KR19980035314A - PD data transmission and reception method - Google Patents

Abstract

The present invention relates to a method of data transmission and reception of a PLC, the conventional apparatus is to send the data through the queue to the task by putting the pointer value of the queue of the data stored in the task to the counterpart, at this time due to noise, etc. If the queue pointer value is broken, all data is lost because the queue area is initialized by the error detection method. The present invention provides a first step of presetting an area of a queue corresponding to the number of data to be transmitted in order to solve such a conventional problem; A second step of creating a list of pointers of the data to be transmitted; It is determined whether the pointer value of the queue is normal when transmitting or receiving data in the area of the first step, and if it is not normal, it is a third step of updating the value of the corresponding area by checking the pointer list created in the second step. In this way, when a high-speed repetitive data is transmitted and received in this way, the buffer is reserved and used as a buffer in advance for the set number of repetitive data, so the high-speed repetitive data can be read and written only in a predetermined area, thereby improving memory efficiency. By increasing the number of pointers for each data in the list, if the queue is broken due to noise or the like, only the corresponding data is updated, thereby preventing data loss.

Description

PD data transmission and reception method

1 is a block diagram of a conventional PLC interface device,

2 is a detailed block diagram of a queue in a common RAM according to FIG.

3 is a flowchart of a data transmission / reception operation of a conventional PLC,

4 is a block diagram of a PLC interface device of the present invention;

5 is a table showing a pointer list according to the present invention;

6 is a flowchart of data transmission and reception of the present invention.

* Description of the symbols for the main parts of the drawings *

100: PLC interface controller 200: Link interface controller

300: common ram 310: queue

320: cupid manager

The present invention relates to a method of data transmission and reception of PLC, and in particular, in the case of sending and receiving high-speed repetitive data, the queue is reserved in advance as a buffer as the number of set blocks of repetitive data, and the data pointers are created as a list. The present invention relates to a method of data transmission and reception of PLC, which is suitable for preventing data loss.

Transmission of data and commands between the PLC and the communication module is stored in the queue 310 in the common RAM 300 and transmitted by the PLC interface controller 100 in the PLC as shown in FIG. All data from the module is also transmitted by the link interface controller 200 to the PLC through the queue 310 in the common RAM (300).

The common RAM 300 has four types of QUEUE POOLs 321 to 324 according to the size of interface data, as shown in FIG. 2, for efficient management of queues. This is referred to as the cue manager 320.

The head number (HEAD NO) of the queue pool (321-324) is stored a pointer of the first queue available, the tail number (TAIL NO) is stored the last pointer available to the head number indicated when using the common RAM When using the queue of address, and returning the already used cue, register the used cue's address in tail number to enable the next use.

For example, in case of transferring data from the PC to the communication module, the counterpart puts the pointer value of the queue pool that stores the data into the task and causes the counterpart to process it.

Then, when the other party completes the task of the head number, the queue puts the queue into the tail number of the queue manager and releases the task to send and receive data.

At this time, if the cue pointer value inserted into the task is broken due to noise, the entire area of the queue is initialized by the error detection method as shown in the operation flowchart of FIG.

As described above, in the case of transmitting data through a queue, the conventional apparatus puts a pointer value of a queue pool storing data into a task to process the counterpart, and when the queue pointer value inserted into the task is broken due to noise, etc. There is a problem that all data is lost because the queue area is initialized by the error detection method, and there is a problem that the memory cannot be efficiently used because a constant size area is always allocated regardless of the number of HS link data.

An object of the present invention is to solve the conventional problems, when using the same number of blocks of the repetitive data in the case of sending and receiving high-speed repetitive data, the queue is reserved in advance as a buffer, and the pointer of the data to create a list When the queue is broken, it provides a method of data transmission and reception of PL so that only data in the corresponding area can be updated to prevent data loss.

In order to achieve the object of the present invention, the data transmission / reception method of PLC includes a first step of presetting an area of a queue corresponding to the number of data to be transmitted; A second step of creating a list of pointers of the data to be transmitted; The third step is to determine whether the pointer value of the queue is normal when transmitting / receiving data in the area of the first step, and if not, check the pointer list created in the second step and update only the value of the corresponding area.

Hereinafter, the operation and effects of the present invention will be described with reference to the accompanying drawings.

First, as shown in FIG. 4, when transmitting and receiving high-speed repeated data, the present invention reserves a predetermined area of the queue 310 in the common RAM 300 in advance by the number of set blocks of the repeated data. Read and write only in the designated area.

The PLC interface controller 100 and the link interface controller 200 prepare pointers of the data to be transmitted as 64 lists as shown in FIG.

In this way, a pointer of data to be transmitted is prepared in advance, and data is transmitted and received only in a predetermined area of the queue 310 in the common RAM 300.

That is, the counterpart puts a pointer value of a queue pool that stores data into a task and causes the counterpart to process it.

In this case, if the pointer value of the queue pool put into the task is broken, not all the queues are initialized, but only the corresponding data is updated through the pointer list.

As described in detail above, the present invention reads and writes high-speed repeated data only in a predetermined area by using a reserved queue as a buffer in advance for transmitting and receiving high-speed repeated data. The efficiency can be increased, and if the queue is broken due to noise or the like by creating a list of pointers to each data, only the corresponding data is updated, thereby preventing data loss.

Claims (1)

A first step of presetting an area of a queue corresponding to the number of data to be transmitted; A second step of creating a list of pointers of the data to be transmitted; And a third step of determining whether the pointer value of the queue is normal when transmitting and receiving data in the first step area, and if not, checking the pointer list created in the second step and updating only the value of the corresponding area. How to send and receive data.