CN201672988U - Changing circuit of temperature transmitter - Google Patents

Abstract

The utility model relates to a changing circuit of a temperature transmitter. The changing circuit comprises an R/V circuit, an amplification and linearization circuit, a V/I circuit, a constant-current source circuit and a bootstrap circuit, wherein the R/V circuit is respectively connected with the amplification and linearization circuit, the V/I circuit, the bootstrap circuit and the constant-current source circuit, the constant-current source circuit is connected with a power supply, the bootstrap circuit is connected with the V/I circuit, and the V/I circuit outputs 4-20mA standard signals by the aid of a load resistor RL. The changing circuit is characterized in that the 4-20mA direct-current standard signals are outputted, the output signals are in linear relationship with measured temperature, the changing circuit adopting epoxy resin for encapsulation is corrosion-resistant, fine in shock resistance and high in reliability, ensures precision and reliability, has stable and reliable linear standard signals and reduces cost by 24%.

Description

The translation circuit of temperature transmitter

Technical field

The utility model relates to a kind of circuit, and particularly a kind of industry and scientific research fields such as weaving, light industry, food processing, medicine, petrochemical complex of being used for carry out the robotization temperature detection, become the translation circuit of the temperature transmitter send and to control.

Background technology

The temperature transmitter that existing market is used is import and homemade two kinds, general two (integrated circuit chip) machines or the single chip circuit of adopting of inlet temperature transmitter, its cost is big, price is higher, homemade temperature transmitter adopts the multi-disc machine circuit more, its failure rate height, reliability, less stable, cost is big, and price is also higher.

Summary of the invention

In view of the deficiency that prior art exists, the utility model provides a kind of conversion control circuit of temperature transmitter.This circuit adopts advanced two-wire system circuit transmission mode, adopts the IC technology that circuit is made the miniaturization module, and volume is little, and is safe and convenient to use, and has nonlinearity correction circuit, can directly measure the temperature of various media in the industrial process.

The utility model for achieving the above object, the technical scheme of being taked is: a kind of translation circuit of temperature transmitter, it is characterized in that: comprise R/V circuit, amplification and linearizer, V/I circuit, constant-current source circuit and boostrap circuit, described R/V circuit is connected with amplification and linear circuit, V/I circuit, boostrap circuit and constant-current source circuit respectively, constant-current source circuit connects power supply, described boostrap circuit is connected with the V/I circuit, and described V/I circuit is by pull-up resistor RL output 4～20mA standard signal.

Characteristics of the present utility model are: 1,4～20mA direct current standard signal output.2, output signal and dut temperature are linear.3, adopt epoxy encapsulation, corrosion-resistant, shock resistance is good, the reliability height.4, can directly pack in the terminal box, form the integrated temperature converting unit.

Single-chip microcomputer or two-chip computer circuit with the employing of inlet temperature transmitter compares in a word, and precision is 0.2%, be higher than general industry and use 0.5% precision, and cost reduced by 70%; The multi-disc machine circuit that adopts with domestic temperature transmitter has relatively been simplified circuit, has reduced failure rate, has guaranteed precision and reliability to have reliable and stable linear standard signal, and reduce cost 24%.

Description of drawings

Fig. 1 is that circuit of the present utility model connects block diagram and as Figure of abstract.

Embodiment

As shown in Figure 1, the translation circuit of temperature transmitter, comprise R/V circuit, amplification and linearizer, V/I circuit, constant-current source circuit and boostrap circuit, the R/V circuit is connected with amplification and linear circuit, VI circuit, boostrap circuit and constant-current source circuit respectively, constant-current source circuit connects power supply, boostrap circuit is connected with the V/I circuit, and the V/I circuit is by RL pull-up resistor output 4～20mA standard signal.

Principle of work

The resistance signal that thermal resistance temperature sensor received amplifies by input circuit, through V/I conversion and gamma correction, and the output constant current signal.

The key technical indexes:

1, limit of intrinsic error: resistance and temperature transmitter: ± 0.2%FS.

2, output signal: 4～20mA two-wire system transmission.

3, operating voltage: 24VDC.

4, operating ambient temperature :-5 ℃～+ 55 ℃ (10 ℃ of the every changes of environment temperature, its output valve changes: thermal resistance≤0.4%)

5, disconnected resistance is reported to the police: when temperature transmitter input broken string, transmitter is exported greater than 20mADC

6, power consumption: less than 0.5W.

Claims (1)

1. the translation circuit of a temperature transmitter, it is characterized in that: comprise R/V circuit, amplification and linearizer, V/I road, constant-current source circuit and boostrap circuit, described R/V circuit is connected with amplification and linear circuit, V/I circuit, boostrap circuit and constant-current source circuit respectively, constant-current source circuit connects power supply, described boostrap circuit is connected with the V/I circuit, and described V/I circuit is by negative RL live resistance output 4～20mA standard signal.

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