JPS5928793A - Signal transmitter - Google Patents

Abstract

PURPOSE:To prevent external disturbance such as noise from being transmitted to a control circuit, by providing a parallel circuit connected/disconnected with on/off of each analog switch and extracting an impedance output from both ends of the parallel circuit. CONSTITUTION:A voltage between connecting terminals 42, 43 is changed via remote control lines 40, 41 attended with the change in the resulting resistance of a variable resistor circuit 59 depending of the selected position of a temperature set switch 58. This voltage is applied to non-inverting inputs A2-A4 of operational amplifiers OP2-OP4 of a temperature set circuit 60 and compared respectively with a reference voltage of connecting points 65-67. Further, the amplifiers OP2-OP4 and analog switches AS1-AS3 are operated and plural kinds of impedance signals are transmitted from set signal lines 73, 74 connected across the parallel circuit 72 to a burning control circuit 75. Even if the remote control wires 40, 41 are made long, there is no care about the transmission of external disturbance such as noise invaded to the lines 40, 41 into the circuit 75 directly through the constitution above.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a signal transmission device suitable for transmitting setting signals such as temperature from a remote control circuit to a main body control circuit.

(B) Background Art In the conventional persimmon signal transmission device, a voltage signal corresponding to a set value is created in a remote control circuit, and this voltage signal is transmitted to a control circuit on the main body side via a remote control line. Because the remote control wire is long (if it is long, noise may enter the remote control wire and cause the control circuit on the main unit to malfunction. Also, it is difficult to generate a voltage signal to the control circuit at a remote location). When sharing the power supply for the control circuit on the main unit side, at least three remote control wires must be used for power supply and signal transmission, making it impossible to use inexpensive two-core cords and making wiring work complicated. It had the disadvantage of becoming

(c) Purpose of the Invention The present invention has been made in view of the above-mentioned facts, and is designed to be less affected by disturbances such as noise, and to allow two remote control wires to be used for both power supply and signal transmission. The purpose is to

B) Key Points of the Invention The feature of the present invention is that two connection terminals are interposed in a resistive voltage divider circuit that divides a predetermined DC voltage, and two remote control wires are led out from the two connection terminals. A variable resistance circuit is also connected between the terminals of the remote control line, and a plurality of operational amplifiers are provided to compare the voltage generated at the connection terminal with each different voltage, and the output of each operational amplifier is used as an input to turn on and off.
The idea is to provide a plurality of analog switches that are turned off, a parallel circuit that includes a plurality of resistors that are connected and separated when each analog switch is turned on and off, and to take out an inopedance output from both ends of the parallel circuit. A voltage corresponding to the resistance value of the variable resistance circuit is generated between the connecting terminals installed in the circuit, and the voltage is compared using an operational amplifier, and the output of the operational amplifier turns on and off multiple analog switches. By doing so, a plurality of resistors in the parallel circuit are connected and separated, and an impedance output that changes stepwise is taken out from both ends of the parallel circuit.

(E) Effects of the Invention Since the present invention is constructed as described in 5 above, it has the following effects.

(1) Since the voltage according to the set resistance value of the variable resistor installed between the terminals of the remote control line is finally converted to an impedance output, noise that has entered the remote control line is directly transmitted to the control circuit on the main unit side. B. Even if the remote control wire becomes long, there is no disturbance (・).

(11) Multiple operational amplifiers turn analog switches on and off by comparing the voltage at their connection terminals with different voltages, so that the impedance output changes step by step, so the operational amplifiers and amplifiers are able to withstand noise. The output is less likely to fluctuate and there are fewer malfunctions.011) Since the Ichihara voltage supply from the connection terminal to the variable resistance circuit and the voltage signal transmission from the variable resistance circuit to the connection terminal are performed simultaneously using two remote control wires, the remote control An inexpensive 2-core cord can be used for the wire,
Vinegar also makes line work easier.

(F) Embodiment of the Invention Below, in figure e, an embodiment in which the present invention is applied to a control circuit of a hot water boiler is explained based on the drawings, (1) is an AC power supply, (2) is a power switch, (3) is a drive device that drives combustion devices such as hot water boiler burners and fans, (4) is a step-down transformer, and (5) is a DC power supply circuit that performs AC-DC conversion, consisting of a rectifier, fixed type, pressure circuit, etc. , ((i) is the Inn constant power supply circuit 5), the common terminal (6c) is connected to the output terminal, and the normally open contact (6a
) and a normally closed contact (6b). (7) is an oscillator circuit with an alarm power terminal (6a) connected to the normally open contact (6a). 8) and the operating power supply terminal (9) connected to the normally closed contact (6b), directly fAf, and 71 to the Denryanagi circuit (5), respectively, and the first and second diodes (10) in the forward direction (marked). The 1st m wire (12) connected through 1)
an operational amplifier (OPI) to which power supply terminals (BA) and (BB) are connected, respectively; and a resistor (
15) and capacitor (Ifil, and resistor 07),
f18J, first bus bar (121, resistor (17), (18
), a resistor C(1) connected between the intermediate connection point O9 of (OPI) and a resistor 231 connected between the inverting input terminal (B1) of the resistor 05) and the intermediate bI power of the capacitor (16).

&, l) is a switching circuit, and the operating power supply terminal (9
A resistor C9, l connected in series between 1 and the second bus line αa
:41il, and resistance (3), C81 and NPN)
Ranjista 2! l+ and the base is a resistor 25), Q)))
NPN transistors C3'! whose collectors are connected to the intermediate connection points (2) and the emitters connected to the connection points (2 and 04) via resistors C31), respectively. A PNP transistor (351 and transistor 0) whose emitter is connected to the operating power supply terminal (9), whose base is connected to the intermediate connection point CS between
! ll) and a resistor (36) connected between the base of the second bus 04).

On is a remote control circuit installed in a place away from the hot water boiler, and the input/output terminals C38] and C39 are connected to the main unit side connection terminal (401, (old)) via the remote control wire (401, (old)
21, +431. In addition, the connection terminal (42) is connected to an operational amplifier (OPI) via resistors (411, (451)
is connected to the output terminal (C1) of the connection terminal (4:9 is connected to the base of the resistor (4G), (through the second motherboard 04) and the transistor 9), respectively. Resistance (45
), 4++;), resistor (+4), (voltage dividing resistor circuit that divides the constant voltage across the Zener diode (49) connected between the four intermediate connection points (18: and the second bus (11) The remote control circuit c37i has an input terminal (dl), (
1)) of the full-wave rectifier connected to d2), and the full-wave #current device 6
[Operation switch 51), resistor 521 and light emitting diode 63) connected in series between output side terminals (d3) and (d4) of V, resistor 6L'l and light emitting diode G: parallel to () Connected resistor 54) or ON series circuit, and resistor (55) or I5 depending on the input position.
Temperature setting switch that short-circuits 3 out of n (temperature setting switch)
5□, and the resistor l54) or an open series circuit and the temperature setting switch constitute a variable resistance circuit 69).

1) is a temperature setting circuit, and the non-inverting input terminal (A2) or A4) is commonly connected to the connection terminal (4; 9) through a resistor 61).
), the positive feedback R resistance 2) or 64) of the operational amplifier (OF2) or OF2), the connection point (48) and the second
Connected in series between the busbar (141 and the intermediate connection point 151
or Gη is the operational amplifier ((IF5) or (I
A resistor ((B2 or C11) connected to the inverting input terminal (B2 or B4) of F5) and an operational amplifier (OF2)
) or 0P4) output terminal (C2) or C4)
Analog switch (ASI) whose input ends are connected to
or AS3), an analog switch (ASI), a 1a series circuit of an analog switch (AS2) and a resistor (R1), a series circuit of an analog switch (AS3) and a resistor (R2), and a parallel circuit consisting of a resistor (R3). (1'
Connect 1. l+ to both ends of the parallel circuit. Setting signal line 7
31. C4) and an operational amplifier (OPl, )
or 0P4) uses a single power supply multiple operational amplifier IC that shares the power supplied to the operational amplifier (OPl). -1σ is a combustion control circuit, which includes a flame detection element such as CdS (σ6), a hot water temperature detection element such as a thermistor,
Connect the setting signal lines ff3) and (7, i) to the input side,
Based on these input signals, the relay for pre-barge operation and the relay for combustion operation σ9) are operated to give drive commands for the burner and fan to the drive device (3), and the safety relay 0) is operated in the event of an abnormality. There are 5 to 17 components that switch the safety switch (6) from normally closed contact (6b) to normally open contact (6a), and includes sequence circuit, switching circuit, memory circuit, width control) C11 circuit, timer circuit, etc. Next, the first example of the above-mentioned embodiment will be explained. Assuming that the power switch (2) is always closed, the 1114th
f+'! A DC power supply circuit (
5), a predetermined DC heavy pressure is supplied via the normally closed contact (6b) of the safety switch (6), the operating power terminal (9), and the second diode (11). At this time, transistor c3' of switching circuit 2.1+! I is a resistor C2(2ε1)K that divides the voltage of the operating power supply terminal (9),
4. More pace biased and conductive. Capacitor (
16) is short-circuited, the voltage of the first bus 02) appears at the output terminal (C1) of the operation up (OPI).
■It emits a 1″ output, and the oscillation circuit (force oscillation stops + h
I'm there. In addition, when the operation switch (51) is open, the light emitting diode 5: () is turned off, indicating that the hot water boiler is in the stop F state, and the pace potential of the transistor (, '9+ is The transistor 09) is cut off and the transistor OFF 35) is not conductive, and there is no voltage between the output terminal C34) and the reference terminal 03), so the combustion control circuit a9
is not operating, and the drive circuit 3) is also stopped.

When the operation switch 6υ is turned on from such a state, the operational amplifier (OPI) outputs a "H" output and the DC constant voltage generated across the Zener diode (49) becomes a resistance (center, (flit and the combined resistance of the remote control circuit (3γ).
), the light emitting diode 6.3j lights up (continuously), indicating that the hot water boiler is in operation.
, (4, Due to the voltage generated at dusk, the transistor C29
) & a pace bias is applied, and the transistor (2
9J7! In order to make the transistor C3m conductive, the power supply voltage of the DC power supply circuit (5) is supplied between the reference terminal 031 and the combustion control circuit (75
) starts operating, and also the temperature setting switch 68)
The combined resistance of variable resistance circuit 5'l is 4 depending on the input position of
As the level changes, the voltage at the connection terminal (4:N) changes, and this voltage is applied to the operational amplifier (O
F2) or OF2) is supplied to the non-inverting input terminal (A2) or A4), respectively, and is compared with the reference voltage of the operational amplifier (O
F2) (・Shuku0P4) and analog switch (ASI)
) or AS3) operates as shown in Table 1, and the parallel circuit is 0.
Four types of impedance signals are sent from the setting signal line +731 (74) connected to both ends of 2) to the combustion control circuit ff5). This is a state in which the voltage at the input terminal is higher than the voltage at the inverting input terminal, and the voltage at the first bus (12) appears at the output terminal, and 'L''
In the opposite case, the output terminal of the operational amplifier is connected to the second bus (1
4) is at the same potential.

In this way, when the operation switch 6υ of the remote control circuit U71 is turned on, the combustion control circuit σ9 is energized and starts operating, and the hot water temperature is detected while monitoring the presence or absence of ignition based on the input from the flame detection element ffb). The input from the element (77) is compared with the impedance input from the set signal lines σ, ri, and σa to instruct the drive 1 path (3) to perform a blip-purge or combustion operation. For example, depending on the closing position of the temperature setting switch 68), the setting signal Katsutetsu, (IIJ (
1) By changing the impedance, the hot water temperature is controlled as shown in Table 2. In other words, when the temperature setting switch (58) is in the ON position 16' from A to C, the hot water temperature is 80' respectively. C160℃
It is maintained at 40°C, and when it is put into the oven, it is maintained at 5 to 1°C to prevent freezing in winter.

If any abnormality occurs while turning on the J switch 61), the combustion control circuit 1 i'? The safety relay (6) is operated and the safety switch (6) is switched from the normally closed contact (6h) to the normally open contact (6a). Therefore, the j1F transfer market υ9 terminal (9) loses voltage and is replaced by the alarm power terminal (8
1KiNM "Power supply circuit (51&") A predetermined DC voltage is supplied. Then, DC voltage is supplied through the first motherboard diode (10), but the switching circuit ( 21), the second diode (11) acts as a reverse VC and the voltage increases.

Transistors 1 and 9), ((!+,C)5
) are all shut off and the operation of the combustion control circuit (7!'i) is stopped.
At the same time, the capacitor Q6 of the oscillation circuit (7)
Therefore, all combustion operations in the hot water boiler will be stopped and the hot water boiler will be maintained in a safe state. In addition, the oscillation circuit (7) alternately outputs I-1" and "(, D) to the output terminal (C1) of the operational amplifier (OPI) by charging and discharging the capacitor (16) via the resistor (15). In order to generate an output, the oscillation output of the oscillation circuit (7) is also connected to the input side of the remote control circuit (3η light emitting diode 5: () to blink to indicate an abnormal condition. In this case, the temperature setting circuit 0). However, since the combustion control circuit 65) has stopped operating, there is no problem. Then, after turning off the +4 source switch (2) and repairing the abnormality, the hot water boiler resumes normal operation by manually returning the safety switch (6) to the normally closed contact (6b).

According to this implementation, the Zener diode is 0.
→2 ill￥1 to the resistor voltage divider circuit that divides the voltage across both ends of →
Interpose the connection terminal 0 (4, ri) and connect the connection terminal (41 (,
(Deriving the two remote control wires C4 [(411) from the mouth and connecting the remote control wires (41, (resistance 54 between the terminals of 4υ)
Connect the variable resistance circuit 61[) consisting of the temperature setting switch 6→ and the temperature setting switch 6→, and connect the connection terminal (the voltage generated on the fourth floor and the voltage generated at the junction point !i) or σj7+I・ζ to generate different voltages. Three operational amplifiers (OF2 or OF2) are provided to compare the voltage, and three analog switches (ASI) are used to turn on and off the output of each operational amplifier as input.
or AS3) is provided, and a parallel circuit 62) including three resistors (R1 or R3) connected and separated by turning on and off each analog switch is provided, and the parallel circuit ffa
Since the impedance output is taken out from the setting signal lines σ3) and C4) connected to both ends of and supplied to the combustion control circuit (75) as a set temperature signal for hot water, the remote control wires (4tl) and ( Even if the remote control line (41) becomes long, there is no worry that disturbances such as noise that have entered the remote control line (4(σ, (41)) will be directly transmitted to the combustion control circuit q(g).

In addition, the reference voltage of the operational amplifier (OF2) or OF2) is set to a different value, and the impedance output is taken out in stages, so the output of the operational amplifier (OF2) (OF2) fluctuates with respect to noise. This reduces the risk of the combustion control circuit (75) malfunctioning. Furthermore, two remote control wires (41υ, (connection terminal (42
1, (4, 9 variable resistance circuit 159) and the voltage signal transmission from the variable resistance circuit t59) to the connection terminal (42) and old are performed at the same time, and the operation signal is It is possible to perform simple remote control using an inexpensive two-core cord, such as transmission of transmission and display signals, and wiring and wiring can be easily performed.

[Brief explanation of drawings]

The figure is an electrical circuit diagram showing an embodiment in which the present invention is applied to a control circuit for a hot water boiler. (401, (41)...remote control line, f121, (4
3 [... connection terminal, f! i! l) ・Variable resistance circuit,
(l!(・-1) and column circuit, ((II)2)~(o
p, +)... operational amplifier, (Sl to 7) ~ (A
S3)...Analog switch, (R1)~(R
3)...Resistance. Applicant: Sanyo City Machinery Co., Ltd. (Yu) 1 person

Claims (1)

[Claims] (1) Two connection terminals are interposed in a resistive voltage divider circuit that divides a predetermined DC voltage, two remote control wires are led out from the two connection terminals, and a variable resistor is connected between the terminals of the remote control wires. Connect the circuit, provide multiple operational amplifiers that compare the voltage generated at the connection terminal with each different voltage, provide multiple analog switches that turn on and off using the output of each operational amplifier as input, and A signal transmission device characterized by providing a parallel circuit including a plurality of resistors that are connected and separated by turning on and off, and extracting an impedance output from both ends of the parallel circuit.