JPH03189802A - Host link unit for programmable controller - Google Patents

Abstract

PURPOSE:To immediately return the data by receiving a monitor data request by holding the monitor data by a monitor operation command request issued by a host computer, reading out the held data at the time of receiving the monitor data request and returning it to the host computer. CONSTITUTION:By a monitor operation command from a host computer 1, a host link unit 2 executes a monitor operation of a programmable controller 4, and inputs and holds monitor data of the controller 4. Subsequently, when a monitor data request is received, the monitor data held by the host link unit 2 is returned immediately to the host computer 1 without accessing the controller 4. In such a way, with respect to the monitor data request, access holding, etc., of the controller 4 are omitted, and the monitor data can be returned to the host computer by a quick response.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an upper link unit of a programmable controller provided between a host I computer and a programmable controller.

[Conventional technology]

Conventionally, an upper link unit of a programmable controller (hereinafter referred to as a PC) operates asynchronously with the PC and is connected to a host computer for bidirectional communication.

When it receives a request command such as a monitor data request or a setting command from the host computer, it interprets the command, accesses the data area of C, reads the data, executes the entire process, and then displays the processing results, etc. Send it back to the host computer.

At this time, in order to prevent any influence on the control of the PC, the PC has access rights to the data area, and the link unit accesses the data area based on the permission control of the PC.

Since data for each point number in the data area is generated and updated every sequence control cycle of the PC, access permission to the data area occurs at intervals of the sequence control cycle.

Therefore, when receiving a monitor data request from the host computer, the monitor operation based on this reception issues an access request to the PC, waits until permission is granted, and then accesses the data area to access the specified one or more points. The latest data of the number is taken in, and after this data is taken in, the data is sent back to the host computer.

[Problem to be solved by the invention]

In the case of the conventional PC upper link unit, since it accesses the data area of the PC after receiving the monitor data request, there is a problem in that it takes time to send the data back to the host computer.

In other words, the upper link unit operates faster than the host computer due to differences in programming language, etc.
It operates asynchronously with the PC, and the sequence control period of the PC changes depending on the control contents, reaching several 100 m5ec during long control, so even if an access request is immediately issued upon receiving a monitor data request, the maximum Number 1
The data is returned to the host computer with a delay of 00m5ec.

Therefore, real-time monitoring of the host computer cannot be performed.

In addition, communication between the host computer and the host link unit is carried out by serial transmission, which has a slow transmission speed in consideration of economic efficiency, and when multiple host link units are connected to the host computer, monitor data requests are Communication with other link units is prohibited from the time it is issued until the data is returned.

Therefore, if the return of data from the host link unit is delayed, communication switching between the host computer and each host link unit will be extremely slow, which will limit the number of host link units that can be monitored and severely reduce the host computer's monitoring ability. do.

SUMMARY OF THE INVENTION An object of the present invention is to provide an upper link unit for a PC that immediately returns data upon receiving a monitor data request.

[Means to solve the problem]

In order to achieve the above object, the upper link unit of the PC of the present invention includes a monitor data holding means that executes only a monitor operation and holds monitor data in response to a monitor operation command request issued by a host computer; and monitor data return means for reading data from the holding means and returning it to the host computer without accessing the PCB when a monitor data request is received.

[Effect]

In the case of the first link unit of the present invention configured as described above, in response to the monitor operation command request transmitted from the host computer prior to the monitor data request, the monitor data holding means executes the monitor operation before receiving the monitor data request. Execute to maintain the latest PC monitor data.

Then, upon receiving the monitor data request, the monitor data return means returns the monitor data in the holding means to the host computer.

Therefore, when receiving a monitor data request, P
The latest monitor data is immediately returned to the host computer without waiting for access permission from C.

〔Example〕

One embodiment will be described with reference to FIGS. 1 and 2.

As shown in FIG. 1, the host computer (1) and the upper link unit (2) are connected via a serial transmission line (3) for bidirectional communication, and the upper link unit (
2) and PC+41 are connectors t5+, +61'
Pass line connection is made via i.

The host computer 11) differs from conventional host computers in that it has the function of issuing a monitor operation registration command as a monitor operation command request and the function of issuing a monitor operation cancellation command for an operation cancellation command of this command. be.

In addition, the upper link unit (2) is formed by connecting the CPU (71, communication controller (8), system program area (9:, work area flol, monitor parameter area l+), e-monitor data area (12), and memory configuration to the bus. The difference from the conventional upper link unit is that areas (ul, (12)k) are added and the program of area (9) is changed to provide monitor data holding means and monitor data holding means.

The CPU (71 is the system program area (9)
), and executes all the various calculations using the work area +lO1.

In addition, the communication controller (8) is the host computer 1]
) and monitor parameter area (
11) holds all control parameters such as the point number specification parameters of the monitor operation request command, and the monitor data area (
12] holds the monitor data of PC+41 taken in by the monitor operation.

Furthermore, PC+4+ has a CPU like a conventional PC! +3
), memory configuration system program area (+4)
, work area (+5) *User program area (
+6+, shared data area Q 7) and buffer on the PC unit side (+8) * peripheral unit side buffer (
In addition to connecting the 191 bus, the access control circuit
It is formed by providing

And the CPU (+3) is the system program area (
14) operates in accordance with the system program stored in the device, performs input/output processing of the input/output device (not shown) on the controlled equipment side, and interprets the knee subprogram (control program) stored in the user program area (1G). .

Execution: Service processing for the upper link unit (2) is performed cyclically every sequence control period.

At this time, the work area (15) is used for calculations by the CPU (13)).
1B) p Q! It is shared by the upper link unit [21 and PC[4+] for exchanging data, etc. under the control of llI.

The access control circuit (20) also includes a CPU (7),
Based on the access request from +131, both CPUs +7) and (+31 are granted permission to access the shared data area (17), giving priority to sequence control.

When the upper link unit (2) is connected to the PC (41), it is supplied with power from the PCi41 and becomes operational, at the same time it is reset and executes all the processes from the second worst star H.

That is, in step (51), the system program is loaded, areas t10) to (12) are initialized, and the operating environment is prepared.

Furthermore, the system processing in step (S2) puts the system in a reception standby state, and steps (S3) and (S4) until all commands etc. are received from the host computer (1).
Pass with NO and return to step (S2).

When there is reception from the host computer ill, the process moves from step (S3) to step (S5), and a transmission error is checked in the communication controller (8).

At this time, if there is a transmission error, select No in step (S6).
The process passes through step (S7) and is returned to the host computer (1) as a full response such as a retransmission request.

On the other hand, if there is no transmission error, the process moves from step (S6) to step (S8), where the CPU (7) interprets the received command using the work area (10).

If this received command is a monitor operation registration command,
Step (S9) The process moves to step (510) and the control parameters of the registered command, that is, parameters such as the point number to be monitored, are held in the monitor parameter area (11).

Furthermore, in step (511), a monitor flag for specifying monitor operation is sent to the monitor parameter area (11), and the monitor operation of the upper link unit (21 is PC+4) is started, and in step (512), c p u
(7) is the shared data area (17) access request 2P
Issued to C(4).

Then, the process returns from step (512) to step (S2), passing through steps (S3) and (S4) with QNO and waiting for access until access permission is issued from the access control circuit I20).

On the other hand, the communication between the host computer (1) and the upper link unit (2) is completed, and the host computer fl) executes the following process.

Next, based on sequence control, the CPU (+3) checks the latest monitor data for each point number. After writing to the shared data area (lη), when the access control circuit (20) issues access permission to the upper link unit (2), based on this access permission, steps from step (S4) to step (S1
3, the process moves to step (514).

Then, the CPU (7) or the monitor parameter area (shared data area 07 with reference to the river control parameters)'e
The monitor data of each specified point number is read out and held in the monitor data area (12).

Furthermore, during the monitor operation, every time an access permission of 1η is issued to the synergistic data area (1η) until it passes through step (515) iNo and receives a monitor data request from step (S1, hereafter, the host computer 11). Then, step (S4) is passed, and the monitor data of each point number is read from this data area (17) to update the data in the monitor data area (12).

Next, when the host computer receives a monitor data request of [+1], steps (53), (S5), and (S6) are performed.
, (58), (S9) and step (516) k to proceed to step (517).

Then, the CPU (7) reads the monitor data area (monitor data of each point number of 1 powder) and sends it to the communication controller (8).
send to

Furthermore, the process moves from step (517) to step (S7), where the latest monitor data of each read point number is returned to the host computer (1), and the host computer fil *upper link unit (
2) Communication between ends.

At this time, processing is performed when receiving a normal command, which will be described later.

In other words, access to the PCl 41, which is required when receiving a conventional monitor data request command, etc., can be omitted, and the latest monitor data of each point number is immediately returned without waiting for access depending on the sequence control cycle, and the latest monitor data of each point number is returned to the host computer H. * Communication between upper link units (2) ends in a short time.

Then, when the process returns from step (S7) to step (S2), the monitor operation continues until a monitor operation cancellation command is received from the host computer [11].During this period, the monitor data area (1
The monitor data for each point number in 2) is stored in the host computer (1
) will be returned to.

Next, when the monitor operation cancellation command is received, the process passes through and moves to step (519).

At this time, the CPU (7) resets all of the monitor parameter area (river monitor flags) and then proceeds to step (520).
, stops issuing access requests to PCl41, and cancels the monitoring operation of PCl3).

In addition, all sections of monitor operation from the host computer (1),
When receiving commands that are the same as conventional commands other than monitor registration and monitor operation cancellation (hereinafter referred to as normal commands), steps (59), (516), and (518) (pass through with i-NO and move to step (S21) For example, after setting the normal access flag to monitor parameter engineering (11),
An access request for the common data area is issued to the PCl 41, and the CPU u (7) starts full normal operation.

In this case, after issuing the access request in step (521), the CPU (7) performs steps (S2), (53), and (54).
), wait for all access permissions from PCl41, and when access permission is issued, step (513) e NO
Step (515) to step (S22)
to access the Kyori data area (17) and import or write necessary data.

Furthermore, when the data import or write is completed, the process moves to step (S23) to stop issuing access requests to the PC[41], and then the process moves to step (S7) to transfer the read data etc. to the host computer+11. and terminates processing of the received normal command.

When a normal command is received, communication between the host computer +11 and the upper link unit (21) continues until the return to the host computer i11 based on this reception is completed, and during that time the host computer (1) communicates with the other upper link unit. etc. cannot be communicated.

On the other hand, in any of the normal operations of the monitor operation 9, when a new command or the like is received in step (S3), the received command is processed.

Therefore, especially when a new monitor operation registration command is received during monitor operation, the monitor parameter area (one control parameter is updated and the point number to be monitored is changed,
Deletion takes place.

From then on, monitor data is held in the monitor data area (12) based on the updated control parameters, and when a monitor data request is received, the latest monitor data for each point number based on the latest monitor operation registration command is returned. be done.

In addition, based on differences in operating languages, etc., upper link
2) works as quickly as I'C+4 +, and Phos I-
Computer + If is t position 11 link unit (2), P
The operation is slower than C(4).

Moreover, the transmission of bidirectional communication with the host computer H upper unit 22-+21 using the transmission line (3) is also slower than the operation of the upper link unit 71121.

Therefore, most of the monitor operations are
(Without burden on 21, the host computer (1) and -
Communication, etc. with F position unit 1-I2) will not be delayed due to monitor operation.

Since the time from issuing a monitor data request to returning the monitor data is a short time with no access wait time etc. on the PC (41), the host computer (11 is PCI
4. The time spent on monitoring the 4j is greatly saved,
The number of PCs that can be monitored per unit time increases, improving monitoring ability.

In addition, when the number of point numbers specified in the monitor operation registration command is small and the registration command - monitor data request command can be issued within one sequence control cycle, the control is performed based on the return data from the upper link unit (2). , PC+4), real-time monitoring of the PC (41) by the host I-computer full can also be performed by changing the registration command every sequence control cycle according to the operation of the PC (41).

Of course, the same effects as described above can be obtained even when communication between the host computer (1) and the t-sink unit (2) is performed by a transmission method other than serial transmission.

〔Effect of the invention〕

The present invention is configured as described above (A).
This produces the effects described below.

Is the upper link unit programmable by the monitor operation command from the host computer? Monitor operation of the controller? When a monitor data request is received, the monitor data held by the h-rank unit is immediately returned to the host computer without accessing the controller. Monitor data can be returned to the host computer in response to a request with a quick response that eliminates the need for a conventional controller to wait for access, etc., thereby improving the computer's monitoring ability.

[Brief explanation of drawings]

Figures 1 and 2 show the programmable controller of the present invention]
One actual example of a roller position link unit is shown, FIG. 1 is a block diagram, and FIG. 2 is a flowchart for explaining the operation. (1) Host computer, (2)...upper link unit l-, 13), real transmission line, (4)...
...Programmable controller, ("t), (13
+...CPU, i8j...Communication controller, (
II)...Monitor parameter area, (+2)...Monitor data area, (17)...Shared data area, (
20)...Access control circuit.

Claims (1)

[Claims] (1) Connected to a host computer for bidirectional communication, when receiving a monitor data request issued by the host computer, captures monitor data that is updated every control cycle of the controller by access from a programmable controller based on a monitor operation; In the upper link unit of the programmable controller that returns the monitor data to the host computer, a monitor data holding unit that executes only the monitor operation and holds the monitor data in response to a monitor operation command request issued by the host computer; An upper link unit of a programmable controller, comprising: monitor data return means for reading data from the holding means without accessing the controller when receiving the monitor data request, and returning the data to the host computer.