DD264518A1 - ELECTRONIC SLIP MEASURING DEVICE - Google Patents

Abstract

For measuring and monitoring tasks on belt and vehicle drives, an electronic slip measuring device is specified. This allows fast, gapless and accurate measurement of slip, requires only simple speed encoders, and the ratio of drive drum and roller diameters can be any value. The aim of the invention is to increase the reliability of the drives. The object is essentially achieved in that the slip measuring device comprises a reference frequency multiplying phase-locked loop and a digital circuit consisting of a counter with two memories and comparators, two D flip-flops, one RS NAND flip-flop, two NAND gates and one NOR gate contains. Thus, from the reference frequency and frequency-frequency input signals, an isochronous rectangular pulse train with a slip-proportional pulse duty factor is formed whose time average is exactly proportional to the slip.

Description

P Γ.)

12 1 f

(6)

2 _1 f

^f o

Since the diameters of the drive current wheel and the roller are generally unequal and also the increment numbers of the two pulse generators can be different, the frequencies of the pulse sequence P _c and Pj have different values at zero slip:

a = 4- = - - beis = O (7)

fo Po Di

To measure the slip several solutions are known. The closest technical solution to the present invention is the electronic device specified in DD - PS 220145 for measuring the slip of asynchronous motors. This slip measuring device essentially comprises a line frequency multiplying phase-locked loop and a consisting of a gate circuit, a frequency divider, a pulse shaper and a flip-flop digital circuitry. With the phase-locked loop and this digital circuit arrangement of the power-frequency and the rotational frequency input signals a rotational frequency rectangular pulse train with schiupfproportionalem duty cycle, the time-center word exactly the slip proportion.il ict. The disadvantage of this Schlupfmeßeinrichtung as well as all other known analog frequency Schlupfmeßeinrichtung is that they only from the two input frequencies f _o and f j produce a slip-proportional output signal when the actual frequency is equal to the reference frequency with zero slip.

Object of the invention

The aim of the invention is to measure the slip in belt drives and vehicle drives with relatively simple means and high accuracy and thus to increase the reliability and the life of these drives.

Explanation of the essence of the invention

The invention is based on the Aufgäbe to create a simple electronic device with continuous frequency-analog and digital information processing and analog display to 'measure the slippage in tape drives and vehicle drives, which has a high accuracy, in which only small demands are placed on the pulse and at the ratio of diameters of drums and barrels can have any values.

According to the invention, this object is achieved in that the electronic slip measuring device comprises a phase-locked loop multiplying the reference frequency f ₀ by a constant factor and one comprising a counter with two memories and two digital comparators, two D flip-flops, one RS NAND flip-flop, two NAND and a NOR gate existing digital circuitry includes and that at the output of Schlupfmeßeinrichtung an indicative of the time average instrument is connected.

The single elements de; Slip measuring device are connected together in the following manner: The reference frequency pulse train P ₀ is located at the input of the phase locked loop, the isf rnquento pulse train P _t at the data input of the first D-Flipf iops. The data input of the second D flip-flop is at the output of the first D flip-flop. Both D-Flinflops are clocked at the multiplied reference frequency. The count input of the counter of the digital circuitry is connected to the output of the voltage controlled oscillator of the phase locked loop, the control input for taking over the counter reading in the first memory of the counter is at the output of the NOR gate whose inputs are at the outputs of the two D flip-flops, connected, the reset input of the counter is connected to the EQUAL output of its second digital comparator. The reset input of the RS-NAND flip-flop, the output of which forms the output of the slip measuring device, is connected to the output of the first NAND gate whose inputs are connected to the outputs of the two D flip-flops. The set input of the RS-NAND flip-flop is at the output of a second NAND gate whose inputs are connected to the EQUAL output of the first digital comparator of the counter at the output of the first NAND gate.

With the phase-locked loop din reference frequency f ₀ is multiplied by a constant, largest possible factor. This factor is determined by the count of the counter or by the divider ratio of the frequency divider of the phase locked loop. With the phase-locked loop and the digital circuit arrangement, the reference frequency and the frequency-input signals, the pulse sequences P ₀ and P _; , generates a third rectangular pulse train P ₃ , which has the frequency of the pickup speed ν or actual frequency f | and whose duty ratio (ratio of pulse width to pulse period) is proportional to the slip. This is achieved by

- that pulses of the multiplied reference frequency are continuously paid into the counter of the digital circuitry,

~ that with the leading edge of a pulse of the rectangular pulse train Pi, the current counter reading is taken over into the first memory and the RS-NAND flip-flop is reset,

That the instantaneous counter reading z ₇₄ (t) is continuously compared with the stored counter reading | - »i Z7 <t (tk) with the first digital comparator,

In that the equality of the instantaneous and the stored counter reading is set to the RS-NAND flip-flop,

In addition, the current counter reading Z74 (t) is continuously compared with the value M stored in the second memory jfc with the second digital comparator and

r ~ -i - that the counter is reset when the current count Z ₇₄ It) reaches the value M.

The advantages achieved with the invention compared to the known slip measuring devices are, above all,

That the slippage can be measured with high accuracy by the continuous frequency-analogue or digital information processing,

That no special device for quotient formation, which would represent a source of error, is required,

That only simple pulse generators are required for obtaining the reference frequency and the pulse frequencies P ₀ and P,

- that nevertheless the measured value is formed quickly,

- That the ratio of the diameter of the drive drum and roller (Bandantriebon) or of driving and running wheels (vehicles) and the ratio of the increment numbers can have any value,

- that nevertheless the output of the slip measuring strictly linear and without offset dsm in Eq. (1) defined slip follows,

- that the slip is measured completely,

- That only a few standard digital circuits are required to realize the slip measuring device and

- That thereby a cheap Schlupfmeßgemt is made possible.

embodiment

An embodiment of the invention will be described in more detail with reference to the following drawings. Show it

Figure 1: the derivation of the reference and the istfrequenton pulse trains in a tape drive, Figure 2: the circuit diagram of the electronic slip measuring and Figure 3: the timing diagram of the electronic slip.

In order to be able to achieve a good adaptation of the slip-measuring device to the different drum or wheel diameters while simultaneously achieving short measurement times, the programmable counter / divider (64) and the counter (74) must each have the largest possible count. The phase-locked loop (6), consisting of the phase detector (61), a low-pass filter (62), a voltage-controlled oscillator (63) and the counter / divider (64), ensures that the counter (64) is synchronized with the reference frequency circulates.

The two rectangular pulse trains P ₀ with the reference frequency f ₀ and Pi with the actual frequency f 1, which are derived from the belt drums or wheels according to FIG. 1 by means of a speed sensor, serve as input variables. The description of the electronic slip measuring device is expediently made on the basis of its pulse diagram shown in FIG. The count of the counter (74) with two memories and comparators is determined by the contents of the second memory. If the instantaneous count of the stored in the second memory, this soli are designated M, so the wire ¹ reset the counter by the responsive second comparator. The counter (74) therefore operates at a frequency which corresponds exactly to the product N / M * f ₀ . The count of the two counters (64,74) is suitably gewähK that the condition

with a corresponding to Eq. (7) is fulfilled.

At the leading edge of the IF pulses Pi, the pulses of the sequences Pj and P) are formed with the D flip-flops (71, 72) and the gates (73, 75). By an impulse of Folgo P) in each case dor instantaneous counter reading of the counter (74) is taken into the first memory. In parallel with this, the pulse of the sequence Pi of the RS-NAND flip-flop (77) goes back to "low." The count recorded in the first memory is constantly compared with the current count, both agreeing with the simultaneous absence of a pulse in the sequence P) , the pulse of the sequence P2 formed by the first comparator via the gate (76) sets the RS-NAND flip-flop (77) to "high". This state is maintained until the next leading edge of the pulse train Pi initiates a renewed reset and thus a new conversion period. The pincushion pulse sequence P3 produced at the output of the flip-flop (77) therefore has the actual frequency f | and their duty cycle exactly corresponds to the slip when the condition according to Eq. (8) is fulfilled. The time average of the rectangular pulse train P ₃ is proportional to the slip to be measured and the pulse height. The influence of the pulse height can be eliminated that the output flip-flop (77) is advantageously implemented in CMOS technology, thus occurs in both Schaltzuständon a low-ohmic Ausgnngswiderstand and in principle no offset voltage oin. In addition, the supply voltage of the output flip-flop (77) is kept constant by a voltage control.

From the output at the flip-flop (77) resulting voltage square pulse sequence P3 with the constant pulse height is formed with a rotary coil instrument (8) of the time average and displayed. The embodiment is based as a counter with two memories and comparators of the circuit U125D.

Claims (1)

Electronic slippage measuring device, in which the ßenzugsgeschwindigkßit v ₀ by the frequency f _{o of} the pulse train P ₀ and the slip-speed actual speed ν are given by the frequency fi of the pulse train P ₁ , gekonnzeichnet characterized in that the slip measuring a the reference frequency f ₀ by a constant factor N multiplying phase-locked loop (6) includes one of two D flip-flops (71, 72), a NOR gate (73), a two-store counter and two comparators (74), two NAND gates (75, 76) and an RS-NAND flip-flop (77) existing digital circuitry (7) is provided, that the counting input of the counter (74) and the clock inputs of the two D flip-flops (71,72) at the output of the voltage controlled oscillator (63) of the phase locked loop ( 6) are connected, that the bezugsfrequente pulse train P is ₀ the input of the phase-locked loop (6) that the istfrequente pulse train P ₁ is located at the Dateneingarig of the first D flip-flop (71), as the data input of the second D flip-flop (72) is connected to the output of the first D flip-flop (71), that the control input (P4, LMD for taking over the count into the first memory of the counter (74) at the output of the NOR gate (73) whose inputs are at the inverting output of the first D flip-flop (71) and the non-inverting output of the second D flip-flop (72) that the reset input of the counter (74) at the EQUAL output (COMP O) of its second comparator is connected such that the inputs of the first NAND gate (75) at the non-inverting output of the first D flip-flop (71) and the inverting output of the second D flip-flop (72) are that the inputs of the second NAND gate ( 76) are connected to the EQUAL output of the first comparator of the counter (74) and to the output of the first NAND gate (75) such that the set input of the RS NAND flip-flop (77) is connected to the output of the second NAND gate (76 ) and the reset input of RS-NA ND flip-flops (77) are connected to the output of the first NAND gate (75) and that at the output of the RS-NAND flip-flop (77) is connected a time-averaging indicating instrument. For this 3 pages drawings Field of application of the invention The invention relates to an electronic device for measuring the slip, in particular for measuring and monitoring tasks in belt drives and vehicle drives. Characteristic of the prior art For belt drives and vehicle drives !! is called slip according to definition the reference to the reference speed V ₀ referred deviation of the slip-afflicted actual speed ν from the reference speed. The reference speed V _{0 is} determined by the rotational speed n ₀ and the diameter D _{0 of} the drive drum or drive wheels: V ₀ = D ₀ π n ₀ (2) The slip-speed actual speed is usually detected in belt drives by means of a roller. Between the belt speed ν and the speed ni of the roller with the diameter D _{1 there} is the relationship: ν = D ₁ π η, (3) By means of a pulse generator, the drive drum and the roller impulse sequences P ₀ and P | whose frequencies f ₀ and f | are linked to the rotational speeds n ₀ and ni via the increment numbers of the pulse generators p _u and pi: fo = Po n ₀ '(4) fi = Pi n, (5) Taking into account GIn. !! ') to (5), Eq. (1) on: