JPH0954603A - Programmable controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the programmable controller which can secure an arithmetic speed similar to that of a batch refreshing system while making good use of the advantages of an each-time refreshing system. SOLUTION: A control part 5 receives the signal from a control part 3 and decides whether or not the signal is a signal to an output part 4, and temporarily holds data as an arithmetic result, and further the control part generates a select signal and a write signal and holds the data for a time matching the access time of the output part 4. Meanwhile, an arithmetic part 1 already advances to next arithmetic execution and there is no stagnation of arithmetic operation.

Description

Detailed Description of the Invention

[0001]

[0001] The present invention relates to a programmable controller.

[0002]

2. Description of the Related Art As a method of input / output transfer (I / O refresh) of a programmable controller, data is collectively transferred to an internal data memory, and calculation is performed while exchanging data with the data memory. There is a batch refresh method for performing the above operation and a refresh method (a direct method) for exchanging data each time a calculation is performed in response to an I / O.

Each of the methods will be described with reference to FIG. 3. In the case of the batch refresh method, the data of the arithmetic unit 1 is temporarily stored in the data memory 2 (arrow), and after all the arithmetic operations are completed, the control unit 3 including the CPU collectively performs the operation. Data in the data memory 2 is transferred (written) to the output unit 4. (Arrow) In the case of the refresh method each time, the data as the calculation result of the calculation unit 1 is stored in the data memory 2 each time the calculation is performed (arrow) and is also transferred (written) to the output unit 4 (arrow). . In this case, since the access time of the output unit 4 is slower than that of the data memory 2, the operation speed of the operation unit 1 is reduced accordingly.

[0004]

In the case of the refresh method for outputting the operation result each time, the output can be changed many times in one scan cycle of the program, so that the description of the program becomes easy. There is and is useful. However, the speed of the computing unit 1 has increased and
The operation can be executed in several hundreds to several tens of ns per step, whereas access to the external output requires about 1 μs per step because it is necessary to strengthen the resistance of the signal line and the disturbance. . That is, it requires a longer time than the access time of the arithmetic unit 1. Therefore, if the refresh method is adopted each time, there is a drawback in that it is necessary to extend the operation cycle according to the external output.

The present invention has been made in view of the above drawbacks of the refresh method each time, and it is an object of the present invention to provide a programmable controller capable of ensuring the same operation speed as the batch refresh method while taking advantage of the advantage of the refresh method each time. .

[0006]

In order to achieve the above object, the present invention provides an arithmetic unit for executing a program operation, a data memory for temporarily storing the arithmetic result of the arithmetic unit, and an external output to which the arithmetic result is transferred. In a programmable controller that includes an output unit that drives a control unit and a control unit that transfers the calculation result to the output unit, the calculation result from the calculation unit is temporarily held so that the calculation unit is not affected by the response time of the output unit. It is provided with another control unit for transferring to the output unit, and the operation speed of the calculation unit can be secured by the function of the other control unit as in the batch refresh method.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of an embodiment of the present invention. What is different from the conventional example is that another control unit 5 for temporarily holding the calculation result from the calculation unit 1 is added, and the refresh system is basically the same. The refresh method is adopted every time.

Next, the operation of this embodiment will be described based on the time chart shown in FIG. First, when the operation result data is output from the operation unit 1 as shown in FIG. 2A, the control unit 3 sends a select signal for identifying a device such as an address or a chip select as shown in FIG. 2B. The data is output and the write signal is output as shown in FIG. 2C, the data of the operation result is stored in the data memory 2, and is transferred to the output unit 4 side.

Here, the control unit 5 receives the signal from the control unit 3 and determines whether it is a signal to the output unit 4, and temporarily holds the data of the calculation result as shown in FIG. Similarly to the unit 3, a select signal (FIG. 2E) and a write signal (FIG. 2F) are created, and the data is held for a time corresponding to the access time of the output unit 4. In the meantime, the arithmetic unit 1 shifts to the next arithmetic operation execution, and there is no delay in the arithmetic operation. In a normal program, the output unit 4 is not continuously accessed, so that in the present embodiment, it is possible to secure the refresh time for each output unit 4 without delaying the operation. Only when the output unit 4 is continuously accessed, it is sufficient to secure the access time by weighting the control unit 3 (not moving to the next calculation) as in the conventional refresh method.

[0010]

According to the present invention, an arithmetic unit for executing a program operation, a data memory for temporarily storing the arithmetic result of the arithmetic unit, an output unit for transferring the arithmetic result and driving an external output, and an arithmetic result output. In the programmable controller including a control unit for transferring to the output unit, another control unit for temporarily holding the operation result from the operation unit so that the operation unit is not affected by the response time of the output unit and transferring it to the output unit is provided. The operation of the separate control section can ensure the operation speed of the operation section as in the batch refresh method, and the advantage of the refresh method can be utilized each time.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a timing chart for explaining the above operation.

FIG. 3 is a configuration diagram for explaining a conventional example.

[Explanation of symbols]

 1 arithmetic unit 2 data memory 3 control unit 4 output unit 5 control unit

Claims (1)

[Claims] 1. A calculation unit for calculating a program, a data memory for temporarily storing a calculation result of the calculation unit, an output unit for transferring the calculation result and driving an external output, and a calculation result for the output unit. A programmable controller including a control unit further includes another control unit that temporarily holds the calculation result from the calculation unit so that the calculation unit is not affected by the response time of the output unit and transfers the calculation result to the output unit. And programmable controller.