JPH0452687Y2 - - Google Patents

Description

[Detailed description of the invention] <Field of industrial application> The present invention is an improvement of a two-range indicator that switches and indicates the input signal voltage of two thermocouples via a range unit using a commonly provided indicator. Regarding.

<Prior Art> FIG. 3 is a configuration diagram showing an example of the conventional technology.
1 is an input selection relay box, and 2 is a two-range indicator, which has a first range unit 201 and a second range unit 202, and the output voltages E _p1 and E _p2 of these range units are controlled via a changeover switch 203. and is input to the instruction section 204.

In input selection relay box 1, 101, 102
is an input selection switch, which selectively switches the input signal voltages E _i1 and E _i2 to the range units 201 and 20.
2, and if it is not selected, the input of the range unit is opened.

In the range unit 201, _A1 is a buffer amplifier with a gain of 1, which inputs the input signal voltage E _i1 through a filter circuit consisting of a resistor R ₁₁ and a capacitor C ₁₁ , and outputs an output voltage E _p1 .

E _b1 is a burnout voltage source, which is connected to the filter circuit via an input resistor R ₁₂ and overscales the output voltage E _p1 when the input signal voltage E _i1 becomes open due to a disconnection or the like.

That is, the operator notices an abnormality occurring in the indicator section due to overscaling of the output voltage E _p1 and determines that there is an abnormality such as a disconnection in the input section.

The burnout voltage source E _b1 and the input resistor R ₁₂ are set in the following relationship with respect to the input signal voltage E _i1 so that there is no error in the input signal voltage E _i1 during normal operation.

{E _b1 (ri + r) / (R ₁₂ + r _i + r)} {E _i1 where r _i is the internal resistance of the signal source that generates the input signal voltage E _i1 , r is the line resistance from the signal source to the filter circuit It is.

Note that the time from input abnormality to overscale can be arbitrarily set by changing the relationship between burnout voltage source E _b1 and input resistor R ₁₂ within a range that satisfies this condition.

The configuration on the range unit 202 side is exactly the same as the configuration on the range unit 201 side, and elements corresponding to those in 201 are indicated with a suffix 2.

<Problem to be solved by the invention> The problem with this configuration is that the input signal voltage of the range unit on the non-selected side is open, and the output is affected by the input voltage from the burnout voltage source. is in a saturated state due to overscaling, so even if the input signal voltage is connected to the input of the range unit by the selection switch, it takes time for the indication to stabilize.

The object of the present invention is to provide a two-range indicator that solves these problems.

<Means for Solving the Problems> The structural feature of the present invention is to apply two input signal voltages to range units each having a corresponding burnout voltage source, and to switch the outputs of these range units. In a two-range indicator that leads to a common indicator via means, the input of the range unit on the side not selected by the switching means is separated from the input signal voltage and connected to voltage dividing means for dividing the burnout voltage. The point is to encourage them.

<Function> According to the present invention, the input of the range unit on the side where the input signal voltage is not selected is inputted with the burnout voltage divided by the voltage dividing means, and the output voltage of the buffer amplifier is inputted to the input of the range unit on the side where the input signal voltage is not selected. Since the level within is maintained, the time required for the instruction to stabilize immediately after switching is shortened.

<Example> An embodiment of the present invention will be described based on FIG.

In this embodiment, we will mainly explain the characteristic parts of the present invention, and we will explain the burnout voltage source explained in Fig. 3.
E _b1 , input resistance R ₁₂ , and each component are given the same reference numerals, and their explanation will be omitted.

The feature of the present invention is that the input selection switches 101 and 102 in the input selection relay box have input signal voltages E _i1 ,
If E _i2 is not selected, connect dummy resistors R _d1 and R _d2 for voltage division to the inputs of range units 201 and 202, and set burnout voltages E _b1 and E _b2 with input resistors R ₁₂ and R ₂₂ . Voltage divider and buffer amplifier A ₁ ,
A feed into the input of ₂ .

The relationship between the dummy resistor and the input resistor is selected so that the value of the divided voltage is a value within the normal range output range of the output voltages E _p1 and E _p2 , for example, a value of 50%.

FIG. 2 shows another embodiment of the present invention, in which the input selection relay box is connected to the range unit 20.
It is divided into 1 ₁ and 1 ₂ corresponding to 1 and 202, and each relay box has the function of switching and inputting a plurality of input signals.

N ₁₁ , N ₁₂ ...N _1o is a group of input signals input to the relay box ₁₁ , and the changeover switches x ₁₁ , x ₁₂ ...
One is selected by x _1o and inputted to range unit 201 as E _i1 .

x ₁₁ ′, x ₁₂ ′……x _1o ′ is the changeover switch x ₁₁ ,
x ₁₂ . . . is a switch linked to x _1o , and has a function of connecting the dummy resistor R _d2 on the range unit 202 side to the input of the range unit 202.

N ₂₁ , N ₂₂ ...N _2o is a group of input signals input to the relay box ₁₂ , and the changeover switches x ₂₁ , x ₂₂ ...
One is selected by x _2o and input to the range unit 202 as E _i2 .

x ₂₁ ′, x ₂₂ ′...x _2o ′ is the changeover switch x ₂₁ ,
x ₂₂ . . . is a switch linked to x _2o , and has a function of connecting the dummy resistor R _d1 on the range unit 201 side to the input of the range unit 201.

<Effects of the invention> As explained above, according to the invention, for a range unit that does not select an input signal voltage, it is possible to divide the burnout voltage by connecting a dummy resistor, so that the output voltage can be adjusted within the range. Since the voltage can be maintained at a voltage within the range of 100 to 100, the stabilization time for instructions when switching range units can be shortened to the same level as when switching the input signal voltage of the same range unit.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing another embodiment of the present invention, and FIG. 3 is a block diagram showing an example of the prior art. DESCRIPTION OF SYMBOLS 1... Input selection relay box, 2... Range indicator, 201, 202... First and second range units, 203... Changeover switch, 204... Indicator, R _d1 , R _d2 ... Dummy resistor, E _b1 , E _b2 ...Burnout voltage source.

Claims (1)

[Scope of utility model registration request] In a two-range indicator, in which two input signal voltages are applied to range units each having a burnout voltage source provided correspondingly, and the outputs of these range units are led to a common indicator via a switching means, the switching means described above is provided. A two-range indicator characterized in that the input of the range unit on the side not selected is separated from the input signal voltage and connected to voltage dividing means for dividing the burnout voltage.