CN111722581A - The method of improving the communication transmission and data processing efficiency between PLC controller and upper computer - Google Patents

Abstract

The invention provides a method for improving the efficiency of communication, transmission and data processing between a PLC controller and a host computer. In the application situation where the amount of data monitored by the PLC is large and the data changes are small, the invention is adopted. In the first communication data packet, Occupies several data registers as status registers, which are used to transmit information with the host computer. In the PLC controller, open up space, place the temporary data packet, compare the temporary storage register in the temporary data packet with the register corresponding to the current data packet, and set its status bit for the current data packet with changed data, The key reading of data packets with changed data is achieved, which significantly improves the reading speed and processing speed of the changed data by the host computer. In addition, the storage and reading states of the data packets are set to ensure the consistency of the data packets and the status bits.

Description

The method of improving the communication transmission and data processing efficiency between PLC controller and upper computer

technical field

The invention relates to a method for improving PLC transmission and processing efficiency, and belongs to the PLC application field.

Background technique

PLC has a wide range of applications with large amount of monitoring data and little data change, such as the wind and water power system of subway stations, its monitoring of wind and water power is based on BAS (Building Automation System, hereinafter referred to as BAS) system using PLC (Programmable Logic) Controller, hereinafter referred to as PLC) to monitor.

The data monitored by the PLC is stored and transmitted in registers, and a register usually occupies two bytes. PLC communication is usually based on the MODBUS communication protocol, and a normal packet of data contains 125 registers, that is, 250 bytes. The digital input data monitored by a PLC in a subway station usually has three packets, and the analog input data usually has more than ten packets. It takes 300 milliseconds to query one packet of data. At present, the PLC adopts full data upload, so the transmission of all data takes time. If it exceeds 3 seconds, the polling cycle is long and the data refresh in the upper computer system is slow. The host computer also needs to eliminate the time and filter the changed data. If the number of registers included in the data packet is increased, although the number of data packets can be reduced, the number of communication link establishments can be reduced correspondingly, and the link time can be reduced, but the length of the packet increases, which greatly increases the possibility of communication failure, resulting in the need for repeated communication. , wasting communication time.

In the traditional method, the host computer reads each data packet in sequence, even if there is no changed data, which wastes time. In an unfavorable case, the host computer has just finished reading a data packet, and the data packet changes, then the host computer needs to poll a circle of data packets to read the changed data is a data packet, if there are more than a dozen data packets , then the delay for the host computer to feed back the changed data is the time it takes to read more than a dozen data packets, resulting in slow refresh of the changed data.

SUMMARY OF THE INVENTION

Purpose of the invention: The purpose of the present invention is to provide a new technical solution to improve the reading speed and processing speed of the changed data by the host computer.

Technical solution: In order to solve the above technical problems, the present invention provides a method for improving the communication transmission and data processing efficiency between the PLC controller and the upper computer:

The PLC is generally divided into two categories, namely PLC controller and remote IO module;

The remote IO module has analog and digital input and output functions for measurement and control, and the remote IO module also has the function of communicating with the subsystem PLC;

PLC controller with communication function and data processing function;

The communication function of the PLC controller is used to complete various communication tasks, including communication with the upper computer and communication with the lower computer. Communication with the lower computer includes communication with the remote IO module, communication with the subsystem PLC, and communication with the subsystem communication module. These communication tasks are not controlled by the user program of the PLC controller. After the PLC communication configuration is completed, it communicates autonomously, and the communication data is stored in the register for communication in the PLC controller;

The data processing function of the PLC controller is controlled by the user program, and the data read into the register for communication by the communication function is logically judged, a decision is made, and then written into the register for communication. Communication function to communicate for the purpose of control;

The register for communication of the above-mentioned PLC controller is filled in according to the point table agreed with the equipment on the opposite side of the communication. The equipment on the opposite side of the communication includes the upper computer and the lower computer, and the lower computer includes the remote IO module, the subsystem PLC, and the subsystem communication module. ;

The aforementioned PLC controller communicates with the upper computer, and the data is stored in several communication data packets. The length of the data packet is limited by the length of the message communicated with the upper computer. The communication data packets are divided into three types, which are digital data. Packets, analog data packets that represent digital, pure analog data packets, digital data packets are put into digital data, digital analog data packets are put into digital analog data, and pure analog data packets are put into pure analog data Data; the setting variables of each communication data packet are stored in the PLC controller and the host computer;

The aforementioned digital quantity refers to the switching quantity of the external contact, which has two states of on and off, which are represented by 0 and 1 respectively;

The aforementioned analog quantity representing digital refers to the data used for counting, which is represented as an analog quantity, but is treated as a digital quantity;

The aforementioned pure analog quantities refer to the measured values of voltage, current, temperature, humidity, etc. that will fluctuate;

The aforementioned digital quantities and analog quantities representing digital are collectively referred to as non-pure analog quantities;

The aforementioned communication data packet is composed of several data registers, which are called communication registers;

Each communication data packet includes input data of multiple remote IO modules, or includes input data of multiple subsystems;

The first communication data packet between the PLC controller and the host computer is used as a special data packet. According to the total amount of data packets, it occupies several data registers as status registers, which are used to transmit information with the host computer;

The communication data packets other than the first communication data packet between the PLC controller and the upper computer are called subsequent data packets:

Each bit of the aforementioned status register is used to indicate the "PLC controller data packet has changed data flag", "PLC controller is storing the data packet flag", "the host computer is reading the data packet flag" of each subsequent data packet. ”, “host computer data packet read completion flag”;

The definition of "the PLC controller data packet has changed data flag": "1" corresponds to at least one data change in the data packet stored by the corresponding PLC controller; "0" corresponds to its corresponding None of the data in the data package stored by the PLC controller has changed;

The definition of "the PLC controller is storing the data packet flag": "1" corresponds to the corresponding data packet PLC controller is storing; "0" corresponds to the corresponding data packet PLC controller is not in storage. ;

The definition of "the host computer is reading the data packet flag": "1" corresponds to that the corresponding data packet is being read by the host computer; "0" corresponds to the corresponding data packet that the host computer is not reading. ;

The definition of "host computer data packet reading completion flag": "1" corresponds to the completion of the reading of the corresponding data packet by the host computer; "0" corresponds to the corresponding data packet that the host computer has not read. ;

Open up storage space in the PLC controller to store the temporary data packets of subsequent data packets. The data registers inside the temporary data packets are called temporary storage registers. The definition of the corresponding communication register in the communication data packet communicated with the host computer is exactly the same, and the aforementioned data packet corresponding to the temporary storage data packet for communication with the host computer is called the corresponding data packet; the aforementioned data packet corresponding to the temporary storage register is used. The register in the data packet communicated with the host computer is called the corresponding data register;

When the PLC controller is initialized, the following operations are performed in sequence: all subsequent data packets "the host computer is reading the data packet flag" is set to "0", and all subsequent data packets "the PLC controller is storing the data packet flag" is set to "1" ”; copy the data stored in the register of the lower computer obtained by the communication corresponding to each data packet to the data register corresponding to each data packet; all subsequent data packets “PLC controller data packets have changed data flags” Set to "1"; all subsequent data packets "PLC controller is storing data packet flag" set to "0";

When the PLC controller starts the normal processing process, it first copies the data stored in the register of the lower computer obtained by the communication stored in the register corresponding to the first data packet to the data register corresponding to the first data packet; Copy the data of the lower computer corresponding to the communication stored in the register corresponding to the subsequent data packet to the data register corresponding to the temporary data packet corresponding to the subsequent data packet;

The "PLC controller current data packet processing number" variable is set to "2", and this "PLC controller current data packet processing number" variable is set in the PLC controller to indicate the number of the data packet currently being processed by the PLC controller program. ;

Now enter the processing flow of subsequent data packets: "PLC controller current data packet register processing number" variable is set to "1", and this "PLC controller current data packet register processing number" variable is set in the PLC controller to indicate PLC the number of the register in the packet that the controller program is currently processing;

The PLC controller sequentially compares and processes the temporary data packets and the corresponding data packets with or without change data according to the pure analog data packets and the non-pure analog data packets one by one for the subsequent data packets;

When it is found that there is changed data in the register in the current data packet, if the current data packet "the host computer is reading the data packet flag" is "0", and the "host computer data packet reading completion flag" is "1", then The current data packet "PLC controller is storing the data packet flag" is set to "1", the current data packet "PLC controller data packet has changed data flag" is set to "1", the current data packet "The host computer data packet read complete" The flag bit" is set to "0", the subsequent data of this data packet will not be compared, and all the data in the current temporary data packet will be copied to the data register corresponding to the current data packet. After the copy operation is completed, the current data packet "PLC" The controller is storing the data packet flag" and set it to "0", add 1 to the "current data packet processing number of the PLC controller", and enter the next cycle until the comparison of all subsequent data packets is completed; If the flag bit of the data packet is being read by the computer is "1", or the flag bit of "reading completion of the data packet of the upper computer" is "0", then the setting and copying operation of the aforementioned flag bit will be abandoned, and the "current data packet of the PLC controller" will be Add 1 to "processing number" and enter the next loop until the comparison of all subsequent data packets is completed;

When the current data packet is compared and no changed data is found, if the current data packet "host computer is reading the data packet flag" is "0", and the current data packet "host computer data packet reading completion flag" If it is "1", the current data packet "PLC controller is storing data packet flag" is set to "1", the current data packet "PLC controller data packet has changed data flag" is set to "0", the current data packet " The host computer data packet read completion flag is set to "0"; for pure analog data packets, copy all data in the current temporary data packet to the data register corresponding to the current data packet, for non-pure analog data packets, Do not perform this copy operation; then set the current data packet "PLC controller is storing the data packet flag" to "0", add 1 to the "PLC controller current data packet processing number", and enter the next cycle until the comparison is completed. data of subsequent packets;

The aforementioned data registers are compared one by one to determine whether there is a change, including the comparison of pure analog data packets and non-pure analog data packets;

The aforementioned comparison of non-pure analog quantities, that is, the comparison of digital quantities or analog quantities representing digital means, compares the temporary register with the corresponding register one by one, and when it is inconsistent, it is considered that the current temporary register is the change data. ;

The aforementioned comparison of pure analog quantities refers to configuring variables corresponding to pure analog quantities in the PLC controller to set the change threshold and amplitude threshold corresponding to each pure analog quantity. Compare the value of the buffer with the corresponding amplitude threshold one by one. When the amplitude threshold is exceeded, the current temporary register is considered to be changed data; the value of the pure analog temporary register and the corresponding register value are subtracted one by one. Comparison, when the change threshold is exceeded, the current temporary register is considered to be the change data;

The aforementioned data packet "PLC controller data packet has changed data flag" is set to "0", which means that the data packet has no changed data. For digital data packets or analog data packets representing digital, it is each temporary register. It is the same as the corresponding register value, that is, there is no change; for pure analog data packets, the value of each temporary register does not exceed the set change threshold and amplitude threshold;

In the host computer, set the variable of "the host computer has changed data packet flag", the variable is "1", it means that in one round of data packet processing by the host computer, there is "the PLC controller is storing the data packet flag" as "0" , and the subsequent data packets whose "PLC controller data packet has changed data flag bit" is "1", that is, the host computer has subsequent data packets with changed data that need to be processed;

In the host computer, set the variable of "the host computer records the data packet read with change bit" variable for each subsequent data packet. The variable is "1", indicating that the subsequent data packet has changed data, which is used to mark the subsequent data packets with changed data. Use The host computer performs subsequent processing on the changed data packet; when the host computer completes the processing of the changed data packet, set the variable of this data packet "the host computer records the data packet to read the changed bit" to "0";

The aforementioned each round refers to the upper computer processing all the data packets in turn;

In the host computer, set the variable "current data packet processing number of the host computer" to record the number of the data packet processed by the current host computer;

When the host computer is initialized, set the variable of "cyclically read a data packet number" to "2";

When the host computer starts a new round of data processing, it first unconditionally reads the data of the first data packet, so as to process the subsequent data packets in turn according to the status register in the first data packet; Change data packet flag" is set to "0", and all subsequent data packets are set to "0" for "the host computer records the data packet read change bit", and "the current data packet processing number of the host computer" is set to "2";

The host computer does not process the subsequent data packets whose "PLC controller is storing the data packet flag" is "1", and adds 1 to the "current data packet processing number of the host computer" to process the next data packet;

For the subsequent data packets whose "PLC controller is storing data packet flag" is "0" and "PLC controller data packet has changed data flag" is "0", the host computer puts the current data packet "The host computer is reading "Data packet flag" is set to "1", the current data packet "host computer data packet read completion flag" is set to "1", the current data packet "host computer is reading the data packet flag" is set to "0", "host computer is reading the data packet flag" Add 1 to the current data packet processing number of the machine to process the next data packet;

The host computer performs the following operations in sequence for the subsequent data packets whose "PLC controller is storing data packet flag" is "0" and "PLC controller data packet has changed data flag" is "1": the current data packet "host" The computer is reading the data packet flag" is set to "1", read all the data of the current data packet, the current data packet "host computer data packet read completion flag" is set to "1", the current data packet "host computer is reading "Data packet flag bit" is set to "0", "the host computer has changed data packet flag" is set to "1", the current data packet "the host computer records the data packet read change bit" is set to "1", "the host computer current data packet" is set to "1" "Processing number" plus 1, and then go to process the next data packet;

After the host computer completes the reading processing of the above three data packets in all subsequent data packets, when the "host computer has changed data packet flag" is "1", it enters the next round of processing data packets; When the machine has changed data packet flag" is "0", read a data packet cyclically;

The aforementioned loop reads a data packet, and the steps are as follows: set the "loop read a data packet round count" to "2", and assign the value of the "loop read a data packet number" variable to the "current data packet of the upper computer" handle number" variable;

When the current data packet "PLC controller data packet has changed data flag" is "0" and "PLC controller is storing data packet flag" is "0", the following operations are performed in sequence: "Reading data packet flag" is set to "1", read all data of the current data packet, the current data packet "host computer data packet read completion flag" is set to "1", the current data packet "host computer is reading data" "Packet flag bit" is set to "0", "cyclically read a data packet number" is incremented by 1, when "cyclically read a data packet number" is greater than the number of data packets, "cyclically read a data packet number" is set to "2" , enter the next round of data packet processing cycle; when the "cycle read a data packet number" is not greater than the number of data packets, enter the next round of data packet processing cycle; when the current data packet "PLC controller data packet has changed When the "Data flag bit" is "1" or the "PLC controller is storing the data packet flag bit" is "1", the following operations are performed in sequence: "The current data packet processing number of the upper computer" is incremented by 1, when the "current data packet processing number of the upper computer" is "1" When the "processing number" is greater than the number of data packets, set the "current data packet processing number of the host computer" to "2", and add 1 to the "cycle reading a data packet round count"; when the "current data packet processing number of the host computer" is not When the number of data packets is greater than the number of data packets, add 1 to the "count of one round of reading a data packet cyclically"; when the "count of one round of reading a data packet circularly" is not greater than the number of data packets, process the next data packet until " When the cycle count of reading a data packet in a loop is greater than the number of data packets, the cycle ends and the next cycle of processing data packets is entered;

The above-mentioned variable "cyclically read a data packet number" is set in the host computer, so that when the host computer does not read a changed data packet after processing a round of data packets, it will read one in each round in turn. Data packets of changing data; the aforementioned cyclic reading refers to sequential reading;

The aforesaid variable of "circularly read one data packet for one round" is set in the host computer to ensure that one data packet in all subsequent data packets is read cyclically.

Further, the data register in the first data packet of the PLC controller stores frequently changing pure analog data, and fills the data packet as much as possible.

Further, the status register set in the first data packet of the PLC controller is selected to be two registers, one register, or three registers according to the stored data capacity, and the placement position of the status register is in the first data packet. or the end of the first packet.

Further, the first data packet of the PLC controller is only used as a data status packet, that is, only the status register is stored, and no data is stored, so that the original data of the first data packet is stored in the second data packet, and the total number of data packets is Add one, and the aforementioned subsequent data packets include the original first data packet.

Further, the status of the subsequent data packets represented by the PLC controller in bits, or represented by registers, that is, "the PLC controller data packet has a changed data flag", "the PLC controller is storing the data packet flag", "The host computer is reading the data packet flag", "the host computer data packet reading completion flag", or use "PLC controller data packet has changed data flag register", "PLC controller is storing data packet flag register" , "the host computer is reading the data packet flag register", "the host computer data packet read complete flag register" to indicate.

Further, choose not to set the current data packet "host computer data packet read completion flag" in the PLC controller, that is, the PLC controller will update the storage without judging that the host computer reading is completed, so as to improve the storage speed of the PLC controller.

In the technical solutions provided above, the temporary storage data packets are added to the PLC controller, and the comparison and processing of the temporary storage data packets and the corresponding data packets with or without change data are carried out one by one, and then through the set in the first data packet. The status register transmits information with the host computer, indicating that the "PLC controller data packet has changed data flag", "the PLC controller is storing the data packet flag", "the host computer is reading the data packet flag" of each subsequent data packet bit", "host computer data packet read completion flag bit". Therefore, in most cases, the traditional method can avoid invalid transmission of data packets without any changed data, thereby greatly improving the communication transmission and data processing efficiency between the PLC controller and the upper computer.

In the process of comparing the changed data of a subsequent data packet, once the PLC controller finds that there is changed data, it will no longer compare the data, and mark the data packet as a data packet with changed data, so as to communicate and transmit with the host computer. It is to reduce the CPU overhead of the PLC controller and increase the data processing rate.

The data register in the first data packet of the PLC controller stores frequently changing pure analog data, and fills the data packet as much as possible. Because the first data packet is a special data packet, it needs to be transmitted every round, and even if the pure analog quantity does not exceed the threshold value, there may be fluctuations below the threshold value, and it is best to reflect it in the host computer in time.

The data that is traditionally distinguished by digital and analog is changed to be distinguished by digital, analog representing digital, and pure analog, that is, dividing analog into digital analog and pure analog, and expressing Digital analog quantities, such as the number of fan starts and the number of fan failures, are regarded as digital quantities for comparison and processing. If the current and last two data are the same, the number of times is considered to be the same; when the data are different, the number of times is considered to have changed, which simplifies the representation. Comparison and processing of digital and analog quantities.

In the vast majority of cases, the host computer does not have subsequent data packets with changed data that need to be communicated. Therefore, the variable "Read a data packet number cyclically" is set in the host computer, which is used when the host computer finishes processing a round of data packets. Afterwards, when no change data packet is processed, a data packet with no change data is sequentially read in each round. For the reading of digital and analog data packets representing digital, although the data does not change, the reading is used to refresh the data, so as to prevent the data in the host computer from being tampered with due to memory leaks and other reasons; for pure analog data packets Although no pure analog quantity exceeds the threshold value, the pure analog quantity will still fluctuate slightly below the threshold value, and the purpose of reading is to update the data. In this case, another advantage is that even if the subsequent data packets that have not changed in the upper computer need to be read, a subsequent data packet is still read.

In the host computer, set the variable of "cycle reading a data packet for one round count", which is used for counting, to find and read an unchanged data and no data packet is being stored. When the count is greater than the number of data packets, that is, the PLC controller If there is no such data packet as described above, then it will no longer search for such data packet, and enter into a new round of data packet judgment and processing.

Setting the status register in the first data packet of the PLC controller improves the efficiency of data transmission and processing. This status register occupies several registers in the data packet that were originally used to store data. Since there are 125 or more registers in a packet, the impact on the storage capacity of data is small.

beneficial effect

Compared with the prior art, the technical solution provided by the present invention can have the following beneficial effects:

By adopting the present invention, in the first communication data packet, several data registers are occupied as status registers for transmitting information with the upper computer. In the PLC controller, open up space, place the temporary data packet, compare the temporary storage register in the temporary data packet with the register corresponding to the current data packet, and set its status bit for the current data packet with changed data, The key reading of data packets with changed data is achieved, which significantly improves the reading speed and processing speed of the changed data by the host computer. In addition, the storage and reading states of the data packets are set to ensure the consistency of the data packets and the status bits.

Description of drawings

Fig. 1 is the logic diagram of PLC controller data processing.

Fig. 2 is the logic diagram of the data processing of the upper computer.

Detailed ways

1 and 2, the present invention provides a method for improving the communication transmission and data processing efficiency between the PLC controller and the host computer, including the PLC controller data processing logic shown in FIG. 1, as shown in FIG. 2 . The upper computer data processing initialization logic.

In the applications where the amount of data monitored by the PLC is large and the data changes are small, such as the wind, water and power system of the subway station, using the present invention, it is appropriate to use a short data packet, such as 125 registers in a data packet, rather than a long data packet such as a data packet. Pack 2000 registers, because increasing the number of registers contained in a data packet can reduce the number of data packets, but if there is an analog quantity exceeding the threshold value in the long data packet, or there is a changing digital quantity, then for this one Data, the entire packet must be sent, resulting in inefficiency, so using long packets is not as good as using short packets.

In the PLC controller, open up space, place the temporary data packet, compare the temporary storage register in the temporary data packet with the register corresponding to the current data packet, and mark the current data packet with changed data "PLC controller data packet has Change data flags".

In addition, for each subsequent data packet, set the "PLC controller is storing the data packet flag", "the host computer is reading the data packet flag", "the host computer data packet reading complete flag" flag, which is used to control the PLC. The controller stores data in data packets and restricts the data packets read by the host computer, so that part of a data packet read by the host computer is old data and the other part is new data, so as to avoid possible data packets and status bits. inconsistent.

In some occasions that seek to improve the storage speed of the PLC controller and do not pursue the host computer to read every data, it is not necessary to set the current data packet "host computer data packet read completion flag" in the PLC controller, that is, the PLC control If the controller does not judge that the reading of the upper computer is completed, it will update the storage.

The traditional method, that is, the method of reading the PLC controller by the traditional host computer of the present invention is not adopted. Regardless of whether the data packet has changed data, the host computer reads each data packet in turn, which wastes time. Since the host computer polling may not read the data packets with changed data exactly, in the worst case, the host computer has just read a data packet, and the data packet changes, then the host computer needs to poll the data again. If the total number of data packets is more than a dozen, the time delay for the host computer to feed back the changed data is the time it takes to read more than a dozen data packets, resulting in slow update of the changed data. But if the method of the present invention is adopted:

In most cases, there is no subsequent data packet with changed data that needs to be read, and the host computer sequentially reads only one data packet with no changed data in each round. If a change data appears in the process of polling to read a data packet with no changed data, the host computer can immediately read the data packet corresponding to the changed data in the next round of data packet processing, and the delay is the time to read one packet, which is much faster than traditional methods.

When there is a subsequent data packet with changed data that needs to be read, the host computer immediately reads the data packet. If another data packet with changed data appears in the process of reading this data packet with changed data, in the next round of data packet processing, the data packet with changed data can be read immediately, and the delay is the time to read one packet, which is much faster than traditional methods.

When there is a subsequent data packet with changed data that needs to be read, the host computer immediately reads the data packet. If during the process of reading this data packet with changed data, there are several other data packets with changed data, then in the next round of data packet processing, these data packets with changed data can be read immediately , the latency is the time to read a data packet, and the reading speed is much higher than the traditional method.

When there is a subsequent data packet with changed data that needs to be read, the host computer immediately reads the data packet. If an extreme situation occurs in the process of reading this data packet with changed data, that is, each data packet has changed data, then in the next round of data packet processing, each data packet is read in turn, and the reading speed Same as traditional method.

In addition to the traditional method, it is very time-consuming for the host computer to find the changed data for subsequent processing during the reading process of each round of data packets, but using the method of the present invention, in the host computer, each subsequent data packet is set. The host computer records the data packet read with a changed bit" variable, the variable is "1", indicating that the subsequent data packet has changed data, which is used to mark the subsequent data packets with changed data, which is convenient for the host computer to follow up on the changed data packets. deal with.

Claims (6)

1. a method for improving PLC controller and host computer communication transmission and data processing efficiency, is characterized in that, The PLC is generally divided into two categories, namely PLC controller and remote IO module; The remote IO module has analog and digital input and output functions for measurement and control, and the remote IO module also has the function of communicating with the subsystem PLC; PLC controller with communication function and data processing function; The communication function of the PLC controller is used to complete various communication tasks, including communication with the upper computer and communication with the lower computer. Communication with the lower computer includes communication with the remote IO module, communication with the subsystem PLC, and communication with the subsystem communication module. These communication tasks are not controlled by the user program of the PLC controller. After the PLC communication configuration is completed, it communicates autonomously, and the communication data is stored in the register for communication in the PLC controller; The data processing function of the PLC controller is controlled by the user program, and the data read into the register for communication by the communication function is logically judged, a decision is made, and then written into the register for communication. Communication function to communicate for the purpose of control; The register for communication of the above-mentioned PLC controller is filled in according to the point table agreed with the equipment on the opposite side of the communication. The equipment on the opposite side of the communication includes the upper computer and the lower computer, and the lower computer includes the remote IO module, the subsystem PLC, and the subsystem communication module. ; The aforementioned PLC controller communicates with the upper computer, and the data is stored in several communication data packets. The length of the data packet is limited by the length of the message communicated with the upper computer. The communication data packets are divided into three types, which are digital data. Packets, analog data packets that represent digital, pure analog data packets, digital data packets are put into digital data, digital analog data packets are put into digital analog data, and pure analog data packets are put into pure analog data Data; the setting variables of each communication data packet are stored in the PLC controller and the host computer; The aforementioned digital quantity refers to the switching quantity of the external contact, which has two states of on and off, which are represented by 0 and 1 respectively; The aforementioned analog quantity representing digital refers to the data used for counting, which is represented as an analog quantity, but is treated as a digital quantity; The aforementioned pure analog quantities refer to the measured values of voltage, current, temperature, humidity, etc. that will fluctuate; The aforementioned digital quantities and analog quantities representing digital are collectively referred to as non-pure analog quantities; The aforementioned communication data packet is composed of several data registers, which are called communication registers; Each communication data packet includes input data of multiple remote IO modules, or includes input data of multiple subsystems; The first communication data packet between the PLC controller and the host computer is used as a special data packet. According to the total amount of data packets, it occupies several data registers as status registers, which are used to transmit information with the host computer; The communication data packets other than the first communication data packet between the PLC controller and the upper computer are called subsequent data packets: Each bit of the aforementioned status register is used to indicate the "PLC controller data packet has changed data flag", "PLC controller is storing the data packet flag", "the host computer is reading the data packet flag" of each subsequent data packet. ”, “host computer data packet read completion flag”; The definition of "the PLC controller data packet has changed data flag": "1" corresponds to at least one data change in the data packet stored by the corresponding PLC controller; "0" corresponds to its corresponding None of the data in the data package stored by the PLC controller has changed; The definition of "the PLC controller is storing the data packet flag": "1" corresponds to the corresponding data packet PLC controller is storing; "0" corresponds to the corresponding data packet PLC controller is not in storage. ; The definition of "the host computer is reading the data packet flag": "1" corresponds to that the corresponding data packet is being read by the host computer; "0" corresponds to the corresponding data packet that the host computer is not reading. ; The definition of "host computer data packet reading completion flag": "1" corresponds to the completion of the reading of the corresponding data packet by the host computer; "0" corresponds to the corresponding data packet that the host computer has not read. ; Open up storage space in the PLC controller to store the temporary data packets of subsequent data packets. The data registers inside the temporary data packets are called temporary storage registers. The definition of the corresponding communication register in the communication data packet communicated with the host computer is exactly the same, and the aforementioned data packet corresponding to the temporary storage data packet for communication with the host computer is called the corresponding data packet; the aforementioned data packet corresponding to the temporary storage register is used. The register in the data packet communicated with the host computer is called the corresponding data register; When the PLC controller is initialized, the following operations are performed in sequence: all subsequent data packets "the host computer is reading the data packet flag" is set to "0", and all subsequent data packets "the PLC controller is storing the data packet flag" is set to "1" ”; copy the data stored in the register of the lower computer obtained by the communication corresponding to each data packet to the data register corresponding to each data packet; all subsequent data packets “PLC controller data packets have changed data flags” Set to "1"; all subsequent data packets "PLC controller is storing data packet flag" set to "0"; When the PLC controller starts the normal processing process, it first copies the data stored in the register of the lower computer obtained by the communication stored in the register corresponding to the first data packet to the data register corresponding to the first data packet; Copy the data of the lower computer corresponding to the communication stored in the register corresponding to the subsequent data packet to the data register corresponding to the temporary data packet corresponding to the subsequent data packet; The "PLC controller current data packet processing number" variable is set to "2", and this "PLC controller current data packet processing number" variable is set in the PLC controller to indicate the number of the data packet currently being processed by the PLC controller program. ; Now enter the processing flow of subsequent data packets: "PLC controller current data packet register processing number" variable is set to "1", and this "PLC controller current data packet register processing number" variable is set in the PLC controller to indicate PLC the number of the register in the packet that the controller program is currently processing; The PLC controller sequentially compares and processes the temporary data packets and the corresponding data packets with or without change data according to the pure analog data packets and the non-pure analog data packets one by one for the subsequent data packets; When it is found that there is changed data in the register in the current data packet, if the current data packet "the host computer is reading the data packet flag" is "0", and the "host computer data packet reading completion flag" is "1", then The current data packet "PLC controller is storing the data packet flag" is set to "1", the current data packet "PLC controller data packet has changed data flag" is set to "1", the current data packet "The host computer data packet read complete" The flag bit" is set to "0", the subsequent data of this data packet will not be compared, and all the data in the current temporary data packet will be copied to the data register corresponding to the current data packet. After the copy operation is completed, the current data packet "PLC" The controller is storing the data packet flag" and set it to "0", add 1 to the "current data packet processing number of the PLC controller", and enter the next cycle until the comparison of all subsequent data packets is completed; If the flag bit of the data packet is being read by the computer is "1", or the flag bit of "reading completion of the data packet of the upper computer" is "0", then the setting and copying operation of the aforementioned flag bit will be abandoned, and the "current data packet of the PLC controller" will be Add 1 to "processing number" and enter the next loop until the comparison of all subsequent data packets is completed; When the current data packet is compared and no changed data is found, if the current data packet "host computer is reading the data packet flag" is "0", and the current data packet "host computer data packet reading completion flag" If it is "1", the current data packet "PLC controller is storing data packet flag" is set to "1", the current data packet "PLC controller data packet has changed data flag" is set to "0", the current data packet " The host computer data packet read completion flag is set to "0"; for pure analog data packets, copy all data in the current temporary data packet to the data register corresponding to the current data packet, for non-pure analog data packets, Do not perform this copy operation; then set the current data packet "PLC controller is storing the data packet flag" to "0", add 1 to the "PLC controller current data packet processing number", and enter the next cycle until the comparison is completed. data of subsequent packets; The aforementioned data registers are compared one by one to determine whether there is a change, including the comparison of pure analog data packets and non-pure analog data packets; The aforementioned comparison of non-pure analog quantities, that is, the comparison of digital quantities or analog quantities representing digital means, compares the temporary register with the corresponding register one by one, and when it is inconsistent, it is considered that the current temporary register is the change data. ; The aforementioned comparison of pure analog quantities refers to configuring variables corresponding to pure analog quantities in the PLC controller to set the change threshold and amplitude threshold corresponding to each pure analog quantity. Compare the value of the buffer with the corresponding amplitude threshold one by one. When the amplitude threshold is exceeded, the current temporary register is considered to be changed data; the value of the pure analog temporary register and the corresponding register value are subtracted one by one. Comparison, when the change threshold is exceeded, the current temporary register is considered to be the change data; The aforementioned data packet "PLC controller data packet has changed data flag" is set to "0", which means that the data packet has no changed data. For digital data packets or analog data packets representing digital, it is each temporary register. It is the same as the corresponding register value, that is, there is no change; for pure analog data packets, the value of each temporary register does not exceed the set change threshold and amplitude threshold; In the host computer, set the variable of "the host computer has changed data packet flag", the variable is "1", it means that in one round of data packet processing by the host computer, there is "the PLC controller is storing the data packet flag" as "0" , and the subsequent data packets whose "PLC controller data packet has changed data flag bit" is "1", that is, the host computer has subsequent data packets with changed data that need to be processed; In the host computer, set the variable of "the host computer records the data packet read with change bit" variable for each subsequent data packet. The variable is "1", indicating that the subsequent data packet has changed data, which is used to mark the subsequent data packets with changed data. Use The host computer performs subsequent processing on the changed data packet; when the host computer completes the processing of the changed data packet, set the variable of this data packet "the host computer records the data packet to read the changed bit" to "0"; The aforementioned each round refers to the upper computer processing all the data packets in turn; In the host computer, set the variable "current data packet processing number of the host computer" to record the number of the data packet processed by the current host computer; When the host computer is initialized, set the variable of "cyclically read a data packet number" to "2"; When the host computer starts a new round of data processing, it first unconditionally reads the data of the first data packet, so as to process the subsequent data packets in turn according to the status register in the first data packet; Change data packet flag" is set to "0", and all subsequent data packets are set to "0" for "the host computer records the data packet read change bit", and "the current data packet processing number of the host computer" is set to "2"; The host computer does not process the subsequent data packets whose "PLC controller is storing the data packet flag" is "1", and adds 1 to the "current data packet processing number of the host computer" to process the next data packet; For the subsequent data packets whose "PLC controller is storing data packet flag" is "0" and "PLC controller data packet has changed data flag" is "0", the host computer puts the current data packet "The host computer is reading "Data packet flag" is set to "1", the current data packet "host computer data packet read completion flag" is set to "1", the current data packet "host computer is reading the data packet flag" is set to "0", "host computer is reading the data packet flag" Add 1 to the current data packet processing number of the machine to process the next data packet; The host computer performs the following operations in sequence for the subsequent data packets whose "PLC controller is storing data packet flag" is "0" and "PLC controller data packet has changed data flag" is "1": the current data packet "host" The computer is reading the data packet flag" is set to "1", read all the data of the current data packet, the current data packet "host computer data packet read completion flag" is set to "1", the current data packet "host computer is reading "Data packet flag bit" is set to "0", "the host computer has changed data packet flag" is set to "1", the current data packet "the host computer records the data packet read change bit" is set to "1", "the host computer current data packet" is set to "1" "Processing number" plus 1, and then go to process the next data packet; After the host computer completes the reading processing of the above three data packets in all subsequent data packets, when the "host computer has changed data packet flag" is "1", it enters the next round of processing data packets; When the machine has changed data packet flag" is "0", read a data packet cyclically; The aforementioned loop reads a data packet, and the steps are as follows: set the "loop read a data packet round count" to "2", and assign the value of the "loop read a data packet number" variable to the "current data packet of the upper computer" handle_number" variable; When the current data packet "PLC controller data packet has changed data flag" is "0" and "PLC controller is storing data packet flag" is "0", the following operations are performed in sequence: "Reading data packet flag" is set to "1", read all data of the current data packet, the current data packet "host computer data packet read completion flag" is set to "1", the current data packet "host computer is reading data" "Packet flag bit" is set to "0", "cyclically read a data packet number" is added 1, when "cyclically read a data packet number" is greater than the number of data packets, "cyclically read a data packet number" is set to "2" , enter the next round of data packet processing cycle; when the "cycle read a data packet number" is not greater than the number of data packets, enter the next round of data packet processing cycle; when the current data packet "PLC controller data packet has changed When the "Data flag bit" is "1" or the "PLC controller is storing the data packet flag bit" is "1", the following operations are performed in sequence: "The current data packet processing number of the upper computer" is incremented by 1. When the "processing number" is greater than the number of data packets, set the "current data packet processing number of the host computer" to "2", and add 1 to the "cycle reading a data packet round count"; when the "current data packet processing number of the host computer" is not When the number of data packets is greater than the number of data packets, add 1 to the "count of one round of reading a data packet in a loop"; when the "count of one round of reading a data packet in a loop" is not greater than the number of data packets, process the next data packet until " When the cycle count of reading a data packet in a loop is greater than the number of data packets, the cycle ends and the next cycle of processing data packets is entered; The above-mentioned variable "cyclically read a data packet number" is set in the host computer, so that when the host computer does not read a changed data packet after processing a round of data packets, it will read one in each round in turn. Data packets of changing data; the aforementioned cyclic reading refers to sequential reading; The aforesaid variable of "circularly read one data packet for one round" is set in the host computer to ensure that one data packet in all subsequent data packets is read cyclically. 2. the method for improving PLC controller and host computer communication transmission and data processing efficiency as claimed in claim 1 is characterized in that, the data register in the first data packet of PLC controller stores the pure analog data that changes frequently , and fill as many packets as possible. 3. the method for improving PLC controller and host computer communication transmission and data processing efficiency as claimed in claim 1, it is characterized in that, the status register that is set in the first data packet of PLC controller, according to the stored data capacity , the choice is two registers, one register, or three registers, and the status register is placed at the beginning of the first packet or at the end of the first packet. 4. the method for improving PLC controller and host computer communication transmission and data processing efficiency as claimed in claim 1, is characterized in that, the first data packet of PLC controller is only as data status packet, namely only stores status register, No data is stored, so that the data of the original first data packet is stored in the second data packet, and the total number of data packets is increased by one, and the aforementioned subsequent data packets include the original first data packet. 5. the method for improving PLC controller and upper computer communication transmission and data processing efficiency as claimed in claim 1, it is characterized in that, PLC controller uses the subsequent data packet state of bit representation, or represents with register, i.e. subsequent data packet "PLC controller data packet has changed data flag", "PLC controller is storing data packet flag", "host computer is reading data packet flag", "host computer data packet read completion flag", Or use "PLC controller data packet has changed data flag register", "PLC controller is storing data packet flag register", "host computer is reading data packet flag register", "host computer data packet read completion flag register" To represent. 6. the method for improving PLC controller and host computer communication transmission and data processing efficiency as claimed in claim 1, is characterized in that, in PLC controller, choose not to set current data packet " host computer data packet read completion flag position ”, that is, the PLC controller will update the storage without judging that the reading of the upper computer is completed, so as to improve the storage speed of the PLC controller.

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