JPH1047990A - Grounding structure of input amplifier unit of measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure a grounding route separately when the input amplifier unit is mounted on a measuring instrument main body. SOLUTION: Of the measuring instrument 11 having the input amplifier unit 21 mounted on the measuring instrument main body 12, the input amplifier unit 21 is formed of an amplifier main body part which contains an amplifier substrate and a resin panel part 25 which has conductive insert metal fittings 26 provided with a through hole 26a enabling free screw fitting to the measuring instrument main body 12 and is put in a resin casing. The resin panel part 25 is equipped with a conductive connection plate 28, which has a through hole 29 in the surface facing the through hole 26a and is fixed to the resin panel part 25 and provided with a grounding route with the amplifier substrate, on the side of a back surface including the insert metal fittings 26, and the input amplifier unit 21 is mounted on the measuring instrument main body 12 by leading the grounding route to the chassis part 14 of the measuring instrument main body 12 by engaging a screw 31 threadably with the chassis part 14 from the through hole 26a and bringing the conductive connection plate 28 and insert metal fittings 26 into close contact with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grounding structure of an input amplifier unit in a measuring instrument which can secure a more preferable grounding route when the input amplifier unit is mounted on the measuring instrument main body.

[0002]

2. Description of the Related Art In a measuring instrument such as a waveform recorder, FIG.
As shown in FIG. 1, a measuring instrument 1 comprises an measuring instrument main body 2 and an input amplifier unit 4 which is detachably attached to a mounting portion 3 provided in the measuring instrument main body 2 according to the number of measurement channels. Some are formed entirely.

In this case, the input amplifier unit 4 has a resin panel portion 6 covered on the front side of a resin casing 5, and through input holes 6 a provided at both upper and lower ends of the resin panel portion 6. It can be fastened to the measuring instrument body 2 side by screws 7.

Each of the input amplifier units 4 has an internal structure (not shown) capable of forming a ground route between the input amplifier unit 4 and the mounting unit 3 when the input amplifier unit 4 is mounted on the mount unit 3. Is provided to reduce the occurrence of a potential deviation between the input amplifier units 4 after mounting, and to prevent the generation of noise, induced voltage, and the like entering the measurement system.

[0005]

However, in the case where only a grounding route is internally formed between the measuring instrument main body 2 and the input amplifier unit 4 as in the above-mentioned conventional example, It is not always possible to sufficiently reduce the potential deviation occurring between the input amplifier units 4 after the mounting, and the input amplifier units 4 and 4 interfere with each other to perform stable measurement. There were inconveniences such as being unable to do.

SUMMARY OF THE INVENTION In view of the above-mentioned problems in the prior art, the present invention provides an input amplifier unit in a measuring instrument in which a more preferable grounding route can be separately secured when the input amplifier unit is attached to the measuring instrument body. It is an object to provide a grounding structure.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object, and its structural features include a measuring instrument main body and a detachably mounted one which is attached to the measuring instrument main body.
In a measuring instrument including at least the input amplifier unit described above, an amplifier main body in which an amplifier substrate is housed in a resin casing having an opening on the front side, and a through hole that can be freely screwed to the measuring instrument main body. The input amplifier unit is formed by a resin panel part having a conductive insert fitting provided and covered by the opening of the resin casing, and the resin panel part is provided on a back side including a portion where the insert fitting is located. A conductive hole having a through hole on a surface facing the through hole to allow a screw to be inserted therein, fixed to a resin panel portion below the through hole, and having a ground route provided with the amplifier substrate; The input amplifier unit is provided with a connection plate, and a screw is screwed into a chassis portion of the measuring instrument main body through a through hole of the resin panel portion to make the conductive connection plate and the insert metal fitting close to each other. There the ground route provided between the conductive connection plate that is attached to the instrument main body is guided to the chassis portion.

[0008]

FIG. 2 is a longitudinal sectional view showing a main part structure of the present invention at a portion corresponding to the resin panel section 6 side of the input amplifier unit 4 in the measuring instrument 1 shown in FIG. FIG. 1 is an enlarged cross-sectional view of a main part showing a mounting structure of an input amplifier unit to a measuring instrument main body at a portion located in a circle surrounded by a dashed line in FIG.

[0009] According to these figures, the entire measuring instrument 11 includes, in addition to a display unit, a resin case main body 13 provided with an operation knob and a push button, and necessary parts (not shown) in the resin case main body 13. The main body 12 is composed of a chassis 14 used for arranging components and the like, and the main body 12 is detachably mounted to the mounting portions 15 provided on the main body 12 according to the number of measurement channels. And at least one input amplifier unit 21.

The input amplifier unit 21 covers an amplifier main body 22 in which an amplifier board 24 is housed in a resin casing 23 having an opening 23a on the front side, and the opening 23a of the resin casing 23. It is formed with the resin panel portion 25.

In this case, the resin panel section 25 has a through hole 26a for fastening to the chassis section 14 of the measuring instrument main body 12 using the screw 31, and contacts the front surface 13a of the resin case main body section 13. It is formed with a conductive insert fitting 26 at its upper end.

Further, as shown in FIG. 2, the resin panel portion 25 has a through hole 26a at a rear portion including the insert fitting 26.
Has a through hole 29 on the surface opposite to it, through which the screw 31 can be inserted. The lower side of the through hole 29 is fixed to the resin panel portion 25 via the caulking portion 27, and to the ground side of the amplifier board 24. And a conductive connecting plate 28 grounded via a lead wire 30
It has.

The conductive connecting plate 28 has a rear surface 28.
The surface height of the resin panel portion 2 is set to be equal to or higher than the surface height of the resin panel portion 25 on the back surface 25a side.
5.

Further, when the resin casing 23 is placed in the mounting portion 15 of the measuring instrument main body 12, the input amplifier unit 21 is mounted on the insert fitting 26 of the resin panel portion 25 which comes into contact with the front surface 13a of the resin case main body 13. On the other hand, a screw 31 is tightly screwed from the through hole 26a toward the screw hole 14a of the chassis portion 14 so that the screw 31 is detachably mounted on the measuring instrument main body 12 side.

As described above, by screwing the screw 31 into the screw hole 14a of the chassis portion 14 of the measuring instrument main body 12, the conductive connection plate 28 in a positional relationship facing the insert fitting 26 of the resin panel portion 25 is formed. , Is pressed toward the front surface 13a of the resin case main body 13, and as a result, the insert fitting 2 is
6, the ground route provided between the amplifier board 24 and the conductive connection plate 28 is changed to the conductive connection plate 28 → the insert fitting 26 → the screw 31 → the chassis part 1.
You can lead to 4.

Since the present invention is configured as described above, one or more input amplifier units 21 are detachably mounted on the mounting portion 15 of the measuring device main body 12 to be used as the measuring device 11. be able to.

More specifically, the side of the amplifier main body 22 of the input amplifier unit 21 is set in the mounting portion 15, and the upper end of the resin panel 25 is located on the front surface 1 of the resin case main body 13.
The screw 31 is sent from the through hole 26a of the insert fitting 26 to the through hole 29 of the conductive connection plate 28 under a positional relationship such that the screw 31 abuts on the screw hole 14a of the chassis portion 14. Accordingly, the input amplifier unit 21 can be mounted on the measuring instrument main body 12 side.

Further, by screwing the screw 31 into the screw hole 14a of the chassis portion 14 in this manner, the conductive connection plate 28 located between the front surface 13a of the resin case main body 13 and the insert fitting 26 is formed. As a result, the chassis portion 14 is pressed into contact with the insert fitting 26 through the screw 31.
A ground route is formed between the amplifier board 24, the conductive connection plate 28, the insert fitting 26, the screw 31, and the chassis 14.

Therefore, after the input amplifier unit 21 is mounted on the measuring instrument main body 12, a grounding system different from the conventional internal structural grounding route formed between the measuring instrument main body and the input amplifier unit is used. A new route can be formed to strengthen the grounding system.

For this reason, the mounting portion 15 of the measuring instrument body 12
Even if one or more input amplifier units 21 are installed,
The occurrence of a potential deviation occurring between the input amplifier units 21 is reliably suppressed so that the input amplifier units 21 and 21 are prevented.
Since undesired phenomena such as interference with each other can be eliminated, stable measurement can be performed.

It should be noted that the conductive connection plate 28 has a rear surface 28a.
When the resin panel portion 25 is disposed on the resin panel portion 25 such that the surface height on the side thereof is higher than the surface height on the back surface 25a side of the resin panel portion 25, the conductive connecting plate for the front surface 13a of the resin case body portion 13 is provided. 28 can increase the pressure contact force,
As a result, the grounding route from the amplifier board 24 to the chassis part 14 can be more reliably formed.

[0022]

As described above, according to the present invention, when one or more input amplifier units are mounted on a measuring instrument body via screws, the grounding route from the amplifier board to the chassis via the screws. Can be newly formed and the grounding system can be strengthened, so that the occurrence of potential deviations occurring between the input amplifier units is surely suppressed and the input amplifier units interfere with each other. A stable measurement can be performed by eliminating the undesired phenomena.

In the case where the conductive connecting plate is disposed on the resin panel portion such that the surface height on the back side thereof is higher than the surface height on the back side of the resin panel portion, the resin case body portion The contact pressure with the insert fitting can be increased accordingly by increasing the pressure contact force of the conductive connection plate against the front surface of the base plate, so that a grounding route from the amplifier board to the chassis can be formed more reliably.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a main part structure of the present invention corresponding to a circular surrounding portion in FIG. 2;

FIG. 2 is a longitudinal sectional view of a main part of an input amplifier unit constituting the present invention.

FIG. 3 is an essential part perspective view showing an example of a measuring instrument provided with an input amplifier unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Measuring instrument 12 Measuring instrument main body 13 Resin case main body part 14 Chassis part 15 Attachment part 21 Input amplifier unit 22 Amplifier main body part 23 Resin casing 23a Opening 24 Amplifier board 25 Resin panel part 25a Back surface 26 Insert fitting 26a Through hole 27 Caulking Part 28 conductive connection plate 28a back surface 29 through hole 30 lead wire 31 screw

Claims (2)

[Claims] 1. A measuring instrument comprising at least a measuring instrument main body and one or more input amplifier units detachably attached to the measuring instrument main body, wherein an amplifier substrate is provided in a resin casing having an opening on the front side. The amplifier main body accommodated therein, and a resin panel part covered with the opening of the resin casing having a conductive insert fitting having a through hole that can be screwed to the measuring instrument main body. An input amplifier unit is formed, and the resin panel portion has a through-hole on a back side including a portion where the insert metal fitting is located, the through-hole allowing a screw to be inserted in a surface facing the through-hole, and a lower side of the through-hole. The input amplifier unit is fixed to the resin panel portion and provided with a ground route between the amplifier substrate and the input amplifier unit. Screw The conductive connection plate and the insert fitting are brought into close contact with each other, whereby the grounding route provided between the amplifier board and the conductive connection plate is guided to a chassis portion and mounted on the measurement device main body. The grounding structure of the input amplifier unit. 2. The measurement according to claim 1, wherein the conductive connecting plate is disposed on the resin panel portion such that the surface height on the rear side is higher than the surface height on the rear side of the resin panel portion. Grounding structure of the input amplifier unit in the vessel.