JP3878312B2 - Serial communication device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a serial communication device that can synchronize operation timing between control devices or measurement devices connected by serial communication.
[0002]
[Prior art]
In recent years, with the opening of numerical control devices, a numerical control device and a plurality of devices such as a plurality of servo controllers that control movable axes are connected in a ring shape for the purpose of improving the connectivity between devices constituting the numerical control system. Network-type numerical control systems connected by a bus-like serial communication network have been used. In such a network type system, it is impossible to connect necessary signals using individual wiring as in the previous system, and serial communication is used for the operation timing of the numerical controller and each servo controller. It was necessary to synchronize accurately.
[0003]
FIG. 4 shows an example of a network type numerical control system in which a network is configured in a ring shape. 5 and 6 show a conventional example of a communication device built in these devices, and FIG. 7 shows a case where the conventional communication device of FIGS. 5 and 6 is applied to the network type numerical control system of FIG. T1, T11, T12, T13, T13, T12, T13, T13, T12, T13, T13, T12, T13, It is a timing chart shown by the signal name of T14.
In the conventional network type numerical control system in which the communication device of FIG. 5 and the communication device of FIG. 6 are incorporated in each of the servo controllers 21, 22, 23, and 24 in the numerical control device 20 of FIG. An interrupt request signal INT output by 32 at a constant cycle is output to the microcomputer 31. When the microcomputer 31 receives the interrupt signal INT, the interrupt process for transmitting the control data is started. First, a signal CS for starting communication is sent to the parallel-serial converter 5 and then the system is transmitted through the data bus SD. Are sequentially output to the parallel / serial converter 5. Further, the microcomputer 31 sends a communication end signal CE to the parallel-serial converter 5. The parallel-serial converter 5 encodes parallel data input mainly through the data bus SD, converts it into serial data, and outputs it to the driver 6. The driver 6 amplifies the power of the input signal and transmits a communication frame to the communication line N1. The time setting command communication frame FSYNC includes a start flag portion SF indicating the start of the communication frame, a destination information portion DA indicating the destination of the transmission partner, a code indicating the time setting command as a command portion CM, a frame check data portion CR, and a frame. It is composed of an end flag portion EF indicating the end, and the destination information portion DA is an address code indicating all devices. The start flag section SF, the frame check data section CR, and the end flag section EF are automatically output by the parallel / serial converter 5 using the communication start signal CS and the communication end signal CE as triggers. After transmitting the communication frame for the time setting command, the microcomputer 31 performs the same operation as the transmission of the time setting command, thereby positioning the motors 25, 26, 27, and 28 to the servo controllers 21, 22, 23, and 24, respectively. 4 communication frames FRAM1, FRAM2, FRAM3, and FRAM4 including control information data necessary for the transmission are transmitted.
[0004]
The servo controller 21 receives serial data from the communication line N1 by the receiver 18 and converts the signal level. Then, the serial / parallel converter 17 performs parallel data conversion and decoding of the serial data, and outputs the parallel data to the data bus RD1. In addition, the serial / parallel converter 17 outputs the identification of the start flag part SF and the end flag part EF, the check result of the frame check data part CR, etc. to the microprocessor 19 and the reception frame identification circuit 29 as the status signal ST1. When the reception frame identification circuit 29 recognizes from the status signal ST1 and the data on the data bus RD1 that the command unit CM of the reception frame is a time setting command, it outputs a setting signal ST1 to the timer 30. When the setting signal ST1 is input to the timer 30, the value of the timer being counted is changed to initial timer data (09) set in advance by the microprocessor 19. The received frame identification circuit 29 outputs a switching signal SL1 to the switch 10 if the destination information section DA of the received frame indicates a destination to another station, and converts the data on the data bus RD1 into parallel serial data through the data bus PD1. The communication start signal CS 1 and the communication end signal CE 1 are output to the parallel / serial converter 15. As described above, when the servo controller 19 receives the communication frame FSYNC of the time setting command, the timer 30 is reset to a fixed value (09), and the communication frames of the frames FSYNC, FRAM2, FRAM3, and FRAME4 other than the destination only for the own station. Is transmitted from the driver 16 to the communication line N2. When the servo controller 21 receives the communication frame FRAM1 addressed to its own station, it outputs the communication start signal CS1 to the parallel-serial converter 15 in parallel with the reading of the contents by the microcomputer 19, and then the switch 10 The information data related to the motor 25 is sequentially output via the data buses SD1 and PD1, and the communication end signal CE1 is further output to output from the driver 16 as the communication frame FRAM11. The servo controllers 22, 23, and 24 perform the same processing as the servo controller 21 except that the timer setting value at the time of receiving the time setting command communication frame is different. Thereby, the control timing of each apparatus of the whole numerical control system can be substantially synchronized.
[0005]
[Problems to be solved by the invention]
In the conventional method of matching the timing between each device, it is necessary to transmit a communication frame for a time setting command in a fixed cycle, and since this is performed by interrupt processing, no matter how high the priority level of interrupt processing is, immediately before Since the interrupt process cannot be entered until the executed instruction is completed, there is a problem in that there is a time variation in the timing of sending the communication frame for the time setting command due to the instruction immediately before the interrupt is performed. However, the operation timing between the devices could not be aligned, and the entire system could not be operated accurately at the same timing.
In addition, if the time setting command communication frame is transmitted at a fixed timing in hardware, the data necessary for other control must be adjusted to avoid the time setting command communication. When the device is integrated into an IC and installed in another control or measurement system device, there is a problem that the degree of freedom in designing the timing of communication is restricted.
In addition, in the system connected in the ring shape described in the conventional example, a time delay occurs when relaying the time setting command communication frame, and each servo controller cannot receive the time setting command communication frame at the same time. The value to be set in the timer when receiving the time setting command needs to be set in advance in consideration of the relay delay for each movable axis, which requires time and effort on the communication protocol.
[0006]
The present invention has been made to solve the above-described problems, and an object of the present invention is to accurately match the timing between devices connected by a serial communication network, and by using various serial communication networks. An object of the present invention is to provide a serial communication device that can be flexibly applied to a configured control or measurement system.
[0007]
[Means for Solving the Problems]
The present invention relates to a serial communication device that receives a command code of a time setting command and time information data by serial communication, and relays and transmits the serial data. The serial / parallel conversion means converts serial data into parallel data, and a timer counts time. The time setting command identifying unit 1 for identifying the time setting command from the code output from the serial / parallel converting unit, and the serial / parallel converting unit when the time setting command identifying unit 1 recognizes the time setting command. Automatic time changing means for setting time information data to be set in the timer, parallel serial converting means for converting parallel data to serial data, and receiving data when receiving data addressed to other stations is output to the parallel serial converting means Relay means for input and input to the parallel serial conversion means The time setting command identifying means 2 for identifying the time setting command from the generated code, and when the time setting command identifying means 2 recognizes the time setting command code, the time information data from the relay means is received after the time setting command code. Automatic time information replacing means for replacing the time information data indicated by the timer and automatically sending to the parallel-serial conversion means.
[0008]
[Action]
The present invention adds the time instant of transmission of the communication frame of the time setting command to the communication frame as time information data and transmits it, and the receiving side device sets this time information data in the timer. Even if a time setting command communication frame is transmitted, the time of the timer of the receiving device can be adjusted accurately, so it is not affected by time variations such as interrupt processing, and the transmission procedure can be changed freely. Can be done. In addition, when relaying a time setting command, it is not necessary to consider the relay delay of the communication frame of the time setting command because the time information data is always replaced with the time of relay transmission. There is no need to set the parameters for each device.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a communication apparatus according to the present invention built in a numerical control device or the like on the general numerical control system shown in FIG. FIG. 2 shows a communication apparatus according to the present invention incorporated in the servo controllers 21, 22, 23, 24, etc. of FIG. 3 shows a case where the numerical control device or the like on the numerical control system of FIG. 4 incorporates the communication device of FIG. 1, and the servo controllers 21, 22, 23, and 24 incorporate the communication device of the communication device of FIG. It is a timing chart which shows the value of the timer which the line | wires N1, N2, and N3, the numerical control apparatus 20, and the servo controllers 21 and 22 incorporate in the signal name of T, T1, and T2. In FIG. 1 and FIG. 2, the same elements as those in FIG. 5 and FIG.
[0010]
In the network type numerical control system in which the communication device of the present invention of FIG. 1 is included in the numerical control device 20 of FIG. 4 and the communication device of the present invention of FIG. An interrupt request signal INT output from the timer 2 at a constant period in the apparatus 20 is output to the microcomputer 1. When the microcomputer 1 receives the interrupt signal INT, an interrupt process for transmitting control data is started. First, a signal CS for starting communication is sent to the parallel-serial converter 5 and the transmission frame identification circuit 3, and then The time setting command data for synchronizing the system is sequentially output to the parallel-serial converter 5 and the transmission frame identification circuit 3 through the data buses SD and PD via the switch 4. When the transmission frame identification circuit 3 identifies that the code of the command part CM of the time setting command is the time setting command from the communication start signal CS and the data of the data bus PD, the switching signal SL is input to the switch 4 and the communication end signal CE is input. Output until As a result, the time data T of the timer 2 is output from the switch 4 to the parallel-serial converter 5 through the data bus PD. As described above, the communication frame FTIME of the time setting command is output to the communication line N1 through the parallel-serial converter 5 and the driver 6. This communication frame FTIME includes a start flag portion SF indicating the start of the communication frame, a destination information portion DA, a code indicating a time setting command as a command portion CM, and output data T (04) of timer 2 which is time information data of the time setting command. And a frame check data section CR and an end flag section EF indicating the end of the frame. After transmitting the communication frame FTIME for the time setting command, four communications including control information data necessary for positioning the motors 25, 26, 27, and 28 addressed to the servo controllers 21, 22, 23, and 24, respectively, as in the conventional example. The frames FRAM1, FRAM2, FRAM3, and FRAM4 are transmitted.
[0011]
The servo controller 21 receives serial data from the communication line N1 by the receiver 18 and converts the signal level. Then, the serial / parallel converter 17 performs parallel data conversion and decoding of the serial data, and the parallel data is output to the data bus RD1. In addition, the serial-parallel converter 17 outputs the identification of the start flag SF and the end flag EF, the check result of the frame check data section CR, etc. to the microprocessor 9 and the reception frame identification circuit 14 as the status signal ST1. When the reception frame identification circuit 14 recognizes from the status signal ST1 and the parallel data RD1 that the code of the command portion CM of the reception frame is a time setting command, it outputs the setting signal ST1 to the timer 12. When the setting signal ST1 is input, the timer 12 stores time information data (08) of a time setting command on the data bus RD1, and adds a value (0C) obtained by adding a communication processing delay time TD (08) to this value as a status. After confirming that the communication frame of the time setting command is completed without any abnormality by the signal ST1, it is set as a timer value during counting.
[0012]
When the microprocessor 9 identifies that the time setting command communication frame FTIME is data addressed to another station, the microprocessor 9 confirms that the time setting frame received from the status ST1 is normal, and transmits another frame. After confirming that it is not in the middle, the communication start signal CS1 is output to the parallel-serial converter 15, the received data is sequentially output to the data bus SD1, and the communication end signal CE1 is further output. When the transmission frame identification circuit 11 identifies that the code of the command part of the frame data is a time setting command from the communication start signal CS1 and the data on the data bus SD1 via the switch 10, the switch signal SL1 is sent to the switch 10 as a communication end signal. Output until CE1 is input. As a result, the time data T1 (12) of the timer 12 is output from the switch 10 to the parallel-serial converter 15 through the data bus PD1. As described above, the time setting command communication frame FTIME1 to be output to the communication line N2 through the parallel-serial converter 15 and the driver 16 has the parameter part of the time setting command corrected by the amount delayed from the time setting command FTIME of the communication line N1. Will be sent.
[0013]
In addition, when the microprocessor 9 receives the communication frame FRAM1 addressed to its own station, it outputs the information related to the motor 25 to the data bus PD1 via the switch 10 to the parallel / serial converter 15 and outputs it as the communication frame 11 from the driver 16. Transmit to the communication line N2. In addition, the data of the communication frames FRAM2, FRAM3, and FRAME4 addressed to other stations are also output to the parallel-serial converter 15, and the relay is transmitted from the driver 16 to the communication line N2 by controlling the communication start signal CS1 and the communication end signal CE1. Process. In the servo controllers 22, 23, and 24, the same processing as that of the servo controller 21 is performed, and the control timing of each device of the entire numerical control system can be accurately synchronized.
[0014]
3 shows a case where the servo controller happens to be in the middle of transmitting the communication frame FRAM21 at the time of relaying the communication frame of the normal time setting command. In such a case, the transmission of the communication frame FTIME2 of the time setting command is performed. This shows how the time information parameter is corrected normally even if it is later than normal.
In the description of the embodiment, the communication processing delay time TD of the time setting command parameter is corrected on the timer side and set to the timer. However, the time setting command parameter is corrected in advance by the communication processing delay time TD amount at the time of transmission. You may send it.
[0015]
【The invention's effect】
As described above, according to the method of the present invention, it is possible to accurately match the timing between devices connected by a serial communication network, and the communication frame (time setting command) for matching the timing is an arbitrary timing. Output can be made easy, and timing design becomes easy, and it can be flexibly applied to control or measurement systems composed of various serial communication networks. In addition, unlike the conventional system, it is not necessary to set different values in advance for each device in consideration of the relay delay, and the communication protocol is not required for that purpose.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of a communication device built in a numerical control device in the present invention.
FIG. 2 is a diagram showing an embodiment of a communication device built in a servo controller in the present invention.
FIG. 3 is a timing chart for explaining the operation of the communication apparatus of the present invention.
FIG. 4 is a diagram showing a connection between devices of a network type numerical control device.
FIG. 5 is a diagram showing an example of a communication device built in a conventional numerical control device.
FIG. 6 is a diagram showing an example of a communication device built in a conventional servo controller.
FIG. 7 is a timing chart for explaining the operation of a conventional communication apparatus.
[Explanation of symbols]
1 microcomputer, 2,12 timer, 3,11 transmission frame identification circuit, 4,10 switcher, 5,15 parallel serial converter, 6,16 driver, 7,17 serial parallel converter, 8,18 receiver, 9 Microprocessor, 14 Received frame identification circuit, 20 Numerical controller, 21, 22, 23, 24 Servo controller, 25, 26, 27, 28 Motor.

Claims (1)

In a serial communication device that receives and relays a time setting command code and time information data by serial communication, serial-parallel conversion means for converting serial data into parallel data, a timer for counting time, and the serial Time setting command identifying means 1 for identifying a time setting command from a code output from the parallel converting means, and time information output from the serial / parallel converting means when the time setting command identifying means 1 recognizes the time setting command Automatic time changing means for setting data in the timer, parallel serial converting means for converting parallel data to serial data, and relay means for outputting received data to the parallel serial converting means when data addressed to another station is received And the input to the parallel-serial conversion means. The time setting command identifying means 2 for identifying the time setting command from the mode, and when the time setting command identifying means 2 recognizes the time setting command code, the time information data from the relay means is added to the timer after the time setting command code. An automatic time information replacing unit that replaces with the time information data indicated by and automatically sends the data to the parallel-serial conversion unit.

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