JPH0683223B2 - Programmable controller link unit - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a link unit used when performing data communication between programmable controllers (hereinafter referred to as PCs).

<< Outline of the Invention >> In the present invention, based on the data read from the input unit for designating the master station or the slave station and the auxiliary relay area of, for example, the input / output memory of the PC body, the priority number and polling frequency are registered. A registration means is provided to perform polling frequency for each priority machine so that when the master station is designated, the polling frequency for priority machines will be the registered frequency, regardless of the number of connected units. The transmission delay time for the priority machine can be kept within a certain time.

<Prior art and its problems> In the conventional PC link unit of this type, the master station polls the slave stations once, respectively, while cyclically transmitting data by the broadcasting method. It is configured.

Therefore, as the number of link units connected increases, one polling cycle time also increases, and the transmission delay time for each link unit increases evenly. As a result, the transmission delay time for a specific link unit increases. There is a problem that the number of connected devices is restricted in order to keep the number of connections within a fixed time.

<Object of the Invention> An object of the present invention is to enable a PC link unit of this type to maintain a transmission delay time for a specific link unit within a fixed time regardless of the number of connected units.

<< Structure and Effect of the Invention >> In order to achieve the above object, the present invention registers the priority number and the polling frequency based on the input means for designating the master station or the slave station and the data read from the PC body. As a condition that the polling frequency for the priority number becomes the registered frequency, the number of registration units for performing the polling and the polling frequency for each priority number will be sequentially polled, and a response will be sent when the own unit is polled. Then, the master station mode control means for transmitting data to the other device by broadcasting method and receiving the data from the other device in response to the polling of the other device, and the slave station being designated In response to the polling of the own device, the data is transmitted to the other device by the broadcasting method, and the other device responds to the polling of the other device. It is characterized in that it comprises and a slave mode control means for receiving data from.

According to such a configuration, in the user program of the PC main body, as long as each data of the priority number and polling frequency is written in the auxiliary relay area, this can be read by the unit connected to the PC main body, As a result of registering the priority machine and polling frequency, if the link unit is designated as the master station, the polling frequency for the priority machine will automatically become the registered frequency so that each machine will be polled sequentially. Therefore, regardless of the number of connected link units, the transmission delay time with respect to the priority machine can be maintained within a fixed time.

<< Description of Embodiments >> FIG. 1 shows a PC to which a link unit according to the present invention is applied.
It is a block diagram which shows the structure of a system.

This PC system connects a plurality of PC link units 1 via a transmission line 3, and further connects each PC link unit 1 to a PC.
By connecting the main body 2 to the main body 2 via the system bus, each PC main body is configured to perform data communication.

FIG. 2 is a block diagram showing the electrical hardware configuration of the PC body 2.

As shown in the figure, the PC main body 2 includes a CPU 20, a system program memory 21, a work memory 22, an input / output interface 23,
It has an input / output memory 24 and a user program memory 25, which are connected to each other via a PC bus.

The CPU 20 is mainly composed of a microprocessor, and executes various system programs stored in the system program memory 21 to perform various processes necessary for the operation of the PC body 2.

The basics of these processes are input update processing for writing the input data read from the input / output interface 23 to the input area of the input / output memory 24, and read from the user program memory 25 based on the input / output data of the input / output memory 24. Command execution process that executes the user command that is executed and rewrites the content of the output data of the input / output memory 24 with the execution result, and the output data of the input / output memory 24 that has been rewritten as a result of the command execution, Output update processing to send to the outside, give HALT ready from the CPU 20 to the PC link unit, open the control right of the PC bus, and then control from the PC link unit side, necessary in the I / O memory 24 A PC link server that reads data to the PC link unit side, and then receives a HALT release command from the PC link unit side to restore control of the PC bus to the CPU20 side. Service processing.

Here, the address space of the input / output memory 24 is divided into an input data area, an output relay area, an auxiliary relay area, a keep relay area, a counter area, a timer area and other various data areas. As shown in the figure, channel 0 of the auxiliary relay area is assigned as the polling data area and
As shown in the figure, priority machine number data, polling frequency data and polling type data are stored.

That is, as shown in FIG. 4, a 4-bit binary code indicating a priority machine number is stored in b _{0 to} b ₃ .
The b ₄ ~b _6, the binary data of 3 bits indicating the polling frequency is stored, the b ₇ 1 bit polling type data is stored.

By setting b _{0 to} b ₃ to 0, 1, 2, ... 15, Unit 0, Unit 1, Unit 2 ... Unit 15 can be set as priority units, respectively, and b _{4 to} b ₆ this 0,1, ... by a 7, by setting the polling frequency to 1 / 2,1 / 3 ... 1/9, further normal polling by the b ₇ to 0 and the 1 The special polling according to the invention can be set.

Further, as shown in FIG. 5, b ₇ is assigned as a specific auxiliary relay X in the user program, and by connecting an arbitrary input condition 100 to this, the content of the polling type data is set to 1 or It can be switched to 0.

Similarly, the priority machine number data consisting of b ₀ ~b _3, b ₄ ~b
_The polling frequency data consisting of ₆ can also be rewritten arbitrarily by the command word that can be used in the user program.

Next, FIG. 6 is a block diagram showing an electrical hardware configuration of the PC link unit 1.

As shown in the figure, the PC link unit 1 includes a CPU 10, a system program memory 11, a work memory 12, a peripheral interface 13, a machine designation switch 14, a communication controller 15,
A driver receiver 16 is provided, which are connected to each other via a PC link unit internal bus, and the PC link unit internal bus and the PC bus can be connected via a PC interface 4.

The CPU 10 is mainly composed of a microprocessor, and executes the system program stored in the system program memory 11 to execute various operations necessary for the PC link unit as described later.

Further, the machine designation switch 14 is composed of a DIP type digital switch or the like, and its output data is read into the CPU 10 via the peripheral interface 13.

Further, the CPU 10 uses the work memory 12, the communication control unit 15, and the driver receiver 16 to transmit and receive data between other PC link units, and input / output in the PC main body via the PC interface 4. It is adapted to access the memory 24.

Next, referring to the flowcharts of FIGS. 7 to 10,
The operation of the PC link unit according to this embodiment will be systematically described.

As described above, the PC main body 2 side cyclically repeats the input update processing, the instruction execution processing, the output update processing, and the PC link service processing, and especially when the PC link service starts, HALT ready is sent to the CPU 10 of the PC link unit. Make an interrupt.

Then, as shown in FIG. 10, the PC link unit 1
On the CPU 10 side, the communication process with the PC main body is executed by an interrupt.

In this process, first, a HALT command is given to the CPU 20 of the PC body to set the CPU of the PC body to the HALT state (step 100
1) Then, the input / output data is updated between the PC body and the PC link unit (step 1002).

In this input / output data update processing, the input / output memory 24 of the PC main body 2 is accessed to store the data in the area specified in advance.
Transfer to the work memory 12 of the PC link unit 1.

In this transfer, particularly in connection with the present invention, as shown in FIG. 3, the polling data area corresponding to channel 0 of the auxiliary relay area is transferred as it is to the PC link unit 1 side.

Then, the CPU side of the PC link unit, based on the 0 contents of the channel b ₇ of the auxiliary relay area, polling type, i.e. register another normal polling or special polling (step 1003), further 0 channel b of the auxiliary relay area from ₀ ~b _3, performs priority Unit registered (step 1004), further 0 channel auxiliary relay area b ₄
Register the polling frequency K (meaning that polling is performed once every K times) based on the contents of ~ b ₆ (step
1005) Finally, a HALT release command is given to the CPU 20 of the PC main body (step 1006), and the interrupt processing is ended.

Thereafter, the PC link unit 1 side selectively executes the normal polling process or the special polling process by executing the programs shown in FIGS. 7 to 9.

It is assumed that, as shown in FIG. 11 (a), channel 0 of the auxiliary relay area stores $ 00 which is a hexadecimal number display. In this case, since b ₇ is 0, normal polling registration is performed.

Then, although a specific control program is not shown, similarly to the conventional example, each link unit is sequentially polled once, and cyclic data transmission is performed with a polling cycle time T0.

On the other hand, as shown in FIG. 11 (b), it is assumed that hexadecimal $ 80 is stored in channel 0 of the auxiliary relay area. In this case, b ₇ is 1, so the polling type is registered as special polling, and b _{4 to} b ₆ are 0, so the polling frequency K is 2 (that is, polling is performed once every two times). ) Is registered, and further b ₀
Since ~b ₃ is 0, the priority issue machine registration is performed as 0 Unit.

Then, on condition that the polling type is determined to be special polling, the control programs of FIGS. 7 to 9 are started to be executed.

In this example, when the PC link unit is set as the main station, it is arranged to set the unit number of the unit to Unit 0.

As shown in FIG. 7, when the control program for special polling is started, the output state of the machine designating switch 14 is first read (step 100), and then it is determined that the machine is machine 0 (step 100). Affirmative (101), the preparation process as the main station is performed (step 102). In this preparation process, the polling frequency K is set and the own machine number is recognized.

On the other hand, although not shown, a PC set as a slave station
In the link unit, since it is not Unit 0 in the flowchart of FIG. 7 (No at Step 101),
Preparation processing as a slave station is performed (step 130).

Then, as shown in FIG. 8, on the control program side of the No. 0 machine, while sending the polling address from the No. 1 machine in sequence (steps 103, 104, 110), the response from each polling destination is waited to be received (Yes at step 105), and received. Data interpretation (step 106), connection confirmation (step 10)
Confirm the number of connected PC link units by repeating 7).

On the other hand, during this period, the slave stations Nos. 1 to N wait for the polling address transmission from the master station (No at step 231) and interpret the received data (step 231 affirmative, 232). If it is determined that the polling is the confirmation of the number of connected units to the Unit No. (Yes at Step 233),
While the corresponding response is sent to Unit 0, which is the main station (Step 234), when it is confirmed that the number of connected units for other Units is polled (Step 235).
Affirmative), no response is sent.

From the above, the master station No. 0 to the slave station No. 1-
By sequentially polling the N-th car once, the presence / absence of connection of each car is confirmed, and the number of connected machines is simultaneously registered (step 107).

When the processing for confirming the number of connected devices is completed in this way, the data transmission processing by the special polling shown in FIG. 9 is started thereafter.

That is, first, on the control program side of No. 0 machine, polling corresponding to the priority No. machine (No. 0 machine) is applied (step 11
1) After that, on condition that the own machine is the priority machine (Yes at step 112), the machine data is transmitted to all other machines by the broadcasting method (step 11).
3).

At this time, if another machine is set as the priority machine (No at step 112), the data from the priority machine is received (step 114).

Then, the polling frequency counter C is initialized (step 115), the machine number counter N is further initialized (step 116), and the condition is that the machine N is not the priority machine (No in step 117). Is polled (step 118), and subsequently, on condition that the N-th machine is not its own machine (step 120), the N-th machine data is received (step 121) and each counter C, N is updated by +1 ( Step 123), until the value of the polling frequency counter reaches the designated frequency K (No at Step 124), the condition is that the machine number N is smaller than the maximum value (No at Step 125). Step 118) and the Nth machine data are transmitted or received (step 121 or 122).

On the other hand, when the value of the polling frequency counter C reaches the designated polling frequency K (step 124)
Yes, poll the priority machine again (step
111), data of its own is transmitted to the priority machine (step 113) or data is received from the priority machine (step 114).

On the other hand, in the control program on the side of No. 1 to No. N, which is the slave station, when the priority No. polling is received (step 236
Affirmative), while the data from the priority machine is received (step 237), when the data request polling for the own machine is received (Yes at step 238), the own machine data is transmitted to the other machine by the broadcasting method. It is then transmitted (step 239).

By repeating the processing shown in FIG.
As shown in the figure (b), when the value of the polling frequency K is 2, polling is always performed once every two times to the priority machine No. 0, and the machines No. 1 to N are sequentially processed. By polling, the data will be sent and received between each machine by the broadcasting method.

Furthermore, as shown in FIG. 11 (c), 0 in the auxiliary relay area
If the channel data is hexadecimal $ 90,
Polling type is special polling, polling frequency is 3,
As a result of the priority machine being registered as machine 0, when the control programs shown in FIGS. 7 to 9 are executed, polling the machine 0, which is the priority machine every three times,
The polling is sequentially applied from the first machine, and the data is transmitted and received by the broadcasting method.

As described above, according to the embodiment described above, by specifying the polling type, the polling frequency, and the priority machine in the user program of the PC body, and setting the master station or the slave station on the PC link unit side, While the polling frequency from the PC link unit designated by the main station to the priority machine becomes the designated frequency, cyclic transmission can be performed by the broadcasting method.

Therefore, even if the number of connected machines increases, the transmission delay time for the priority machine can be reliably maintained at a fixed time by appropriately designating the priority machine and the polling frequency. By assigning highly sensitive sensors to the PC main unit connected to the priority machine, the output of the high-speed response sensor can be used on each PC while the PC main unit is located at a remote place in the industry through the transmission line. Thus, sequence control with high response can be performed.

[Brief description of drawings]

FIG. 1 shows the application of the PC link unit according to the present invention.
2 is a block diagram showing the configuration of the PC system, FIG. 2 is a block diagram showing the electrical hardware configuration of the PC main body, and FIG. 3 is
Memory map showing the contents of the input / output memory of the PC, No. 4
Fig. 5 is an explanatory diagram showing the details of the polling data area.
Figure is a ladder diagram showing an example of user instructions when using this PC link unit. Figure 6 is a block diagram showing the electrical hardware configuration of the PC link unit. Figure 7 is a PC link designated as the master station. FIG. 8 is a flow chart showing a part of the control program of the unit, FIG. 8 is a flow chart showing the process of confirming the number of connected units while transmitting / receiving the polling address between the master station and the slave stations, and FIG. 9 is a sequence from the master station to each slave station. Flow chart showing the configuration of the control program when sending and receiving data by special polling while polling, Figure 10 shows the PC main unit executed by interrupt in response to HALT ready from the PC main unit in the PC link unit FIG. 11 is a time chart for explaining the polling sequence according to the present invention. 1 …… PC link unit 2 …… PC body 3 …… Transmission line 14 …… Unit designation switch 24 …… I / O memory

Claims (1)

[Claims] 1. An input means for designating a master station or a slave station, a registration means for registering a priority machine and a polling frequency based on data read from a PC body, and a condition that the master station is designated. As a result, polling is sequentially performed on each machine so that the polling frequency for the priority machine becomes the registered frequency, and in response to the self machine being polled, data is transmitted to other machines by the broadcasting method. In addition, in response to the polling of the other device, in response to the master station mode control means for receiving data from the other device and the slave station specified, it responds to the polling of the own device. A slave station mode control means for transmitting data to another device by a broadcasting method and receiving data from the other device in response to polling of the other device. Programmable controller link unit, characterized by comprising.