JP3996446B2 - CAN data converter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a CAN data converter for converting CAN data flowing on a CAN bus into an analog signal and outputting the analog signal from an analog output port.
[0002]
[Prior art]
A control area network (CAN: Controller Area Network) of an international standard (ISO11898) is known as a network in which a plurality of devices such as an in-vehicle network, a home appliance network, and an industrial control device network are connected. The CAN has a feature that its transmission rate is 1 Mbps at the maximum, and it is very high-speed compared with the communication method conventionally used in each network described above. In addition, since CAN is serial communication that replaces the high and low of a digital signal with a differential voltage between two wires on the network, it also has a feature of excellent noise resistance. For this reason, CAN is currently used in many fields.
[0003]
CAN is a bus system having multi-master capability, and all devices can transmit CAN communication packets on the bus as long as the CAN bus (hereinafter simply referred to as “bus”) is available. Also, a plurality of devices can simultaneously receive CAN communication packets on the bus (broadcasting method). On the other hand, the CAN communication packet flowing on the bus is defined by a variable data length format (CAN data format), and represents an ID part indicating the type of CAN data included in the CAN communication packet and the content of the CAN data itself. It has a data structure divided into a data part. In this case, the ID part is not a so-called station ID for specifying each device, but indicates the type of CAN data included in the data part (for example, in the vehicle-mounted network, the engine speed, temperature, etc.) It has the function of determining the access priority on the bus. The data part is configured to be usable by being divided into a plurality of data areas, and the position and size of each data area can be arbitrarily set for each CAN communication packet as described above. However, when communicating between devices connected to the same bus, if the CAN data format is different for each device, the partner device cannot extract the desired CAN data from the data area. It becomes. For this reason, between the devices connected to the same bus, the number of data areas in the data section, the position of the data area for each type of CAN data, and the size of each data area are standardized, and the CAN data format is unified. Has been.
[0004]
On the other hand, each device connected to the bus has identification information (a type of CAN data, etc.) for identifying a CAN communication packet including CAN data to be acquired, position information of a data area in which the CAN data is stored, and CAN definition data defining scaling information of the CAN data (scaling value (maximum value or minimum value) and unit; hereinafter the same) is stored. In this case, each device receives the CAN communication packet flowing on the bus, and compares the content of the ID part in the received CAN communication packet with each stored CAN definition data, so that the received CAN communication packet is It is determined whether or not CAN data defined in each CAN definition data is included. When it is determined that the defined CAN data is included, each device extracts the CAN data from the data area defined by the CAN definition data. On the other hand, when outputting CAN data to the bus, each device configures an ID portion and, based on the type of CAN data to be output, a CAN communication packet in which CAN data to be output is stored in a predetermined data portion. Generate. Next, when the bus is free, the generated CAN communication packet is output on the bus. As a result, all other devices can receive the CAN data on the bus.
[0005]
In such a CAN, when observing (measuring) predetermined CAN data included in a CAN communication packet flowing on a bus, an analog input recorder generally used in the field of measurement is used. It is convenient if you can. However, since this type of recorder cannot be directly connected to the bus, it is usually connected to the bus via a CAN data converter. In this case, the CAN data conversion device receives a CAN communication packet including CAN data to be acquired (observation target) from the bus, extracts the CAN data, converts the CAN data into an analog signal, and then outputs the analog signal to the analog output. Output from the port to the recorder. In general, this type of recorder is provided with a plurality of input ports so that a plurality of analog signals input through the input ports can be observed simultaneously. Accordingly, the CAN data conversion apparatus also has a plurality of analog output ports corresponding to this.
[0006]
Further, the CAN data conversion device has a memory, and in this memory, in the same manner as the above-mentioned device connected to the bus, the type of CAN data to be taken in, the position information of the data part in which the CAN data is stored, The CAN definition data defining the scaling information of the CAN data is stored in the same number as the number of analog output ports corresponding to each analog output port. Further, the memory stores correspondence data indicating the correspondence between the fetched CAN data and the analog output port as the output destination of the CAN data. In this case, these CAN definition data and corresponding data are generally created using a personal computer in which dedicated application software for generating these data is installed. Specifically, a CAN data converter is connected to a personal computer, CAN definition data and corresponding data are created using dedicated application software, and the created data is transferred from the personal computer to the memory of the CAN data converter. . Thereby, each said data is memorize | stored in the memory of a CAN data converter.
[0007]
When observing predetermined CAN data included in a CAN communication packet flowing on the bus using this CAN data conversion device and recorder, first, bring the CAN data converter and recorder into the measurement site. The CAN data converter is connected to the bus, and the recorder is connected to the CAN data converter. On the recorder side, the operation unit provided in the recorder is operated to set the scaling value and unit of the CAN data to be observed for each input port.
[0008]
At the time of observation, this CAN data converter receives a CAN communication packet flowing on the bus in the same manner as each device described above, and determines a CAN communication packet to be acquired based on each CAN definition data. In the case of a CAN communication packet to be acquired, the CAN data is extracted from the CAN communication packet. Further, in the CAN data conversion device, the extracted CAN data is sequentially stored in the memory in correspondence with each analog output port based on the corresponding data. The CAN data converter converts the stored CAN data into an analog signal and outputs the analog signal to the recorder from the corresponding analog output port. As a result, predetermined CAN data included in the CAN communication packet flowing on the bus is observed by the recorder.
[0009]
[Problems to be solved by the invention]
However, the conventional CAN data converter has the following problems. That is, the CAN definition data stored in the memory of the CAN data conversion device is defined in the same number as the number of analog output ports corresponding to each analog output port. For this reason, for example, when it becomes necessary to acquire and measure CAN data that was not assumed at the measurement site, it is necessary to change the CAN definition data. In this case, it is necessary to remove the CAN data conversion device from the bus, connect the CAN data conversion device to the above personal computer, create new CAN definition data and corresponding data on the personal computer, and transfer them to the CAN data conversion device. There is. Therefore, there is a problem that it takes a long time to change the CAN definition data.
[0010]
The present invention has been made in view of such problems, and a main object of the present invention is to provide a CAN data conversion device that can change CAN data to be acquired in a short time.
[0011]
[Means for Solving the Problems]
To achieve the above object, a CAN data converter according to claim 1 identifies a CAN bus interface unit, a D / A converter, a plurality of analog output ports, and a CAN communication packet including CAN data to be acquired. A plurality of CAN definition data defining at least the position information of the CAN data in the CAN communication packet together with the identification information, and each CAN data extracted from the CAN communication packet and converted into an analog signal by the D / A converter; The CAN communication received from the CAN bus via the CAN bus interface unit via a CAN bus interface unit, and a memory that stores correspondence data indicating a correspondence relationship with the analog output port as the output destination CAN communication parameters including the CAN data to be acquired from the packet. The CAN data to be acquired is extracted from the corresponding CAN communication packet with reference to the CAN definition data, and the extracted CAN data is converted to the D / A conversion. A CAN data converter for outputting the analog signal to an analog signal and outputting the analog signal to the analog output port indicated by the corresponding data, wherein the memory has a number equal to or greater than the number of the analog output ports. The CAN definition data can be stored, and the control unit can be configured to change the correspondence in the correspondence data according to an input command.
[0012]
According to a second aspect of the present invention, there is provided a CAN data conversion device according to the first aspect, further comprising an operation unit capable of inputting the command.
[0013]
According to a third aspect of the present invention, there is provided a CAN data conversion device according to the first aspect, further comprising a communication interface unit capable of inputting the command from an external device.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of a CAN data conversion device according to the invention will be described with reference to the accompanying drawings.
[0015]
First, the configuration of the CAN data conversion apparatus 1 will be described with reference to the drawings.
[0016]
As shown in FIG. 1, the CAN data converter 1 includes a CAN bus interface unit 11, a transceiver 12, a CAN controller 13, a CPU 14, a memory 15, a D / A converter 16, a signal switcher 17, n (n is 2). An analog output port OP1 to OPn (hereinafter referred to as “analog output port OP” unless otherwise specified), an operation unit 18 having operation keys and the like, and a communication interface unit 19 are provided.
[0017]
The CAN bus interface unit 11 has a function of electrically connecting the CAN data conversion device 1 to the bus 21. As an example, it is assumed that the bus 21 is used for CAN data transmission between the devices 22, 23, and 24 as shown in FIG. The transceiver 12 receives a CAN communication packet represented by a differential voltage on the bus 21 via the CAN bus interface unit 11 and converts it into a binary digital signal. The CAN controller 13 identifies the ID part and the data part in the CAN communication packet converted by the transceiver 12 and transfers them to the CPU 14. The memory 15 stores a program for defining the operation of the CPU 14. Further, the memory 15 stores a plurality of CAN definition data, correspondence data indicating the correspondence between the CAN data and the analog output ports OP1 to OPn, and the acquired CAN data. The D / A converter 16 converts the acquired CAN data Dca into an analog signal Sa and outputs the analog signal Sa. The signal switch 17 selects one of the analog output ports OP1 to OPn according to the input selection signal Ss, and outputs the output analog signal Sa to the selected analog output port OP. The operation unit 18 is operated by an operator and used to input commands to the CPU 14. The communication interface unit 19 is used to connect the CAN data conversion apparatus 1 to a recorder 31 or a personal computer (not shown). For example, an RS232C interface is employed. The CPU 14 functions as a control unit in the present invention, operates based on a program stored in the memory 15, and controls each component in the CAN data conversion apparatus 1.
[0018]
Next, the configuration of the recorder 31 as an external device will be described with reference to the drawings.
[0019]
As shown in FIG. 1, the recorder 31 includes N analog input ports IP1 to IPn (hereinafter also referred to as “analog input ports IP” unless otherwise specified), A / D converters ADC1 to ADCn (hereinafter, particularly, When not distinguished, it is also referred to as “A / D converter ADC”), and includes a memory control unit 32, a storage memory 33, an internal memory 34, a CPU 35, a display unit 36, a communication interface unit 37, and an operation unit 38. In this case, the A / D converters ADC1 to ADCn are arranged in the same number corresponding to the analog input ports IP1 to IPn, and convert analog signals input via the corresponding analog input ports IP into digital data. Output. The memory control unit 32 sequentially stores the digital data output by each of the A / D converters ADC1 to ADCn in the storage memory 33 in association with each analog input port IP. The internal memory 34 stores a program that defines the operation of the CPU 35. The internal memory 34 stores CAN data scaling information (scaling value and unit) for each analog input port IP. The display unit 36 displays the input display data in an analog manner. The communication interface unit 37 is configured by the same interface as the communication interface unit 19 of the CAN data conversion device 1 (RS232C interface as an example), and is used to connect the CAN data conversion device 1 to the recorder 31. The CPU 35 operates based on a program stored in the internal memory 34 and controls each component in the recorder 31. The operation unit 38 includes various operation keys and the like.
[0020]
Next, an example in which CAN data included in a CAN communication packet output from each device 22, 23, 24 and flowing on the bus 21 is observed using the CAN data conversion device 1 and the recorder 31 will be described.
[0021]
First, the CAN data conversion device 1 is connected to a personal computer (not shown) via the communication interface unit 19 and then the application software is activated to create CAN definition data Dde and corresponding data Dco. Dde and Dco are transferred from the personal computer to the CAN data converter 1. In the CAN data conversion apparatus 1, the CPU 14 receives these data Dde and Dco via the communication interface unit 19 and stores them in the memory 15. In this case, using the personal computer, the same number of CAN definition data Dde as the number of analog output ports OP1 to OPn is created in the same manner as in the past, and the CAN definition data Dde and each of the analog output ports OP1 to OPn are generated. Correspondence data Dco indicating the correspondence is generated. Further, the CAN definition data Dde for the CAN data that can be observed is created as spare CAN definition data Dde. Since this spare CAN definition data Dde does not correspond to any analog output port OP at this stage, it is not included in the corresponding data Dco, but the CAN definition data Dde included in the corresponding data Dco Similarly, it is stored in the memory 15.
[0022]
Next, the CAN data conversion device 1 is removed from the personal computer and transported together with the recorder 31 to the installation location of the bus 21 to be observed. The CAN data conversion device 1 is connected to the bus 21 and the recorder 31 is connected to the CAN data. Connect to the converter 1. In this case, the analog output ports OP1 to OPn of the CAN data converter 1 are connected to the analog input ports IP1 to IPn of the recorder 31, respectively, one to one. Further, the communication interface unit 19 of the CAN data conversion device 1 and the communication interface unit 37 of the recorder 31 are connected by an interface cable CB as a transmission path.
[0023]
In this state, the CAN data converter 1 and the recorder 31 are turned on. At this time, the CAN data conversion apparatus 1 first executes the scaling information transfer process shown in FIG. 2 and is included in each CAN definition data Dde stored in the memory 15 of the CAN data conversion apparatus 1. The scaling information Dsc is transferred to the recorder 31 via the interface cable CB.
[0024]
Specifically, as shown in FIG. 2, the CPU 14 of the CAN data converter 1 determines whether or not communication with the CPU 35 of the recorder 31 is possible (step 101). In this case, when the CPU 14 determines that the communication is not possible, the CPU 14 ends the transmission process of the scaling information Dsc. On the other hand, when determining that communication is possible, the CPU 14 selects each CAN associated with (assigned to) each analog output port OP1 to OPn by the corresponding data Dco among the CAN definition data Dde stored in the memory 15. The definition data Dde is read from the memory 15 (step 102). Next, the CPU 14 extracts the scaling information Dsc included in the read CAN definition data Dde, and uses the extracted scaling information Dsc as identification data (for example, corresponding port number) of the analog output port OP to which the scaling information Dsc is applied. And the communication interface unit 19, the interface cable CB, and the communication interface unit 37 (step 103). That is, the CPU 14 outputs to the CPU 35 each scaling information Dsc related to each CAN data Dca having a corresponding relationship with each analog output port OP1 to OPn. Further, the CPU 14 determines whether or not the CAN definition data Dde associated with the analog output ports OP1 to OPn by the corresponding data Dco is not extracted from the scaling information Dsc (step). 104) If there are any remaining ones, the above steps 102 to 103 are repeated. Thus, the CPU 14 transfers all the scaling information Dsc of each CAN definition data Dde associated with each analog output port OP1 to OPn to the recorder 31. On the other hand, in the recorder 31, the CPU 35 stores the transferred scaling information Dsc and identification data in the internal memory 34.
[0025]
Next, in the CAN data conversion apparatus 1, the CAN controller 13 identifies the ID part and the data part of the CAN communication packet received via the CAN bus interface part 11 and the transceiver 12 and transfers them to the CPU 14. The CPU 14 compares the content of the ID part of the CAN communication packet with each CAN definition data Dde stored in the memory 15 to compare the CAN defined in each CAN definition data with the transferred CAN communication packet. Determine whether data is included. When the CPU 14 determines that the defined CAN data is included, the CPU 14 extracts the CAN data Dca from the CAN communication packet, and refers to the corresponding data Dco to extract the extracted CAN data Dca to each analog output port OP1. Are stored in the memory 15 corresponding to .about.OPn. The CPU 14 repeatedly performs the operations of discriminating, extracting, and storing these CAN data Dca. The CPU 14 repeatedly detects whether or not the CAN data Dca stored for each analog output port OP1 to OPn stored in the memory 15 has reached a predetermined data amount, and the analog output port OP having reached the predetermined data amount is detected. Corresponding CAN data Dca is read from the memory 15 and output to the D / A converter 16. At the same time, the CPU 14 outputs the selection signal Ss to the signal switch 17 to set the analog output port OP corresponding to the CAN data Dca reaching the predetermined data amount as the output destination of the signal switch 17. As a result, the analog signal Sa generated by the D / A converter 16 is output from the corresponding analog output port OP.
[0026]
In the recorder 31, each A / D converter ADC converts the analog signal Sa taken in via each analog input port IP into digital data and outputs it to the memory control unit 32. The memory control unit 32 sequentially stores these digital data in the storage memory 33 in association with each analog input port IP. As an example, the CPU 35 requests the memory control unit 32 for digital data corresponding to the analog input ports IP1 to IPn in this order. The memory control unit 32 sequentially outputs digital data corresponding to the analog input ports IP <b> 1 to IPn stored in the storage memory 33 to the CPU 35 in response to a request from the CPU 35. The CPU 35 converts each input digital data into display data Dds and outputs the display data Dds. Further, the CPU 35 reads the scaling information Dsc from the internal memory 34 and outputs it to the display unit 36. On the other hand, the display unit 36 displays the display value Dds in an analog manner, and displays the scaling value and its unit based on the scaling information Dsc. As a result, the CAN data on the bus 21 is accurately observed by the recorder 31.
[0027]
Next, a method for changing the acquisition target CAN data will be described.
[0028]
First, the operation unit 18 is operated to input a corresponding data change command to the CPU 14. The CPU 14 changes the correspondence between the CAN data Dca and the analog output port OP according to the contents of the input command. Specifically, for example, an example in which twelve CAN definition data Dde1 to Dde12 are stored in the memory 15 in advance for five analog output ports OP1 to OP5 will be described. In this case, each of these CAN definition data Dde1 to Dde12 defines the CAN data Dca1 to Dca12 as an acquisition target, and the corresponding data Dco before the change is (OP1, Dde1), (OP2, Dde2), (OP3, Assume that the contents of Dde3), (OP4, Dde4), and (OP5, Dde5) are recorded in the memory 15. The above (OPM, DdeL) means that the CAN definition data DdeL is associated with the analog output port OPM (M and L are integers). In this case, for example, instead of the CAN data Dca4 and the CAN data Dca5, a command with the content that the CAN data Dca11 and the CAN data Dca12 are changed to acquisition targets is input. At this time, the CPU 14 generates new corresponding data (OP1, Dde1), (OP2, Dde2), (OP3, Dde3), (OP4, Dde11), (OP5, Dde12) and stores them in the memory 15. Let Thereafter, after executing the scaling information transfer process, the CPU 14 repeatedly executes the above-described operations for determining, extracting, storing, and outputting the CAN data Dca according to the corresponding data after the change.
[0029]
As described above, according to the CAN data conversion apparatus 1, the CAN definition data Dde as many as the number of the analog output ports OP1 to OPn is stored in the memory 15 in advance, and a command is input via the operation unit 18 to input CAN. By changing the correspondence between the data Dca and the analog output port OP, the CAN data conversion device 1 is reconnected to the personal computer, and the new CAN definition data Dde generated using the personal computer is converted into the CAN data conversion device 1. Unlike the conventional method of transferring to the CAN data Dca, since these operations can be omitted, the CAN data Dca that was not the acquisition target is replaced with a part or all of the CAN data Dca that was the acquisition target. The correspondence with the analog output port OP as the output destination can be easily changed in a short time. It can be. That is, any CAN definition data Dde among the CAN definition data Dde stored in advance can be easily associated with any analog output port OP in a short time. As a result, when the CAN data Dca is an observation target, the efficiency of the observation work can be sufficiently increased.
[0030]
Further, the CAN definition data Dde is configured including scaling information related to the CAN data Dca defined as an acquisition target (in other words, scaling information related to the analog signal Sa generated based on the CAN data Dca) Dsc, and CAN data conversion is performed. The CPU 14 of the apparatus 1 transmits the respective pieces of scaling information Dsc relating to the CAN data Dca included in the CAN definition data Dde and corresponding to the analog output ports OP1 to OPn to the communication interface unit 19. , The recorder 31 can automatically store the scaling information Dsc in the internal memory 34 in association with the analog input ports IP1 to IPn. Therefore, unlike the conventional recorder, the scaling information for each of the analog input ports IP1 to IPn can be automatically set without operating the operation unit, so that the operation of the recorder 31 can be simplified. . As a result, the time required for the observation work of the CAN data Dca on the CAN bus 21 can be sufficiently shortened. Furthermore, since the scaling information Dsc need only be set once for the CAN data converter 1, the setting contents of the scaling information Dsc of the CAN data converter 1 and the setting contents of the scaling information Dsc of the recorder 31 are different. It is possible to reliably prevent setting errors.
[0031]
The present invention is not limited to the configuration shown in the above-described embodiment of the present invention. For example, in the embodiment of the present invention, the example in which the command for changing the corresponding data is input via the operation unit 18 provided in the CAN data conversion apparatus 1 has been described. However, the CAN data conversion apparatus is connected by the interface cable CB. 1 can also be used to input a command for changing the corresponding data. In this case, the operation unit 38 provided in the recorder 31 is operated to input a corresponding data change command to the CPU 35. The CPU 35 transmits this command to the CAN data conversion device 1 via the interface cable CB. Then, the CPU 14 of the CAN data conversion apparatus 1 receives the command transmitted by the recorder 31 via the communication interface unit 19. Thereafter, the CPU 14 operates in the same manner as when a command is input through the operation unit 18 to change the correspondence between the CAN data Dca and the analog output port OP as its output destination. According to this configuration, the CAN data Dca to be acquired can be changed while observing the CAN data Dca with the recorder 31. Therefore, in the case where the CAN data conversion device 1 and the recorder 31 are installed apart from each other, the labor of moving to the CAN data conversion device 1 can be saved, so that the operability of observation work can be improved. In the embodiment of the present invention, the recorder 31 has been described as an example of the external device connected to the CAN data conversion device 1. However, the CAN data conversion device 1 can be used for devices other than the recorder 31. Of course, it can be used.
[0032]
【The invention's effect】
As described above, according to the CAN data conversion device of the first aspect, the number of CAN definition data equal to or greater than the number of analog output ports is stored in the memory, and the correspondence relationship in the corresponding data is determined according to the command input by the control unit. By changing, it is possible to save work such as reconnecting the CAN data conversion device to the personal computer and transferring new CAN definition data generated using the personal computer to the CAN data conversion device. It is possible to easily change the correspondence relationship between the CAN data and the analog output port as the output destination of replacing the CAN data that has not been replaced with a part or all of the CAN data to be acquired in a short time. That is, any CAN definition data stored in advance can be easily associated with any analog output port in a short time. As a result, for example, when observing CAN data, the efficiency of the observation work can be sufficiently increased.
[0033]
According to the CAN data conversion device of the second aspect, since the operation unit capable of inputting a command for changing the correspondence relationship is provided, the CAN data conversion device can be used without using a device for changing the correspondence relationship. The correspondence between CAN data and analog output ports can be changed independently.
[0034]
Further, according to the CAN data conversion apparatus of the third aspect, the correspondence relationship between the CAN data and the analog output port is provided by providing the communication interface unit capable of inputting a command for changing the correspondence relationship from an external device. Can be remotely controlled on the external device side. Therefore, for example, when the external device is a recorder, the correspondence can be changed while observing the CAN data.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a configuration of a CAN data conversion device 1, a bus 21 to which the CAN data conversion device 1 is connected, and a recorder 31 according to an embodiment of the present invention.
FIG. 2 is a flowchart of scaling information transfer processing by the CAN data conversion apparatus 1 that transfers scaling information Dsc to the recorder 31;
[Explanation of symbols]
1 CAN data converter
11 CAN bus interface
12 Transceiver
13 CAN controller
14 CPU
15 memory
16 D / A converter
17 Signal selector
18 Operation unit
Dca CAN data
Dde CAN definition data
OP1 to OPn Analog output port
Sa Analog signal

Claims (3)

The CAN bus interface unit, the D / A converter, the plurality of analog output ports, and identification information for identifying the CAN communication packet including the CAN data to be acquired, and at least the position information of the CAN data in the CAN communication packet is defined. A plurality of CAN definition data and correspondence data indicating correspondence between each CAN data extracted from the CAN communication packet and converted into an analog signal by the D / A converter and the analog output port as the output destination A CAN memory packet including CAN data to be acquired from the CAN communication packet received from the CAN bus via the CAN bus interface unit. Recognize by referring to CAN definition data The CAN data to be acquired is extracted from the CAN communication packet with reference to the CAN definition data, and the extracted CAN data is output to the D / A converter and converted into an analog signal, and the analog signal is converted into the analog signal. A CAN data conversion device for outputting to the analog output port indicated by corresponding data,
The memory is configured to be able to store the CAN definition data in a number equal to or greater than the number of the analog output ports.
The CAN data conversion device configured such that the control unit can change the correspondence relationship in the correspondence data in accordance with an input command. The CAN data conversion apparatus according to claim 1, further comprising an operation unit capable of inputting the command. The CAN data conversion apparatus according to claim 1, further comprising a communication interface unit capable of inputting the command from an external device.

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