the positioning movement is switched off. Here are only relative Low standing speeds applicable if one overflows over the coincidence position avoid or at least keep it very small.

But there are also many applications in which the Coincidence does not interfere. Here, therefore, with a view to the necessary Effort with advantage an arrangement used, which only the coincidence as well as the Determines the sign of the control deviation.

The previously known arrangements of this type, generally known as Position comparators are called, use the known, certain mathematical Logical linking elements that obey laws, such as B. "And" - or "Or" terms. In such arrangements, however, the advantage of standardizing the assemblies must can sometimes be bought at a very high cost. It is now the goal of the present Invention to create an arrangement that requires only a relatively small effort requires.

The present invention thus relates to an arrangement for determining the coincidence and the sign of the difference between a given one Target value and an existing actual value, d. H. thus a circuit for a position comparator. This circuit does not contain any of the usual logic elements, but rather makes use of a completely different technique, using mainly passive ones Elements. Above all, it has the advantage that in addition to the clarity of the Function a particularly low number of components is required, reducing the probability of failure is reduced and a very compact structure is possible.

The arrangement according to the invention is characterized in that both the 1-out-of-10 code is used for entering the actual value as well as the target value and accordingly ten separate inputs are provided that two of each eight diodes connected in series, oppositely acting diode chains are provided, one to the negative difference and the other to the an output indicating a positive difference results in the nine terms of the to the positive output via a chain of diodes from the actual to the target value input active diode to inputs 0 to 8 of the actual value input and via one in the same Directional diode connected to the corresponding inputs of the setpoint input are and that the nine terms of the for leading to negative input Diode chain in the same way, each via one from the actual to the target value input Working diode connected to inputs 1 to 9 of the actual and target value input are. Between each actual value input and that of the link points of the diode chains Dicden leading to him a resistance is switched on.

The arrangement according to the invention is therefore only made up of diodes and Resistors, d. H. thus built exclusively from passive components. this means that it is relatively cheap to manufacture and because of the small number elements of the same type can also be built up in a very limited way.

As the above statements show, with the new arrangement both The 1-out-of-10 code is used for entering the actual value as well as the target value. on This code is located on the actual value page, provided that the actual value is displayed using a numeric display takes place before. Is the setpoint value through a keypad or a selector switch specified, which is the case, for example, with sorting devices, is also the case here the 1-out-of-10 code is available. In this case, the effort is particularly low. Come other encodings, e.g. B. when entering perforated tape, these can easily be converted into the 1-out-of-10 code to convict. This requires less effort than if z. B. a code with 4 bits must be converted into another with 4 bits as well. The proposed Using the 1-out-of-10 code for position comparators is therefore particularly advantageous.

With the new arrangement, the actual signal arrives when the coincidence is present from the respective actual value input via the between this input and the associated Setpoint value input arranged diodes directly to this, and at none of the outputs a signal appears. This case can be converted into the coincidence statement using a Nor gate be transformed.

In all other cases, i. H. if there is a difference between Actual and target value only gives a signal to one of the diode chains, namely according to the sign of this difference at the one to the positive or that to the negative Output leading diode chain. The signal reaching the other diode chain is activated via the closed switch at the respective setpoint input Zero derived.

The arrangement described here is used to determine the coincidence as well as the sign of the difference between target and actual value for a single digit Decimal number. Should be the sign of this difference for multi-digit decimal numbers are determined, one of the arrangements described is for each decimal place necessary. The outputs of all these arrangements must now, as known, through a circuit can be evaluated in such a way that only the highest is ever used for the overall statement Decimal place is used in which there is a sign statement. this will advantageously caused by the fact that the outputs of the first through (n-1) -th arrangements are each connected to switches via a diode, the outputs of the second to the n-th arrangement are each assigned a switch which, if there is a Signal in one of the outputs of the associated arrangement connected to it Put diodes at zero potential and thus the outputs of the preceding decimal places makes ineffective. Apart from the switches are also only in this arrangement Diodes, d. H. so passive circuit elements are used. All exits are each connected via a diode to a positive or a negative overall output, so that from the highest decimal place at which a sign statement is present, the signal supplied appears at the associated overall output.

It is advantageous to design the switches mentioned as transistors, which each have the mentioned diodes with all outputs up to a certain one Decimal place and which are connected via the output of the following decimal place being controlled.

The arrangement according to the invention can not only be used in that mentioned above Way can be used in metrology, but it offers a variety of other Possible applications.

So it is possible to use the arrangement to distinguish a multitude to use existing actual values according to size classes. For example, this problem occurs in sorting devices, which are used to test workpieces for their dimensional accuracy to serve. Such facilities can be used to match workpieces to classify their dimensional accuracy in different quality classes and / or outside Sort out workpieces lying within a more or less wide tolerance interval. With the aid of the arrangement according to the invention, such sorting devices can be used build in a particularly simple manner.

The arrangement according to the invention and some application examples will be in the following with reference to FIG. 1 to 6 of the drawings explained in more detail. It shows F i g. 1 the circuit diagram of the arrangement for determining the coincidence and the sign the control deviation for one decimal place, F i g. 2 one equipped with transistors Target value input, by means of which a lead or lead present as a potential Target size in the arrangement according to FIG. 1 can be entered, FIG. 3 a circuit for evaluating the outputs of four according to FIG. 1 assembled arrangements, F i g. 4 one using the in F i g. 1 shown arrangement constructed device for testing workpieces for their dimensional accuracy, F i g. 5 one using the in F i g. 1 shown arrangement constructed device for the classification of Objects to be measured in an arbitrarily large target value range; F i g. 6 one using the in F i g. 1 shown arrangement constructed device for the classification of Measurement objects in several size classes.

In Fig. 1, the actual and target value inputs are each with 0 to 9 designated. The setpoint inputs lead to the zero conductor marked M, while the actual value inputs are connected to a device, which for example a digital statement in the 1-out-of-10 code from the position of any element derives.

Two chains of diodes made up of eight diodes each are provided, wherein the chain made up of the diodes 50 to 57 leads to the output E6, while the chain made up of diodes 58 to 65 leads to output 67. One to the exit Signal reaching 66 shows a positive difference between the actual value and the setpoint value on, while a signal coming to output 67 is negative difference indicates. No signal at both outputs 66 and 67 indicates the presence of coincidence at.

The nine links in the diode chain 50 to 57 are above the diodes 68 to 76 with the interposition of a resistor 105 with the actual value inputs 0 to 8 connected. At the same time, these link points are connected via the diodes 77 to 85 connected to the setpoint inputs 0 to 8. The terms of the Diode chain 58 to 65 via diodes 86 to 94 with the actual value inputs 1 to 9 and connected to the nominal value inputs 1 to 9 via the diodes 95 to 103. The diodes 68 to 103 each act in the direction from the actual to the setpoint input.

The setpoint input is shown in the illustration in FIG. 7. through the keypad symbolized by the switch 104 is formed. In the representation the F i g. l the switch corresponding to input 4 is closed while all other switches are open (1-at1S-IO code).

In each case one actual value input comes from the one that records the measured value Set up the information in the form of a low resistance to resistor 105 negative voltage. There is zero potential at all other inputs.

To explain the mode of operation of the circuit according to FIG. 7 it should be assumed that the number 4 is keyed in on the nominal value page. This means that switch 104 corresponding to input 4 is closed. If the (negative) signal labeled L now arrives at the actual value input 4, it arrives via the diodes 71, 100 and 72, 81 in addition to the closed setpoint value input 4. This is indicated by the solid arrows. In this case, a signal does not appear on either of the two diode chains, so that a signal does not appear either at input 66 or at input 67. This case can, for example, be converted into the coincidence statement using a Nor gate.

If the actual value 7 is present, then the signal L arrives at input 7 The signal reaches the upper Dicden chain via diode 75 and overflows there the diodes 56, 55 and 54 to diode 81. This is via the closed switch the set value input is connected to zero potential so that the signal as through the dashed arrows indicated, is derived from zero. This signal arrives at the same time via the diode 92 to the lower chain of diaths. Since none of the setpoint inputs 7 to 9 is closed, the signal arrives at output 67 and shows a negative Sign of the difference. The signal runs accordingly when shown If the actual value corresponds to a number greater than 4.

If the actual value corresponds to the number t, Co appears at input 2 the signal L, This reaches the lower diode chain via the diode 87, which short-circuited to zero via the diode 100 connected to the closed switch is. As a result, the signal reaching the lower biod chain overflows the diodes 64 and 63 from zero. At the same time, the signal arrives via the diode 70 on the upper diode chain and flows there via the diodes 51 and 50 to the output 66. This indicates a negative difference. The same case occurs with the in F i g. 1 assumed example always occurs when the actual value of a number is smaller than corresponds to 4.

Is in place of the in F i g. 1 depicted keypad the target value as potential, s3 are expediently those shown in FIG. 1 switch 104 shown by the in F i g. 2 replaced transistors 106 shown. Their collectors 107 are connected to the nominal value inputs, while the emitters 108 are connected to the Neutral conductors M are connected. The transistor switch is activated via the line 109 leading to the base controlled. The in F i g. 2 is mainly used when the nominal value signal is supplied by a transcoder.

In Fig. 3 are with 110, 111; 112, 113; 114, 115 and 116, 117 the Outputs of four different, each according to FIG. 1 constructed arrangements referred to. The inputs 110, 111 correspond to the first decimal place, while the inputs 116, 117 correspond to the fourth decimal place. All positive inputs are over the diodes 118 to 121 are combined to form the overall positive output 126, while the negative individual inputs via diodes 122 to 125 to the negative overall output 127 are merged.

A transistor is designated by 128, the collector of which is connected to the diodes 129 and 130 connected to the inputs 110 and 111. The emitter of the transistor is connected to the neutral conductor marked M. Two diodes 131 and 132, which are connected via a resistor 133 to the base of transistor 128 which is at positive potential, are arranged between inputs 112 and 113. If a signal occurs at the output 112, it reaches the base of the transistor 128 via the diode 131 and the resistor 133 and makes this transistor conductive. The outputs 110 and 111 are then connected to zero potential via the diodes 129 and 130. As a result, when a signal is present at output 112, no signal from outputs 110 or 111 can reach overall output 126 or 127. When a signal is present at output 113, transistor 128 becomes conductive via diode 132 and resistor 133.

The transistor 134 is connected via the two between the outputs 114 and 115 located diodes 139 and 140 controlled and conducts if necessary, i. H. when a signal is present at output 114 or 115 via diodes 135 to 138 the signals appearing at the outputs 110 to 113 decrease to zero.

The mode of operation of the transistor 141, which through the diodes 148 and 149 located between the outputs 116 and 117 are controlled will. This transistor conducts the signals via the diodes 141 to 147, if necessary at all outputs of the preceding decimal places to zero.

In the case of the in FIG. 3 distribution of the signals at the inputs 110 to 117 becomes the transistor 141 by the signal L appearing at the input 116 conductive, so that all other inputs 110 to 115 be placed at zero potential. As a result, a signal appears at output 126, which indicates a positive difference.

Between the outputs 126 and 127 there is a conventional one Transistor unikehrstufe 150 arranged, which via the diodes 151 and 162 with the Outputs 126 and 127 is connected (Nor gate). Neither occurs at exit 126 nor a signal at output 127, the inverter 150 delivers this at output 153 Coincidence signal.

As is readily apparent, the circuit according to FIG. 3 can be expanded to any number of decimal places. Then there are only more Switches and dissipators required. It should also be mentioned that a structure of the in F i g. 3 with the circuit shown in the logic Circuit technology common elements is much more complex than that in F i g. 3 circuit shown.

F i g. FIG. 4 shows a device for testing workpieces for their dimensional accuracy, which is carried out using the methods shown in FIG. 1 is constructed. This arrangement is shown in FIG. 4 the reference number 155 and will be referred to below as a position comparator. With 157 a device for digital recording of measured values is designated, which measures the parts to be tested and delivers a digital signal characterizing the measured value. The reference value input is denoted by 156, which can consist, for example, of a keypad or selector switches. If one of these keys is pressed, a certain tolerance value is specified. The measured value is now determined for each workpiece by means of the device 157, and the position comparator 155 decides whether the measured value (actual value) is greater, less than or equal to the setpoint value. If the difference between the setpoint and the actual value is negative, a signal is sent to device 158, which indicates that the workpiece is "too big". This device can also be used to set a switch via which the workpiece is transported into a specific container. If the difference between the setpoint and the actual value is positive, a signal is sent to the device 159, which indicates that the workpiece is "too small". If the position comparator 155 does not supply a signal, this statement is converted into a signal by means of the NOR gate 160, which is sent to the device 161. This signal indicates that the workpiece is "in tolerance".

As a rule, the target value is not only given a certain value, but assign a size range. As long as this range has one decimal place does not exceed, only one position comparator is required, and at To enter the target value, press several keys at the same time. The tolerance range is then determined by the number of set value keys pressed.

In the facility according to FIG. 5, two position comparators 162 and 163 are used. By means of the set value input 164 is the upper tolerance value z. B. Enter the value 40. By means of the device 165, the lower tolerance value, for. B. Enter the value 20. The device for digital recording of measured values is again designated by 157.

If the measured value (actual value) is greater than 40, the position comparator 162 emits an L signal at the output labeled -. As a result, the device 166 responds, which indicates that the test object is "too large". If the measured value is less than 20, the position comparator 163 sends an L signal to its output labeled +. As a result, the device 167 responds, which indicates that the test object is "too small". If, on the other hand, the measured value is between 20 and 40, none of the used outputs of the position comparators 162 and 163 responds, and the Nor gate 168 determines an L signal from this statement, which is fed to the device 169. This indicates that the DUT is "in tolerance".

As shown in FIG. 5, only one output is used by the position comparators 162 and 163, so that these position comparators only need to contain one diode chain. When setting up according to F i g. 6, four position comparators 170, 171, 172 and 173 are used. Devices for inputting nominal values are designated by 174 to 177, while the device for digital recording of measured values is again designated by 157. The position comparators 170 to 173 are each provided with an output indicating a negative and a positive difference signal and a coincidence output. Each position comparator is constructed in the same way as the switching arrangement according to FIG. 1, although a Nor gate is also provided, which supplies the coincidence statement.

178 to 180 are AND gates and 181 to 183 OR gates. 184 denotes a device which indicates that the test object is "too small", as soon as a signal is fed to it. Accordingly, the device 185 indicates that the test object is "too big". With 186, 187 and 188 facilities are designated, which different size classes of the objects to be measured are assigned.

To explain the function of the device according to FIG. 6 assume that via the target value inputs 174, 175, 176 and 177 the target values 10, 20, 30 and 40 are entered. If a measurement object now has a dimension that is less than 10, in this way, a occurs at the output of the position comparator 170 labeled + Signal which is fed to device 184 and consequently indicates that the DUT is "too small". The outputs marked with -; - deliver at the same time the position comparators 171, 172 and 173 a signal, but these signals only get to the AND gates 178 to 180.

It is assumed that the measurement object has a dimension which corresponds to the digital value 28 corresponds to the output of the position comparator labeled - 171 and the output labeled -f- of the position comparator 172 is a signal which is fed to the device 187 via the AND gate 179 and the OR gate 182 will. As is easy to verify, this device indicates that the DUT has a dimension which corresponds to the digital values between 20 and 29. That with this one Measurement of the output of the position comparator 170 labeled with - and the with -f- labeled output of the position comparator 173 arrives only up to the AND gates 178 or 180. Accordingly, only the device speaks 187 at.

If it is assumed that the measurement object has a dimension which corresponds to the digital value 20, then the coincidence output of the position comparator 171 supplies a signal which reaches the device 187 via the OR gate 182. All other signals delivered simultaneously by the position comparators 170, 172 and 173 only reach the AND gates 178, 179 and 180.

As can be seen immediately after this explanation, shows the Means 186 indicates that the measurement object has a dimension which is a digital value between 10 and 19, means 187 indicates that the dimension is between 20 and 29 is while the device 188 indicates that the dimension is between 30 and 39.

When setting up according to F i g. 6, the objects to be measured are divided into three different Classes classified. In a similar way, facilities can be built that make a classification in any number of adjustable classes. As without further ado can be seen one more position comparator is always necessary, as classes are desired.

The in F i g. 6 device shown can also be advantageous in digital Controls or regulations are applied. You can go here for signaling different approaches to the target value are used. With a point control For example, the approach areas decide on the delivery speed, d. H. whether to drive with high speed, pre-creep or creep speed. A subdivision of measured values into areas or classes is sometimes also possible with two-stage Measuring systems necessary, where the fine measuring system, if necessary, at the zero crossing the coarse measuring system must correct.

Claims (7)

Claims: 1. Arrangement for determining the coincidence as well the sign of the difference between a specified target value and an existing one Actual value, characterized in that for both the actual and the nominal value input the 1-out-of-10 code is used and therefore ten separate inputs are provided are that two consisting of eight series-connected diodes, opposite acting diode chains (50 to 57 or 58 to 65) are provided, one of them to the one indicating a negative difference and the other to the one indicating a positive difference Output (66 or 67) results in the nine elements of the leading to the positive output Diode chain in each case via a diode (68 to 76) with inputs 0 to 8 of the actual value input and via one in the same Directional diodes (77 to 85) with the corresponding inputs of the set value input are connected and that the nine term points of the leading to the negative input. Diode chain in the same way, each via one from the actual to the target value input Active diode (86 to 94 or 95 to 103) with the inputs for the actual and setpoint input are connected. 2. Arrangement according to claim 1, characterized in that between each actual value input and those leading to it from the link points of the diode chains A resistor (l05) is switched on. 3. Arrangement according to claim 1 and 2, characterized in that each setpoint input is provided with a transistor (106) is connected, with one of the transistors as closed when entering the desired value Switch works. 4. Arrangement for determining the coincidence and the sign the difference between a specified target value and an existing actual value for n-digit decimal numbers, characterized in that for each decimal place an arrangement constructed according to claims 1 to 3 is provided that the outputs of the first to (ra-1) -th arrangements each via a diode with switches are connected, the outputs of the second to n-th arrangement in each case a Switch is assigned to the when a signal is present in one of the outputs associated arrangement puts the diodes connected to it at zero potential and so that the outputs of the preceding decimal places make ineffective that all positive ones and all negative outputs of the arrangements each via a diode with a positive or negative overall output are connected and that an arrangement is provided, which supplies a coincidence signal in the absence of a signal in one of the overall outputs. 5. Arrangement according to claim 4, characterized in that each of the switches as Transistor is formed, whose collector with the diodes and its emitter with Zero potential is connected, and that the outputs of the associated arrangement over in each case one diode acting in the direction of the transistor base is connected to it are. 6. Arrangement according to claim 4, characterized in that between the total outputs a transistor reversing stage is arranged, each one in the direction of the step input acting diode is connected to the outputs. 7. Arrangement according to claims 1 to 3, characterized by the application to distinguish one Large number of available actual values according to size classes. B. Arrangement according to claim 7, characterized by the application in a for testing workpieces for their Sorting device serving dimensional accuracy. Considered publications: VDE book series, Vol. 8, "Digital signal processing in control technology", published 1962 in VDE-Verlag, Berlin, pp. 173 to 175.