JP2001125608A - Programmable logic controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a programmable logic controller which permits program modification, instruction addition, and customization through simple operation without requiring any special hardware such as a PROM writer and a device adapter. SOLUTION: At least, part of a system program memory is composed of a nonvolatile memory which is rewritable in a mounted state and the rewritable nonvolatile memory is provided with a system program storage area which corresponds to an additional function; and this controller is provided with a mode setting means which sets an operation mode to a system program part modification mode, a connector where an external storage medium stored with a system program corresponding to the additional function is fitted detachably, and a program transfer means which transfers the system program corresponding to the additional function stored in the external storage medium connected through the connector to the system program storage area corresponding to the additional function of the system program memory on condition that the operation mode is set to the system program part modification mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a programmable logic controller capable of partially changing a system program by a simple operation without requiring special equipment such as a PROM writer and a device adapter.
In particular, the present invention relates to a programmable logic controller suitable for changing or adding a user instruction function.

[0002]

2. Description of the Related Art A programmable logic controller (hereinafter, referred to as a PLC) of this kind includes a system program memory for storing a system program for realizing functions inherent to the apparatus such as a user instruction execution process and an I / O refresh process. And a user program memory for storing a user program corresponding to the user's control specifications.

Conventionally, a PLC system program and instruction data (instruction function realization program) of this kind have conventionally been used.
To change or add a program, delete the entire contents of the memory where the system program / instruction is stored, and then collectively create /
In a writing method (hereinafter, referred to as a first method) and an instruction addition, a method of creating and storing instruction data to be added as a part of a user program using the additional instruction (hereinafter, referred to as a second method). And physically replacing the PROM with another PROM whose data has already been changed (hereinafter referred to as the third method).
Method) was adopted either. The second method is shown in FIG. 11 for ease of understanding. 11A is a memory map showing the contents of the user program memory before customization, and FIG. 11B is a memory map showing the contents of the user program memory after customization. As you can see from these figures, before customization,
The system program area in the user program memory is an empty area. On the other hand, after customization, a new instruction function realizing process is stored in the system program area in the user program memory. As described above, in the second method, in adding an instruction, data for an instruction to be added is created as a part of a user program that uses the additional instruction, and is stored in the user program memory.

[0004]

However, the following problems have been pointed out in the first to third methods.

[0005] The system program modification / instruction addition / customization can only be performed by the maker for data creation / reflection processing.
When LC occurs, its resolution requires a certain period of time and cannot be dealt with immediately.

When writing (reflecting) system program data to a PROM / FROM or the like, the PRO
Equipment such as an M writer and a device adapter is required.

[0007] Also, since system programs and instructions are handled as a series of data, it is not possible to separate and respond to portions that need to be changed or customized. Therefore, in order to perform customization such as change / addition, program data other than the changed portion is required, and even if only instructions are added, the system program itself needs to be changed.

Further, in the case of an instruction adding method using a user program and an additional instruction as program data,
The man-hour for creating the program data is generated separately. For this reason, an extra man-hour is required for creating a user program that the user should focus on.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has as its object to provide a simple operation without requiring special equipment such as a PROM writer and a device adapter. An object of the present invention is to provide a programmable logic controller capable of changing programs, adding instructions, and customizing.

[0010]

A programmable logic controller according to the present invention comprises: a system program memory for storing a system program for realizing functions inherent to the apparatus such as a user instruction decoding execution process and an I / O refresh process; It is assumed that it has at least a user program memory for storing a user program corresponding to the control specification.

In addition, at least a part of the system program memory is composed of a rewritable nonvolatile memory (for example, a flash memory) in a mounted state, and the rewritable nonvolatile memory has an additional function. A corresponding system program storage area is provided.

Further, the programmable logic controller of the present invention has a mode setting means for setting an operation mode to a system program partial change mode, and a detachable external storage medium storing a system program corresponding to an additional function. And a system program corresponding to an additional function stored in an external storage medium connected via the connector, provided that the operation mode is set to the system program partial change mode. And a program transfer unit for transferring the program to a system program storage area corresponding to the additional function.

According to such a configuration, the external storage medium storing the system program corresponding to the additional function is stored in the PL.
After setting the operation mode to the system program partial change mode using the mode setting means after mounting on the C body, the system program corresponding to the additional function stored in the external storage medium connected via the connector is Are automatically transferred to the realization program storage area corresponding to the additional function of the system program memory.
Partial changes in the system program can be easily made without using special equipment such as a ROM writer or a device adapter.

Further, the programmable logic controller of the present invention stores an instruction function realization program (instruction data) corresponding to each user instruction in a system program memory, and reads and executes the program appropriately when decoding the user instruction. And a programmable logic controller that realizes control specifications specified by a user program.

In this programmable logic controller, at least a part of the system program memory is constituted by a rewritable non-volatile memory (for example, a flash memory or the like) in a mounted state. Is provided with an instruction function realizing program storage area corresponding to the additional instruction.

Further, in this programmable logic controller, mode setting means for setting an operation mode to a system program partial change mode and an external storage medium storing an instruction function realizing program corresponding to an additional instruction are detachably attached. Connector for
Provided that the operation mode is set to the system program partial change mode, an instruction function realizing program corresponding to the additional instruction stored in the external storage medium connected via the connector is executed by the instruction in the system program memory. Program transfer means for transferring the program to the function realization program storage area.

According to such a configuration, after the external storage medium storing the instruction function realizing program corresponding to the additional instruction is mounted on the connector, the operation mode is set to the operation mode system program partial change mode using the mode setting means. ,
The instruction function realization program corresponding to the additional instruction stored in the external storage medium connected via the connector is automatically transferred to the instruction function realization program storage function of the system program memory. PRO
The instruction adding process can be performed by a simple operation without requiring special equipment such as an M writer and a device adapter.

In a preferred embodiment, a storage logical address of each instruction function realization program generated by instruction decoding is converted into a storage physical address in a mounted rewritable nonvolatile memory constituting a system program memory. An address conversion table storage area is provided, and the program transfer means includes a function of updating the contents of the address conversion table storage area according to each storage address of the transferred instruction function implementing program.

According to such a configuration, even if a so-called instruction table in which an instruction word is associated with a storage address of an instruction function realizing program is stored in a non-rewritable part of the system program, the instruction table is generated by decoding the instruction. The contents of the address conversion table that translates the storage logical address of each instruction function realization program into its storage physical address are updated according to each storage physical address of the instruction function realization program after transfer, thereby affecting surrounding system programs. , It is possible to write an instruction function realizing program corresponding to the additional instruction.

Further, the programmable logic controller of the present invention stores an instruction function realizing program corresponding to each user instruction in a system program memory, and appropriately calls and executes the program when decoding the user instruction, thereby executing the user program. It assumes a programmable logic controller that achieves the specified control specifications.

Also in this programmable logic controller, at least a part of the system program is constituted by a rewritable nonvolatile memory (flash memory or the like) in a mounted state, and a new instruction is stored in the rewritable nonvolatile memory. An instruction function realizing program storage area corresponding to.

The programmable logic controller includes a mode setting switch attached to the outer surface of the housing and capable of setting at least a program change mode and a normal mode, and one or more instruction function realizing programs provided on the outer surface of the housing. And a power switch used to turn on the operating power.

The state of the mode setting switch is read into the system program stored in the system program memory immediately after the power switch is turned on. The instruction function realizing program stored in the memory card mounted on the memory card is transferred to the instruction function realizing program storage area of the system program memory.
A function for performing a normal operation including a refresh process is included.

According to such a configuration, after the memory card storing one or more instruction function realizing programs is mounted on the slot provided on the outer surface of the housing, the mode setting switch mounted on the outer surface of the housing is mounted. The instruction function realizing program stored in the memory card mounted in the slot is executed by simply performing a simple operation such as setting the program partial change mode and turning on the operating power using the power switch. Is transferred to the instruction function realizing program storage area. On the other hand, after setting the mode setting switch to the normal mode and turning on the operating power again using the power switch, the normal operation including the instruction execution processing and the I / O refresh processing is started.

According to such a configuration, it is possible to change the system program portion for adding a user command or the like with a simpler operation.

In a preferred embodiment, a storage logical address of each instruction function realization program generated by instruction decoding is converted into its storage physical address in a mounted rewritable nonvolatile memory constituting a system program memory. An address conversion table storage area is provided, and the program transfer means includes a function of updating the contents of the address conversion table storage area according to the storage address of each instruction function implementing program after transfer.

Thus, only the instruction function implementing program corresponding to the additional instruction can be selectively rewritten without affecting other system programs.

In some of the inventions described above, in a further preferred embodiment, when the instruction function realizing program is transferred to the system program memory, a distinction is made between the normal execution of the write, the occurrence of the abnormal write, and the normal end of the write. Display means is provided.

According to this configuration, the operator can visually confirm the progress of the system program writing operation.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the programmable logic controller according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a hardware configuration of the entire PLC to which the present invention is applied. As shown in the figure, the PLC 1 includes a CPU 101,
I / O memory 102 and user program memory 103
, A system program memory 104, a work memory 105, an I / O interface 106, an input / output device 107, a connector 108, a memory card 109,
An interface 110, a DIP switch 111, and a display unit 112 are provided.

The CPU 101 is mainly composed of a microprocessor, and has a system program memory 1
By executing various system programs stored in the CPU 04, various functions as a PLC are realized. Here, typical functions realized by executing the system program include a user program execution function, an I / O refresh function, and a system service function.

The I / O memory 102 has an input / output device 107
It is used as a storage area for input data taken in from the server and output data to be sent to the input / output device 107. The I / O memory 102 is constituted by a RAM that can be constantly rewritten.

The user program memory 103 is a memory for storing a user program corresponding to a control specification desired by the user.
It is composed of OM and flash PROM.

The system program memory 104 stores the PL
A system program for realizing various functions required for C1 is stored. As a storage medium, a normal PROM which can be rewritten only with equipment such as a PROM writer, and a flash memory (FROM) which is a nonvolatile memory which can be easily rewritten in a mounted state
It is composed of

Then, as described later, a normal PROM
The side stores a fixed part of the system program, while the FROM stores an instruction function realization program corresponding to an additional instruction and the like and an address conversion table (see FIG. 6) described later. .

The work memory 105 is used as a storage area or the like for an intermediate calculation result when the CPU 101 executes a system program. A rewritable RAM is used as a storage medium.

The input / output device 107 includes an input device for receiving input data from an external input device (switch, sensor, etc.) and an output device for sending output data to an external output device (relay, display, etc.). It is composed of This input / output device 107 has an I / O interface 1
06, it is connected to the internal bus of PLC1.

The connector 108 is built in a slot provided in the housing of the PLC 1. The connector 108 has a memory card 10 as an external storage medium.
9 is detachably mounted. In the memory card 109,
An instruction function realizing program corresponding to the additional instruction and an address conversion table described later are written in advance. This writing operation can be performed by the manufacturer or the vendor.

FIG. 2 shows a flowchart of the entire system processing which is realized by the CPU 101 executing the system program stored in the system program memory 104.

In FIG. 4, when the process is started by turning on a power switch (not shown), an initial process is executed, and various flags and registers necessary for the operation of the system are initialized (step 201). In particular,
In the present invention, this initial processing (step 201)
, A system program partial change process is executed.

After the execution of the initial processing (Step 201) is completed, the user program execution processing (Step 202) and the I / O refresh processing (Step 2)
03), the system service process (step 204) is cyclically executed.

That is, in the user program execution process (step 202), each instruction word is sequentially read from the user program memory 103 and decoded, and a corresponding instruction function realization program (instruction data) is stored in the system according to the result of the decoding. It is read from the program memory 104 and executed.

I / O refresh processing (step 20)
In 3), the input data fetched from the input / output device 107 is written to the input area of the I / O memory 102, and the output data read from the output area of the I / O memory 102 is output to the output terminal of the input / output device 107. Execute the process of sending to.

System service processing (step 204)
Then, various system services are executed by communicating with a support tool (not shown) or by communicating with another PLC or remote I / O.

The details of the system program partial change process executed in the initial process (step 201) are shown in the flowchart of FIG.

In the figure, when the processing is started, the state of the DIP switch 111 is read via the interface 110 (step 301). The DIP switch 111 can set the operation of the PLC 1 between a program partial change mode and a normal mode.

Subsequent to the DIP switch setting reading process (step 301), an operation mode determination process is executed (step 302). Here, if it is determined that the mode is the system program partial change mode (step 302 YES),
The change program is read from the memory card 109 which is an external storage medium (step 303), and is written to the FROM constituting the system program memory 104 (step 304). Is transferred to the FROM area. This change program includes instruction function realization programs PR1 to P
Rn (see FIG. 7) and a logical / physical address conversion table (see FIG. 6) are included. Therefore, as will be described later, when the change program is updated, not only the instruction function realization programs PR1 to PRn but also the logical / physical address conversion table are automatically updated.

If the writing of all the programs is completed while repeating the above (step 308), the processing is terminated.

If a write error occurs during the change program transfer process (step 305 NO), an error occurrence display is performed (step 307). If the writing is normal (YES in step 305), a normal execution display is performed (step 306). If all the writing is completed (YES in step 308), a normal end of writing display is performed (step 309).

FIG. 9 shows an example of the display section 112. In this example, three light emitting diodes (LED1, L
ED2, LED3) are used to perform a normal execution display, an abnormality occurrence display, and a normal end display.

That is, the normal execution display is performed by simultaneously turning on the LED 1 and the LED 3 as shown in FIG.

An abnormality occurrence display is performed by blinking the LED 1 as shown in FIG. 9 (b).

As shown in FIG. 9C, the normal termination display is performed by three LEDs (LED1, LED2, LED3).
At the same time.

FIG. 4 is a detailed flowchart of the user program execution process.

In the figure, when the process is started, the value of the program counter is initialized (step 40).
1) The instruction specified by the program counter is read from the user program memory 103 (step 40).
2), by referring to the instruction / logical address conversion table shown in FIG. 5, an instruction program (instruction function realization program) (PR1) corresponding to each instruction (OP1 to OPn)
To PRn) in the first logical address (LAD1) of the storage area.
1 to LADn1) and the tail logical address (LAD12
To LADn2) are obtained (step 403).

Subsequently, based on the obtained start and end logical addresses, the corresponding start and end physical addresses are obtained by referring to the logical / physical address conversion table shown in FIG. 6 (step 404). ).

As shown in the memory map of FIG. 7, the physical addresses AD11 to ADn1, A
D12 to ADn2) are actually each instruction (OP1 to OPn)
n) corresponds to the storage address of the instruction program (meaning the instruction function realization program) (PR1 to PRn) corresponding to (n).

Thereafter, based on the finally obtained physical addresses of the beginning and end, the corresponding instruction program (PR
1 to PRn), the corresponding instruction function is realized (step 405).

Thus, until the END instruction described at the end of the user program is detected (step 406N).
O), increment the program counter (step 40)
7) The above processing is repeated (steps 402 to 40).
5) With the detection of the END instruction (step 406YE)
S), the process ends.

Next, the arrangement of the above-described instruction / logical address conversion table (see FIG. 5), logical / physical address conversion table (see FIG. 6), and instruction program area (see FIG. 7) will be described.

The instruction / logical address conversion table (see FIG. 5) is stored in a PROM area of the recording medium constituting the system program memory 104 which cannot be rewritten in the mounted state. The PROM area stores fixed instruction program portions (PR1 to PRm) in the instruction program shown in FIG. In this example, since the instruction function is intended to be added, the capacity of the fixed instruction program portion is about 70 to 80% of the entire instruction program.
Degree.

On the other hand, in the instruction program shown in FIG. 7, a changeable instruction program portion (PRm +
1 to PRn), the system program memory 1
04 is stored in the FROM area. In the example on the left, the capacity of the changeable instruction program is about 20 to 30% of the entire instruction program. Also, this FROM
The area also stores the logical / physical address conversion table shown in FIG.

Therefore, when a part of the instruction program area shown in FIG. 7 is rewritten, the logical / physical address conversion table shown in FIG. 6 is used in accordance with the physical address of the new instruction program after the rewriting. Is updated.

As described above, by changing the configuration of the instruction program area and updating the logical / physical address conversion table (see FIG. 6), the instruction / logical address conversion stored in the PROM area of the system program 104 can be performed. There is no need to change the table (see FIG. 5). That is, in order to add a new instruction function, FIG.
Even if a part of the instruction program area shown in FIG. 5 is changed, the logical / physical address conversion table shown in FIG. 6 is updated in accordance with the change, so that the instruction / logical address conversion table stored in the PROM area (FIG. ) No longer needs to be changed and does not hinder the execution of the entire system program.

FIG. 8 shows a memory map of a system program rewriting range in a partial change. As can be seen from the figure, according to this embodiment, only a part of the entire system program can be rewritten, and even after rewriting, consistency with other system program parts can be maintained. Can be maintained. In addition,
In the drawing, the area described as “no change” following the area to be rewritten is an area in which another system program other than the instruction function realizing program is stored.

Therefore, according to this embodiment, FIG.
As shown in (a), a plurality of existing instructions (OP1 to OP
FIG. 10 shows a user program described using Pn).
As shown in (b), it can be described as one new customization instruction (OPP1). If know-how unique to each user appears in the user program, this part is replaced with one new customization instruction. Customize instruction (O
By replacing with PP1), leakage of know-how can be avoided.

As described above, according to this embodiment, when the user needs to customize the system program, add a command, or the like, the maker or the vendor requires the external storage such as the memory card 109 to be used. All that is required is to write the program data for customization on the medium and distribute it to the user. The user inserts the memory card 109 into a predetermined slot, connects the connector 108, and sets the DIP switch 111 to the program partial change mode. Then, when a power switch (not shown) is turned on, the system program partial change processing shown in FIG. 3 is executed, and the customization correspondence program data stored in the memory card 109 is automatically stored in the FROM area of the system program memory 104. Transferred and stored At the same time, by updating the logical / physical address conversion table shown in FIG. 6, the consistency of the entire system program memory is maintained.

Therefore, the user know-how can be easily concealed in the form of an instruction, and the processing can be speeded up by creating a plurality of processes conventionally described in a ladder language as one instruction. Further, no equipment for writing data to the system program is required, and the cost and man-hour can be reduced, including the preparation work for that.
Furthermore, by realizing a mechanism that makes the current system program and additional parts independent, it is possible to create program data for customization only by developing additional / changed parts, reducing development man-hours and customizing data. Is added to the existing system program, the customization data itself can be directly managed. That is, there is no need to be aware of the version of the existing system program.

In the above embodiment, the present invention is implemented for adding a user instruction. However, the system program partial change processing of the present invention is not limited to this. Alternatively, the present invention can be applied to a partial change of a system program having an arbitrary function. Further, in the above embodiment, the system program to be written itself includes a logical / physical address conversion table in addition to the instruction function realizing program, and the rewriting of the system program causes the relevant logical / physical Although the address translation table is configured to be automatically updated, this is only one mode of updating the address translation table. In other words, the system program to be written itself includes only the instruction function realizing program, and the physical address after rewriting is separately written in the above conversion table, thereby updating the address conversion table. Can be.

[0071]

As is apparent from the above description, according to the present invention, a system program can be changed, instructions can be added / customized by a simple operation without special equipment such as a PROM writer and a device adapter. An enabled programmable logic controller can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a hardware configuration of an entire PLC.

FIG. 2 is a flowchart of the entire system processing.

FIG. 3 is a flowchart of a system program partial change process.

FIG. 4 is a detailed flowchart of a user program execution process.

FIG. 5 is an explanatory diagram of an instruction / logical address conversion table.

FIG. 6 is an explanatory diagram of a logical / physical address conversion table.

FIG. 7 is a memory map of an instruction program area.

FIG. 8 is a memory map of a system program rewriting range in a partial change.

FIG. 9 is an explanatory diagram illustrating an operation mode of a display unit.

FIG. 10 is an explanatory diagram showing a comparison between a user program described by an existing instruction and a user program described by a new customization instruction;

FIG. 11 is a memory map showing the contents of a user program memory of a conventional PLC.

[Explanation of symbols]

 1 PLC 101 CPU 102 I / O memory 103 User program memory 104 System program memory 105 Work memory 106 I / O interface 107 I / O device 108 Connector 109 Memory card 110 Interface 111 DIP switch 112 Display unit

Claims (3)

[Claims] 1. A system program memory for storing a system program for realizing functions inherent to the apparatus such as a user command decoding execution process and an I / O refresh process, and a user program corresponding to a user's control specification. A programmable logic controller having at least a user program memory, wherein at least a part of the system program memory is configured as a rewritable nonvolatile memory while being mounted, and the rewritable nonvolatile memory corresponds to an additional function. Mode setting means for setting an operation mode to a system program partial change mode, and a connector for detachably attaching an external storage medium storing a system program corresponding to an additional function. And a system program corresponding to the additional function stored in the external storage medium connected via the connector, provided that the operation mode is set to the system program partial change mode. A program transfer means for transferring a program to a system program storage area corresponding to a function; 2. A control function specified by a user program is realized by storing an instruction function realizing program corresponding to each user command in a system program memory and reading and executing the program appropriately when decoding the user command. In the programmable logic controller, at least a part of the system program memory is configured as a rewritable nonvolatile memory while being mounted, and the rewritable nonvolatile memory has an instruction function realization program storage area corresponding to an additional instruction. Mode setting means for setting the operation mode to the system program partial change mode; a connector for detachably attaching an external storage medium storing an instruction function realization program corresponding to the additional instruction; and an operation mode. Is a system program The instruction function realizing program corresponding to the additional instruction stored in the external storage medium connected via the connector is stored in the system program memory, provided that the instruction function realizing program is set in the system partial change mode. A programmable logic controller comprising: a program transfer means for transferring data to an area; 3. A control function specified by the user program is realized by storing an instruction function realizing program corresponding to each user command in a system program memory and reading and executing the program appropriately when decoding the user command. In the programmable logic controller, at least a part of the system program memory is configured as a rewritable nonvolatile memory in a mounted state, and the rewritable nonvolatile memory has an instruction function realizing program storage area corresponding to a new instruction. A mode setting switch mounted on the outer surface of the housing and capable of setting at least a program partial change mode and a normal mode; and a memory card provided on the outer surface of the housing and storing one or more instruction function realization programs. Wearing Noh slot, a power switch used for turning on the operating power,
In the system program stored in the system program memory, the state of the mode setting switch is read immediately after the power switch is turned on, and when the state is the program partial change mode, the While transferring the instruction function realization program stored in the attached memory card to the instruction function realization program storage area of the system program memory, in the normal mode, normal operation including instruction execution processing and I / O refresh processing A programmable logic controller that includes the function of performing