JP2723232B2 - Serial transmission method of parallel sensor signals - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Overview] The present invention serializes parallel outputs of a large number of sensors provided in a sensor unit having no power supply, and changes a power supply voltage level from a control unit to a different signal level according to a clock signal. When a serial signal is received, a sensor output is superimposed on each clock signal and transmitted to the control unit. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial transmission system in which, when a serial clock signal is transmitted from a control unit, output states of a large number of sensors of distant sensor units are sequentially superimposed on the serial clock signal and transmitted. . 2. Description of the Related Art Collecting the output of a sensor that senses the state of a device provided at a remote position in response to a command from a control device or a monitoring device is widely used in technical fields such as automatic control and measurement. In such technology, for example, in the technology of automatic control machines such as robots, fluid is used for control, and opening and closing control of the fluid is performed by a solenoid valve, and a so-called solenoid valve manifold in which a solenoid valve is connected to the manifold saves space. It was used to make it smaller. In the automatic control, the state of the device as a result of the control by the command is detected by a sensor, and is used as data for determining the next control. In this case, the object to be sensed by the sensor is the physical state of the control device or the surrounding state (on / off state, position, angle, temperature, etc.), and the sensor for detecting these states is the control device's Along with miniaturization and centralization, there has been a demand for miniaturization and centralization and simplification of connection arrangement with a control unit. [Prior Art] In order to transmit outputs of a large number of sensors to a control unit in accordance with a control signal from the control unit, as a conventional example, a control signal line, a power line, and a clock are individually provided from the control unit to each sensor. There is a method in which a signal line is arranged and an output of each sensor is supplied to a data line by driving a control signal line. Further, as a second conventional example, a control signal line is connected to each sensor,
Instead of arranging a large number of lines such as power supply lines, there is also a method of shifting a signal of a clock signal line and driving a sensor corresponding to the shift position by a power supply supplied from the power supply line to output the signal to the signal line (shown in FIG. Zu). [Problems to be Solved by the Invention] According to the above-described conventional technique, first, in the method of the conventional example, a plurality of wires are wired to each sensor unit, so that wiring work and space are required. In the second conventional example, there is a problem in that a power supply line for supplying power for driving a circuit or a sensor is required in addition to a control signal line from the control unit to each sensor. There was a problem that there were many. [Means for Solving the Problems] FIG. 1 shows the basic configuration of the present invention. In FIG. 1, reference numeral 10 denotes a control unit, 101 denotes a serial-parallel conversion unit, 102 denotes a timing signal conversion unit, 103 denotes a data extraction conversion unit, and 11 denotes a sensor unit. Converter of configuration (not shown)
Reference numerals 121 and 131 denote stabilized power generation means for circuits (indicated by CV in the figure), 122 denotes a sensor driving power generation means, 123 denotes a start signal (start signal) detection means, and 132 denotes a clock signal. Extraction means, 133 is a signal distribution means composed of two-stage flip-flop circuits, 134 and 135 are AND circuits, 138
Denotes a next-stage start signal generating means, and 140 and 141 denote the sensors 1 and 2. According to the present invention, when a clock signal and power are supplied from the control circuit to the sensor unit through the same signal line, power is generated in the sensor unit, the clock signal is extracted and the signal is distributed, and the signal is distributed according to the sensor output at each distribution position. Thus, the voltage level of the clock signal position on the signal line is made different, and the state of each sensor is received by detecting the level by the control unit. [Operation] In FIG. 1, a control unit 10 converts a clock signal from an oscillator OSC and a power supply (voltage V _x ) into a timing signal conversion unit 10.
2, the timing signal conversion means 102 converts the voltage output of the power supply by the clock signal, generates an output signal OUT having a waveform shown by a solid line in FIG. Then, when a start instruction signal indicating the start of data extraction is given from the serial / parallel conversion means 101, the start signal (S) shown in (b) of FIG.
TART) is generated and output to the signal line 105, and the control unit 10 outputs a signal GND representing the ground level to the signal line 106. A signal whose voltage level is different from the level (V _x ) of another period (level V _x / 2) by the pulse width of the clock signal is output to the signal line 104. When a serial output signal OUT indicated by a solid line in FIG. 1A is received by the sensor unit 11 via the signal line 104, the sensor driving power generation unit 122 drives the driving power supply Vs for the sensors 140 and 141 and the like.
Generate (same voltage substantially V _x), the regulated power supply generating unit 12
Etc. 1,131 generates each unit constituted by an electronic circuit (a start signal detecting means, clock signal extraction means, etc.) (a voltage lower than V _x) power. The power supply Vs, which is the output of the sensor driving power supply generation means 122, is supplied to the conversion unit 13 and is connected to the connector 124 on the control unit 10 side. Normally, this connector is not used. In addition, when the power supply capacity is insufficient, the sensor means can be independently driven using a connector to receive an external power supply (for example, from the control unit 10). In parallel with the generation of the power supply, the start signal (start signal) detection means 123 has a function of detecting the appearance of the start signal on the signal line 105, and starts at time t1 as shown in (b) of FIG. When the (START) signal is detected, an output st is generated and supplied to the signal distribution means 133. On the other hand, the clock signal extraction means 132 determines the signal level of the serial output signal OUT (FIG. 1 (a)) on the signal line 104, extracts the clock signal component, and generates the clock signal output ck. Upon receiving the output st from the start signal detection means 123, the signal distribution means 133 shifts the "1" signal by the clock signal ck from the clock signal extraction means 132, and generates a "1" output from the first-stage output Q1. I do. When this output Q1 is generated, both the clock signal and the output Q1 become “1” in the AND circuit 134, and the output signal (“1” or “0” binary) of the sensor driven by the power supply Vs at this time. If the signal is "1" at this time, a "1" output is generated from the AND circuit 134, and a ground level signal is supplied to the signal line 104 via the inverter circuit 136 and the resistor R1. As a result, the signal level of the serial output signal OUT becomes the ground level (0 volt) as shown by the dotted line during the period of the clock signal at the time t1 in FIG. At this time, the signal line
The signal on 104 substantially represents the serial input signal transmitted from the sensor unit 11. If sensor 1 (140)
Is "0", the level of the clock signal is maintained at the same level (V _x / 2) as that supplied from the control unit. When the second clock signal from the start signal is extracted by the clock signal extraction means 132 at time t2, the signal distribution means 133
The "1" state of the output Q1 is shifted to the second stage, and the output Q2
Becomes “1”. As a result, the clock signal ck and “1” of the output Q2 are input to the AND circuit 135, and the sensor 2 at that time is input.
If the state of (141) is "0", the AND circuit 135 generates a "0" output and has no effect on the signal line 104.
The signal on the signal line 104 at this time is shown by a waveform at time t2 in FIG. In the control unit 10, the first
While generating an output including a clock signal indicated by a solid line in FIG. 2A, the output signals of the sensors 1 and 2 sent in series from the sensor unit 11 to the signal line 104 are detected. That is, the level of the signal line 104 during the clock signal period is detected by the data
_{If the} voltage is lower than _x / 2, a "1" output is generated; otherwise, a "0" output is generated. Therefore, at time t1 and time t2, the data extraction / conversion means 103 outputs "1" and "0", which are the states of the sensors 1 and 2, respectively. While being latched according to the signal, the data of each stage is sequentially shifted to the next stage. In the case of FIG. 1, the conversion unit 13 of the sensor unit 11 is configured to detect the state of the two sensors 1 and 2. Needless to say, a conversion unit having the same configuration can be connected to the next stage. . The next-stage start signal generator 138 is driven by the output 2 of the signal distributor 133 to supply a start signal to the next-stage converter. Thus, the output signal of the sensor is generated as shown by the dotted line superimposed on the clock signal in the serial output signal OUT of FIG. 1A, and the sensor 1, the sensor 2, and the sensor 3 (not shown) Indicates that the state is ON, OFF, ON, ON, etc., and accordingly, in the serial-parallel conversion means 101,
The sensor information “1”, “0”, “1”, “1”,... Is sequentially stored. In FIG. 1, a dedicated line is provided for transmitting the start signal. However, the line for the serial output signal may include the start signal. In this case, the start can be realized by a level different from the data signal level in synchronization with the clock signal, or by using a pulse width different from the clock signal. Further, as a signal format for displaying the "1" and "0" outputs of the sensor, besides the method of changing the signal level as shown in FIG. 1, a change in pulse width can be used. [Embodiment] FIGS. 2A and 2B show the configuration of an embodiment of the present invention.
And a time chart of the operation is shown in FIG. FIG. 2 shows the configuration of a control unit 20 corresponding to the control unit of FIG. 1, and FIG. 2 (b) shows the configuration of a plurality of units corresponding to the sensor unit of FIG. In FIG. 2A, reference numeral 20 denotes a control unit, 21 denotes an output interface circuit (having an LED display function), 22 denotes a serial-in / parallel-out register, 23 denotes a timing generation circuit, 24 denotes an amplification circuit, and 25 denotes an amplification circuit. The amplifier 26 represents a comparison circuit. In FIG. 2B, reference numeral 30 denotes a start bit unit 1, 31 denotes a conversion unit 1 including a sensor 1 and a sensor 2, and 32 denotes a conversion unit 2 including a sensor 3 and a sensor 4.
Reference numeral 33 denotes an end bit unit, reference numeral 34 denotes a start bit unit 2, CV in the unit is a stabilized power supply, FF1 and FF2 are flip-flop circuits, and 312 is a clock signal detection circuit (DT1). ), 313, 314 are inverter circuits, 315, 316 are sensor output detection circuits (DT2, D
T3). The control unit 20 shown in FIG. 2A and the sensor unit shown in FIG. 2B have a serial output (serial input) signal line 200, a start bit signal line 201, and a ground level signal line 202.
And a 24V power supply line (indicated by a dotted line in the figure) as necessary, such as when an emergency stop or a large sensor drive load is required, and this connection is made during normal use. Absent. The operation of the embodiment will be described below with reference to the time chart of FIG. First, the operation of the control unit 20 shown in FIG. 2A will be described. The timing generation circuit 23 generates a clock signal from the output of the oscillator OSC, and supplies the amplifier 25 and the serial-in / parallel-out register 22 (hereinafter simply referred to as a register). 22)
And so on. The amplifier 25 receives the clock signal and the electric wire (24 V) from the power supply line 203, converts the power supply voltage level according to the waveform of the clock signal, and outputs the serial output signal OU shown in FIG.
T (s) is generated and output to the signal line 200. OUT
S in (s) represents a signal of a send component, and in fact, since the level of the clock signal position is converted by the sensor output, this waveform is a virtual signal waveform. The signal OUT (s) is a signal that becomes 12 V only while each clock signal appears, and maintains 24 V during other periods. The register 22 receives the clock signal at the terminal cp, and
The sensor output detected at 26 is received by the data terminal DATA and serially in-sequenced. At the start of the period for collecting data from each sensor (one period ends when the last bit position is reached by the shift operation), the register 22 starts from the terminal STB in synchronization with the clock signal as shown in FIG. Signal (STAR
T) is generated and output from the amplifier circuit 24 to the signal line 201. Next, the operation of the sensor unit in FIG. 2B will be described with reference to the time chart of FIG. The series output signal OUT (s) and the ground signal from the control unit 20 are cascade-connected to all units by signal lines 200 and 202, and the stabilized power supplies CV1 to CV4 in each unit (using a zener diode, a capacitor and a resistor) A power supply for an electronic circuit is generated by a known circuit configured by the above-described method, and a diode 301 and a capacitor C1 (3
02) generates a power supply for driving each sensor. The start signal is received at the terminal START1 of the start bit unit 1 (30) 30 at time t1 in FIG. 3. When the start signal is received, the light emitting diode PD1 emits light, and the light receiving transistor PT1 of the conversion unit 1 (31) is activated. The "1" signal obtained from the driven emitter is output to the flip-flop circuit FF1
Is input to the data input terminal D. At this time, since a clock signal detection output is generated from the clock signal detection circuit DT1 (312), the output is input to the clock terminal cp, so that the flip-flop circuit FF1 is set and the output Q
(See FF1 output in FIG. 3). There are various types of the sensor 1 depending on an object to be sensed. As a specific example, there is a configuration in which a signal output input to a sensor amplifier Amp is output to a collector of a transistor as shown in FIG. Further, the conversion unit (one circuit) of the present invention is incorporated in the sensor, and it is possible to easily realize a sensor having a parallel-in / serial-out function. In the case of FIG. 2 (b), the output of the sensor 1 is detected by the detection circuit DT2 (315) of the conversion unit (13) and the AND circuit 317.
Supplied to When the flip-flop circuit FF1 turns to "1" at the timing of the clock signal ck at time t1, and at this time generates a "1" output indicating that the sensor 1 has sensed the ON state, the input of the AND circuit 317 Are all "1" and their outputs are inverted by the inverter (NOT) circuit 313, so the signal line
The data of the sensor output is transmitted by setting the signal level of 200 to 0V (earth level). To explain this operation in detail, the inverter 313 (similarly to 314) is an open collector type output, and when this is turned on, an output close to 0V is generated on the signal line 200, and when 24V is supplied from the control unit 20, The output goes to 24V (when the clock signal ends). Then, the resistor R1 (R2) is connected to the signal line 2
When the 24V is controlled at 00, it works to prevent the inverter from being destroyed. That is, the loop of the signal line 200, the clock signal detection circuit 312, the AND circuit 317, and the inverter 313 forms the clock signal ck
Is held at a low level (12 V), but when 24 V is supplied to the signal line 200, the lock circuit is released by the impedance of the resistor R1. The level conversion output on the signal line 200 is shown in FIG.
The control terminal 20 of FIG.
A signal labeled OUT (SR) is obtained. Here, R means reception (RECEIVE), and S · R means that a transmission signal and a reception signal are included. This signal OUT (SR) is output to the comparison circuit 2 of the control unit 20.
6 and compared with the reference signal level V _x / 2 (12V)
When 0 V lower than the reference level is input, a "1" output is generated, and the data is shifted in from the DATA terminal of the register 22. At time t2 of the next clock signal, "1" of the output Q of the flip-flop circuit FF1 is shifted to FF2 by the clock signal ck in the conversion unit 1 (31) of FIG. Is generated, and the output Q of the FF1 becomes "0" because "0" is input to the FF1 (at this time, the light receiving transistor PT1 is turned off). Output Q of flip-flop circuit FF2 and clock signal ck
Is output to the AND circuit 318, the output of the sensor 2 at that time is detected by the detection circuit DT3 (316) and supplied to the AND circuit 318. Has been output. At this time, the detection circuit DT3
Is "0", the output of the AND circuit 318 becomes "0", the output of the inverter circuit 314 becomes the same level as the clock signal, and the signal level of the signal line 200 is the same as that transmitted ( (Refer to the waveform at time t2 of OUT (SR) in FIG. 3). When the output Q of the flip-flop circuit FF2 becomes "1" at the time t2 of the second clock signal (the output is "0" at this time), the light emitting diode PD2 emits light and the conversion unit 2
The (32) light receiving transistor PT2 is driven. But,
At this time, since the clock signal at t2 has disappeared, the flip-flop circuits FF1 and the like of the conversion unit 2 (the same configuration as the conversion unit 1) do not operate. Then, when the clock signal at the next time t3 is received, the flip-flop circuit FF1 operates, and at the next time t4, the same operation is performed. As shown in FIG. 3, the outputs of the sensors 3 and 4 (time t3 , T4) “1”, “1”
Is obtained on the signal line 200, and the register 22 of the control unit 20 is
Are sequentially stored by shift-in. End bit unit after conversion unit 2 (32)
33 is connected and the light emitting diode of the conversion unit 2 (32)
The light-emitting signal from PD3 is detected by light-receiving transistor PT3 to generate an end bit signal. This end bit signal is input from the terminal END1 to the START2 terminal of the next start bit unit 2 (34) via a line, performs the same operation as the already described start bit unit 1 (30), and performs the clock signal time t5 , T6h... The operation of transmitting the outputs of the sensors 5, 6 and the like at the positions corresponding to the following times is started. Each unit 30, 31, 32, 33, 34 in FIG. 2 (b) is expanded by cascading necessary units according to the number of sensors to be detected. FIG. 4 shows an application example of the present invention. Fig. 4 shows a large number of sensor terminals for devices such as robots.
An application example in which the outputs of the respective sensor groups are transmitted to the control unit 40 by connecting 41, 42, 43. The control unit 40 corresponds to the configuration of FIG. 2 (a), and the sensor unit includes a start bit (SB) unit and a sensor terminal including a sensor group and an end bit (EB) unit of FIG. 2 (b). And one unit is connected in cascade as necessary, so that data of many sensors can be transmitted. FIG. 5 shows an application example of the present invention. 5, 50 to 52 represent sensor terminals, 53 represents a control unit, and 54 and 55 represent output terminals. A signal from each sensor indicating the state of the device is input in parallel to each of the sensor terminals 50 to 52 and transmitted to the control unit 53 as a serial signal. The control unit 53 receives the data serially at the input interface 531, converts this to a parallel signal, and inputs the signal to the sequencer 532. The sequencer 532 outputs a control output of a sequence programmed in advance according to the content of the input signal to the parallel output interface 533. The interface 533 converts this into a serial signal and outputs it to each output terminal. In the case of FIG. 5, two of the sensor output from the sensor terminals 50 and 51 and the sensor output from the sensor terminal 52 are shown.
The configuration is such that the sensor output of the system is transmitted to the input interface 531 (two sets of shift registers are used), and both can be operated in parallel to improve the speed. According to the present invention, when a large number of sensors are mounted on an automatic control device, the number of lines between the sensor unit and the control unit can be significantly reduced, and the sensor device can be mounted in a small space. Can be increased, wiring work can be simplified, and costs can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing the principle configuration of the present invention, FIG.
2 (b) is a diagram showing the configuration of the embodiment of the present invention, FIG. 3 is a diagram showing a time chart of the operation of the embodiment, FIG. 4 is a diagram showing an application example of the present invention, and FIG. It is a figure showing the example of application of the present invention. In FIG. 1, 10: control unit 11: sensor unit 12: start bit unit 13: conversion unit 123: start signal detection unit 132: clock signal extraction unit 133: signal distribution unit 138: next stage start signal generation unit 140, 141 : Sensor 1, Sensor 2

   ────────────────────────────────────────────────── ─── Continuation of front page    (56) References JP-A-64-65375 (JP, A)                 JP-A-64-89839 (JP, A)                 JP-A-58-132894 (JP, A)                 JP-A-56-127294 (JP, A)                 JP-A-55-147796 (JP, A)                 JP-A-56-161737 (JP, A)                 Shokai Sho 59-142888 (JP, U)

Claims (1)

(57) [Claims] In a serial transmission method of parallel sensor signals for serially transmitting sensor signals of a plurality of sensor units including a control unit and a sensor without a power source provided at a position separated from the control unit, Are connected by a common series signal line and a signal line for transmitting the ground level signal, and start between the control unit and the first sensor unit and between each sensor unit after the first sensor unit. The control unit is connected by a signal line, the control unit generates a clock signal, a start signal output to the start signal line, and a clock signal at each timing assigned to each sensor of the plurality of sensor units. synchronously generates an intermediate voltage of the power supply voltage (V _x / 2), the serial signal line period intervals of the clock signal and the next clock signal generates a serial signal as a power supply voltage (V _x) A signal generator for generating power from the serial signal line, a start signal detector for detecting a start signal, and a signal on the serial signal line. Clock extracting means for extracting a clock pulse from the signal, signal distributing means for distributing the extracted clock signal to corresponding sensors in response to a start signal detected by the start signal detecting means, and the distributing means The intermediate voltage (V _x / 2) of the power supply voltage is not changed or converted to a ground voltage according to the state of the sensor which is driven at the timing when the output is generated and is provided at the corresponding position. Signal modulation means, and next-stage start signal generation means driven by the output of the signal distribution means to supply a start signal to the next-stage sensor section The provided, serial transmission scheme for parallel sensor signals in the control unit, characterized in that identify the state of each sensor by the data extracting converting means for extracting an input signal level of each clock signal the position of the serial signal.