JPH0612263B2 - Transducer - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a transducer for converting a physical quantity such as current, voltage, temperature, or pressure into a linearized output in a predetermined range, and is particularly characterized by a relay output. It concerns a transducer.

[Outline of Invention]

Transducers according to the present invention include current, voltage, temperature,
The input signal within a predetermined range of physical quantity such as pressure is converted into a signal of a predetermined level, and the upper and lower limit values of the input signal are set in the storage means in advance, and when the input signal exceeds the upper and lower limit values, a relay is performed. It is an integrated function of the meter relay that outputs the output. And when only one of the upper and lower limits is set,
I am trying to operate the relays at the same time.

[Background of the Invention]

A conventional transducer, for example, a voltage transducer, converts an input voltage of, for example, AC0 to 150V of an instrument transformer (PT) into a DC voltage in a predetermined range, and a current transducer converts a current obtained from a current transformer (CT) in a certain range. Converted to DC voltage. Such various conventional transducers have only the function of converting into a DC voltage in a predetermined range corresponding to the input physical quantity. Then, it is necessary to use a meter relay to display the input value and set the lower limit value and the upper limit value of the input value, and to obtain the output when exceeding the range. However, since the transducer and the meter relay are independent devices and need to be separately wired, the wiring becomes complicated and the installation space becomes large. In addition, the output voltage of the transducer and the upper and lower limit values at which the meter relay operates do not always match, which makes it difficult to use.

[Object of the Invention]

The present invention has been made in view of the above-mentioned problems of the conventional transducers, and when a transducer for converting an input signal into a DC voltage in a predetermined range has a function of setting a predetermined range of an input value and exceeding the range. It is an object of the present invention to provide a transducer in which the function of a meter relay for obtaining an output is added and integrated, and the relays are simultaneously operated when only one of the upper and lower limit values is set.

[Constitution and effect of the invention]

The present invention is a transducer for converting an input signal into a signal of a predetermined level corresponding thereto, an A / D converter for converting an analog input signal into a digital signal, and upper and lower limits for setting an upper limit value and a lower limit value of the input signal. A value setting means, a storage means for storing the current value and the upper and lower limit values set by the upper and lower limit value setting means, an input signal A / D converted by the A / D converter, and the storage means. A comparing means for comparing the lower limit value, two relays which are respectively driven when the current value exceeds the upper and lower limit values by the comparison of the comparing means, and A
When a D / A converter for converting an input signal A / D converted by the / D converter into a signal proportional to the level of the input signal and either one of the upper and lower limit values by the upper and lower limit value setting means is not set, And a control means for driving the two relays at the same time when the value exceeds the set upper and lower limit values.

According to the present invention having such a feature, it is possible to obtain a linearized output in a predetermined range corresponding to the input signal, and when the input signal exceeds the range of the upper and lower limit values set by the upper and lower limit value setting means. It is possible to obtain a transducer having a function of a meter relay that obtains an output. When either the upper limit value or the lower limit value is set in the transducer, the respective relays are operated simultaneously when the input signal exceeds the upper and lower limit values. In this way, the power supply switching capability can be increased by using the two relays, and the second relay output can be used for controlling a circuit different from the normal operation. The display of the transducer and the output when the upper and lower limit values are exceeded are not different, and the transducer can be easily used. Further, the wiring of the input portion is reduced as compared with the case where the conventional transducer and meter relay are used, and the configuration can be simplified. Further, it is possible to reduce the size and cost as compared with the case where two devices are used.

[Explanation of Examples]

(Structure of Embodiment) FIG. 1 is a block diagram showing an electric structure of an embodiment of a transducer according to the present invention, and FIG. 2 is a front panel view thereof. In this embodiment, an AC input of 0 to 150 V is set to 0
It is a transducer that converts to a DC output of 5V. In these figures, the input buffer 2 is connected between the input terminals 1a and 1b. The input buffer 2 receives an AC input with high impedance, divides the voltage, rectifies the divided output, and supplies the rectified output to the A / D converter 3. The A / D converter 3 converts an analog signal given at a predetermined timing into a digital signal and gives its output to the microcomputer 4. The microcomputer 4 is a control element having a microprocessor, an input / output interface, and a storage means having a control program and a register group shown in the drawing. A register in the microcomputer 4 has a PV flag, an H flag, an L flag indicating a display state, and an XH flag, an XL flag, and an upper limit value which are set when the current value exceeds the upper limit value and the lower limit value and the relay is driven. or each stand is H _P flag when the lower limit value is set, the flag register is provided with a L _P flag, further PV value register which stores the current value, H set value register for storing an upper limit set value, the lower limit set An L set value register for storing a value is provided. The microcomputer 4 is also connected with a slide switch SL1 for switching between the set mode and the run mode, push button switches PB1 to PB4 for setting numerical values for sequentially switching the display of each digit of the display, and a push button switch PB5 for switching the display contents. Further, the output of the model selection switch 5 is given. The model selection switch 5 provides data for setting this transducer to a predetermined input / output specification, and it is necessary to use the input buffer 2 corresponding to the input / output specification. The microcomputer 4 gives the present value to the display 6 and the latch circuit 7 at predetermined time intervals based on these inputs given from the outside.
The latch circuit 7 holds the output of the microcomputer 4 for a predetermined time, and supplies the output to the D / A converter 8. The D / A converter 8 converts the digital signal into an output corresponding to the signal, for example, a direct current output of 0 to 5 V, and then a terminal 9
It is given to the outside via a and 9b. The microcomputer 4 checks whether the input value exceeds the upper limit value and the lower limit value, and if the upper limit value and the lower limit value are exceeded, an output is given to the output buffer 10. Output buffer 1
0 is relay XH or relay XL corresponding to these inputs
Is to drive. The relays XH and XL have normally-open contacts connected between the terminals 11a, 11b and 12a, 12b, respectively, and output from these terminals to the outside. Further, when driving the relays XH and XL, the output buffer 1
From 0, the light emitting diodes 13 and 14 (hereinafter referred to as LEDs) on the upper part of the panel are respectively driven. Also, L for PV display showing the current output of the display 6 from the microcomputer 4.
An ED 15, an H display LED 16 and an L display LED 17 are connected. On the other hand, commercial AC power is applied to the power supply unit 19 from the terminals 18a and 18b to supply DC power to each unit.

(Upper / Lower Limit Value Setting Operation) Next, the operation of the transducer of the present embodiment will be described with reference to the flowchart. FIG. 3 is a flow chart showing the operation when setting the upper limit value and the lower limit value for giving a relay output from this transducer, and FIGS. 4 and 5 are flow charts in the operation mode. When the operation is started, first in step 21 of FIG. 3, it is checked whether or not it is the set mode. If the switch SL1 is set to the set mode, the routine proceeds to step 22, where it is checked whether or not the push button switch PB5 is pushed. If this push button switch is pressed, the PV flag, H flag, and L flag of the flag register are updated so as to be sequentially set (step 23), and the process proceeds to steps 24 and 25 to see if the H flag or L flag is set. Check if Step if H flag is set
From 24, proceed to step 26, turn off LED17, LED1
6 is turned on, "H" is displayed on the panel surface, and the upper limit value setting routine 27 is entered. In this routine 27, if the push button switches PB1 to PB4 for setting the numerical values are pressed, the display 6
The numerical value of each digit is set, and the upper limit value is stored in the H set value register. Then, in step 28, it is checked whether or not there is an upper limit value setting input. If there is an input, the process proceeds to step 29 to set the _HP flag. repeat. When the L flag is set in step 23 by updating the flag register, the process proceeds from step 25 to step 30 to turn off the LED 16 and turn on the LED 17 to display "L" on the panel surface. When the push button switches PB1 to PB4 are pressed, as in the routine 27, the numerical value of each digit of the display 6 is set, and the lower limit value is stored in the L set value register in the memory. To do. And checks whether there is a lower limit setting input proceeds to step 32, sets the L _P flag in step 33 if there is setting. If there is no lower limit input, the process returns to step 21 and the same process is repeated without performing this process. In this way, the setting process of the upper and lower limit values in the set mode ends.

(Operation in run mode) Changeover switch SL when setting of upper limit and lower limit is completed
Set 1 to run mode. In step 21 and step 40, the microcomputer 4 of the transducer checks whether it is the set mode or the run mode. If it is not the run mode, the procedure proceeds to step 21, and if it is the run mode, the procedure proceeds to step 41 and the subsequent push button switch. Inputs PB1 to PB4 are invalidated. And step
At 42, the data of the model selection switch 5 is read and the input / output specifications are determined correspondingly. For example, if the transducer of the present embodiment is a transducer that converts an AC voltage of 0 to 150 V into a DC voltage of 0 to 5 V corresponding to it, the specifications are set so as to meet the respective specifications from steps 43 and 44. Then, the input voltage applied from the input terminals 1a and 1b is rectified by the input buffer 2 and divided. Since the output is added to the A / D converter 3,
A sampling pulse is given from the microcomputer 4 to the A / D converter 3 at predetermined intervals, the data converted into a digital value is fetched and written in the PV value register in the memory (step 45). Then, the routine proceeds to step 46, where it is checked whether or not the H flag is set, and if this flag is set, the upper limit value held in the already stored H set value register is displayed on the display unit 6 and , LEDs 15 and 17 are turned off and LED 16 is turned on to display the H set value (steps 47 and 48). Step 49
If the L flag is set at, the lower limit value held in the L set value register in the memory is displayed on the display 6 in the same manner (step 50), the process proceeds to step 51, and the LEDs 15 and 16 are turned on. It is turned off and the LED 17 is turned on to display the L set value. Further, if the H flag and the L flag are not set in steps 46 and 49, the PV flag is set, so the routine proceeds to step 52 and step 45.
The present value in the PV value register fetched by is displayed on the display 6 and is also given to the latch circuit 7 to be temporarily held. Next, in step 53, the LEDs 16 and 17 are turned off, the LED 15 is turned on to display the current value, and the D / A
A DC voltage of 0 to 5V corresponding to the input voltage is output from the converter 8 to the outside from terminals 9a and 9b (step 5).
Four).

Then H _P flag goes to step 55 as shown in Figure 5 to check whether erected. Since the upper limit is H _P flagged if set, checks whether Similarly L _P flag goes to step 56 is erected. Since only the upper limit value is set when the L _P flag is not set, step 57
Then, it is checked whether the current value in the PV value register exceeds the set value in the H set value register (step 57). If the current value does not exceed the H set value, XH, X
The L flag, the XH, XL relays, and the LEDs 13, 14 are turned off (step 58). If the H set value is exceeded, the XH, XL flags and the XH, XL relays are turned on and the LEDs 13, 14 are turned on in step 59. . Further checks whether Unless H _P flag is set at step 55 is L _P flag goes to step 60 are erected. If this flag is set, only the lower limit value has been set, so the routine proceeds to step 61, where it is checked whether the current value in the PV value register is less than or equal to the L set value. If it is not less than the L set value, the same processing as step 58 is performed in step 62, and if it is less than the L set value, the same processing as step 59 is performed in step 63. Since upper and lower limit value is set if the L _P flag is set in step 56, the set value of the current value H setting value register PV value register proceeds to step 64 without performing the processing described above Check if it is over. If the current value does not exceed the H set value, the XH flag, the XH relay and the LED 13 are turned off (step 65),
If it exceeds the H set value, the XH flag and the XH relay are turned on and the LED 13 is turned on in step 66.
Then, in step 67, it is checked whether or not the current value in the PV value register is less than or equal to the L set value. If there is X
The L flag and the XL relay are turned on to turn on the LED 14 (step 69). After completing these processes, the routine proceeds to step 70, where it is checked whether or not the push button switch PB5 is pushed. Meanwhile After the process of step 58, 59 or step 62, 63, or proceeds in step 60 to step 70 without performing these processing unless L _P flagged. If the push button switch PB5 is not pressed, the process returns to step 40 and the same processing is repeated. If the push button switch PB5 is pressed, the PV flag, the H flag and the L flag in the flag register are sequentially updated. Then (step
71) Return to step 40.

By doing this, it is possible to display the input voltage and obtain a DC linearized output corresponding to the input voltage. Furthermore, if the upper and lower limits of the input are set by two set value registers, and if these ranges are exceeded, A transducer having a function of a meter relay that obtains an output can be obtained. When only one of the upper limit value and the lower limit value is set, the two input / output relays are opened and closed at the same time, so that the power supply opening / closing capability is increased and the control of another circuit becomes possible. .

Although the present embodiment has described the transducer that converts an AC voltage in a predetermined range into a DC voltage, a transducer that accepts different inputs by changing the input specifications in the input buffer and the operation mode, for example, an AC current or a DC current is detected. The present invention can be applied to a transducer that converts the temperature of a transducer or thermocouple or the output of a tacho generator or the output of a potentiometer into a signal in a predetermined range.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a transducer according to the present invention, FIG. 2 is a front panel view thereof, and FIG. 3 is a flow chart showing an operation in a set mode for setting upper and lower limit values, FIGS. FIG. 5 is a flowchart showing the operation in the run mode. 2 ... Input buffer, 3 ... A / D converter, 4 ... Microcomputer, 5 ... Model selection switch, 6 ... Display, 7 ... Latch circuit, 8 ... D / A converter, 10 …
... Output buffer, XH, XL ... Relay, 13-17 ...
… Light emitting diode

Claims (1)

[Claims] 1. A transducer for converting an input signal into a signal of a predetermined level corresponding thereto, wherein an A / D converter for converting an analog input signal into a digital signal and an upper limit value and a lower limit value of the input signal are set. Upper and lower limit value setting means, storage means for storing a current value and upper and lower limit values set by the upper and lower limit value setting means, an input signal A / D converted by the A / D converter, and the storage means A comparing means for comparing the held upper and lower limit values, two relays that are respectively driven when the current value exceeds the upper and lower limit values by the comparison of the comparing means, and an A / D converter for the A / D converter. A D / A converter for converting the converted input signal into a signal proportional to the level, and an upper / lower limit to which a current value is set when one of the upper / lower limit values is not set by the upper / lower limit setting means. value And a control means for driving the two relays at the same time.