JPH0333080Y2 - - Google Patents

Description

[Detailed description of the invention] "Field of industrial application" This invention is installed in a socket in which a thermocouple converter is to be installed, and is used for cold junction compensation for the thermocouple measurement signal to be converted in the thermocouple converter. The present invention relates to a cold junction compensation module including a cold junction compensation element.

BACKGROUND OF THE INVENTION Thermocouple converters are used to convert a thermocouple measurement signal into a predetermined range of voltage or current. Since the cold junction side of the thermocouple is generally at room temperature T ₁ °C, the thermoelectromotive force (thermocouple measurement signal) input to the thermocouple converter is reduced by an amount corresponding to the temperature T ₁ °C. Therefore, the thermoelectromotive force corresponding to that T ₁ °C is added to the input thermoelectromotive force. This is the so-called cold junction compensation.

Conventionally, as shown in FIG.
is attached to the mounting board 12, and its socket 11
A thermocouple converter 13 is attached as shown in FIG. Terminal pin insertion holes 14 are arranged in a circular manner in the socket 11, and terminal pins protruding from the back surface of the thermocouple converter 13 are inserted into the terminal pin insertion holes 14. A pair of thermocouple lead wires (cold junctions) are connected to terminals 16 and 17 of the socket 11, and a cold junction compensation temperature sensing element 21 is connected to terminals 18 and 19. The measurement signal is subjected to cold junction compensation by the cold junction compensation temperature sensing element 21 in the thermocouple converter 13, and is converted into a signal within a predetermined range and output between terminals 22 and 23. The terminals 24 and 25 are terminals for supplying operating power to the thermocouple converter 13.

``Problems to be Solved by the Invention'' As described above, in the past, the cold junction compensation temperature sensing element 21 is provided at the position of the socket 11 to which the cold junction of the thermocouple is connected. Air based on the generated heat rises from the gap between the thermocouple converter 13 and the socket 11 and passes through the cold junction compensation temperature sensing element 21, so that the temperature of this element 21 and the cold junction of the thermocouple, In other words, the temperatures of the terminals 16 and 17 no longer match, making it impossible to perform accurate cold junction compensation. Additionally, in the past, accurate cold junction compensation was difficult due to the fact that the measurement output fluctuated due to the influence of wind caused by opening and closing a door, for example, and was also affected by heat radiation from nearby equipment. Ta.

"Means for Solving the Problem" According to this invention, plate-shaped first to fourth terminals are attached to one surface of the insulating material body so as to protrude, and these terminals are used for thermocouples in thermocouple converter sockets. The thermocouple mounting terminal is arranged so as to be able to be electrically connected to the terminal and the cold junction compensation terminal, and the thermocouple mounting terminal is provided within the main body and is connected to the first and second terminals, respectively.
A lead wire hole is formed in the main body to lead the thermocouple lead wires connected to these thermocouple mounting terminals to the outside, and a temperature sensing element for cold junction compensation is located in the main body in close proximity to the thermocouple mounting terminal. The temperature sensing element for cold junction compensation is connected to the third and fourth terminals.

As described above, in this invention, since the thermocouple mounting terminal and the temperature sensing element for cold junction compensation are provided in the main body, their temperatures are substantially the same and are not affected by wind or the like. Moreover, the module is held by attaching the first to fourth terminals to the converter socket.

Embodiment FIG. 1 shows an example of the appearance of a cold junction compensation module according to this invention. The main body 31 is constructed as a molded product of an insulating material, has a substantially rectangular parallelepiped shape, and is composed of a box-shaped body 32 and a lid 33 that covers the box-shaped body 32.
The lid 33 is connected to the box-shaped body 32 by a hinge 34 so as to be openable and closable. As shown in FIG. 2, the lid 33 is fixed to the box-like body 32 by tightening a screw 36 to a nut 35 provided at the center of the box-like body 32.

Plate terminals 41, 4 protrude from one surface of the main body 31.
2, 43, and 44 are attached. These terminals 41
-44 are thermocouple converter sockets 11 (first
In this example, these sockets are arranged on the same plane with terminal intervals so that they can be connected directly to the terminals 16, 17, 18, and 19 in FIG. The terminals 41 to 44 are positioned and arranged on the surface of the box-like body 32 facing the lid 33, and the small protrusions 45 of the box-like body 32 are inserted into the small holes and fixed by heat caulking.
When the lid 33 is placed on the box-shaped body 32, the terminals 41 to 44 are pressed against the box-shaped body 32 by the lid 33.

A wiring board 46 is attached close to the inner surface of the main body 31 facing the protruding surfaces of the terminals 41 to 44, and the inner ends of the terminals 41 to 44 are inserted into the wiring board 46 and connected to the wiring of the wiring board 46. Also, the first terminal 4
Screw holes are formed at the inner ends of the thermocouple mounting terminals 47 and 42, which are screw terminals.
48 are screwed into each. Thermocouple lead wires (cold junctions) can be connected to the thermocouple attachment terminals 47 and 48. A thermocouple lead wire outlet hole 5 is provided on the side plate of the main body 31 that closely faces the wiring board 46.
1,52 are formed. Lead wire outlet hole 5
1 and 52 are formed across the box-shaped body 32 and the lid 33, respectively. With the lid 33 open, the thermocouple lead wires are connected to the thermocouple mounting terminals 47 and 48, and the lead wires are connected to the box-shaped body 32 and the lid 33. These lead wires are held down by disposing them in the notches of the holes 51 and 52 of 32 and leading them out to the outside, and closing the lid 33.

A transistor 53 is disposed as a temperature sensing element for cold junction compensation and is attached to the wiring board 46 in close proximity to the thermocouple attachment terminals 47 and 48. The transistor 53 is connected to the terminals 43 and 4 through the wiring of the wiring board 46.
Connected to 4. A resistor 54 and a variable resistor 55 are attached to the wiring board 46 near the inner ends of the terminals 43 and 44. This variable resistor 5
An adjustment driver insertion hole 56 is formed in the main body 31 facing the end surface of the adjustment shaft 5 .

Note that the connections shown in FIG. 3 are made by wiring on the wiring board 46. Both ends of the thermocouple 57 are connected to terminals 41 and 4.
2, the collector and base of the transistor 53 are connected to the terminal 43, and the emitter is connected to the terminal 42.
and a resistor 54 and a variable resistor 55.
The terminal 44 is connected to the terminal 44 through the terminal 44. Terminals 43, 44
are connected to power supply terminal 61 through resistors 58 and 59 in thermocouple converter 13 (FIG. 2), respectively, and to the inverting and non-inverting terminals of operational amplifier 64 through resistors 62 and 63, respectively. Therefore, for the electromotive force of the thermocouple 57, the terminal 4
Compensation voltages corresponding to the temperatures of 7 and 48 are added by the operational amplifier 64 from the transistor 53 (the transistor 53 operates as a temperature-sensitive resistance element), and cold junction compensation is performed.

"Effect of the invention" According to the cold junction compensation module of this invention described above, the thermocouple mounting terminals 47, 4 are provided in the main body 31.
8 is housed, and a cold junction compensation temperature sensing element 5 is placed nearby.
3, even if wind flows outside, the temperature of the thermocouple mounting terminals 47 and 48, that is, the temperature of the cold junction of the thermocouple, and the temperature of the cold junction compensation temperature sensing element 53 are always equal, ensuring accurate cooling. Contact compensation becomes possible.

Moreover, simply by connecting the terminals 41 to 44 to the socket terminals, the module is fixedly held in the socket. By providing the variable resistor 55 as in the above example, if the variation in the characteristics of the temperature sensing element 53 is adjusted by the variable resistor 55, the thermocouple converter only needs to be adjusted. Conventionally, cold junction compensation was used. The entire adjustment was made with the temperature sensing element connected to the thermocouple converter, and the adjustment was complicated.
According to this embodiment, adjustment is simple and only needs to be done individually.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the appearance of an example of the cold junction compensation module according to this invention, FIG. 2 is a plan view showing the module in FIG. 1 in an open state, and FIG.
FIG. 4 is a perspective view showing a socket for a thermocouple converter; FIG. 5 is a perspective view showing a thermocouple converter attached to the socket shown in FIG. 4. be. 31: Main body, 32: Box-shaped body, 33: Lid, 41~
44: Terminal, 47, 48: Thermocouple mounting terminal, 5
1, 52: Lead wire outlet hole, 53: Temperature sensing element for cold junction compensation, 55: Variable resistor.

Claims (1)

[Scope of Claim for Utility Model Registration] A main body of an insulating material; first to fourth terminals in a plate shape protruding from one surface of the main body and attached in substantially parallel arrays; provided within the main body; Thermocouple mounting terminals connected to the first and second terminals, respectively; and thermocouple leads formed on the main body, from which thermocouple lead wires connected to the thermocouple mounting terminals are led to the outside. A cold junction compensation module comprising: a wire lead-out hole; and a temperature sensing element for cold junction compensation provided in the main body in close proximity to the thermocouple mounting terminal and connected to the third and fourth terminals.