CN204286644U - Thermal resistance loop-around test device - Google Patents

Abstract

The utility model discloses a thermal resistance loop tester, which comprises a circuit board. A selector switch is arranged in the center of the circuit board. Three or more resistors are welded on the circuit board. Each resistor or more than two resistors connected in parallel correspond to a temperature value file. The input contact of the selection switch is tightly connected to the corresponding resistance pin, the output contact of the selection switch is welded to the two compensation wires, and the output end of the compensation wire is welded firmly to the two small clips. The utility model has the characteristics of simple manufacture, low price, flexible use, no power supply, energy saving, environmental protection, and convenient portability. It is mainly used when the thermal instruments on the construction site have been installed, the integrated control system has been powered on, and the programming of the automatic operating system has been completed, and the terminals, internal lines, modules, programs, flow chart legends, and ranges in the automation cabinet are transmitted from the field line. , display accuracy and other tools for testing thermal resistance circuits.

Description

RTD Loop Tester

technical field

The utility model belongs to the field of thermal instruments, in particular to a thermal resistance loop tester.

Background technique

In the loop test of on-site thermal instruments, most of the instruments currently used are signal generators. It is more convenient to use for transmitters installed on the platform during loop testing, but due to its large size, heavy weight, and inconvenient portability, it is inconvenient to perform loop testing on steep pipe walls or furnace walls that require rock climbing , Not easy to test. In addition, the construction site is complex, and the number of loop tests for thermal instruments is relatively large, and the commissioning personnel undertake heavy testing work.

Utility model content

In order to solve the problems existing in the prior art, the utility model provides a thermal resistance loop tester, which overcomes the problems of complex loop test engineering, heavy workload, inconvenient testing and low work efficiency in the prior art.

The technical scheme of the utility model is:

A thermal resistance loop tester, including a circuit board, the center of the circuit board is provided with a selection switch, three or more resistors are welded on the circuit board, each resistor or more than two resistors connected in parallel corresponds to a temperature value gear, the selection The switch input contact is tightly connected to the corresponding resistance pin, the select switch output contact is welded to two compensation wires, and the output end of the compensation wire is firmly welded to two small clips.

The circuit board is equipped with a supporting shell, and the side of the shell leads out the compensation wire of the output resistance, and the output position is fixed firmly.

The precision of the resistors or parallel resistors in the circuit board should not be less than the display precision required by the circuit, so as to select the precision of the resistors forming the circuit.

The resistance value arranged in the circuit board is determined by the resistance value and temperature relationship table of the thermal resistance used in the design.

The shell is made of good insulating material.

The beneficial effects of the utility model are: the thermal resistance loop tester of the utility model ensures the display accuracy, the selected color ring resistance is small in size, high in precision, and easy to obtain; it is welded on the circuit board and fixed firmly so that it is not easy to drop; The use of the selection switch makes it more convenient, quick and easy to change the output resistance; the length of the two output compensation wires can be freely selected for the convenience of control; the two small clips make it convenient and fast to connect the instrument to the circuit, and the connection is firm; It also has the characteristics of simple production, low price, convenient portability, no power supply, and ready availability.

Description of drawings

Fig. 1 is a schematic diagram of the internal structure of the thermal resistance loop tester of the present utility model;

Fig. 2 is the front view of the appearance of the thermal resistance loop tester of the present utility model;

Among them, 1: 0°C corresponds to resistance; 2: 18°C corresponds to resistance; 3: 50°C corresponds to resistance; 4: 74°C corresponds to resistance; 5: 100°C corresponds to resistance; 6: 131°C corresponds to resistance; 7: 187°C corresponds to resistance ;8: selector switch; 9: two compensation wires; 10: two small clips; 11: shell.

Detailed ways

The utility model is described in detail below in conjunction with accompanying drawing.

As shown in Figure 1-2, the thermal resistance loop tester of the utility model is composed of several resistance elements welded on the circuit board to form a parallel circuit respectively, and outputs the resistance value corresponding to the thermal resistance, and realizes each resistance value by controlling the selection switch. conversion between. The output line connects the resistance value with the tested circuit, and the corresponding temperature value can be displayed on the display.

The resistor element used in this embodiment is a 5-color ring resistor with an accuracy of E96 (1%) series. 0°C corresponds to resistor 1 with a resistance value of 100Ω, and the color code of the resistor is brown-black-black-black-brown; 18°C corresponds to resistor 2 in parallel, the resistance values are 118Ω and 1.15KΩ respectively, and the color code of the resistor is They are brown-brown-gray-black-brown, brown-brown-green-brown-brown respectively; 50℃ corresponds to resistance 3 and two resistors are connected in parallel, the resistance values are 165Ω and 432Ω respectively, and the color ring codes of the resistors are brown-blue respectively -Green-black-orange, yellow-orange-red-black-brown; 74℃ corresponds to resistance 4. Two resistors are connected in parallel, the resistance values are 196Ω and 374Ω respectively, and the color ring codes of the resistors are brown-white-blue-black- Brown, orange-purple-yellow-black-brown; 100℃ corresponds to resistance 5. Two resistors are connected in parallel, the resistance values are 140Ω and 13KΩ respectively, and the resistance color ring codes are brown-yellow-black-black-brown and brown-orange -Black-Red-Brown; 131℃ corresponds to resistance 6. Two resistors are connected in parallel, the resistance values are 280Ω and 324Ω respectively, and the resistance color ring codes are red-gray-black-black-brown, orange-red-yellow-black- Brown; 187°C corresponds to resistance 7. Two resistors are connected in parallel, the resistance values are 174Ω and 10KΩ respectively, and the color ring codes of the resistors are brown-purple-yellow-black-brown, brown-black-black-red-brown. A number of resistors with different resistance values are selected through the relationship between platinum resistance and temperature, and the accuracy of the output resistance value should not be less than the need for automatic display accuracy. In view of the requirements of the relevant provisions of the thermal instrument circuit test, only three points are needed to test the thermal resistance circuit, that is, 0°C corresponds to resistance 1, 50°C corresponds to resistance 3, and 100°C corresponds to resistance 5, but in order to further meet different ranges and The test of display accuracy needs to select the remaining four points to supplement, that is, 18°C corresponds to resistance 2, 74°C corresponds to resistance 4, 131°C corresponds to resistance 6, and 187°C corresponds to resistance 7. Operators can also choose different ranges according to their needs.

The manufacturing method is as follows: make a shell 11 with the same size as the circuit board, and the volume is similar to the size of a matchbox. Solder the corresponding resistors 1 to 7 on a multi-pin circuit board, and do not need to consider the order when connecting in parallel. Fix the selector switch 8 at the center of the circuit board, and make its input contacts closely connected with the corresponding resistance pins. The output compensation wire 9 is welded to the output contact of the selector switch 8, and is led out from the corresponding position of the shell 11, and the output position must be fixed firmly. Two compensation wires, the length of which can be selected according to actual needs, are easy to operate, simple and flexible during testing. The two small clips 10 are firmly welded to the output end of the compensation wire 9, which facilitates the connection between the measuring line and the measured circuit, and improves the efficiency. Making the shell 11 according to this model will be more convenient and durable for use and storage. The shell can be made of good insulating materials such as plastic and wood, and the volume is the same as that of the circuit board to facilitate fixing. Put the soldered circuit board in the casing, open a hole on the side of the casing to lead out the compensation wire and fix it firmly to avoid tearing the welding wire during use.

How to use: Turn the knob of the thermal resistance loop tester to make it output the corresponding resistance value. Remove one of the wires connected to the thermal resistance, and clamp the clips at the output end on the binding post of the unremoved wire and the removed wire respectively. At this time, the corresponding temperature value should be displayed on the operation panel.

The utility model has the characteristics of simple manufacture, low price, flexible use, no power supply, energy saving, environmental protection, and convenient portability. It is mainly used when the thermal instrument has been installed on the construction site, the integrated control system has been powered on, and the programming of the automatic operating system has been completed. , display accuracy and other tools for testing thermal resistance circuits.

The utility model has been schematically described above with reference to the accompanying drawings and embodiments, and the description is not limiting. Those of ordinary skill in the art should understand that in practical applications, some changes may occur in the arrangement of the components in the present invention, and other people may also make various forms of similar designs under their inspiration. It should be pointed out that, as long as they do not deviate from the design purpose of the present utility model, all obvious changes and similar designs are included in the protection scope of the present utility model.

Claims (5)

1. A thermal resistance loop tester, comprising a circuit board, characterized in that, the center of the circuit board is provided with a selector switch, and three or more resistors are welded on the circuit board, and each resistor or two or more resistors connected in parallel correspond to a temperature value gear position, the selector switch input contact is tightly connected to the corresponding resistance pin, the selector switch output contact is welded to two compensation wires, and the output end of the compensation wire is welded firmly to two small clips. 2. The thermal resistance loop tester according to claim 1, wherein the circuit board is equipped with a matching shell, the side of the shell leads out the compensation wire for output resistance, and the output position is fixed firmly. 3. according to the described thermal resistance loop tester of claim 1, it is characterized in that, the precision of resistance or parallel resistance in the described circuit board should not be less than the display precision of loop requirement, select the resistance precision of forming circuit with this. 4. The thermal resistance loop tester according to claim 1, wherein the resistance value configured in the circuit board is determined by the resistance value and temperature relationship table of the thermal resistance used in the design. 5. The thermal resistance loop tester according to claim 2, wherein the shell is made of a material with good insulation.