SU679814A1 - Device for the calibration of multichannel apparatus - Google Patents

Description

The invention relates to a measuring technique and can be used to calibrate multichannel equipment, for example, vibration measuring instruments, carried out simultaneously on all channels. A multichannel measuring instrument calibrator is known, which contains a constant voltage source and a single trapezoidal pulse shaper. Sequential calibration of the channels is carried out by pulses obtained by recharging the capacitor, followed by amplification l. A disadvantage of the known calibrator is the long calibration time due to the reloading of capacitors and transient processes occurring in the channels during the sequential switching of their input circuits. A closer technical solution to the described invention is a device for calibrating multichannel equipment, comprising a calibration signal generator connected via a switch to the inputs of the n-measuring channels 2. This device also performs a sequential calibration of channels, however, the time of error is reduced by reducing transient time processes in the measuring channels by pre-switching their input circuits (with the help of an additional multi-channel switch), with Secondly, monitored sensors are disconnected in advance from measuring channels, and the latter are prepared for connection to their inputs of a calibration signal generator. However, the calibration time of multichannel equipment using a known device is still significant, since the voltage of the calibration generator is applied to the measuring channels sequentially, so the total time needed for calibration is the sum of the calibration time of each channel and the transit time in the most inertial canape as a preliminary switching of the input circuits of all channels is carried out simultaneously. The purpose of the invention is to reduce the calibration time of multi-channel equipment.

This is achieved by the fact that the calibration signal generator is designed as a master oscillator, a frequency divider and a voltage divider with an adjustable division factor, a logic unit, t-controlled key elements and an emitter repeater / voltage divider connected between the master oscillator output and the emitter repeater input The serially connected frequency divider, logic block and t-controlled key elements are connected between the output direction-. generator and controlled inputs of the voltage divider, and the switch is made in the form of a two-position switch key switch,

Such an embodiment of the device allows the calibration of all channels at the same time by a multi-stage voltage, whereby the calibration time is reduced.

FIG. 1 shows a functional diagram of the device; in fig. 2 is a time diagram of the fault voltage supplied to the inputs of all measurement channels simultaneously in FIG. 3 - voltage diagrams at the output of one of the measuring channels, tuned, for example, to the amplitude range of the MM channel, contains n measuring channels, each of which is intended to measure the signals of the corresponding sensor 1, for example, a piezoelectric sensor, and consists of series-connected matching stage 2, low pass filter 3 and output amplifier 4, Calibration signal generator, connected in calibration mode between sensors 1 and: zero bus matching stages of all measuring channels, includes a master oscillator 5, a frequency divider 6, a voltage divider 7 with an adjustable division factor, a logic unit 8, controllable key elements 9.10 ... t and an emitter follower 11. Using a two-position switch 12, the channels of measuring equipment are switched from measurement mode to calibration mode and vice versa. . The device works as follows.

In the calibration mode, the switch 12 sends the voltage of the calibration generator through sensor 1 to the inputs of all measuring channels simultaneously, the output voltages of which are fixed to the multichannel aTopte register, for example magnetic.

A multistage calibration voltage is generated using a master oscillator 5, which produces a rectangular voltage with a maximum amplitude and

a frequency f which is applied to the inputs of frequency dividers b and voltage 7 ..

The frequency divider b converts this voltage into a low frequency voltage of 2 tT which is fed to the input of logic block 8, which ensures the sequential switching on of the controlled key elements | Ment 9.10 .., The key elements alternately open, change the division factor of the divider 7 for example and, therefore, the amplitude of the calibration voltage applied to the measuring channels in steps from the lakDO UK.min. The number of stages m and the magnitude of the voltage amplitude of the calibration of each stage are determined respectively by the number of amplitude ranges and the gains of the measuring channels.

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.max v2 hrs} .. “.lins pre-installed according to the measurement program. The duration t of each stage is selected based on the time of establishing the amplitude of the calibration signal, which depends on the time constant of the measuring channel and the frequency of the master oscillator. Typically, the duration t of each step can be (10-50) T

Since the amplitude ranges of the amplifiers of the measuring channels are pre-calibrated before calibration (according to the measurement program), the analysis of the amplitude of the calibration voltages at the output of the measuring channels during the calibration process is not required. The voltages recorded at the output of the measuring channels recorded on the magnetic recorder are used as a reference when deciphering the measurement results for the corresponding channel.

So, for example, when calibrating measuring channels scaled to the gilplit diagonal range O, which corresponds to the gain, the voltage at the output of these channels will be recorded with a nominal amplitude and,. (See Fig. 3), the voltage of the first stage will be recorded with the minimum amplitude of the oscillations, c I of the voltage of the other stages is at the level of the limitation U ... because of the excess of the linear

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amplification areas of this channel.

Thus, this device provides a significant reduction in calibration time, allowing simultaneous calibration

all measuring channels.

At the same time, the number of functional units included in the device is constant and independent of the number of measuring canopies, and only

the number of key elements to be controlled according to the number of amplitude ranges of amplifiers of measuring channels.

invention formula

A device for calibrating multi-device equipment, containing a calibration signal generator connected via switches to the inputs of p-measuring channels, which is connected to the circuit for reducing the calibration time, the calibration signal generator is designed as a master oscillator, frequency divider, voltage divider with an adjustable division factor, a logic unit, t-controlled key elements — and an emitter follower; a voltage divider is connected between the output of the master oscillator and the input; an emitter A repeater, a serially connected frequency divider, a logic unit, and t-controlled key elements, are connected between the output of the generator and the controlled inputs of a voltage divider, and the switch is configured as a two-position switch.

Sources of information taken into account in the examination

1. The author's certificate of the USSR W386358, G 01 R 35/00, 1971.

2. USSR author's certificate No. 1309245.6 01 I 1/08, 197U.

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