DE1623794C3 - Digital position measuring device - Google Patents

Description

) The invention relates to improvements to the Digi-Posilionsmeßvorrichtung, which is described in the German ent 14 98 173.

The subject of the main patent is a digital positioning device for the knife «the adjustment of a · moving part with respect to a fixed part with an internal counter whose in AnaU> gforn converted digital content continuously with a dii actual position of the moving part) Analogue is compared to an error signal /. deliver, which controls the supply of counting pulses in the counter, the counter optionally under different Payment speeds depending on the de: speed of the moving part can work

In the according to the embodiment of the main pa tents described Digilal position measuring deviceuii} the analogy and the production of the error are compared Icrsignals through a cyclic Pqsilionsinßtransformator carried out and the internal counter came a digital display of the Jst-Posifion of the movable! Deliver part in each cycle range of the Positionmeßtrans fornialors. Furthermore, the digital positions * riveting device an external counter that is used by the the same counting pulses that are given on the internal counter, and the opposite the internal counter shows and reads a greater number of levels than the counting cycles of the internet Counter minimizing counter can be effective.

Due to the design of the position measuring transformer mators, which contains several position zero points, dii are separated by a constant division, gives dei internal counter a digital position display that siel refers to one of the divisions.

According to the embodiment described in the main patent from the external counter with a device provided in order to bring the digital content to zero independently of the internal counter or to advance it to the.

Thus, the external counter can display a digital position in relation to the absolute zero position the machine or in relation to another freely selected zero position of the machine

In normal use (/. B. Checking the workpiece dimensions or adjusting the moving borrowed part of a machine on predetermined positions) it is generally necessary to adjust the size to control the coordinates along several axes in order not to override the digital display get involved and mainly you no longer increase the total cost of the facility Therefore, the digital position measuring devices used here are also of the main type the type described in the message (more precisely one of them for each adjustment axis of the machine) have a visual display st) that the content of the ex learn to read the meter can graze.

lis has already been explained in the main sponsor that if the an / own of the absolute counter (and somi of the viewer) on the absolute zero position de Machine are to be brought, the movable Tc i should first be adjusted in this position, which can be determined from the fact. that the digital positions measuring device is provided with F.inriehtungen. dii the adjustment of the moving part with the absolute be able to show the reference position. In this too the external counter is set to zero. Whom hicniadi the moving part / u begins to move characterize the digitalau / .cigen. which are displayed by the viewer are the absolute coordinates each of the positions reached by the moving part.

With an analogous process, another can Zero position of the machine can be selected from which the coordinates of the individual positions are measured that are occupied by the moving part.

It ' ^c l η ·· ⁰ sometimes useful to recognize the relative position of the moving part in the range of a division of the position measuring transformer, ie the content of the internal counter: ».

With the giial position measuring device described in the main patent it is possible to get this size by a subtraction process derived from is performed by an operator.

However, the operations required for this require time and practice on the part of the operator. In addition, there is the task that the digital position measuring device the display of a position can be rebuilt if it has been destroyed due to a power failure or because the system has a Was out of power for a while without moving the moving part / u.

With a digital position measuring device. with which the displacement of a part can be measured, Yes with respect to a fixed part along an axis associated with a sequence of position zeros is provided, equidistantly spaced, is movable, and which includes a first counter, its digital content, which represents the relative position of the substantial part within each division, in Analog form is converted in order to be continuously compared with an analog quantity representing the actual position of the movable part for supplying a fault signal which represents the supply of the counting pulses to the first counter and at the same time to the second counter, which controls in the same way again The first counter working and connected to a display for its digital content will do this job according to the invention achieved in that means are provided to measure the digital content of the first counter to be transmitted to the second meter in order to display the relative Position of the moving part that is located in the area of one of the divisions mentioned!

The invention is illustrated in the following description of two embodiments with reference to the drawings explained in more detail. It shows

1 shows an arrangement of the position zero points along the adjustment axis of the digital position measuring device according to the invention,

Figure 2 is a block diagram of the circuitry of a first embodiment of the digital position measuring device according to the invention and

Figure 3 is a block diagram of the circuitry of a second embodiment of the digital position measuring device according to the invention.

With reference to Fig. 1 of the drawings, it is assumed that ZA is the absolute zero position for the adjustment of the movable part on the X-axis and that RO. Rl ₁ R2 ... Rl ... are the zero positions, which characterize the starting points of the respective successive divisions p \, p2 ... pl ... of the position measuring transformer. Assume that all of these divisions are equal and of known size. In addition, we assume that \ is the distance of the absolute zero ZA from the starting point «0 of the next division. The distance A is a design value of the machine and is therefore known. It is finally accepted.

that P is the actual position of the movable part and that XP is the absolute or xP relative coordinate of the position P , ie measured with reference to the starting point ZA or R6 (starting point of the division p7, which contains the position P ). Therefore, the following equations must be observed:

XP = η ρ + A + kV (1)

xP = XP - (A + / j ■ ρ) (2)

where μ is the number of whole divisions between the positions RO and P.

In the implementation according to the main patent, with respect to equation (2), the operator

»5 register the digital display of the visual indicator (XP) and then subtract a quantity (6p + A) equal to the distance between the absolute zero ZA of the machine and the relative zero /? 6, which is the starting point of the division p7, in of the Po

so sition P of the moving part is included. The operator can therefore easily deduce the quantity to be measured. In fact, Λ and ρ are known, while it is sufficient to know η to contain the number between RO and P.

* 5 full divisions on the digital position reporting device to count.

In the first exemplary embodiment of the invention shown in FIG. 2, the digital position measuring device MP corresponds to one which has been described in the main application, with

Adding some amendments allows

will solve the task of the current registration.

With regard to the general operation of the

Digital position measuring device is based on the

Reference of the main patent. Here only the modifications made and the working sequence will be described which enable the measurement of the position of the movable part B along the gain axis (e.g. .V) and with respect to a pitch of the position measuring transformer T , ie with reference to FIG , where it was assumed that P represents the actual position of the movable part, that the size of the relative coordinate xP. which is measured with respect to the zero position Rf » which is the starting point of the

Division /> 7 represents, below which the position / 'fills. Such a measurement is possible when the moving part is in any position on the relative Adjustment axis remains stationary.

In Fig. 2, a visual indicator V is a known one

Type shown, which has as many reading positions as there are 42 levels in the external counter. In the example of FIG. 2 there are 4 reading positions which correspond to the four stages 42C, 42D, AlU or 42t 'and are directly controlled by these, each position being able to provide a visible representation of the decimal digit, which is in the corresponding stage of the external Counter 42 is included.

Furthermore, FIG. 2 four selectors RR, 47, 48 and RA , each with four positions RE, Rl), ID, NO, which can be switched simultaneously and by hand using a single button.

The selector RR in the position RE applies the steps of the internal counter 10 to the constant voltage KO, which brings the digital content of the counter 10 to zero. The three other positions AD, / D and NO of the selector RR are free of connections.

The selectors 47 and 48 in the positions RD and NO close by connecting outputs 7,

8 of the converter 9 with the windings 3 or 4 of the stationary part 1, the loop of the servo system; », which has the counter 10, the converter 9, the position measuring transformer 7", the amplifier 14 and the control units 16. In the position RE, ID , selectors 47 and 48 hold the servo system loop open.

Finally, in the RE position, the selector RA connects the stages of the external counter with the constant voltage ^ O, which brings the digital content of the counter and thus also the display connected in parallel to zero. The other positions RD, ID, NO of the selector RA are free of connections. In the normal state, the four selectors RR, 47, 48 and RA are in the NO position.

Provided that the movable part B of the digital position measuring device MP remains in a given position P (FIG. 2) and that the movable part 2 of the position measuring transformer T, which is connected to B via the mechanical connection 6, also remains stationary , and that the control device of the digital position measuring device MP is energized, the servo system assumes a state of equilibrium in which the digital content of the internal counter 10 represents the actual position of the movable part 2 with respect to the zero position λ6 of the fixed part 1. In contrast, the external counter 42 will normally have a different digital content.

If a visible digital display of the position of the movable part B within a division of the position measuring transformer T is required, the content of the external counter 42 is to be brought to zero in order to transmit the digital content of the internal counter 10 there and thus to provide an optical representation through the Visual indicator V to result.

In order to achieve such a result, the procedure described below must be used.

The voters are in the RE position. This breaks the loop of the servo system and both counters 10 and 42 are brought to zero. The selectors are then brought to the position RD in order to restore the closed loop of the servo system, so that the error signal coming from the output 13 of the position measuring transformer controls the counting process of the two counters 10 and 42 via the control unit 16 in order to enable a progressive error cancellation to effect. The equilibrium state is reached when the digital content of the internal counter 10 is equal to one representing the position of the movable part within a division.

In such states, the external counter 42 has a due to the equivalent start condition the internal counter 10 is equal to digital content.

It should be noted with reference to Fig. 1 that if P represents the position of the movable part B within the pitch pl of the position measuring transformer T , the initial zeroing operation of the counters sets the counter 10 to a digital state, the indifferent the zero position R6 or the Represents zero position /? 7. When the loop of the servo system is closed, the counter 10 begins to count until the equilibrium variable xP is reached. The internal counter 10 can, as already described in the main application, count up and down. The counting process is therefore carried out in such a way that the size xP is reached in a short way and in the shortest possible time, ie from one of the two zeros R ( and Rl , which is closer to P. When the counting process from R6 to / 'runs, so if it is a progressive counting process, the control unit IC excites the channel A, which controls the forward counting process, whereas in the case of a counting process from Rl to / \ ie a regressive counting process based on the maximum size contained in the counter, the Stcucr -

»O unit 16 energizes channel I, which does the counting down controls.

The external counter 42 can operate in an identical manner to the counter 10. If, however, how already mentioned in the main patent, it is required that

»5 the external meter has facilities for the It proves to be the case to set up the content and the calibration advantageous that it works as a progressive counter with a negative sign when starting from zero is and the control unit 16 the down counting

ao process controls. It follows from this if Countdown conditions that when the servo systcms loop reaches equilibrium is, the external counter 42 will contain a negative amount equal to the addition of the size. the

»5 is contained in the internal counter 10.

Thus, with reference to Fig. 1 and the aforementioned equilibrium states, the internal counter 10 will contain a quantity which represents the relative coordinate xP , while the external counter will have a size which has a character equal to - (p - xP) . In this case, when reading the last size on the display V , a skilled operator can immediately deduce the size of the relative coordinate xf.

Then the selectors RR, 47, 48 and RA are set to the position ID , in which the loop of the servo system is open and the internal counter 10 keeps its digital content unchanged. In this state, the content of the external counter 42 can be changed.

by introducing, by the means previously mentioned, the quantity AV 'or some other chosen initial quantity.

The selectors are then placed in the NO position where the servo system loop again

is closed, and the digital position measuring device MP is then brought into the normal operating state.

It must also be added that appropriate means are provided for in the event of measuring a Position P, which is located exactly in the center of a division, to prevent the counter 10 after the initial NuIIeinstell-Arbeitsgang can be blocked in this state, which, although a zero error is the output 13 of the position measuring transformer

tors T , but does not represent the size of the relative coordinate xP .

In a second exemplary embodiment of the invention, which is shown in FIG. 3, the digital position measuring device MP is the one described in the parent application.

bene device, with a visual indicator V being added, which is identical to the indicator described in FIG. Furthermore, there are four selectors 49, 50, 51, 52, each of which has four positions RE, IE, EI and NO at the same time and can be operated manually by a single button, ϊη the positions R £ and M? connects the selector 49 the output 13 of the position measuring transformer T with the input of the amplifier 14, the

The sloe of the servo systenis is closed, whereas the slider remains open in the positions //: and 1: 1.

loaded positions //. and /·./ holds the burner 50 by connecting the conductor 53 b / w. 54 to a constant voltage source V1, the gates 57 and 58 are energized. The exit 61, 62 of the gate 57 lvw. 58 wildly excited when the [input 59 or 60 is excited. In this state the gate 41 is actuated and thus allows the transmission of the impulses from the oscillator 12 to the counters 10 and 42. The conductors 59 and> ° 60 are only excited during the time in which the nij'ital content of the counters 10 and 42 is active. 42 is not zero. In the positions Rl. and / Vi) the burrower 50 does not effect a connection.

In the positions // ·. and /./ the selector 51'5 holds the inputs A lvw by connecting the wires 55 and 56 to the constant voltage source VI. / the two payers 10 and 42 energized for forward and backward payment processes. In the positions Rl. and VO, the selector 51 does not effect a connection. «

Finally, the selector 52 (analogous to the selector RA in FIG. 2) in the position RE connects the stages of the external counter 42 to the constant voltage source Vd. which brings the digital content of the counter and thus also the parallel display V ^a 5 to zero. The three v ^ citcren positions //:, Kl and, VO of the voter 52 are free of connections.

In the normal state, the four selectors 49, 50, 51 and 52 are set in the NO position.

Assuming that the movable part ti of the digital position measuring device MP remains in the predetermined position / '(FIG. I), the initial states which have been described with reference to the embodiment of FIG. 2 are present in the system. If a visible display of the position of the movable part Ii within the range of the division /> 7 of the position measuring transformer 7 is required, the process is as follows:

First, the selectors 49, 50, 51 and 52 are brought to the position RIi , whereby the external counter 4 »42 is brought to zero.

Then the voters are in the position // ·. brought, whereby the loop of the servo system is opened and the gate 57 is operated. The presence of a Digital content in counter 10 energizes line 59 and this also energizes output 61 of gate 57, whereby the gate 41 is operated. Under such conditions the oscillator 12 transmits through the gate 41 pulses which are simultaneously introduced into the two counters 10 and 42 through the wire 44 and, since the selector 51 feeds the line / which controls the countdown of these counters, these pulses reduce progressively increase the digital content of the internal counter 10 and progressively increase the digital content of the external counter 42 starting from zero with a negative sign.

The counting process of the two counters 10 and 42 is stopped when the counter 10 reaches the zero state, as a result of which the conductor 59 is de-energized and the gates 37 and 41 have thereby been switched off. Under such conditions, the digital content of the external counter 42 (with a negative sign) is equal to the output of the counter 10, namely in position // :, of the selector, the digital content of the internal counter 10 is transferred to the external counter 42. Thus, reading the display Γ (neglecting the sign) provides the digital display of the coordinate λ / 'of the position of the movable part I).

When this display has been read and written out. the four selectors are set to the position lh in which the loop of the servo system is still open and the gates 58 and 45 are actuated because the wires 54 and 60 are energized. In such circumstances oscillator 12 transmits pulses through gate 41 which are simultaneously applied to counters 10 and 42 through wire 44 and, since selector 51 feeds line A which controls the up / counting of these counters, decrease these pulses progressively increase the digital content of the external counter 42 (since it has a negative sign) and progressively increase the digital content of the internal counter 10, starting from zero.

The counting process of the two counters 10 and 42 is stopped when the counter 42 reaches the zero state, whereby the line 60 is de-energized and the gates 58 and 41 are thus switched off. Under such circumstances the internal counter 10 has resumed its initial digital content, ie the digital content of the external counter 42 is transferred to the internal counter 10 in the position /-./der Wahler. The selectors are then brought to the NO position, in which the loop of the servo system is closed again and the digital position measuring device / V // 'is now in its normal working state.

Thereafter, the operator uses when the indication of the absolute coordinate XP is to appear on the display l · '. as already described, equation (1). where A and ρ are known constructive data. xP was measured by the processes already described and / i is read on a graduated scale that is rigidly connected to the fixed part 1. The operator uses the arrangement according to the parent application to set the content and the sign of the external counter 42.

For both of the exemplary embodiments described here, it should be noted that at the end of the initial setting operations described, the digital content of the internal counter 10 remains unchanged if the movable part has not been shifted during these initial operations. Conversely, if small adjustments occur due to unintended causes when the loop of the servo system is finally closed with the selectors in the NO position, the internal counter IC changes its digital content so that the equilibrium state of the system is reached, and at the same time also changes external counter 42 its digital content by the same value. Therefore, as already described, the measuring process of the relative coordinate does not lose its meaning even when these unintentional small adjustments occur.

For this purpose 2 sheets of drawings

509 646M

Claims (2)

Patent claims: 1. Digital-PositioiisincUeinrichtung for measuring the displacement of a movable part with respect to a fixed part along an axis which is provided with several position zero points, which are arranged at equal intervals, with a first counter, the digital content of which, the relative position of the movable "o represents part within one of the partitions, is converted into a analuge mold to be continuously compared with an analog quantity, the actual PositiOii the respective represents the movable part for providing an error signal, the ¹ S, the application of Zähiimpulse to the controls the first counter and at the same time to a second counter which can count in a manner identical to the first counting and is connected to a display for its digital content. thus »° μ eke η η ζ calibrated. Dull means are provided for transferred the Digitalinhalis of the first counter (10) to the / wide counter (42) via the visual indicator (V) in visible digital form "relative lic position (xP) of the movable part (R)," 5 that is located in the area of one of the subdivisions. 2. Digital Positionsmcßvorrichtung according to claim 1 in which a ^r e-art counter, a digital-to-analog converter, comparing the oir löge on ana- 3 ">, the signals supplied by the converter with the actual position of the moving part / Deep to a Error signal compares and a control unit to which the error signal is given and which controls the transmission of the counting pulses to the first counter in order to cancel the error, form a closed servo system loop, characterized in that the means contain a first device, which in the first working style interrupt the loop of the servo system * and the content of the internal counter (10) and the learning counter (42) to zero and in a while Arbeitsstulc the loop read you can restore vosysteins. 1. Digital position measurement according to claim I. in which a first payer, a digital \ nalog \ vandlcr. a comparator that compares the signals from the converter with the actual position of the movable part in an analogous manner to deliver an error signal and a control unit to which the error signal is sent and which controls the transmission of the counting pulses to the first counter cancel the error, form a uc'chissene servo system loop, characterized in that the means contain a / wide range which bring the content of the external counter (42) to zero in a first working cycle and in a / wide range Arbeitsstule can interrupt the loop of the Scrvosystcms and let the counter (42) count progressively and the internal counter (10) regressively until IcIzleier has been set to zero.