JP2804339B2 - Transmission unit - Google Patents

Description

The present invention relates to a transmission unit applied to an information transmission system such as a disaster prevention and crime prevention system and a robot control.

(B) Conventional technology An information transmission system including a remote sensing system includes a controller, a terminal installed at an arbitrary place, and a transmission line connecting the terminal and the controller. Is collected and processed by the controller, and information is transmitted from the controller to each terminal. In such a remote sensing system, information exchange between the controller side and the sensor terminal side is generally performed by multiplexing signals. That is, multiplex transmission of signals is realized by frequency division or time division.

(C) Problems to be Solved by the Invention However, in the information transmission system by multiplex transmission, it is necessary to provide a transmission control unit on each of the controller side and each sensor terminal side, and there is a disadvantage that it becomes very expensive.

SUMMARY OF THE INVENTION An object of the present invention is to provide a transmission unit of a new system which does not require the transmission control unit as described above.

(D) Means for Solving the Problems According to the invention described in claim (1), a two-wire current path for supplying a current to each of the sensor terminals connected in parallel with the controller as a current source is provided, Each sensor terminal forms a first current path and a second current path in this order from the controller side of the current path to the subsequent sensor terminal side between the input line of the two-wire type current path and the ground line. Shunt circuit, a sensor for opening and closing a second current path constituted by the shunt circuit, and a controller side of the current path is switched to the second current path when not in operation and to a sensor terminal side at the subsequent stage when in operation. A gate circuit, and a delay switching circuit that activates the gate circuit with a certain delay after energizing the shunt circuit, wherein the controller controls the current during the sequential operation of the gate circuits of the sensor terminals. Characterized by comprising a current detecting circuit for detecting the magnitude of current flowing through the road.

According to a second aspect of the present invention, a two-wire current path for supplying a current to each of the sensor terminals connected in parallel with the controller as a current source is provided. A sensor that opens and closes the current path formed between the input line of the path and the ground line, a variable impedance circuit that changes the impedance value of the current path according to the operating state of the sensor, and the input line of the current path is connected to the current source A first gate circuit that connects between the input line of the current path and the sensor in the current path for a certain time T1 from the time when the current is input, and a certain time T2 (T2> T1) a second gate circuit that connects between the controller on the input line of the current path and the subsequent sensor terminal at the time of elapsing, wherein the controller operates while the first gate circuit of each sensor terminal operates sequentially. You And a current path current detection circuit for detecting the magnitude of the current flowing through the current path.

The invention described in claim (3) is characterized in that the sensor is provided so as to be capable of coming and going with respect to the variable impedance circuit, and a data transmission path for transmitting output data from the controller to each of the sensor terminals; An output circuit for switching an output according to the presence or absence of output data on the data transmission path while the gate circuit connects the input line of the current path and the sensor in the current path.

The invention described in claim 4 is the invention according to claim 3, wherein the output data detection means for detecting output data of the data transmission path and a power supply supplied through a path different from the data transmission path. An output signal switching circuit that is driven and outputs an output switching signal when output data is detected by the output data detection means, wherein the output circuit is configured.

The invention described in claim (5) provides the above-described claim (2) to (5).
The invention described in (4) is characterized in that the switch element included in the second gate circuit is constituted by a MOSFET.

The invention described in claim (6) is characterized in that, in the invention described in claims (1) to (5), one or a plurality of the sensor terminals are configured as an integrated terminal block. .

(E) Operation FIG. 1 shows a configuration diagram of a remote sensing system using the transmission unit of the invention described in claim (1). In the figure, 1 is a controller, 2 is a sensor terminal, and each sensor terminal 2 is cascaded in parallel with the controller 1 and connected by a two-wire current path 3.

The sensor terminal 2 is on the current source side (upstream side) of the current path 3 on the sensor circuit side composed of a series circuit of the resistors R1b, R2b,... And the sensors S1, S2. , That is, a shunt circuit including resistors R1a, R2a,... That shunt the current flowing through the current path 3 while providing gate circuits G1, G2,.
A delay switching circuit RY composed of, for example, a relay for operating the gate circuit G (G1, G2,...) To connect the current source side to the load side with a delay for a predetermined time after the current is supplied to the shunt circuit.
(RY1, RY2, ...). Further, the controller 1 includes a current source 1a for supplying a current to the current path 3.
And a current detection circuit 1b for detecting the magnitude of the current flowing through the current path 3.

That is, in each sensor terminal 2, the first R1a of the shunt circuit is connected between the input line of the current path 3 and the ground line.
And a second current path connecting the gate circuit G1, the resistor R1b of the shunt circuit, and the sensor S1 are formed,
When a current is supplied to the sensor terminal 2 via the input line of the current path 3, the gate circuit G1 connects the input line of the current path 3 to the second current path. Thereafter, when a certain time has elapsed, the gate circuit G1 is switched by the delay switching circuit RY1 to the current circuit 3
Is connected to the sensor terminal 2 at the subsequent stage.

In the remote sensing system with the above configuration,
Now, the issue on signal to the current source 1a of the controller 1, first, the closest shunt path of the sensor terminal 2 to the controller 1, i.e., the current i ₁ flows through the resistor R1a. At the same time, current also flows through the delay switching path RY1, and this circuit operates.
The gate circuit G1 is in a non-operating state so that a current flows through a sensor circuit including the resistor R1b and the sensor S1. At this time, if the sensor S1 is off, the current i ₂
Does not flow. That is, ignoring the current flowing through the delay switching circuit RY1, the current flowing with respect to the sensor terminal becomes only the current i ₁ flowing through a shunt circuit resistance R1a.

Next, when the delay switching circuit RY1 is delayed for a certain period of time to activate the gate circuit G1, the gate circuit G1 switches the current source side of the current path 3 to the load side, that is, to the subsequent sensor terminal side. Then, together with the current i ₁ flows with respect to a shunt circuit of the sensor terminal 2 of the second-stage resistor R2a, the drive current flows also to the delay switching circuit RY2. Also in the second stage sensor terminal 2, if the sensor S2 is in the off state, the current flowing to the sensor terminal 2 is i ₁
Only. Therefore, when the sensors S1 and S2 are both off, the current flowing in the current path is i ₁ + i ₁ . When the current i ₁ to the resistor R2a is a predetermined time has elapsed since the flow gate circuit G2 is switched for connection to the load side, followed by a current i ₁ flows with respect to shunt circuit of the third-stage sensor terminal. Hereinafter, the above operation is repeated in a similar manner.

FIG. 2A shows a change in the current flowing through the current path 3 when all 128 sensors are off.
If the resistance value of the shunt circuit (R1a, R2a,...) Of each sensor terminal 2 is kept constant, a constant delay time t as shown in FIG.
Each time, the magnitude I of the current flowing through the current path 3 increases stepwise. The current I flowing through the current path 3 when the n-th gate circuit Gn operates is I = (V / Rx) × n (where Rx = R1a = R2a =... = R128a). On the other hand, if the sensor S is in the ON state in one sensor terminal 2, the current i ₂ flowing until a predetermined time t from when the current starts to flow in the shunt circuit of the sensor terminal 2 has elapsed. Now, assuming that the sensor S4 is in the ON state in the fourth stage sensor terminal having the gate circuit G4, the current path 3
The change of the current I flowing through the circuit becomes as shown in FIG. 2 (B). That is, the magnitude of the current I flowing through the current path 3 when the gate circuit G3 of the third-stage sensor terminal 2 current flows through the sensor terminal 2 of the fourth stage operates is increased by the amount of current i _2. After the current source 1a is turned on and the current starts to flow through the current path 3, the first sensor terminal (n
The current I flowing in the current path 3 when the current starts to flow in (stage 2) 2 is as follows: I = (V / Rx) × n + V / Rs (where Rs = R1b = R2b =... = R128b) .

From the above operation, in the controller 1, the current source
When a current that increases every fixed time t from when 1a is turned on is detected, and when it is detected that the current I at a certain time increases by the current i _2, a sensor at the last stage where the current flows at that time is detected. The position of the terminal 2 is detected. For example, in the example shown in FIG. 2B, the sensor terminal 2 having the gate circuit G4
Of the sensor S4 is in the ON state.

Note that in certain sensor terminal 2, when the sensor S is in the ON state, but will flow a current having a magnitude by adding i ₂ and i ₁ to the sensor terminal 2, a gate circuit G after a predetermined time t for the current source side of the current path 3 becomes operating state is to be connected to the load side, no current i ₂ flows after the switching connection. Therefore, as shown in FIG. 2 (B), when the current source 1a is connected to the next subsequent sensor terminal 2, the magnitude of the current I flowing through the current path 3 becomes small. As a result, when the current source 1a is connected to the last-stage sensor terminal 2, and the gate circuit G operates in the last-stage sensor terminal 2, the magnitude of the current I flowing through the current path 3 is I = (V / Rx) × (number of sensor terminals). Assuming that V is 24 V, Rx is 24 KΩ, and the number of sensor terminals 2 is 64, the current I when the current source 1a is connected to the last-stage sensor terminal 2 and a certain time t has elapsed, ignores the line impedance. In this case, I = (24V / 24KΩ) × 64 = 64mA.

Further, since the current i ₂ does not flow through the plurality of sensor terminals 2 at the same time due to the above operation, the current path 3
The maximum current I _max flowing through the, Rs (= R1b, = R2b = ···)
Is 120Ω, I _max = (24V / 24KΩ) × 64 + (24V / X120Ω) = 64mA + 200mA = 264mA. Thus, the magnitude of the maximum current flowing from the controller 1 to the current path 3 does not increase so much. This is because there is no flow through a current i ₂ is the sensor terminal 2 at the same time as described above. Such a current can be sufficiently supplied in the current source 1a.

In the controller 1, the flow source 1a is turned off once and then turned on again after a certain period of time t has passed since the current source 1a was connected to the last stage sensor terminal. Then, the above operation is repeated again from the beginning.

According to the above operation, the controller 1 and the sensor terminal 2 do not require a conventional transmission control unit, and can be configured with an extremely simple configuration at low cost.

Further, in the transmission unit having the configuration described in claim (2), when the current source on the controller side is driven, first, the first stage sensor terminal closest to the controller has the first terminal.
Is turned on for a certain period of time T1, and a current is supplied to the sensor circuit side of the first stage sensor terminal. Since the circuit impedance of the sensor circuit changes according to the operating state of the sensor, the current flowing in the current path at this time has a magnitude corresponding to the operating state of the sensor.

When the predetermined time T1 has elapsed, the first gate circuit is closed, and no current is supplied to the sensor path side. Then, when a certain period of time T2 (T2> T1) elapses from the time when the current source side of the current path of the sensor terminal is connected to the current source after a further time has elapsed, the second gate circuit is opened. When the second gate circuit is opened, the current source side is connected to the load side. That is, the current source is connected to the sensor terminal of the next stage.
When the current source is connected to the second-stage sensor terminal in this manner, the first-stage sensor terminal of the second-stage sensor terminal is again set for the fixed time T1.
Is opened, and current is supplied to the sensor circuit side. Hereinafter, the above operation is repeated.

That is, on the controller side, the current flows to the sensor circuits in the first, second, third,..., Nth stage sensor terminals at regular time intervals T2 after the current is supplied to the first sensor terminal. The current will be detected. In other words, every fixed time T2, in order from the first sensor terminal,
The sensor operation state of each terminal can be detected from the magnitude of the current on the controller side.

Also, in the above-described sensing method, when a sensor operation state of one sensor terminal is detected, no current flows to the sensor circuit of another sensor terminal. Therefore, even when sensing is performed at a sensor terminal that is far away from the controller side, the magnitude of the current flowing in the current path can be small, and therefore, the drop voltage at the second gate circuit is small, and the sensor terminal that can be connected can be connected. Can be considerably increased.

Further, in the invention described in claim (3), when the current source on the controller side is driven, the first gate circuit is activated for a predetermined time T1 from the sensor terminal close to the controller.
Only during this time, the current source side is connected to the sensor circuit side during this time. At this time, when output data is output from the controller via the data transmission path, the output data is taken into the output circuit, and the output changes according to the output data.

Further, if the sensor constituting the sensor circuit is kept connected, the current state in the sensor circuit is detected on the controller side according to the operation of the configuration described in claim (1), so that each sensor terminal is connected to the sensor terminal. The operating state of the connected sensor can also be detected, and the transmission unit can be used as an input / output unit. On the other hand, when the sensor is removed, the transmission unit can be used as an output unit that only outputs data from the output circuit.

According to a fourth aspect of the present invention, in the configuration according to the third aspect, the output circuit includes an output data detection unit and an output signal switching circuit. Therefore, the output data output from the controller via the data transmission path is detected by the output data detecting means. When the output data detecting means detects the output data, an output switching signal is output by the output signal switching circuit. Here, power is supplied to the output signal switching circuit through a path different from the data transmission path, and the voltage applied to the output signal switching circuit affects input / output data transmitted through the data transmission path. Therefore, data input / output between each sensor terminal is performed accurately.

According to the invention described in claim (5), the second gate circuit constituting the inventions of claims (2) to (4) is an MO.
It is composed of SFET switch elements. Some MOSETs have a sufficiently low on-resistance compared to a transistor.Using a MOSFET with a low on-resistance reduces the voltage drop compared to using a transistor, and also turns on the MOSFET. Since the gate current to be generated is much smaller than that of the transistor, the value of the current flowing in the current path is also small.

In the invention described in claim (6), a terminal block is formed integrally with a single or a plurality of sensor terminals constituting a part of the inventions of claims (1) to (5). Therefore, the sensor terminal side can be made compact by reducing the number of parts, and the mounting operation can be simplified.

(F) Embodiment FIG. 3 shows a configuration diagram of a transmission unit according to an embodiment of the present invention described in claim (1).

The controller 1 includes a transistor TR for supplying a current to the current path 3, a current sensor IS for detecting the magnitude of the current flowing in the current path 3, an A / D converter for A / D converting the sensor output, It consists of a CPU. The CPU outputs an ON signal to the transistor TR when starting sensing. Also, as described later, the A / D conversion value is read every time the timer time (corresponding to the delay time of the present invention) of the timer provided in each sensor terminal elapses, and the sensor value at each sensor terminal 2 is read from the magnitude. The on / off state of S is determined.

The sensor terminal 2 is composed of a resistor R1 constituting a shunt circuit and a MOSFET
A gate circuit including electronic switches P1, P2, and NAND gates, a timer T, a resistor R2, and a sensor S.
And a sensor circuit composed of a series circuit of

In the above structure, when a voltage is applied to the input terminal IN, the electronic switch P1 NAND opens with current i ₁ flows through the resistor R1 is turned on, a voltage is applied also to the sensor circuit. At this time, if the sensor S is off, the current
Although i ₂ does not flow a current i ₂ flows if the sensor S is in the ON state. On the other hand, since the timer T is activated by applying a voltage to the input terminal IN, when the timer T expires after a certain period of time, the electronic switch P2 is turned on and the electronic switch P1 is turned on by closing the NAND. Is turned off. That is, the current source side of the current path 3 is connected to the load circuit from the state where the current source side is connected to the sensor circuit side. As a result, the output terminal OU
A voltage V appears at T, and this voltage V is applied to the sensor terminal 2 of the next stage.
Input terminal IN. In the same manner, the above operation is repeated in each sensor terminal 2 every time until the timer T times out. Therefore, in each sensor terminal 2, when the sensor S is off, the current I flowing through the current path 3 changes as shown in FIG. 2 (A).

On the other hand, when the sensor Sn in the n-th sensor terminal 2 is in the on state, the current i ₁ and i ₂ flows both when the voltage applied to the input terminal IN of the sensor terminal 2. Then, the timer T has elapsed a predetermined time when the time is up, the current flowing through the sensor terminal 2 becomes only i _1, switch
P2 is turned on. As described above, when the sensor Sn in the n-th sensor terminal 2 is in the ON state, the change of the current I flowing through the current path 3 becomes as shown in FIG. 2B.

After turning on the transistor TR, the controller 1 monitors the elapsed time by an internal timer, reads an A / D conversion value for each timer time of the timer T provided in each sensor terminal 2, and determines the magnitude of the A / D conversion value as i. _It is determined whether it corresponds to ₁ × n or i ₁ × n + i ₂ . And if it corresponds to the former, it is determined that the sensor S is in the off state in the n-th stage sensor terminal 2, and if it corresponds to the latter, the sensor S is in the on state in the n-th stage sensor terminal 2. It is determined that there is. This operation is repeated until a voltage is applied to the sensor terminal 2 at the last stage. When the above determination operation in all the sensor terminals 2 is completed, the transistor TR is once turned off. Then, the timer T in each sensor terminal 2 is reset, and the sensor terminal 2 is brought into an initial state. Then, when the transistor TR is turned on again, the above operation is sequentially repeated from the first sensor terminal 2 again.

By the above operation, the controller 1 reads the A / D conversion value of the timer T at every timer time t, and easily knows the on / off state of the sensor S in each sensor terminal 2 by checking the magnitude. it can. In the controller 1, the currently read A / D conversion value is
At that time, the correspondence with the position (number) of the sensor terminal 2 at the last stage to which the current source is connected can be monitored by a timer, but a counter can also be used. When using the counter, the A / D conversion value is always read, and the counter is advanced by one at the rising edge when the value suddenly increases.

Further, the magnitude of the current flowing through the current path 3 does not become so large as described with reference to FIG. Therefore, it is not necessary to use transistors TR, current paths 3 and a power supply having a large capacity.

FIG. 4 shows a configuration diagram of a transmission unit according to an embodiment of the present invention described in claim (2).

In the figure, reference numeral 11 denotes a controller to which a total of 128 channels (128 stages) of sensor terminals 12 are connected. The sensor terminal 12 includes a first gate circuit G1, a second gate circuit G2, and a sensor circuit SC.

In the first gate circuit G1, the timer T1 starts from the time when the input terminal IN is connected to the current source, and turns on the switch element P1 until a certain time T1 elapses. Fixed time T1
Is elapsed, the output of timer T1 becomes “L” and the gate NAND
Is closed, the switch element P1 is turned off. During this fixed time T1, a current i flows from the input terminal IN to the sensor circuit SC. If the sensor S is on at this time, the current i is i = E / R2, and if the sensor S is off, i = E / (R1 + R2).

The second gate circuit G2 includes a switch element P2 and a timer T2 inserted in series in a current path. The timer time of the timer T2 is set longer than the timer time of the timer T1, and the time (T2-T1) elapses after the switch element P1 is turned off, and the switch element T2 is turned on. By the second gate circuit G2, the input terminal IN, that is, the current source side is connected to the output terminal OUT, that is, the load side, when a predetermined time T2 has elapsed since the input terminal IN was connected to the sensor circuit SC.

FIG. 5 shows a change in the current i flowing through the current path 13 at a certain time. In this example, the sensor S is off at the sensor terminal 12 of the m-th channel, and the sensor terminal 12
Indicates that the sensor S is on.

The sensor circuit SC comprises a sensor S and resistors R1 and R2 constituting a variable impedance circuit. When the sensor S is on, the resistance value of the sensor circuit is R2, and when the sensor S is off, the resistance value of the sensor circuit is (R1 + R2 ).

The controller 11 supplies a current to the current path 13 by a transistor TR connected to a power supply + V. The current path 13 is provided with a resistor R3 for current-voltage conversion. The voltage drop of the resistor R3 is detected by the operational amplifier OP, and the output is detected by the comparators C1 and C2. This resistor R3, operational amplifier OP and comparators C1 and C2
Constitute a current detection circuit. Each comparator C1, C2
_Are set as _VCL and _VDATA as reference voltages. Each of the reference voltages V _CL and V _DATA has the magnitude shown in FIG.
That is, A and B in the figure are resistances R3 when the sensor S is in an off state and when the sensor S is in an on state in an arbitrary sensor terminal 12, respectively.
_VCL indicates the resistance caused by the current i flowing into the sensor circuit SC regardless of the on / off state of the sensor S.
VDATA is set to a size that can detect that a voltage drop has occurred at both ends of R3, and _VDATA is set to a size that can detect a voltage drop across the resistor R3 when the sensor S is turned on at the sensor terminal 12. . The output of comparator C1 is a shift register
It is supplied as the S / R clock, and starts the timer T3.

As shown in FIG. 6, the timer time of the timer T3 is set to be at least longer than the timer time of the timer T2, and is constituted by a retrigger timer circuit. The timer T3 does not time up in a state where it is constantly driven by the output of the comparator C1, but times out when the output of the comparator C1 is interrupted, and at that time is detected as the sensor terminal 12 of the last channel. Become. That is, the sensor terminal of the last channel
When a certain time T3 elapses after the current is supplied to 12, the output of the timer T3 rises. The output of the timer T3 is connected to the reset terminal of the flip-flop F and the output circuit OUT.
And the shift register is sent to the reset terminal of the S / R via the delay element D. A start signal ST, which is sent from another circuit when power is turned on and after a certain time has elapsed after the timer T3 has timed out, is led to the set terminal S of the flip-flop F, and the set output of the flip-flop F is supplied to the transistor TR through an open collector inverter INV. Led by the base. Start signal
When ST is output and the flip-flop F is set, the transistor TR is turned on to start sensing. After that, when the output of the timer circuit T3 becomes “H” and the flip-flop is reset, the transistor TR is turned off and the sensing is started. Ends. Further, the contents of the shift register S / R are latched in the output circuit OUT by the output of the timer T3, and the shift register S / R is reset by becoming a reset signal via the delay element D.

The output of the comparator C2 is input to the shift register S / R as data. Since the output of the comparator C1 is input as a clock to the shift register S / R, 0 is input to the shift register S / R when the voltage of A in FIG. 6 is detected, and 1 is input when the voltage of B is detected. Will be done. The number of stages of the shift register S / R is set to at least the total number of the sensor terminals 12, and outputs thereof are latched in parallel by the output circuit OUT.

In the controller having the above configuration, when the start signal ST is supplied first, the flip-flop F is set, and the current is supplied from the transistor TR to the current path 13 to start sensing. Then, from the first sensor terminal 12, sensing of the ON / OFF state of the sensor S, that is, detection of the magnitude of the voltage v across the resistor R3 is performed sequentially from the first sensor terminal 12 every time T2. If the sensor S is off, only the output of the comparator C1 becomes "H" and 0 is input to the shift register S / R. In contrast, the sensor S
Is in the ON state, the outputs of both the comparators C1 and C2 become "H", and 1 is input to the shift register S / R.
As a result of repeating this operation, 1 is stored in the shift register S / R only for the stage corresponding to the sensor terminal in which the sensor S is on, and 0 is stored in the stages corresponding to the other sensor terminals. When the sensing for the sensor terminal of the last channel is completed, the timer T3 times out, the flip-flop F is reset, and the contents of the shift register S / R are latched in the output circuit OUT. / R is reset. One sensing operation is completed by the above operation.

When this sensing operation is completed, the state of the sensor circuit of each sensor terminal 12, that is, the on / off state of the sensor S, can be known by checking the states of the terminals 1 to n of the output circuit OUT.

In the above operation, when sensing is performed by the mth sensor terminal, the 1st to m−1th sensor terminals are used.
Current i does not flow through twelve sensor circuits SC. That is, since there is no unnecessary power consumption, the magnitude of the current flowing from the controller 11 to the current path 13 does not increase even if the number of the sensor terminals 12 is large. If the power consumption of each sensor terminal 12 is large, the voltage drop at the switch element P2 in each sensor terminal 12 located in front thereof increases as the position of the sensor terminal 12 performing sensing increases. In addition to the fact that the magnitude of the current flowing through the current path 13 increases, the rate of change in the voltage across the resistor R3 in accordance with the on / off of the sensor decreases, so that the on-off state of the sensor S is more accurately detected in a later sensor terminal. Although the problem that it cannot be performed occurs, as in this embodiment,
Since the sensor terminals other than the sensor terminal performing the sensing do not consume extra power, the current path 13
Is small, and the on / off state of the sensor S can be accurately detected even in the sensor terminal at the subsequent stage.

When a semiconductor element is used as the switch element P2, the voltage drop at the switch element P2 is not zero even if the current flowing through the current path 13 is not large. So, for example,
When the number of channels of the sensor terminals 12 connected to the current path 13 is 100 or more and the power supply voltage + V is about 24 volts, when sensing is performed at the subsequent sensor terminals 12, There is a possibility that the total sum of the voltage drops of the switch element P2 at the time may not be negligible. In such a case, the reference voltages V _CL , V
_It is necessary to set the size of _DATA as shown in FIG. The figure shows an example in which the total number of channels of the sensor terminal 12 is 128 and the power supply voltage + V is 24 volts. The horizontal axis of the figure indicates the total number of the sensor terminals 12 in which the switch element P2 is in the ON state, and the vertical axis indicates the voltage v across the resistor R3. a
Represents the total voltage drop at the switch element P2, b represents the detection voltage v of the resistor R3 when the sensor S at each sensor terminal 12 is in the OFF state, and c represents the sensor S at each sensor terminal 12. The detection voltage v of the resistor R3 in the ON state is shown.
As shown in the figure, when sensing the sensor terminal 12 of the last stage (128 ch), the sum of the voltage drops of the switch elements P2 at each sensor terminal up to 127 ch is considerably large, so that the sensor terminal 12 of 128 ch The magnitudes of the detection voltages b and c of the resistor R3 according to the ON / OFF of the sensor S also become small as shown in the figure. Therefore, the setting of V _CL and V _DATA
It is necessary to set V _A and V _B in 8ch to a size that can be identified.

If a MOSFET having a small on-resistance is used for the switch element P2, the voltage drop in the gate circuit can be reduced, and the margin of _VCL and _VDATA can be increased. Similarly, the value of the current flowing through the current path 13 can be reduced.

Note that the second gate circuit G2 can be configured as shown in FIG. 8 (A). In this example, timer T1
, The timer T2 'is started, and the switch element P2 is turned on after a predetermined time T2'. The timer times T1 and T2 'have the relationship shown in FIG.

Further, in the controller 11, the voltage between both ends of the resistor R3 can be A / D converted and processed by the CPU, and the output can be output to the outside through, for example, an RS232C terminal.
Further, as the sensor S of the sensor circuit SC, there is a photoelectric switch or the like in addition to the microswitch, and it is also possible to use a sensor whose output changes linearly.

FIG. 9 shows a configuration diagram of a transmission unit according to the embodiment of the invention described in claim (3).

A sensor terminal 22 of a total of 128 channels (128 stages) is connected to a controller 21 having the same configuration as the controller 11 shown in FIG. Each sensor terminal 22 is connected to the controller 21 in a cascade manner on a current path 23 and a data transmission path 24. Each of the sensor terminals 22 includes a first gate circuit including a switch element P1 and a timer T1, a second gate circuit including a switch element P2 and a timer T2, and a resistor R4 forming a variable impedance circuit. , R5 and sensor S
C and an output circuit OC including an output lamp L and a transistor TR2. This output circuit OC includes a flip-flop 26.

In the first gate circuit, the timer T1 starts from the time when the input terminal IN is connected to the current source of the controller 21, and the switch element P1 is turned on until a certain time T1 elapses. When the predetermined time T1 has elapsed, the output of the timer T1 becomes "L", and the switch element P1 turns off. Therefore, the current i flows from the input terminal to the sensor circuit SC during the fixed time T1. At this time, if the sensor S is on, the current i
Is i = E / R4, and i = E / (R4 + R5) when the sensor S is in the off state.

The time measured by the timer T2 constituting the second gate circuit is:
The time is set to be longer than the time measured by the timer T1, and the switch element P2 is turned on after a lapse of time (T2-T1) since the switch element P1 is turned off. When a predetermined time T2 has elapsed since the input terminal was connected to the sensor circuit SC by the second gate circuit, the input terminal, that is, the current source side is connected to the output terminal, that is, the load side.

The output of the timer T1 is also input to the clock terminal ck of the flip-flop 26 included in the output circuit OC. The flip-flop 26 outputs the state of the set terminal s when the clock terminal ck falls from the output terminal Q to the transistor TR2. In each sensor terminal 22, the output lamp L is connected to the power supply path 25.
When the "H" signal is input to the set terminal s of the flip-flop 26 while the timer T1 is counting the time T1, the transistor TR2 is turned on and the output lamp L is turned on. .

With the above configuration, the controller 21 operates in the same manner as the configuration of claim (2) shown in FIG.
By detecting the voltage across R3, the on / off state of the sensor S in each sensor terminal 22 can be detected. For example, if the voltage across the operational amplifier OP changes in the controller 21 as shown in FIG. 10 (A), the waveform shown in FIG.
The waveform shown in FIG. 3C is input as a data signal.
Therefore, the first signal is input by the signal input to the ADD terminal of the CPU.
Sensor terminal where the switch element of the gate circuit is ON
22 can be specified, and whether or not the sensor S of the sensor terminal 22 is on can be detected based on the presence or absence of the data signal at that time.

Further, while the timer T1 is passing the time T1, the data transmission path 24 is transmitted from the controller 21 via the transistor TR3.
Is output, the output lamp L is turned on. The current source side of the controller 21 is connected to the sensor terminal 22 in the next stage every time T2 when the timer T2 elapses. Therefore,
By outputting a signal to the data transmission path 24 at a timing obtained by multiplying the number of stages of the sensor terminals 22 to which data is to be output by the time T2, the output lamp L can be turned on at a desired connection terminal 22. By the operation of the flip-flop 26, the output lamp L once lit turns off when no signal is output to the data transmission path 24 when the output of the timer T1 falls at the time of the next sensing.

In the sensor terminal 22, a flicker circuit may be provided between the flip-flop 26 and the transistor TR2 so that the output lamp L blinks.

As described above, the sensor terminal 22 can be used as an input / output unit. For example, the operation state of the motor or the like can be detected by the sensor S, and the operation state can be displayed by lighting the output lamp L of the sensor terminal 22. In this case, the CPU outputs an ON signal of the output lamp L when a data signal is input.

Further, when the sensor S constituting a part of the sensor circuit SC is disconnected, the sensor terminal 22 can be used as an output unit. In this case, the data signal shown in FIG. 10 (C) is not input to the CPU, and the CPU refers to the address signal shown in FIG. 10 (B) based on a signal input from outside via I / O. Then, an ON signal is output at a predetermined timing.

For example, if the setting input data shown in FIG. 11 (A) is input, the CPU outputs an ON signal at the timing of fetching the input data shown in FIG. 10, and FIG. 11 (B) and (B). As shown in C), the flip-flop 26 of the third and eighth stage sensor terminals 22 outputs ON data.

If a MOSFET having a small on-resistance is used for the switch element P2 constituting the second gate circuit, the same effect as in the configuration shown in FIG. 4 can be obtained due to a voltage drop and a decrease in gate current. it can.

FIG. 12 shows a configuration diagram of a transmission unit according to the embodiment of the invention described in claim (4).

A plurality of sensor terminals 42 are connected in cascade to the controller 41. The controller 41 detects the voltage effect of the current-to-voltage conversion resistor R _S inserted in the current path 50 by the operational amplifier OP, and compares its output with the reference voltage in the comparators C1 to C3. The reference voltage V _Rf set for each of the comparators C1 and C2 is the same as FIG. 10 and FIG.
It corresponds to the reference voltages V _DATA and V _ADD in FIG.
The current path 50 corresponds to the current and the current shown in FIG. The reference voltage V _Rf set in the comparator C ₃ comparators C1, C2 are larger than the reference voltage that is set to correspond to the current that shown in FIG. 14 in the current path 50. This allows the comparator
C3 detects an overvoltage due to a short circuit or the like.

The microprocessor unit MPU of the controller 41 supplies a signal 45 to the FET 1 via the cycle controller. The supply of this signal 45 turns on FET1, and the power path 50
The sensor terminal 42 is connected to the power supply via the. Each sensor terminal 42 has a timer for measuring the time T1, T2. The timer turns off the transistor TR after the time T1, and turns on the FET _M after the time T2. Therefore, FIG. 13 (A)
As shown in (5), the electric power supplied to the M-th stage sensor terminal 42 is supplied to the (M + 1) -th stage sensor terminal after the elapse of the time T2. Further, the resistance Ra, Rb and the sensor SW _M
Sensor circuit is provided consisting of the resistance value of the sensor circuit during on of the sensor SW _M becomes Ra, sensor SW _M is in the OFF becomes (Ra + Rb). Therefore, at the time the sensor SW _M is turned off the current i _{A / B} flows through the current path 50, the current flows i _AS sensor SW _M is at ON. By detecting the operational amplifier OP the current flowing through the current path 50 by current-voltage conversion, address of the sensor terminals 42 (mounting number) and the data (on-signal of the sensor SW _M) is detected. Thus, the controller 42 detects the value of the current flowing through the current path 50 in the state shown in FIG.

The sensor terminal 42 is provided with a photocoupler 43, and the photodiode constituting the photocoupler 43 is connected to the common terminal of the power supply from the current path 51 via the FET0. This FET0 is turned on by the signal 46 output from the MPU. Now, when sensor SW _M is off, signal 46 is output and FET0
Is turned on, the current i _AS flowing through the current path 50 becomes the drive current i _{AT of the} photodiode, and forms the photocoupler 43. The photodiode can be turned on. MPU
Is the sensor terminal powered by the output 48 of the comparator C2
Since the signal 42 can be specified, the signal 46 is output at a predetermined timing to turn on the FET0, thereby turning on the photodiode of the photocoupler 43 in the desired sensor terminal 42 and using the sensor terminal 42 as an output unit. be able to. Therefore, since the transmission drive output current i _AT is the same as the reception sensor detection current i _AS , reliable transmission can be performed under the same conditions in both transmission and reception.

Each sensor terminal 42 includes a retrigger circuit 44 that receives power supply from outside, and the phototransistor of the photocoupler 43 is connected to the retrigger circuit 44. The retrigger circuit 44 outputs a switching signal when the phototransistor turns on. As described above, by including the photocoupler 43 constituting the output data detecting means of the present invention and the retrigger circuit 44 constituting the output signal switching circuit, a signal can be outputted from the sensor terminal 42 used as an output unit. Further, it is possible to use a sensor terminal 42 as input and output units by connecting the sensor SW _M from the current path 53 interposed the FET 0 'through Taiodo D to the common terminal. In this case, the retrigger circuit 44
Power is supplied by another path different from that of the above, so that the drive voltage of the retrigger circuit 44 does not affect the detection voltage of the operational amplifier OP, and the MPU can accurately transmit and receive data and specify the address. . That is, if the signal line and the power supply line are shared by a common line as shown in FIG. 9 to supply power to the retrigger circuit 44, a large voltage is applied to the common line when a large number of retrigger circuits are turned on at the same time. Although a drop occurs, this problem can be solved by driving the retrigger circuit with a separate power supply as in this embodiment, and data transmission / reception and address identification can be accurately performed. Note that a battery or a power supply unit of an external device to be controlled is used as a power supply for driving the retrigger circuit.

15 (A) and 15 (B) are an assembly view in the front direction and an assembly view of a main part in the back direction, respectively, showing an embodiment of the invention described in claim (6).

A printed circuit board 32 attached to the back surface of the terminal block 31 has attached thereto an IC chip 33 constituting a gate circuit and a switch circuit and resistors 34 and 35 constituting a part of a sensor circuit. Are integrally formed. With this configuration, there is an advantage that the work of attaching the sensor terminal 22 to each workstation or the like configuring the LAN can be simplified.

(G) Effects of the Invention According to the invention described in claim (1), it is not necessary to provide a transmission control unit on the controller side and the sensor terminal side as in the related art. Therefore, there is an advantage that the configuration can be made at very low cost and simple. Further, since the current flowing in the current path can be DC, it is possible to perform extremely accurate detection without being affected by noise from the outside on the current path.

Further, according to the invention described in claim (2), it is not necessary to provide a transmission control unit on the controller side and the sensor terminal side unlike the related art. Therefore, there is an advantage that the configuration can be made at very low cost and simple. In addition, since the current flowing in the current path can be DC, accurate detection is possible without being affected by noise from the outside on the current path. Furthermore, since current is not passed through the sensor circuit of another sensor terminal when sensing is performed by one sensor terminal, there is no wasteful power loss. Therefore, there are advantages that the configuration on the controller side can be simplified and that a considerable number of sensor terminals can be connected to the controller.

Furthermore, according to the invention described in claim (3), the sensor terminal can be used as an input / output unit or an output unit by connecting and disconnecting the sensor.

In addition, according to the invention described in claim (4), since power is supplied to the output signal switching circuit of the output circuit through a path different from the data transmission path, input / output is performed via the data transmission path. There is an advantage that accurate data can always be input and output when the transmission unit is used as an input / output minute or an output unit without affecting the data to be output by the driving power of the output circuit.

According to the invention described in claim (5), when the switch element included in the second gate circuit is constituted by a MOSFET whose on-resistance is sufficiently smaller than that of the transistor,
As the voltage drop at each sensor terminal decreases,
The gate current that turns on the MOSFET is also very small, and the current flowing in the current path can be reduced.

In addition, according to the invention described in claim (6), one or a plurality of sensor terminals can be integrally formed on a single terminal block, and the work of attaching to the input / output device constituting the information transmission system is simplified. Can be

[Brief description of the drawings]

FIG. 1 is a diagram showing the configuration of the invention described in claim (1);
2A and 2B are diagrams for explaining the operation of the present invention, and FIG. 3 is a diagram showing a configuration of an embodiment of the present invention. FIG. 4 shows a configuration diagram of an embodiment of the invention described in claim (2). FIG. 5, FIG. 6, and FIG. 7 are diagrams for explaining the operation of the embodiment. FIG. 8 (A),
(B) is a partial configuration diagram of another embodiment. FIG. 9 is a diagram showing the configuration of the embodiment of the invention described in claim (3). 10 (A) to 10 (C) are diagrams showing input waveforms to the controller in the invention described in claim (3). FIGS. 11 (A) to 11 (C) are diagrams showing an input waveform from the outside to the controller and a waveform of an ON signal corresponding to this input in the invention described in claim (3). FIG. 12 is a diagram showing the configuration of the controller of the invention described in claim (4), and FIGS. 13 (A) and (B) show the ON state of the current path in each sensor terminal of the transmission unit according to the embodiment of the invention. FIG. 14 is a diagram showing the output voltage of the operational amplifier in the controller / off state and the controller, and FIG. 14 is a diagram showing the detection state of the current in the current path in the controller of the embodiment. 15 (A) and 15 (B) are front and rear views, respectively, of an embodiment of the invention described in claim (6). 1,11,21 ... Controller, 2,12,22 ... Sensor terminal, 3,13,23 ... Current path, G1 ... First gate circuit, G2 ... Second gate circuit, SC ... Sensor circuit, R3 ... (current detection) resistor, TR, TR1 ... current supply transistor, C1, C2 ... comparator, S / R ... shift register, OC ... output circuit, P1, P2 ... switch Element, T1, T2, T3 ... timer, D ... delay element, F, F / F ... flip-flop, S ... sensor.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-45802 (JP, A) JP-A-49-91715 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04Q 9/00-9/16

Claims (6)

(57) [Claims] 1. A two-wire current path for supplying a current to each sensor terminal connected in parallel with a controller as a current source, wherein each sensor terminal is connected to an input line of the two-wire current path and a ground. A first current path and a second current path formed in this order from the controller side of the current path to the sensor terminal side at the subsequent stage between the current path and the second current path; A gate circuit that switches and connects the controller side of the current path to the second current path when not in operation, and to a sensor terminal side at the subsequent stage when in operation, and a fixed time delay after energizing the shunt circuit. A delay switching circuit that activates the gate circuit, wherein the controller includes a current detection circuit that detects a magnitude of a current flowing through a current path while the gate circuit of each sensor terminal sequentially operates. Ete become transmission unit. 2. A two-wire current path for supplying a current to each sensor terminal connected in parallel with a controller as a current source, wherein each sensor terminal is connected to an input line of the two-wire current path and a ground. A sensor that opens and closes a current path formed between the current path and a variable impedance circuit that changes the impedance value of the current path according to the operating state of the sensor; and a fixed time from when the input line of the current path is connected to the current source
A first gate circuit that connects between the input line of the current path in the current path and the sensor by T1, and a fixed time from when the input line of the current path is connected to the current source;
A second gate circuit that connects between the controller on the input line of the current path and the subsequent sensor terminal when T2 (T2> T1) has elapsed, wherein the controller has a first gate circuit of each sensor terminal. A transmission unit including a current detection circuit of a current path for detecting a magnitude of a current flowing through the current path during sequential operation. 3. A data transmission path for transmitting output data from the controller to each of the sensor terminals, wherein the first gate circuit is connected to a current path. 3. The transmission unit according to claim 2, further comprising: an output circuit for switching an output according to the presence or absence of output data on a data transmission path while connecting the input line of the current path and the sensor. 4. An output data detecting means for detecting output data of the data transmission path, wherein the output circuit is driven by a power supply supplied through a path different from the data transmission path, and the output data is output by the output data detecting means. The transmission unit according to claim 3, further comprising an output signal switching circuit that outputs an output switching signal upon detection. 5. The transmission unit according to claim 2, wherein said second gate circuit includes a switch element constituted by a MOSFET. 6. The transmission unit according to claim 1, wherein one or a plurality of said sensor terminals are formed as an integral terminal block.