JP2000216798A - Monitor logging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a node address from being added by suppressing a load of a control device of each node without causing increase in network traffic. SOLUTION: A monitor logging device 30 can receive a frame transmitted into a control system via a device net 2 but does not transmit a frame to the control system. When a frame sent/received via the device net 2 is received, the monitor logging device 30 interprets detailed information of a frame header and a data field in the frame on the basis of the frame information. The monitor logging device 30 acquires the frame on the basis of node information, when the frame is a frame required for monitoring or logging, as a result of interpreting contents of the frame on the basis of the frame information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a monitor / logging device for monitoring control devices such as switches and sensors.

[0002]

2. Description of the Related Art Conventionally, in a monitor / logging device used in a control system, the state of control is displayed on a screen in real time (monitoring), and the state of the control system is recorded at regular intervals (data). Logging), and then analyze the control state.

In recent years, in a control system, for example, as shown in FIG. 14, a control device 10 such as a programmable controller that functions as a master station, and a position control device that functions as a slave station with respect to the control device 10 as a master station. A control device 20 such as a controller and a monitor / logging device 30 are connected to a network 40.

In this system, the control device 10 of the node 1 obtains I / O data from the control device 20, and controls the control device 20 as a slave station based on the obtained I / O data. It has become.

Monitor / logging device 3 provided in node 5
0 acquires the I / O data of the control device 20 and uses the control data to display and monitor the control status on a screen in real time, or to record the status of the control system at regular intervals. Later, when any trouble occurs in the control system, it is used to analyze the cause of the trouble.

In such a control system, a command-response method is generally adopted as a method for transmitting and receiving data.

This command-response method is shown in FIG.
As shown in the figure, the control device 10
When attempting to acquire / O data, a control command frame is transmitted to the control device 20, and after receiving a response frame to the command frame from the control device 20, I / O data is acquired. .

When the monitor / logging device 30 attempts to acquire control data for monitoring / logging from the control device 20, it transmits a command frame for monitor / logging to the control device 20, and transmits a command frame for the command frame. After receiving the response frame from the control device 20, control data for monitor / logging is acquired.

Although the above-described control system has described that a command-response system is generally adopted as a system for transmitting and receiving data, a certain node may have one or more nodes depending on a protocol of a network to be used. Some systems cannot communicate with the node.

[0010]

The monitor / logging device used in the above-mentioned conventional control system employs the above-described command-response method, and thus has the following problems. .

(1) Increase in Network Traffic As shown in FIG. 15, the monitor / logging device transmits a command for monitor / logging on the network 40,
Since the control device 20 of the node which has received this command transmits a response to the command to the network, there is a problem that the traffic on the network 40 increases by this amount and the function of the control system is reduced.

In particular, when the control device 10 is a programmable controller, the programmable controller:
I / O to each control device 20 within a predetermined scan time
Unless O data is acquired, a system error will occur.
An increase in traffic due to a monitor logging command from the monitor logging device 30 and a response thereto is a serious factor that degrades the function of the control system.

(2) Increase in load on nodes In the conventional monitor / logging device, each control device 20
A control command transmitted from the control device 10 is received, a response to the command is transmitted to the control device 10, and a monitoring command received from the monitor / logging device 30 is received, and a response to the command is monitored. -Since the data is transmitted to the logging device 30, the processing load increases.

For this reason, in the conventional system, there is a problem that the processing contents of the control device 20 included in each node are restricted, and in effect, the entire system is restricted.

(3) Occupation of Network Resources (Node Address) Generally, when a command is transmitted to a certain node on the network, a node address (for example, MAC ID) designating a transmission source is included in the command frame. Must have.

Therefore, in the conventional control system, there is a problem that the monitor / logging device 30 occupies one of the node addresses of the network 40, thereby limiting the configuration of the entire system.

(4) It is difficult to use this method depending on the network protocol. As described above, in a control system having a method in which a certain node cannot communicate with one or more nodes depending on the network protocol used, a monitor / monitor cannot be used. There is a problem that it is impossible to add the logging device 30 to the control system.

Therefore, the present invention has been made in view of the above-mentioned problems,
Even in a control system having a protocol that does not increase network traffic, suppresses the load on control devices of each node, does not add a node address, and has a protocol that prevents a certain node from communicating with one or more nodes. The object is to provide a monitor / logging device capable of performing logging.

[0019]

According to an aspect of the present invention, there is provided a monitor / logging device for acquiring data communicated between respective node devices connected to a network. A frame communicated on the network is received without transmitting a command to the network from itself, and the received communication data is decoded.

According to a second aspect of the present invention, there is provided a monitor and logging device for acquiring and communicating data between node devices connected to a network, wherein the monitor and logging device is communicated on the network. Receiving means for receiving the current frame, frame decoding means for decoding the data to be monitored / logged out of the frames received by the receiving means, and monitor / logging data formed from the data decoded by the frame decoding means. Monitor / logging data forming means.

According to a third aspect of the present invention, in the second aspect of the present invention, the frame decoding means selects only a predetermined frame from the frames received by the receiving means, and the reception filter means Based on the node information and the frame information,
Frame analyzing means for decoding the received frame,
Data storing means for storing data of the frame analyzed by the frame analyzing means.

According to a fourth aspect of the present invention, there is provided a data acquisition device which is connectable to a network and acquires data communicated between the node devices connected to the network. A frame received on a network is received and communication data is decrypted without having an address.

According to a fifth aspect of the present invention, in a network connection device connectable to a network, a receiving unit for receiving a frame communicated on the network by an external action for the network connection device, and analyzing the received frame. Then, it has a data acquisition unit for specifying a node connected to the network and obtaining data communicated by the specified node.

According to a sixth aspect of the present invention, in a network connection device connectable to a network, a storage unit for storing frame information and node information in advance, and passively receiving externally based on the frame information. And a data acquisition unit for acquiring control data based on the node information.

According to the present invention, a frame communicated on a network is received without transmitting a command to the network by itself, and the received communication data is decoded, whereby the network is decoded. Addresses can be made unnecessary.

Therefore, since the monitor / logging device does not have a network address, the occupation of the node address can be avoided, and the number of control devices to be operated can be increased accordingly.

In addition, when data is acquired, frames can be received without transmitting a command for acquiring data, so that traffic on the network is reduced, and unnecessary processing is reduced. And the monitoring and logging of the control system can be performed irrespective of the limitation of the network protocol used.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a monitor / logging device according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a control system having a monitor / logging device.

In the control system according to the present invention, the control device 10 provided in the node 1, the control device 20 provided in the nodes 2, 3 and 4, and the monitor / logging device 30 are composed of lower layers (physical layer, data link layer). ) To CAN (Control)
device network (D), which is one of the network protocols using ler Area Network.
deviceNet) and is constructed.

Before explaining the contents of each component constituting the control system, a frame transmitted and received via the device net 2 will be described with reference to FIG.

A frame 6 transmitted / received via the device net 2 is used in the CAN protocol and is a pre-defined master / slave connection set (Predefin) corresponding to the remote I / O system.
seed Master / Slave Connecti
on Set).

As shown in FIG. 2A, the frame 6 includes a CAN header field (CAN HEADER FIELD) 61 composed of 19 bits (Bit),
A data field (DATA FIELD) 62 consisting of a maximum of 64 bits (8 bytes) and a CAN trailer field (CANN TRAILE) consisting of 25 bits.
R FIELD) 63.

1) CAN Header Field 61 As shown in FIG. 2B, the CAN header field 61 has a start bit of one bit (Start).
Bit) and a CAN identifier (CAN Identifier) bit 6 consisting of 11 bits
12, an RTR bit 613 composed of 1 bit, and a control bit 614 composed of 6 bits.

Start bit (Start Bit) 6
11 has information indicating the start of the frame, and CA
N Identifier (CAN Identifier)
er) bit 612 is a definition of a master / slave connection set, that is, node role information indicating whether a transmission / reception destination is a master or a slave, node address information indicating a node address, and communication method information indicating a communication method to be used. have.

The node address information is stored in the device net 2
Is called a MAC ID, and is represented by 6 bits. Therefore, usable numerical values are 0 to 63 as decimal numbers.

Note that, on the device net 2, different MAC IDs are assigned to the respective nodes.

The communication method information includes a bit-strobe method capable of high-speed data communication and a poll method capable of transmitting a large amount of data.

The bit strobe method is a communication method in which a command frame transmitted from the control device 10 as a master station is received by all the control devices 20 as slave stations.
Is configured to recognize information contained in one bit corresponding to its own MAC ID in the data field 62 of this frame as output data to itself.

For example, as shown in FIG. 3, information set to 63 bits in order from 0 bits is output to the control device 20 having MAC ID “63” in order from the control device 20 having MAC ID “0”. Indicates information.

The RTR bit 613 has information for detecting an error, and the control bit 614 has control information.

Here, the communication system between the bit strobe and the poll system will be described in more detail with reference to FIG.

A) Bit Strobe Method As shown in the column of FIG. 4A, in the case of a frame transmitted from the control device 10 as a master station to the control device 20 as a slave station, 9 bits are used. “0” and “1” are set in 10 bits, and the MAC I of the control device 10 as a master station is set in 3 to 8 bits.
D is set, and from 0 bit to 2 bits, “0,
0,0 "is set.

Here, for example, the MAC of the control device 10
When the ID is “63” in decimal notation, “1,1,1,1,1,1” is set in 3 to 8 bits.

As shown in the column of FIG. 4A, in the case of a frame transmitted from the control device 20 as the slave station to the control device 10 as the master station, "1" and "10" are The bits are set to “0”, “1,1,1,0” is set from 6 bits to 9 bits, and the control device 20 is set from 0 bits to 5 bits.
Is set.

For example, if the MAC ID of the control device 20 is 1
When "0" is set in the 0-ary system, "0, 0, 0, 0, 0, 0" is set in bits 0 to 5.

B) Poll Method As shown in the column of FIG. 4B, in the case of a frame transmitted from the control device 10 as a master station to the control device 20 as a slave station, "9 bits""0" and 10 bits are set to "1", the MAC ID of the destination control device 20 is set from 3 bits to 8 bits, and "1, 0, 1" is set to 0 to 2 bits. Is done.

For example, the control device 20 for transmitting a frame
If the MAC ID of the is "62" in decimal,
From 3 bits to 8 bits, “1,1,1,1,1,
0 "is set.

As shown in the column of FIG. 4B, in the case of a frame transmitted from the control device 20 as a slave station to the control device 10 as a master station, "1" is added to 9 bits and 10 The bit is set to “0” and “1,1,1,1” is set from 6 bits to 9 bits,
Further, from 0 bit to 5 bits, the M
The AC ID is set.

For example, the control device 20 for transmitting a frame
If the MAC ID of “1” is “1” in decimal notation, 3
"0, 0, 0, 0, 0,
1 "is set.

2) Regarding the data field 62 In the device net 2, the maximum amount of data that can be transmitted at one time is 8 bytes. Therefore, when transmitting data having a larger data amount, the data must be divided and transmitted.

FIG. 5 is a diagram for explaining the contents of the data field in the case of divided transmission.

As shown in FIG. 5, the data field 62 in the case of divided transmission has a byte number (Bytet).
e Number) ranges from 0 to 5 bits of 1 byte indicated by “0”, and a fragment count (Fragmen) for identifying the frame number of the data.
t Count) information, and fragment type (Fragment Type) information indicating the attribute of the transmitted data in 6 bits and 7 bits.

The data field 62 has an I / O message in the range of 2 to 8 bytes whose byte numbers are indicated by "1" to "7".

The above-described fragment type will be described in more detail with reference to FIG.

As shown in FIG. 6, when the value of the fragment type is “0”, it indicates that it is a first fragment, that is, the first data in the frame, and the value is “2”. In the case of, the last fragment (Last Fragme)
nt), that is, the last data in the frame, and when the value is “1”, a middle fragment (Middle Fragment), that is, between the data corresponding to the first fragment and the data corresponding to the last fragment, Shows some data.

Since the above-described fragment counter is represented by 6 bits, a maximum of 3F (hexadecimal display) is used.
Can be set up. If the number of frames is 3F or more, it is set from 0 again.

In the case of the first fragment, the fragment counter must be 0 or 3F. In the I / O communication of the device net 2, whether to use the divided transmission between the master and the slave is determined by the initial setting before the actual exchange of the I / O data is started.

Therefore, when communication is started once with divisional transmission, even if the data amount ends in one frame, the divisional transmission procedure is followed. In this case, it is the first fragment and the last fragment. In other words, the first fragment having a fragment counter of 3F has a special meaning of the first and last fragments.

FIG. 7 is a diagram for explaining the contents of the data field 62 in the case of not being a fragment.

In this case, the data field 62
As shown, the first byte has no fragment type and fragment count.

Next, the configuration of each component constituting the monitor / logging device will be described. The monitor / logging device is implemented as Windows software.

The control device 10 provided in the node 1 comprises, for example, a programmable logic controller (PLC), a PC (personal computer) on which a soft PLC is mounted, and the like. O data has been acquired, and the acquired I
The arithmetic processing is performed based on the / O data, and based on the result of the arithmetic processing, a command for executing a predetermined operation to the control device 20 of the nodes 2, 3, and 4 is output.

The control device 20 includes a switch, a relay, a temperature sensor, an inverter, an actuator, and the like.
And performs a predetermined operation.

The monitor / logging device 30 does not have an address as a node itself, and receives the frame 6 via the device net 2 without transmitting a network command by itself (see FIG. 1). reference),
The detailed information of the CAN header 61 and the data field 62 in the received frame 6 is decoded based on the frame information (see FIG. 1).

That is, the monitor / logging device 30
Control device 10 and control device 20 via device net 2
It is characterized by passively receiving a frame 6 transmitted and received between them.

In other words, the monitor / logging device receives the frame 6 communicated to the device net 2 by an external action between the control device 10 and the control device 20 without transmitting a network command by itself. It has become.

The monitor / logging device 30 decodes the contents of the frame based on the frame information (see FIG. 1).
), If the frame is necessary for monitoring or logging, this frame is acquired based on the node information.

The frame information is information indicating device net protocol information.
It contains all the formats and meanings of messages exchanged between slaves.

The node information includes information on the size (INPUT, OUTPUT) of I / O data with which the node (slave) for which data is to be collected communicates with the master in each of the polling and strobe I / O communication systems. Contains.

FIG. 8 is a block diagram showing a schematic configuration of the monitor / lobing device.

The monitor / logging device 30 includes an application (Application) unit 310 and a frame decoding unit (Core Module DLL unit) 32.
0, and a DeviceNet I / F unit 330.

The application section 310 has node information described later on software.

The frame decoding unit 320 reads node information from the application unit 310, and the node information is stored in the frame decoding unit 320.

The above-described node information will be described in more detail. As shown in FIG. 9, the node information indicates whether the communication method is based on the polling method or the bit strobe method. And information indicating the data size of the communication I / O data in each system.

Note that OUTSize1, INSi1 in FIG.
ze1 indicates the data size when the poll communication method is used, and OUTSize2, INSize2
Indicates the data size of the bit strobe communication method.

Further, the application (Applcat)
Ion) section 310 sends monitor / logging data formed by frame decoding section 320 described later at regular intervals.
/ O data area and store it in storage means (not shown) such as a hard disk.

The frame decoding section 320 decodes the received frame 6 based on the node information received from the application section 310 and the frame information described in the software, and converts the I / O data from the decoded frame 6. Is formed.

The above-described frame information is described with reference to FIG.
This will be described with reference to FIG.

Here, the group ID (Group I)
D) is an 11-bit C that can be used in the device net 2.
Set the AN ID to group (Group) 1 and group (G
These are values (1 to 4) for identifying groups when the groups are grouped according to use, such as (group) 2, group (Group) 3, and group (Group) 4.

Message ID (Message I)
D) is a value that identifies each message in the message group at a certain endpoint.

The poll command (Poll
Command) is “2” as the group ID,
Also, it has “5” as the message ID, indicating that this command is OUT data.

The bit strobe command (Bit-Strobe Command) shown in the column B is
"2" as the group ID and the message I
D has "0", indicating that this command is OUT data of only one point.

The DeviceNet I / F unit 330
All frames transmitted on the device net 2 are received.

Here, the above-described frame decoding unit 320 will be described in more detail.

FIG. 11 is a block diagram showing the structure of the frame decoding unit.

The frame decoding section 320 includes a reception filter section 320a, an effective frame reception detection section 320b,
The frame analyzing means 320c and a flag buffer (Fra
gment Buffer) 320d, an I / O data buffer 320e, and a fragment counter 320f.
Frame information storage unit 320g having frame description information
And a node information storage unit 320h.

The reception filter means 320a is provided with the CA of the frame 6 received via the device network I / F 330.
With reference to the CAN identifier 612 in the N header field 61, only frames to be received are selected (filtered).

The frame 6 selectively received by the reception filter means 320a is as shown in FIG.

In the case of only OUT data, that is, the frame transmitted to the control device 20 having the target MAC ID is a poll command frame or
For all bit strobe command frames In the case of only IN data, that is, the target MAC
The frame transmitted from the control device 20 having the ID to the control device 10 is a poll response frame or a bit strobe response frame Both of the OUT and IN data, that is, the frame of the above and

Upon receiving the frame 6 from the reception filter means 320a, the valid frame reception detection means 320b determines whether or not the length of the data field 62 in the received frame 6 has a predetermined length. Frame 6 received
If it is determined that the length of the data field 62 in the middle has a predetermined length, the frame interpreting means 3
20c.

The frame analyzing means 320c decodes the received frame 6 based on the frame information stored in the frame information storage section 320g.

Since the detailed contents are described in the operation of the monitor / logging device according to this embodiment described later, the detailed description is omitted.

Fragment buffer (Fragment
Buffer 320d temporarily stores the data of frame 6 when the received frame is of the poll communication system and uses a fragment.

The I / O data buffer 320e stores the formed I / O data.

The fragment counter 320f is of the poll communication system, and every time data of a frame 6 including a fragment is received, 1 is added to the counter value under the instruction of the frame decoding means 320c, and the fragment counter 320f is transmitted. If the received data is the last fragment, the count value is cleared under the instruction of the frame decoding means 320c. These processes are performed by each MA.
This is performed for each C ID.

The frame information storage section 320g has frame information, and the node information storage section 320h has
The node information acquired from the application unit 310 is stored.

Next, the operation of the monitor / logging device of this embodiment will be described with reference to the flowchart of FIG.

When frame decoding section 320 receives frame 6 received at device network I / F 330, reception filter means 320a sets a predetermined device I
Only the / O type (see FIG. 10) frame 6 is selectively received (filtered), and the selectively received frame 6 is output to the valid frame receiving means 320b (step 110).

Upon receiving the frame 6 from the reception filter means 320a, the valid frame reception detecting means 320b determines whether or not the length of the data field 62 in the received frame 6 has a predetermined length ( Step 12
0).

If the valid frame reception detecting means 320b determines that the length of the data field 62 in the received frame 6 has a predetermined length (step 12).
0; Y), this is notified to the frame interpreting means 320c.

On the other hand, the valid frame reception detecting means 320c
If it is determined that the length of the data field 62 in the received frame 6 does not have the predetermined length (Step 120; N), the process proceeds to Step 110 and performs the same processing as described above. continue.

The frame interpreting means 320c sends a notice to the effect that the length of the data field 62 in the received frame 6 has a predetermined length to the valid frame reception detecting means 320c.
b, it is determined with reference to the CAN header 61 in the frame 6 whether the received frame 6 is a message (Poll Message) based on the poll communication method (step 130).

If the frame interpreting means 320c determines that the data is not I / O data (message) according to the poll communication method, that is, the I / O data according to the bit strobe communication method is used.
If the data is O data (step 130; N),
The I / O data is refreshed in the O data buffer 320e (step 140), and thereafter, the process proceeds to step 110 to continue the same processing as described above.

On the other hand, when the frame interpreting means 320c determines that the data is I / O data based on the poll communication method (step 130; Y), the frame interpreting means 320c determines whether or not it has a fragment count based on the node information. (Step 150).

When the frame interpreting means 320c determines that the I / O data in the received frame 6 does not have the fragment type and the fragment count based on the node information (step 150; N), it will be described later. On the other hand, when it is determined that the data field 62 has the fragment type and the fragment count (step 150;
Y), it is determined whether or not the internal state is a state of waiting for the first fragment (step 160).

When the frame interpreting means 320c determines that the internal state is not the state of waiting for the first fragment (step 160; N), the frame interpreting means 320c determines in step 17 which will be described later.
0, while it is determined that the internal state is the state of waiting for the first fragment (step 16).
0; Y), data field 6 in received frame 6
It is determined whether or not the fragment type in 2 is the first fragment (step 180).

When the frame interpreting means 320c determines that the fragment type in the data field 62 in the received frame 6 is not the first fragment (step 180; N), the process proceeds to step 220 described later while the received If it is determined that the fragment type in the data field 62 in the frame 6 is the first fragment (step 180; Y),
It is determined whether or not the fragment count is “0X3F” (Step 190).

If the frame interpreting means 320c determines that the fragment count is not "0X3F" (step 190; N), it proceeds to step 200 described later. On the other hand, when the frame interpreting means 320c determines that the fragment count is “0X3F” (step 190; Y), the frame
The ID is stored in the I / O data buffer 320e (step 210).

Thereafter, the frame interpreting means 320c initializes the fragment information (fragment counter, first fragment waiting state) held therein,
The monitor / logging data written in the I / O data buffer 320e is read out at regular time intervals, and stored in a storage means such as a hard disk (step 2).
20) Then, the process shifts to step 110 to perform the same processing as described above.

In step 160, when the frame interpreting means 320c determines that the internal state is not the state of waiting for the first fragment (step 160;
N), it is determined whether or not the fragment counts contained in the data field 62 of the received frame 6 match (step 170).

If the frame interpreting means 320c determines that the fragment counts contained in the data field 62 of the received frame 6 do not match (step 170; N), the process proceeds to step 220, while the received frame 6 When it is determined that the fragment counts in the data field 62 of No. 6 match (step 170; Y), the I / O data is written to the fragment buffer 320d (step 200).

Next, the frame interpreting means 320c determines whether or not the fragment count contained in the data field 62 of the received frame 6 is the last fragment (step 230).

The frame interpreting means 320 c
If it is determined that the fragment count in the data field 62 is the last fragment (step 230; Y), the process proceeds to step 210,
When it is determined that the fragment count in the data field 62 of the frame 6 is not the last fragment (step 230; N), the frame decoding unit 320
Is added to the fragment counter of (1) to obtain a new count value (step 240), the process proceeds to step 110, and the same processing as described above is continued.

In the monitor / logging device of this embodiment, since it is not necessary to transmit a frame (command) by itself, a network address can be made unnecessary.

Therefore, since the monitor / logging device 30 does not have a network address, the occupation of the node address can be avoided, and the number of operating control devices 20, such as switches and relays, can be increased accordingly.

When acquiring I / O data, the I / O data
Since frames can be received without transmitting a command for acquiring O data, traffic on the network is reduced, and unnecessary processing is reduced.
The function of the control system can be enhanced and
Even systems that use a protocol that can communicate with only one node can be monitored and logged.

Note that the execution timing of the frame analysis is as follows.
This may be the case for each frame reception, or the case where the received frames are temporarily stored and analyzed collectively periodically.

Further, the monitor / login device of this embodiment may or may not include a monitor display screen. If not included, a monitor display screen may be separately connected externally.

[0120]

Since the present invention is configured as described above, it has the following effects.

(1) According to the first aspect of the present invention, a frame communicated on a network is received without transmitting a command to the network itself, and the received communication data is decoded. By doing so,
In the monitor / logging device according to the present invention, a network address can be made unnecessary.

Further, when data is obtained, frames can be received without transmitting a command for obtaining data, so that traffic on the network can be reduced, and unnecessary processing can be reduced. Can be increased.

Further, even in a system adopting a protocol that can communicate with only one node, monitoring and logging can be performed.

(2) According to the second aspect of the present invention, of the frames received by the frame decoding means, the monitor
In order to decode the frame to be logged, data for monitor logging can be obtained.

(3) According to the third aspect of the present invention, since only predetermined frames are selected from the frames received by the receiving means by the receiving filter means, frames unnecessary for monitor logging are discarded. be able to.

(4) According to the fourth aspect of the present invention, without having an address as a node when connecting to a network,
Since a frame communicated on the network is received and the communication data is decoded, occupation of the node address can be avoided.

(5) According to a fifth aspect of the present invention, the data acquisition section analyzes a received frame to specify a node connected to the network and obtains data communicated by the specified node. By doing so, data for the required node can be obtained.

(6) In the invention according to claim 6, since the decoding section decodes the meaning of the received frame based on the frame information, it is possible to acquire monitor logging data.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a monitor / logging system according to the present invention.

FIG. 2 is a block diagram showing a configuration of a frame transmitted and received via a device net in FIG. 1;

FIG. 3 is a block diagram showing a configuration of a command frame in a bit strobe communication method.

FIG. 4 is a block diagram showing a configuration of a CAN identifier in FIG. 2;

FIG. 5 is a block diagram showing the configuration of a data field in FIG. 2 (at the time of fragmentation).

FIG. 6 is a view for explaining the contents of a fragment type and a fragment count in FIG. 5;

FIG. 7 is a block diagram showing a configuration of a data field in FIG. 2;

FIG. 8 is a block diagram showing a schematic configuration of a monitor / logging device in FIG. 1;

FIG. 9 is a block diagram showing device I / O allocation.

FIG. 10 is a view showing the contents of a frame selected by a valid frame check unit in FIG. 9;

FIG. 11 is a block diagram showing a configuration of a frame decoding unit in FIG. 8;

FIG. 12 is a diagram showing the correspondence between I / O data and device net messages.

FIG. 13 is a flowchart showing a processing operation of the monitor / logging device in FIG. 1;

FIG. 14 is a view for explaining the contents of a conventional monitor / logging device transmitting commands and acquiring I / O data in a control system.

FIG. 15 is a diagram showing a configuration of a conventional monitor / logging system.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 control system 2 device net 10 control device 20 control device 30 monitor / logging device 310 application unit 320 frame decoding unit 320a reception filter unit 320b valid frame reception detection unit 320c frame analysis unit 320d fragment buffer 320e I / O data buffer 320f fragment counter 320g Frame information storage unit 320h Node information storage unit 330 Device net I / F

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H215 BB20 CC07 CX08 GG03 KK04 KK06 5K032 BA11 EA06 EA07

Claims (6)

[Claims] 1. A monitor / logging device for acquiring data communicated between node devices connected to a network, wherein the monitor / logging device transmits a command transmitted to the network by itself for a frame communicated on the network. A monitor / logging device which receives data without performing any operation and decodes the received communication data. 2. A receiving means for receiving a frame communicated between node devices connected to a network, and displaying the frame received by the receiving means on a screen in real time or recording the frame at a constant period. A frame decoding means for decoding monitor / logging data for performing the processing, and monitor / logging data forming means for forming the monitor / logging data from the data decoded by the frame decoding means. Logging device. 3. The frame decoding means includes: a reception filter means for selecting only a predetermined frame from the frames received by the reception means; and a frame selected by the reception filter means as node information and frame information. 3. The monitor / logging device according to claim 2, further comprising: frame analyzing means for decoding the received frame based on the received data, and data storing means for storing data of the frame analyzed by the frame analyzing means. 4. Connectable to a network,
A data acquisition device for acquiring data communicated between node devices connected to a network, and receiving a frame communicated on a network without having an address as a node when connected to the network. A data acquisition device for decoding communication data. 5. A network connection device connectable to a network, wherein the reception unit captures a frame communicated on the network by an external action for the network connection device, and analyzes the received frame to connect to the network. A network connection device, comprising: a node that specifies a specified node; and a data obtaining unit that obtains data communicated by the specified node. 6. A network connection device connectable to a network, comprising: a storage unit for storing frame information and node information in advance; and decoding a meaning of a frame passively received from the outside based on the frame information. A network connection device, comprising: a decryption unit that performs control, and a data acquisition unit that acquires control data based on node information.