JP2005285043A - Sensor cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sensor cable for interconnecting the sensor head part and the signal processing part of a separate-amplifier-type sensor and whose overall length can be easily extended in such a way that even if the overall length is increased, signal attenuation and mixing of noise can be controlled as much as possible when signals are transmitted at high speed. <P>SOLUTION: The sensor cable is provided with: a first connector half 31 that retains a conductor terminal 35; a second connector half 32 that retains a conductor terminal 36; an electrical cord 33 for electrically connecting the conductor terminal of the first connector half to the conductor terminal of the second connector half; and a waveform shaping circuit 34 that shapes the waveforms of signals passing through the electrical cord. The first and second connector halves are removably attachable to each other. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sensor cable for connecting a sensor head unit and a signal processing unit of an amplifier-separated type sensor, and in particular, the total length thereof can be easily changed by configuring a plurality of cables so as to be connected and integrated, In addition, the present invention relates to a sensor cable that enables high-speed transmission of accurate signals even when the overall length is long.

  As a so-called “sensor”, there are known a wide variety of sensors having different operating principles such as a displacement sensor, a visual sensor, a proximity sensor, a microwave sensor, a length sensor, and the like. Furthermore, even if the sensors have the same operation principle, there are various variations (specifications).

  By the way, with the recent technological development, the usage purpose and usage mode of these sensors are diversified, and the functions and performances required by users for each sensor are diversified accordingly. In view of such market needs, so-called multi-product low-volume production systems have been introduced by many sensor manufacturers. This high-mix low-volume production system has the advantage of being able to respond appropriately to each user's needs, but the number of parts increases, so the cost is higher than the conventional low-mix high-volume production system and parts management is There is a demerit that it becomes complicated.

Therefore, in recent years, the sensor is composed of a sensor head unit including a detection end (a light emitting / receiving element in the case of a photoelectric sensor, a detection coil in the case of a proximity sensor, etc.), a power supply to the sensor head unit, and a sensor head unit. The signal processing unit that processes the obtained signal is an amplifier separation type that is connected by a sensor cable, and the sensor head unit is prepared for multiple models, while the signal processing unit is shared A sensor has been proposed (see, for example, Patent Document 1). Furthermore, the present applicant, following the above-mentioned amplifier-separated type sensor, has recently been configured with a plurality of types of sensor head units prepared assuming a plurality of types of sensors, and control specifications assuming a predetermined sensor head unit. By combining (connecting) the multiple signal processing units of multiple models with connectors with the specifications common to all models, we have invented a technology that enables appropriate manufacturing of sensors with different operating principles or specifications. I arrived. According to this sensor, since the signal processing unit can be mass-produced as a single product as before, although it is a multi-product / small-quantity production system as a whole, it is possible to reduce the cost.
JP 2003-75117 A

  Since the development of this separated amplifier sensor, the present applicant has attempted further improvements while observing market needs. Of particular importance is the speeding up of signal transmission between the sensor head unit and the signal processing unit. This is because, as the sensor becomes more sophisticated, it is required to increase the capacity of the sensing signal sent from the sensor head unit to the signal processing unit and the control signal sent from the signal processing unit to the sensor head unit. For this reason, in order to maintain a good response speed, it is essential to increase the signal transmission speed.

  In particular, in a displacement sensor using a two-dimensional image sensor that is the mainstream of measurement sensors, speeding up is particularly essential. As a two-dimensional imaging device, a CCD type and a CMOS type are known. In either case, the amount of data output from the two-dimensional imaging device is compared with a general-purpose photoelectric sensor that simply generates an on / off output. Too many.

  High-speed signal transmission via a cable means that the frequency is increased, but as is well known, the higher the frequency, the more susceptible to noise, the waveform due to the capacitance and resistance of the transmission line. The influence of the dullness cannot be ignored, and the transmission speed or transmission distance is limited. For this reason, it is desirable to make the cable length as short as possible. However, in actual sites, it is often necessary to install the signal processing unit and the sensor head unit at a considerable distance (for example, about 50 m). In the past, such cases have been dealt with by providing a repeater driven by an external power source in the middle of the cable. However, there are cases where the repeater cannot be placed due to space constraints, especially when the sensor head is attached to the movable part, and problems such as complicated routing of the power cord of the repeater have been pointed out. There was a need for further improvements.

  The present invention has been made paying attention to the above-mentioned problems, and the object of the present invention is a sensor cable that connects a sensor head part and a signal processing part of an amplifier-separated sensor, and has a large capacity. To provide a sensor cable that can be easily extended by connecting and integrating the appropriate number of the entire length when transmitting a sensing signal or a control signal, and that does not require a separate repeater in the middle. It is in.

  Another object of the present invention is that the total length of the sensor cable connecting the sensor head portion and the signal processing portion can be easily extended, and even if the total length of the sensor cable is increased, the high speed is stable. An object of the present invention is to provide an amplifier separation type sensor that enables signal transmission.

  Other objects and operational effects of the present invention will be easily understood by those skilled in the art by referring to the following description of the specification.

  The sensor cable of the present invention is a sensor cable for connecting a sensor head part and a signal processing part of an amplifier separation type sensor. The sensor cable includes a first connector half for holding a conductor terminal, a second connector half for holding the conductor terminal, a conductor terminal of the first connector half, and a conductor terminal of the second connector half. And a waveform shaping circuit for shaping the waveform of a signal flowing through the electrical cord. The first connector half and the second connector half have a structure that is detachable from each other, thereby enabling signal transmission by connecting and integrating a plurality of the connector halves.

  The electrical cord includes at least a communication line for transmitting a sensing signal output from the sensor head to the signal processing unit. However, when drive control of the sensor head unit is performed by the signal processing unit, a second communication line for transmitting a control signal output from the signal processing unit to the sensor head unit is further included. .

  According to such a sensor cable of the present invention, the cord length can be set to an arbitrary length by connecting and integrating an appropriate number. And since this sensor cable is equipped with a waveform shaping circuit that shapes the waveform of the signal that flows through the electrical cord, even if the total length of the signal transmission cable becomes long, signal attenuation can be minimized. Thereby, stable high-speed signal transmission can be performed. The waveform shaping circuit includes a case where the waveform shaping circuit is provided for the sensing signal or the sensing signal and the control signal.

  In a preferred embodiment, the communication line is a twisted pair, and the sensing signal or the sensing signal and the control signal is a high-speed differential transmission signal. That is, a coaxial cable can be used as the communication line, but the manufacturing cost can be reduced by using an inexpensive twisted pair. Further, by using a twisted pair, bending resistance is improved, and it is possible to use without disconnection even in a usage situation where the sensor head is attached to the movable part and the cable is repeatedly bent. High speed differential transmission signals include low voltage differential transmission (LVDS) signals.

  In a preferred embodiment, the electric cord further includes a power supply line for supplying driving power from the signal processing unit to the waveform shaping circuit. According to such an aspect, since it is not necessary to separately provide a power supply line to the waveform shaping circuit, troubles such as routing of the power cord are eliminated.

  The “waveform shaping circuit” can be configured using a waveform shaping buffer, or a serializer and a deserializer. This waveform shaping circuit may be provided in the middle of the constituent electric cord, or may be provided in the first or second connector half (in the case).

  The present invention is particularly suitable for a displacement sensor or a visual sensor including a two-dimensional image sensor. Sensors employing these two-dimensional image sensors tend to have a large sensing signal capacity, so the effect of adopting the sensor cable of the present invention premised on high-speed signal transmission is even more remarkable. Let's go.

  Preferably, in the present invention, the main body cases of the first connector half and the second connector half respectively holding the conductor terminals are structured so that the connector halves are connected in a fixed state. According to such an aspect, since there is almost no stress on the conductor terminal or the wiring board on which the conductor terminal is mounted, durability as a product can be improved.

  According to the sensor cable of the present invention, since a plurality of cables can be connected and integrated, the total length thereof can be easily changed, and each cable is provided with a waveform shaping circuit. Even if the total length is increased, detection errors due to signal attenuation and noise mixing can be minimized.

  In the following, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. The embodiment described below is merely an example of the present invention, and the gist of the present invention is specified only by the description of the scope of claims.

  A configuration of an amplifier-separated sensor to which the present invention is applied is shown in FIG. As shown in the figure, the separated amplifier type sensor is formed by connecting a sensor head unit 1 and a signal processing unit 2 with one or two or more sensor cables.

  Various types of sensors such as a displacement sensor, a visual sensor, a proximity sensor, a microwave sensor, and a length measurement sensor can be applied as the sensor head unit.

  In this example, the signal processing unit 2 includes a sensor interface 21 that takes in a sensing signal from the sensor head unit 1 and transmits a control signal to the sensor head 1, and an FPGA (Field Programmable Gate Array) that is a programmable logic circuit. 22, a CPU 23 mainly composed of a microprocessor, and an input / output interface 24 are connected in series via a transmission path.

  An example of an amplifier-separated sensor that employs the sensor cable of the present invention is shown in FIG. In this example, the displacement sensor head 1 that irradiates the line beam LB toward the detection target object W and the signal processing unit 2 are connected by two sensor cables (3a, 3b). Each sensor cable includes a female connector 31 and a male connector 32 each including a wiring board on which a waveform shaping circuit is formed, and an electric cord 33 that connects the connectors. In the figure, reference numeral 12 denotes an electric cord drawn from the sensor head 1, and its structure is the same as the electric cord of the sensor cable. In the figure, reference numeral 11 denotes a connector connected to the electric cord 12, and the structure is the same as that of the male connector 32 of the sensor cable.

  FIG. 3 is an internal perspective view showing the structure of the sensor cable according to the present invention. As shown in the figure, a wiring board 34 is mounted in the outer shell case of the female connector 31. Although not clearly shown in the figure, at one end side (left end of the figure) of the female connector 31, there is an opening into which the male connector 32 of another sensor cable of the same specification is inserted and a male connector housing space. The conductor terminal 35 is disposed at a location slightly behind the opening. On the other hand, in the male connector 32, the conductor terminals 36 are arranged in a manner that slightly protrudes from the end surface (right end of the figure) of the outer shell case.

  The detailed structure of the sensor cable according to the present invention is shown in FIG. In addition, the same code | symbol is attached | subjected to the same thing as FIG. 3, and the description is abbreviate | omitted.

  As shown in FIG. 4, the female connector 31 is an assembly of a wiring board 34, an upper outer shell case 31 a and a lower outer shell case 32. The conductor terminal 35 is fixedly connected to the wiring board 34 in this example. In the figure, reference numeral 330 denotes a sensing signal communication line (first communication line) and a control signal communication line (second communication line) included in the electric cord 33. Each communication line is formed of a twisted pair in this example.

  The connection state of the sensor cable of the present invention is shown in FIG. FIG. 4A shows a state before connection, and FIG. 4B shows a state after connection.

  As shown in FIG. 2A, the male connector 32 is inserted (press-fitted) into the opening 310 of the female connector 31. When the two connectors are appropriately connected, the conductor terminal 35 and the conductor terminal 36 are electrically connected in close contact as shown in FIG. In this state, the connection stability of both connectors depends on the connection strength between the outer shell cases of both connectors.

  A conventional general connector structure is shown in FIG. As is apparent from the figure, in many of the conventional connectors of this type, the conductor terminal b of one connector is held in a state of protruding from the outer shell case c. In such a connector connection mode, since the connector is fixed by the coupling strength between the conductor terminals, the connector is moved when the cable is pulled or moved even in the connected state. Is also moved and stress is generated at the connection with the circuit board. This stress was likely to cause failure such as breakage or disconnection of the substrate circuit.

  On the other hand, in the sensor cable of the present invention, since the stress applied to the conductor terminal (circuit board) is small even when the connector is connected, the durability is improved.

  The internal circuit configuration of the female connector 31 of the sensor cable according to the present invention is shown in FIG. In this example, a sensing signal (video signal, synchronization signal) is transmitted from the sensor head side through the communication line S1 (twisted pair) of the electric cord 33. This sensing signal is waveform-shaped by the waveform shaping buffers 71 and 72 mounted on the circuit board, and transmitted to the communication line S2 of the electric cord 33 on the signal processing unit side. Further, a control signal (setting signal, light projection control signal, control signal) is transmitted from the signal processing unit side through the communication line S3 of the electric cord 33. This control signal is subjected to waveform shaping by the waveform shaping buffers 73 and 74 mounted on the circuit board, and transmitted to the communication line S4 of the electric cord 33 on the sensor head side. In this example, a power supply line for supplying drive power from the signal processing unit to the waveform shaping buffers 71, 72, 73, 74 is drawn into the connector 31. The buffer is configured to be supplied with power of 3, 3V.

  The internal circuit configuration of the female connector 31 of the sensor cable according to the present invention may be as shown in FIG. In this example, a sensing signal (video signal, synchronization signal) is transmitted from the sensor head side through the communication line S1 (twisted pair) of the electric cord 33. The sensing signal is converted from a serial signal into a 10-bit parallel signal by a deserializer 81 mounted on a circuit board, and then converted into a serial signal again by a serializer 82. The communication line of the electrical code 33 on the signal processing unit side Is transmitted to S2. Further, a control signal (setting signal, light projection control signal, control signal) is transmitted from the signal processing unit side through the communication line S3 of the electric cord 33. This control signal is converted from a serial signal into a 10-bit parallel signal by a deserializer 83 mounted on a circuit board, and then converted into a serial signal again by a serializer 84. The communication line of the electrical cord 33 on the sensor head side Is transmitted to S4. Also in this example, the connector 31 is provided with a power supply line for supplying driving power from the signal processing unit to the serializers 82 and 84 and the deserializers 81 and 83. 3V power is supplied. In this example, since the serializer and deserializer serve as a waveform shaping circuit, an oscillator (OSC) 85 for supplying a clock to them is mounted.

  A variation of the present invention is shown in FIG. The sensor cable shown in this example is provided with a female connector 31 on one end side and a male connector 32 on the other end side. An electrical cord 33 a is drawn from the female connector 31, and an electrical cord 33 b is drawn from the male connector 31. And between these electric cords 33a and 33b, the repeater 40 which connects both electric cords is provided. In this example, the circuit board 34 is built in the repeater 40.

  FIG. 10 shows an internal circuit configuration of the female connector 31 of the sensor cable according to the modification of the present invention. In this example, a sensing signal (video signal, synchronization signal) is transmitted from the sensor head portion side through the communication line S1 (twisted pair) of the electric cord 33a. This sensing signal is waveform-shaped by the waveform shaping buffers 101 and 102 mounted on the circuit board, and transmitted to the communication line S2 of the electric cord 33b on the signal processing unit side. In addition, a control signal (setting signal, light projection control signal, control signal) is transmitted from the signal processing unit side through the communication line S3 of the electric cord 33b. This control signal is subjected to waveform shaping by the waveform shaping buffers 103 and 104 mounted on the circuit board, and transmitted to the communication line S4 of the electric cord 33a on the sensor head side. In this example as well, a power supply line for supplying driving power from the signal processing unit to the waveform shaping buffers 101, 102, 103, 104 is drawn into the connector 31. The buffer is configured to be supplied with power of 3, 3V.

  Note that the internal circuit configuration of the female connector 31 of the sensor cable according to the modification of the present invention may be configured as shown in FIG. In this example, a sensing signal (video signal, synchronization signal) is transmitted from the sensor head unit side through the communication line S1 (twisted pair) of the electric cord 33a. This sensing signal is converted from a serial signal into a 10-bit parallel signal by the deserializer 111 mounted on the circuit board, and then converted again to a serial signal by the serializer 112, and the communication line of the electric cord 33b on the signal processing unit side Is transmitted to S2. In addition, a control signal (setting signal, light projection control signal, control signal) is transmitted from the signal processing unit side through the communication line S3 of the electric cord 33b. This control signal is converted into a 10-bit parallel signal by the deserializer 113 mounted on the circuit board, and then converted again to a serial signal by the serializer 114, and the communication line of the electric cord 33a on the sensor head side Is transmitted to S4. In this example as well, a power supply line for supplying driving power from the signal processing unit to the serializers 112 and 114 and the deserializers 111 and 113 is drawn into the connector 31. 3V power is supplied. In this example as well, since the serializer and deserializer serve as a waveform shaping circuit, an oscillator (OSC) 115 for supplying a clock to them is mounted.

  As is apparent from the above description, according to the present invention, the overall length can be easily extended, and signal attenuation and noise mixing can be achieved even when the overall length is long when performing high-speed signal transmission. A sensor cable that can be suppressed as much as possible is provided.

  In the above embodiment, an example is shown in which waveform shaping circuits are provided for both the sensing signal and the control signal. However, when high-speed signal transmission is not required for the control signal, only the sensing signal that performs high-speed differential transmission is used. A waveform shaping circuit may be provided.

  In the above embodiment, an example in which two sensor cables are connected has been described, but it is naturally possible to connect three or more cables.

  In the above embodiment, the displacement sensor has been described as an example. However, the sensor cable of the present invention can be widely applied to various amplifier-separated sensors.

It is a block diagram of an amplifier separated type sensor to which the present invention is applied. It is a figure which shows an example of the amplifier isolation | separation type sensor by which the cable for sensors of this invention was employ | adopted. It is an internal perspective view which shows the structure of the cable for sensors. It is a disassembled perspective view which shows the structure of the cable for sensors. It is a figure for demonstrating durability of the cable for sensors of this invention. It is a figure which shows a general connector structure. It is FIG. (1) which shows the internal circuit structure of a connector. FIG. 6 is a diagram (part 2) illustrating an internal circuit configuration of the connector. It is a figure which shows the modification of this invention. It is FIG. (1) which shows the internal circuit structure of the connector of a modification. It is FIG. (2) which shows the internal circuit structure of the connector of a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sensor head part 2 Signal processing part 3 Sensor cable 11 Connector half 12 Electric cord 21 Sensor I / F
22 FPGA
23 CPU
24 I / O I / F
31 female connector 32 male connector 33 electrical cord 34 circuit board 35 conductor terminal 36 conductor terminal 40 repeater 71, 72, 73, 74 waveform shaping buffer 75 DC-DC converter 81, 83 deserializer 84, 85 serializer 330 twisted pair

Claims (10)

A sensor cable for connecting the sensor head part of the amplifier-separated sensor and the signal processing part,
A first connector half holding a conductor terminal;
A second connector half holding a conductor terminal;
An electrical cord for electrically connecting the conductor terminal of the first connector half and the conductor terminal of the second connector half;
A waveform shaping circuit for shaping the waveform of the signal flowing through the electrical cord,
The first connector half and the second connector half have a detachable structure,
As a result, it was possible to connect and integrate multiple wires to transmit signals.
Sensor cable characterized by this.   The electrical cord includes a first communication line for transmitting a sensing signal output from the sensor head to the signal processing unit, and a first communication line for transmitting a control signal output from the signal processing unit to the sensor head unit. 2. The sensor cable according to claim 1, wherein two communication lines are included.   The sensor cable according to claim 2, wherein the communication line is a twisted pair, and the sensing signal or the sensing signal and the control signal are high-speed differential transmission signals.   The sensor cable according to claim 1, wherein the electrical cord further includes a power supply line for supplying driving power from the signal processing unit to the waveform shaping circuit.   The sensor cable according to claim 1, wherein the waveform shaping circuit is provided in the middle of the electric cord.   The sensor cable according to claim 1, wherein the waveform shaping circuit is built in the first or second connector half.   The sensor cable according to claim 1, wherein the waveform shaping circuit is configured using a waveform shaping buffer, or a serializer and a deserializer.   The sensor cable according to claim 1, wherein the sensor head unit is a sensor head unit for a displacement sensor or a sensor head unit for a visual sensor that includes a two-dimensional image sensor.   The main body cases of the first connector half and the second connector half respectively holding the conductor terminals are structured so that the connector halves are connected in a fixed state. Sensor cable as described.   An amplifier-separated sensor comprising a plurality of sensor cables according to claim 1 connected together.

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