SU991175A1 - Electronic digital scales - Google Patents

Description

(54) ELECTRONIC DIGITAL SCALES

one

The invention relates to a technique for measuring mass, in particular to accurate laboratory type weights.

Electronic digital weights are known that contain generators, and a quid reader. frequency, reversible counter, converter code - analogue 1.

A disadvantage of the known weights is the need to manually calibrate the device.

The closest in technical essence to the proposed are electromagnetic digital scales containing a sensitive element with a load receptor platform and a suspension system, a non-compensating transducer, a measuring and reference coil, a command unit connected by a first output to the electromagnetic positioning device of the reference coil containing a switch and a correction current source , a magnetic system, an electrical balancing system, containing two oscillators connected to the subtractor frequencies, in the stroke of which is connected to the reversible counter, cyclic counter, the input of which is connected to the output of the first generator, a coincidence circuit, the inputs of which are connected to the outputs of the reverse and cyclic counter, phase comparator, to the S input of which the overrun of the cyclic counter is connected, current stabilizer connected to the current key, the input of which is connected with the output of the phase key: a 9-paramparator, and the output through an adder, to the second input of which is connected

10, a tare current source connected to the measuring coil, the non-compensating converter being connected to the input of the second generator, and the reversible counter connected to the second output from the reading device 2.

A disadvantage of devices of this type is the relatively large measurement time associated with the need for manual calibration.

20 devices.

The aim of the invention is to provide automation of the calibration mode.

To achieve the goal

25, an electronic key, a storage device and a logic switch are entered into the balance, the input of the recording device is connected via an electronic key to the third output of the reversing counter, and the output is connected to the control current regulator, R input of the phase comparator through the logic switch is connected to the output the code coincidence circuit and to the intermediate output of the cyclic counter, wherein the control inputs of the electronic key and the logic switch are connected respectively to the second and th outputs of the command switch go block. The drawing shows a structural diagram of digital electronic scales. Digital scales contain a sensitive element 1 with a load-receiving platform 2, a suspension system 3 and 4, a non-compensation converter 5. made in the form of a light source 6, a photo detector 7, a slit diaphragm 8 made in a measuring frame 9, a permanent magnet 10, a magnet line 11, a reference coil of an exemplary mass 12, a system of mechanical travel stops, consisting of stops 13-16, an electrical balancing system 17, consisting of a controlled generator 18, generator 19, subtractor frequency 20, reversible counter 21, converter code-analog 22, containing a code converter in the relative length of time interval 23 with a coincidence circuit 24, cyclic counter 25 with intermediate output 26, phase comparator 27 and the converter relates . The duration of the time interval into the current 28 with the current switch 29 and the current stabilizer 30, the reading device, 31, the electronic switch 3, the storage device 33, the logic switch 34, the current source of the container 35, the current accumulator 36, the source correction 37, the switch 38 and the command unit 3 9. The source of the correction current 37, the switch 39, the system of mechanical travel stops with stops 13-16 form an electromagnetic overlay device of the reference coil. Structurally, the sensing element 1, the load-bearing platform 2 and the measuring coil 3 are rigidly fastened to each other and fixed on the suspensions 3 and 4, forming a movable part of the scales. The work of the scales is as follows. In the initial position, in the absence of the measured load on the cargo-loading area 2, i.e. when the slit diaphragm 8 is in the zero, neutral position at which the signal from the non-compensation converter 5 is equal to O, i.e. V O, while the frequency difference at the outputs of the subtractor frequency 20 is zero, i.e. The code combination at the outputs of the reversible counter 21 corresponds to zero, and on the reading device 31 there will be zero readings. From the adjustable source of the container 35, a current J of the initial calibration, which compensates the weight of the moving part of the balance and the container, is supplied through the accumulator 9 to the measuring coil 9. The command unit 39 places the switch 38 in position B, connecting the correction current source 37 to the reference roller 12. The current J of the correction current source 37 has a value sufficient to lift the reference coil 12 of the standard weight i.e. RP 3 LO BQ PQ, where B, is about induction in the gap, LQ is the total length of the reference coil wire. Thus, the reference coil 12 is in its extreme upper position and pressed against the lower stops 14 and 16. With P Pp, call this mode the sensitivity correction mode, the command block 39 connects the storage device 33 to the reversing counter 21 using an electronic key 32 and sets the switch 38 and the logical switch to position A. Then the source 38 is connected to the zero bus and the de-energized coil 12 under the action of its own weight PJJ is lowered onto the stops 13 and 15 located on the frame of the measuring coil 9. Mobile hour The weights are shifted down, the output of the non-compensating converter 5 is the VQ-P signal (5, the generators 1B and 19 are mismatched, and the outputs of the subtractor frequency 20 appear. The differential signal is ± e. Reverse counter 21 counts the pulses of the difference frequency that come during the transient process. The reversible counter code 21 is rewritten into a memory 33, which regulates the current value of the stabilizer 30. The current switch 29 controlled by the phase comparator 27 transmits current pulses into the measuring coil 9 amplitude, but also with a constant relative duration:. current in the measuring coil 9 in the correction mode; adjustable current amplitude from current stabilizer 30; -const- is the relative duration of the current pulses, determined by the pulse frequency from the intermediate output 26 of the cyclic counter 25 and the total capacity of the counter 25.

The process of changing the current -n occurs until a balancing effort is created

4t

-R

Opt for this J - ..: After the balancing has been performed, the frequency difference at the output of the subtractor is & is equal to O, and the reversible counter 21 stops, memorizes the dialed code combination proportional to the mass of the reference coil 12. After that, the command block 39 switches the switch 38 and the logic switch 34 to position B, turning off the memory device 33 RT of the reversing counter 21, and simultaneously the reference coil 12 under the action of the current from the current source, the correction 37 again occupies the extreme position. When a measured load is established at the load receiving platform 2, let us call this measurement mode, РХ - Vor (PO 0) / the movable part of the balance shifts downwards, at the output of the noncompensator 5, an error signal Vx appears proportional to the weight of the measured of the load, generators 18 and 19 are mismatched, and a difference frequency signal, f, appears at the output of frequency subtractor 20. The up / down counter 21 counts the pulses that have arrived during the balancing process and controls the code-analog converter. As the number of pulses grows in the reversible counter 21, the residence time of the phase comparator 27 in the unit state increases, which is determined by the difference between the instants of overflow pulses from the cyclic counter 25 and the code 24 matching circuit. This leads to an increase in the duration impulse ut) t, the current, and therefore to the growth of the compensating current in the measuring coil 9, the process continues until equality is achieved - the compensating current; where is the total length of the wire in the measuring coil 9. Taking into account (1), we get -1iL

Taking into account (2) and (3), we obtain that the mass of the measured load

. РХ УЧ-РОГПу г- ::

Claims (2)

1. USSR author's certificate number 742719, cl. G 01 G 23/36, 1976. 2.Assignment of the USSR on the application 2732751 / 18-10, cl. G 01 G 7/04, 01.03.79 (prototype 101. /., ,, ;: -7 .. ,, U ff.