Parallel calibration device for sensors

Abstract

The utility model discloses a parallel calibration device for a sensor, which comprises a plurality of bridge arm resistors RB, a lead resistor RL is respectively connected between two adjacent bridge arm resistors RB, and a parallel resistor R4, a switch K3, a parallel resistor R5, a switch K4, a parallel resistor R3 and a switch K1 are connected in parallel between a lead resistor RL2 and a lead resistor RL3. A parallel resistor R1 and a parallel resistor R2 are connected between the wire resistor RL1 and the wire resistor RL3, a circuit between the parallel resistor R1 and the parallel resistor R2 is connected with a switch K2, the other end of the switch K2 is connected with a wire resistor RL4, and the circuit is controlled by a switch K3 and a switch K4 to be switched to be connected to a local bridge arm or a remote bridge arm of an input bridge circuit in parallel. According to the utility model, through optimizing the connection line selection of parallel calibration, the measurement error caused by lead resistance is effectively reduced, the calibration precision of the sensor is improved, and the universality and adaptability of the calibration device are enhanced.

Description

TECHNICAL FIELD

[0001] The utility model relates to sensor calibration technical field especially relates to a parallel calibration device for sensor. BACKGROUND

[0002] In the application of sensor, accurate calibration is crucial to ensure the accuracy of measurement results. Traditional calibration methods have many problems, such as complex input connection, easy to introduce measurement error, etc. Especially in the face of different types of bridge arm resistance and different precision requirements of measurement scene, the existing calibration method is difficult to meet the diversified needs. SUMMARY

[0003] The utility model aims at solving above-mentioned technical problem, provides a parallel calibration device for sensor.

[0004] In order to realize above-mentioned technical purpose, reach above-mentioned technical requirement, the utility model adopts the technical scheme that a parallel calibration device for sensor, including several bridge arm resistances R B , adjacent two bridge arm resistances R B Between the connection wire resistance R L , wire resistance R L Including wire resistance R L1 , wire resistance R L2 , wire resistance R L3 , wire resistance R L4 , wire resistance R L2 And wire resistance R L3 Between parallel resistance R4, switch K3, parallel resistance R5, switch K4, parallel resistance R3, switch K1, parallel resistance R4 is connected with switch K3, parallel resistance R5 is connected with switch K4, parallel resistance R3 is connected with switch K1, wire resistance R L1 And wire resistance R L3 Between parallel resistance R1, parallel resistance R2, the circuit between parallel resistance R1 and parallel resistance R2 is connected with switch K2, the other end of switch K2 is connected with wire resistance R L4 , through switch K3, switch K4 control circuit switches and is connected to the local bridge arm or remote bridge arm of input bridge.

[0005] Preferably: parallel resistance R1, parallel resistance R2, parallel resistance R3, parallel resistance R4, parallel resistance R5 are set to low temperature coefficient 10ppm / DEG C. Wire winding or precision metal film resistance.

[0006] Preferably: remote bridge arm parallel is suitable for half bridge or full bridge sensor, and local bridge arm parallel is suitable for 1 / 4 bridge sensor.

[0007] The utility model discloses a mode of parallel connection of known resistance to one bridge arm of input bridge is adopted to carry out calibration, and under normal circumstances, 2 parallel resistances of each channel configuration can control switching and be connected in parallel to local or remote bridge arm.

[0008] Resistance calculation:

[0009] For the calibration step given in the form of mV / V excitation,

[0010] Parallel resistance according to formula: ,

[0011] Where: R C is the calculated resistance value,

[0012] R B is the bridge arm resistance,

[0013] R L is the wire resistance,

[0014] K is the calibration step mV / V.

[0015] For strain sensors, the calibration resistance is calculated in units of microstrain,

[0016] The formula is: ,

[0017] Where: µ is the strain analog value,

[0018] G F is the strain sensor coefficient,

[0019] R C is the calculated resistance value,

[0020] R B is the bridge arm resistance,

[0021] R L is the wire resistance.

[0022] Compared with the traditional structure, the utility model has the beneficial effects that:

[0023] 1. The utility model optimizes the selection of parallel calibration connection lines, effectively reduces the measurement error caused by wire resistance, improves the accuracy of sensor calibration, and is suitable for different types of bridge arm resistance and different accuracy requirements of measurement scene, and meets the diversified needs.

[0024] 2. The utility model provides a resistance calculation method for different types of bridge arm resistance and different accuracy requirements, enhances the universality and adaptability of the calibration method. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the circuit structure of this utility model. Detailed Implementation

[0026] The present invention will be further described below.

[0027] See attached document Figure 1 A parallel calibration device for sensors, comprising several bridge arm resistors R B The resistances R of the two adjacent bridge arms B The wires connected to each other have resistance R. L The resistance R of the wire L Including wire resistance R L1 resistance R of the wire L2 resistance R of the wire L3 resistance R of the wire L4 The resistance R of the wire L2 With wire resistance R L3 A parallel resistor R4, switch K3, parallel resistor R5, switch K4, parallel resistor R3, and switch K1 are connected in parallel. Parallel resistor R4 is connected to switch K3, parallel resistor R5 is connected to switch K4, and parallel resistor R3 is connected to switch K1. The wire resistance R... L1 With wire resistance R L3 A parallel resistor R1 and a parallel resistor R2 are connected between them. A switch K2 is connected on the line between the parallel resistors R1 and R2. The other end of the switch K2 is connected to the wire resistance R. L4 The connection is made by switching the circuit with switches K3 and K4 to connect it in parallel to the local or remote bridge arm of the input bridge.

[0028] In this preferred embodiment, the parallel resistors R1, R2, R3, R4, and R5 are set as wire-wound or precision metal film resistors with a low temperature coefficient of 10ppm / ℃ and good stability.

[0029] In this preferred embodiment, the remote bridge arm parallel connection is suitable for half-bridge or full-bridge sensors, while the local bridge arm parallel connection is suitable for 1 / 4-bridge sensors.

[0030] In practice, the external sensor section is connected to the inside of the data acquisition unit via wires. Parallel resistors R1, R2, R3, R4, and R5, and switches K1, K2, K3, and K4 are located inside the data acquisition unit. Switches K1 and K2 control the switching of the data acquisition unit's bridge circuit. Parallel resistors R4 and R5 serve as crucial calibration resistors, connected to their corresponding switches K3 and K4, respectively. The wire resistance R... L1 resistance R of the wireL3 Connect the bridge voltage, wire resistance R L2 Connect the signal line +In end, wire resistance R L4 Connect the signal line -E end.

[0031] When the full-bridge sensor is connected, the four bridge arm resistors R B in the sensor are connected; at this time, the collector internal switch K1 and switch K2 are opened (the collector full-bridge); when the half-bridge sensor is connected, only the right two bridge arm resistors (R C (R B )2, R C (R B )4) in the sensor are connected; at this time, the collector internal switch K1 is opened, and the switch K2 is closed (the collector switches the half-bridge); when the 1 / 4 bridge sensor is connected, three bridge arm resistors (R C (R B )1, R C (R B )2, R C (R B )3) in the sensor are connected; the collector internal switch K1 is closed, and the switch K2 is opened (the collector switches the 1 / 4 bridge).

[0032] The calibration steps of the utility model include:

[0033] 1) Preparation: determine the bridge arm resistor R B , wire resistance R L , and the desired calibration step K (for a strain sensor, determine the strain analog value µ and the strain sensor coefficient G F );

[0034] 2) Calculate the parallel resistance: according to the above determined parameters, select the appropriate resistance calculation formula to calculate the required parallel resistance R C . If calculated in the form of mV / V excitation, substitute the formula ; if calculated in units of micro-strain, substitute the formula .

[0035] 3) Select the switching appropriate parallel resistance: according to the resistance value of the bridge arm resistor, control the switching parallel resistance R4, R5, select 174K±1% when the bridge arm resistor is 120 ohms (close switch K3 and open switch K4), select 357K±1% when the bridge arm resistor is 350 ohms (open switch K3 and close switch K4), corresponding to the calibration step situation under different bridge arm resistors.

[0036] 4) Calibration operation: after the above connection is completed, the calibration operation of the sensor is performed, and according to the measured results after calibration, the calibration parameters can be further fine-tuned to achieve more accurate calibration effect.

[0037] The above embodiments of the utility model are only used for clearly illustrating the examples made by the utility model, but not used for limiting the protection scope of the utility model, and all equivalent technical solutions also belong to the category of the utility model, and the patent protection scope of the utility model should be defined by each claim.

Claims

1. A parallel calibration device for sensors, characterized by: Includes several bridge arm resistors R B The resistances R of the two adjacent bridge arms B The two sides are connected by wires with resistance R. L The resistance R of the wire L Including wire resistance R L1 resistance R of the wire L2 resistance R of the wire L3 resistance R of the wire L4 The resistance R of the wire L2 With wire resistance R L3 A parallel resistor R4, switch K3, parallel resistor R5, switch K4, parallel resistor R3, and switch K1 are connected in parallel. Parallel resistor R4 is connected to switch K3, parallel resistor R5 is connected to switch K4, and parallel resistor R3 is connected to switch K1. The wire resistance R... L1 With wire resistance R L3 A parallel resistor R1 and a parallel resistor R2 are connected between them. A switch K2 is connected on the line between the parallel resistors R1 and R2. The other end of the switch K2 is connected to the wire resistance R. L4 The connection is made by switching the circuit with switches K3 and K4 to connect it in parallel to the local or remote bridge arm of the input bridge.

2. The parallel calibration device for sensors of claim 1, wherein: The parallel resistance R1, parallel resistance R2, parallel resistance R3, parallel resistance R4 and parallel resistance R5 are set as wire-wound or precision metal film resistors with a low temperature coefficient of 10ppm / ℃.

3. The parallel calibration apparatus for sensors of claim 1, wherein: The remote bridge arm parallel is applicable to a half-bridge or full-bridge sensor, and the local bridge arm parallel is applicable to a 1 / 4 bridge sensor.

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