SU1016811A1 - Multi-channel measuring device - Google Patents

Description

The invention relates to a measuring technique and can be used to measure temperature using resistive sensors. A device for measuring temperature is known, comprising a resistance sensor, a reference resistance of a current source, electronic keys and a deactivating device, the current source being connected at its one end to a neye-nepea normally closed key to the common point of the sensor and the reference resistance through a normally open key to the device and the second end of the current source is connected via a normally closed key to the common point of the reference impedance and subtractive device and through a normally open key to total fl. The drawbacks of the device are low noise immunity and complicated control circuit of transistor switches due to the absence of a common point between the current source and the measurement circuit, as a result of which transistors of transistors relative to the common point of the measuring circuit create voltages of different polarity, which in turn requires generating a two-pole control signal to ensure normal operation of the transistors in the key mode. Closest to the proposed technical entity is a multichannel measuring device containing a power source, the first output of which is connected to the common bus and to the first input of the measuring unit, the control unit, the gating unit, in each measuring channel the transistor and the first transistor the sensor output is connected to the drain of the first transistor of the switch, the source of which is connected to the second output of the power source, the output of the gating unit is connected to the first input of the first element and through the first input the first output terminal of the second element I, whose output is connected to the gate of the first transistor of the switch; the first output of the control source is connected to the first output of the power source; the second output of the control signal source is connected to the second inputs of the first and second And elements; connected to the gate of the second transistor of the switch, the source of which is connected to the second output of the sensor and to the first output of the power source, the drain of the second transistor is connected to the second output of the power supply C2. The disadvantages of the known device are the limited functionality, since it allows measurements to be carried out only using a four-wire sensor switch-on circuit. and does not provide opportunities to apply; the three-wire connection of the sensor. The purpose of the invention is to expand the functionality of the device. The goal is achieved by the fact that in a multichannel measuring device containing a power source, the first output of which is connected to the common bus and to the first input of the measuring unit, the gating unit, in each measuring channel a sensor and switch on the transistors, the first output of the sensor is connected to the drain of the first transistor the switch, the source of which is connected to the second output of the power source, the output of the gating unit is connected to the first input of the first element I and through the first inverter to the first input of the second element And whose output is connected to the gate of the first transistor of the switch, the first output of the control signal source is connected to the first output of the power source, the second output of the control signal source is connected to the second inputs of the first and second And elements, the output of the second And element is connected to the gate of the second transistor of the switch , the source of which is connected to the second output of the sensor and to the first output of the power supply, the drain of the second transistor of the switch is connected to the second output of the power supply, each measuring to The element OR, the second inverter, the third, fourth and fifth AND elements are entered, and the third and fourth transistors in the switch, the output of the second element AND are connected to the first input of the third element AND, and through the second inverter are connected to the first input of the fourth element And, the second input which is connected to the output of the source of control signals, the outputs of the third and fourth elements And are connected to the inputs of the element OR, the output of which is connected to the gate of the third transistor of the switch, the drain of the third transistor of the switch is connected to the first the output of the sensor, and the source is connected to the source of the fourth transistor of the switch and to the input of the measuring unit, the drain of the fourth transistor of the switch is connected to the second output of the sensor, and the gate to the output of the fifth And element, the first input of which is connected to the output of the first And element, the second input The fifth element I is connected to the control input of the measuring channel. Figure 1 shows a diagram of the device, figure 2 - time diagram.

The multichannel measuring device contains sensor 1, power supply 2, switch 3, control signal source 4 measurement unit 5, common bus b, first and second elements 7 and 1, first inverter b, gating unit 9, third, fourth and fifth And 10, 10, and 10 elements, OR element 11, second inverter 12, control input 13 of the measuring channel, first, second, third, and fourth switch transistors 14, 15, 16, and 17. Other channels contain the same elements: 1, 3, 4, g 8, 10, lOg., LOj, 11, 12, 13, 14, 15

16 and 17. The device operates as follows.

With a 3-wire connection, the first output of sensor 1, to which the switch transistors 14 and 16 are connected, has one connecting wire, and with 4-wire 6m - two. The second output of the sensor in both cases has a 2-wire connection, and the switch transistors 15 and 17 are connected to the same wire.

The measurement process consists of two cycles. With a 3-wire switch on input 13, a signal of logical 1 is set, with the result that in the 1st cycle to the power supply 2 and the measuring unit 5 transistors 15 and

17, the connecting wires are connected respectively, and in the second cycle, transistors 14 and 16 connect sensor 1, and the signal at the input of measurement unit 5 has the following meaning:

UjLV V2i ";

where and ujt are input signals

measurement unit 5, respectively, in 1 5 m measurement cycles;

K - wire resistance of the first output of sensor 1; Г «., 1 - resistances of the first and second wires of the second output of the sensor; sensor resistance.

The measurement result is the voltage variability

whether, (R, -n, -r, j ,,).

For 4-wire switching on the sensor 1 at the input 13 a logical O is set, as a result of which the transistor 17 is blocked, and the transistor 16 is controlled by a signal coming directly from the source 4 of the controlled signals through the inverter 12 and the AND 10 and OR 11 elements. device operation is fully consistent with the known.

Introduction to each channel of a device of transistors into a measuring circuit of three elements AND, an inverter and an OR element expands the functionality of the device, as well as high-precision measurements requiring a 4-wire sensor switch-on circuit, the device provides mass measurements in a 3-wire circuit with lower weight that expands its scope.

I In addition, the present invention allows the advent of nporpaf MHo to control the switching process from one type of sensor circuit to another, which further increases the efficiency of using this device.

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Claims (1)

MULTI-CHANNEL MEASUREMENT DEVICE containing a power source, the first output of which is connected to a common bus and to the first input of the measuring unit / gating unit, in each measuring channel the sensor and the switch on transistors / the first sensor output is connected to the drain of the first transistor of the switch, the source of which is connected to the second output power source, the output of the strobing unit is connected to the first input of the first AND element and through the first in-. a converter to the first input of the second element AND, the output of which is connected to the gate of the first switch of the switch, the first output of the control signal source is connected to the first output of the power supply; the second output of the control signal source <A is connected to the second inputs of the first and second elements And, the output of the second transistor a switch; the source of which is connected to the second output of the sensor and the first output of the power source, the drain of the second transistor of the switch is connected to the second output of the power source, which is related to the fact that, in order to expand the scope of the device, into each measurement channel, an OR element, a second inverter, is introduced: 'the third, fourth and fifth elements And, and in the switch - the third and fourth transistors, the output of the second element And is connected to the first input of the third element And and through the second inverter is connected to the first input of the fourth _ element the And, the second input of which is # connected to the output of the source of control ^ signals, the outputs of the third and fourth AND elements are connected to the inputs of the OR element, the output of which is connected} ^ with the gate of the third transistor of the switch, the drain of the third transistor 2 of the switch is connected to the first output of the sensor and the source is connected, to the source of the fourth transistor of the switch and to the input of the measurement unit, the drain of the fourth 'transistor of the switch is connected to the second output of the sensor, and the gate is. with the output of the fifth element And | the first input of which is connected to the Output of the first element And ,. the second * input д of the fifth element And is connected to the control element And is connected to the gate by the second input of the measuring channel. Witt