CN103634076A - Communication data packaging method for monitoring programmable logic controller - Google Patents

Abstract

This invention discloses a communication data packaging method for monitoring a programmable logic controller. The communication data packaging method for monitoring the programmable logic controller is characterized by comprising the steps: step 1, forming continuous effective data packets and an arrangement relationship of the effective data packets; step 2, entering a step 3 if the effective data packets meet the splitting requirement; entering a step 4 if the effective data packets meet the merging requirement; entering a step 5 if the merging requirement and the splitting requirement are not met by the effective data packets; step 3, splitting the effective data packets; step 4, merging the effective data packets; step 5, judging whether all the data packets are packaged after the current effective data packets are packaged; if unpackaged data packets exist, then returning to the step 2 to continue to package a next packet till the packaging is completed. By adopting the communication data packaging method disclosed by the invention, the problem that the efficiency of communication is lowered due to unreasonable data packaging, thus the optimal effect of monitoring the programmable logic controller can not be achieved can be avoided.

Description

A kind of communication data packaging method of monitoring programmable logic controller (PLC)

Technical field

The present invention relates to a kind of communication data packaging method of control logic controller able to programme.

Background technology

Programmable logic controller (PLC) has a wide range of applications in current all trades and professions, as automobile, chemical industry, weaving etc.It adopts programmable memory block, for its internally stored program, actuating logic computing, sequential control, regularly, count and the user oriented instructions such as operation that count, and by numeral or analog pattern input/output various types of machinery of control or production process.

User can use the programmable logic controller (PLC) programming software that equipment supplier provides to debug programmable logic controller (PLC), reaches the effect of real-time monitoring programmable logic controller (PLC) memory block currency.

; in the situation that programmable logic controller program amount is large, monitor, the data volume of periodical communication is more, and the real-time of communication interaction cannot obtain due guarantee; user's friendly visualization interface of an efficient response be can not give, tracking and the debugging of on-the-spot running even affected.How quick, stable is one of them very important problem by the real-time demonstration in the interface of programmable logic controller (PLC) programming software of the value of programmable logic controller (PLC) memory block.

Before how considering head it off, must first understand the whole process of current monitoring programmable logic controller (PLC) communication, as shown in Figure 2, it is divided into collection address, memory block, packing address, memory block, the memory block address information of packing is converted into Frame and sends to programmable logic controller (PLC), waits for Programmable Logic Controller reply data.

From the programmable logic controller (PLC) programming software of current main flow, access the communication message form of programmable logic controller (PLC) memory block currency, send in the request process of Frame, the information that is bound to comprise in the message format of Frame has, start bit, device address, function code, memory block type, first address, quantity, effect position, end mark, as shown in Fig. 3 A and Fig. 3 B.Can obtain thus, during access storage areas, if data are same memory block type, and be continuous, can complete by data exchange process once.In Recovery Process, Programmable Logic Controller by the data recovery of memory block currency of access to Programming of programmable controller software.

Meeting under the prerequisite of main flow communication message format, traditional address, memory block packing manner is: the continuous data of same memory block type is packaged in together, otherwise separately packing.This scheme is not optimum packing scheme, and its reason is:

If the continuous data amount of the first same memory block type is very large, broken into a bag, this wraps in a communication interaction process and completes, and the data volume of reply can exceed the peak load of communication, causes the error rate to improve, and affects communication efficiency.How therefore need to consider its subpackage and the problem of subpackage more in the case.

The second, in the situation that the continuous data amount of same memory block type is very little, if there is disconnection address, a place number centre of continuous same memory block type address seldom, separated packing, break into 2 bags, originally once with regard to achievable reciprocal process, need to carry out now 2 secondary data and just can complete the access to these addresses, memory block alternately, and 2 mutual data have part for repeating data, for example, start bit, effect position, end mark etc.

Summary of the invention

The technical problem that will solve of the present invention is to avoid unreasonable due to data packings, causes communication efficiency to reduce, and cannot reach the optimum efficiency of monitoring programmable logic controller (PLC).

In order to solve the problems of the technologies described above, technical scheme of the present invention has been to provide a kind of communication data packaging method of monitoring programmable logic controller (PLC), it is characterized in that, step is:

Step 1, generation need the data of description of monitoring address, programmable logic controller (PLC) memory block, be designated as valid data, all valid data are divided into groups with successional feature according to address, memory block, continuous valid data are divided into one group, form continuous effective data packets, continuous effective data packets is arranged with address, memory block order from small to large, form the Rankine-Hugoniot relations of effective data packets;

If step 2, effective data packets meet splitting condition, enter step 3; If effective data packets meets merging condition, enter step 4; If effective data packets had not both met merging condition and had not met splitting condition yet, enter step 5, wherein:

Splitting condition is: the size of effective data packets is greater than the maximum number of byte of the error rate held stationary of can guaranteeing to communicate by letter;

Merging condition is: the size after adjacent two effective data packets merge is not more than the maximum number of byte of the error rate held stationary of can guaranteeing to communicate by letter, and the estimation call duration time of adjacent two effective data packets after merging is less than the estimation call duration time before a plurality of effective data packets merge;

Step 3, fractionation effective data packets:

The byte number that note Dbase is current effective data packets, the maximum number of byte that note L is the error rate held stationary of can guaranteeing to communicate by letter, effective data packets is divided into two, the first can guarantee the to communicate by letter maximum byte fractional part of error rate held stationary, be designated as L part, it two is that effective data packets is removed remaining part after the maximum number of byte of the error rate held stationary of can guaranteeing to communicate by letter, be designated as (Dbase-L) part, L part and (Dbase-L) part are broken into respectively to a bag, enter step 5;

Step 4, merging effective data packets:

Note Dafter is the byte number of the effective data packets adjacent with current effective data packets, note Dmid is the invalid continuous data byte number between adjacent two effective data packets, two adjacent effective data packets are merged into one, the value of the master data byte number of new packing is Dbase+Dmid+Dafter, master data byte number with new packing breaks into a bag by adjacent two effective data packets, enters step 5;

After step 5, current effective data packets have been packed, judge whether that all effective data packets have all packed, if also have not packaged effective data packets, return to step 2 and continue to beat next bag, otherwise packing end.

Preferably, described step 2 comprises:

Step 2.1, start to monitor programmable logic controller (PLC) before, first send the communication frame of some regular lengths, measure 4 parameters, comprise v, L, Ts, Tp, wherein, v is communication Mean Speed, Ts is the interval time of the equipment transceiving data of monitoring programmable logic controller (PLC), the interval time of the transceiving data that Tp is programmable logic controller (PLC);

If during step 2.2 Dbase > L, meet the condition that splits effective data packets, enter described step 3, otherwise do not meet the condition that splits effective data packets, enter step 2.3;

If step 2.3 Dbase+Dmid+Dafter > is L, do not meet the condition that is associated with effect packet, enter described step 5, otherwise judge whether the estimation call duration time after adjacent two effective data packets merge is less than the estimation call duration time before a plurality of effective data packets merge, if, enter described step 4, otherwise enter described step 5.

Preferably, in described step 2.3, judge that the step whether estimation call duration time after adjacent two effective data packets merge is less than the estimation call duration time before a plurality of effective data packets merge is:

The call duration time Tuc that step 2.3.1, estimation need before merging:

The call duration time Tc that step 2.3.2, estimation need after merging:

Step 2.3.3, be combined front and merge after the call duration time that needs compare: if Tc-Tuc < 0 enters described step 4, otherwise enter described step 5.

The invention provides a kind of communication data packaging method of control logic controller able to programme, can avoid unreasonable due to data packings, cause communication efficiency to reduce, cannot reach the optimum efficiency of monitoring programmable logic controller (PLC).

Accompanying drawing explanation

Fig. 1 is a kind of whole process of monitoring the communication data packaging method of programmable logic controller (PLC);

Fig. 2 is the whole process that monitoring programmable logic controller (PLC) is communicated by letter at present;

Fig. 3 A is the transmission communication message form of the programmable logic controller (PLC) programming software access programmable logic controller (PLC) memory block currency of current main flow;

Fig. 3 B is the reply communication message form of the programmable logic controller (PLC) programming software access programmable logic controller (PLC) memory block currency of current main flow;

Fig. 4 is the process of splitting datagram;

Fig. 5 is the process of merging data bag;

Fig. 6 A is the transmission communication message form of embodiment;

Fig. 6 B is the reply communication message form of embodiment;

Fig. 7 is the flow chart of embodiment.

Embodiment

For the present invention is become apparent, hereby with preferred embodiment, and coordinate accompanying drawing to be described in detail below.

In conjunction with Fig. 1 and Fig. 7, the invention provides a kind of communication data packaging method of monitoring programmable logic controller (PLC), the steps include:

The address, memory block that need to monitor Programmable Logic Controller is QB1QB2QB3QB5QB6QB7QB8QB53QB54, packing in accordance with the following steps.

Step 1: generate the data of description that needs to monitor address, programmable logic controller (PLC) memory block, form set and the Rankine-Hugoniot relations set of address, memory block.The data of address, all memory blocks are arranged with order from small to large, according to successional feature, be divided into the set of this sequence of QB1QB2QB3, QB5QB6QB7QB8, tri-parts of QB53QB54.

Step 2-1: before starting to monitor programmable logic controller (PLC), first send the communication frame of some regular lengths, measure 4 parameters, comprise v, L, Ts, Tp, obtains

v＝9600bps＝9600bit／s＝1200byte／s，L＝64byte，Ts＝0.003s，Tp＝0.002s

Wherein, V is communication Mean Speed, and L is the maximum number of byte of the error rate held stationary of can guaranteeing to communicate by letter, and Ts is for monitoring the interval time of the equipment transceiving data of programmable logic controller (PLC), the interval time of the transceiving data that Tp is programmable logic controller (PLC).

Step 2-2: derive the Rule of judgment that whether needs splitting datagram.

Conventionally, when packet is greater than the maximum number of byte of the error rate held stationary of can guaranteeing to communicate by letter, there will be error code, the phenomenons such as re-transmission, cause the reduction of traffic rate.So, derive and split and size that the condition of merging data bag is packet is greater than the maximum number of byte of the error rate held stationary of can guaranteeing to communicate by letter, therefore, whether need the Rule of judgment of splitting datagram as follows:

If during Dbase > L, wherein, the size of the byte number that Dbase is current effective data packets, meets splitting datagram condition, otherwise does not meet splitting datagram condition.

Step 2-3: according to Fig. 6 A and the described common communication message form of Fig. 6 B, derive the Rule of judgment that whether needs splitting datagram.

First, after merging, the size of packet can not be greater than the maximum number of byte of the error rate held stationary of can guaranteeing to communicate by letter, namely must meet Dbase+Dmid+Dafter≤L, otherwise do not allow to merge, wherein, Dafter is the byte number of the effective data packets adjacent with current effective data packets, and note Dmid is the invalid continuous data byte number between adjacent two effective data packets.

Then, estimation merges the call duration time needing after front and merging, and it is compared, and the scheme that spended time is few is more suitable for, and derives thus corresponding Rule of judgment.Because this content is emphasis of the present invention, therefore be described in detail to 2-3-3 at following steps 2-3-1.

Step 2-3-1: the call duration time that estimation needs before merging is that two adjacent packets are sent respectively before merging.

Tuc ≈ sends interval time of transceiving data of the time+programmable logic controller (PLC) of data for the first time

+ reply for the first time interval time of equipment transceiving data of time+supervision programmable logic controller (PLC) of data

+ send for the second time interval time of transceiving data of the time+programmable logic controller (PLC) of data

+ reply for the second time the time of data

$\begin{array}{c}\mathrm{Tuc}\&ap;\frac{\mathrm{Zs}+A+F+\mathrm{St}+\mathrm{Sa}+\mathrm{Sc}+P+\mathrm{Ze}}{v}+\mathrm{Tp}+\frac{\mathrm{Zs}+A+\mathrm{Sc}+\mathrm{Dbase}+P+\mathrm{Ze}}{v}+\mathrm{Ts}\\ +\frac{\mathrm{Zs}+A+F+\mathrm{St}+\mathrm{Sa}+\mathrm{Sc}+P+\mathrm{Ze}}{v}+\mathrm{Tp}+\frac{\mathrm{Zs}+A+\mathrm{Sc}+\mathrm{Dafter}+P+\mathrm{Ze}}{v},\end{array}$

Wherein, the front call duration time of merging that Tuc is estimation, Zs is start bit byte number, A is device address byte number, and F is function code byte number, and St is the byte number of memory block type, Sa is the byte number of memory block first address, Sc is connected reference memory block quantum byte number, and P is the byte number of effect position, the byte number that Ze is end mark.

Step 2-3-2: the call duration time that estimation needs after merging is to become a bag once to send two adjacent packet combinings after merging later.

Tc ≈ sends interval time+reply data time of the transceiving data of data time+programmable logic controller (PLC)

$\begin{array}{c}\mathrm{Tc}\&ap;\frac{\mathrm{Zs}+A+F+\mathrm{St}+\mathrm{Sa}+\mathrm{Sc}+P+\mathrm{Ze}}{v}+\mathrm{Tp}\\ +\frac{\mathrm{Zs}+A+\mathrm{Sc}+\mathrm{Dbase}+\mathrm{Dmid}+\mathrm{Dafter}+P+\mathrm{Ze}}{v},\end{array}$

Wherein, Tc is call duration time after the merging of estimating.

Step 2-3-3: be combined the call duration time needing after front and merging and compare, the scheme that spended time is few is more suitable for, and derives thus corresponding Rule of judgment.

$\begin{array}{c}\mathrm{Tc}-\mathrm{Tuc}\&ap;(\frac{\mathrm{Zs}+A+F+\mathrm{St}+\mathrm{Sa}+\mathrm{Sc}+P+\mathrm{Ze}}{v}+\mathrm{Tp}\\ +\frac{\mathrm{Zs}+A+\mathrm{Sc}+\mathrm{Dbase}+\mathrm{Dmid}+\mathrm{Dafter}+P+\mathrm{Ze}}{v})\end{array}$

$\begin{array}{c}-(\frac{\mathrm{Zs}+A+F+\mathrm{St}+\mathrm{Sa}+\mathrm{Sc}+P+\mathrm{Ze}}{v}+\mathrm{Tp}+\frac{\mathrm{Zs}+A+\mathrm{Sc}+\mathrm{Dbase}+P+\mathrm{Ze}}{v}\\ +\mathrm{Ts}+\frac{\mathrm{Zs}+A+F+\mathrm{St}+\mathrm{Sa}+\mathrm{Sc}+P+\mathrm{Ze}}{v}+\mathrm{Tp}+\frac{\mathrm{Zs}+A+\mathrm{Sc}+\mathrm{Dafter}+P+\mathrm{Ze}}{v})\\ =\frac{\mathrm{Dmid}-2\mathrm{Zs}-2A-F-\mathrm{St}-\mathrm{Sa}-2\mathrm{Sc}-2P-2\mathrm{Ze}}{v}-\mathrm{Tp}-\mathrm{Ts}.\end{array}$

If Tc-Tuc < 0,

$\frac{\mathrm{Dmid}-2\mathrm{Zs}-2A-F-\mathrm{St}-\mathrm{Sa}-2\mathrm{Sc}-2P-2\mathrm{Ze}}{v}-\mathrm{Tp}-\mathrm{Ts}<0;$

Dmid＜(Tp+Ts)*v+2Zs+2A+F+St+Sa+2Sc+2P+2Ze；

Namely, as Dmid < (Tp+Ts) * v+2Zs+2A+F+St+Sa+2Sc+2P+2Ze, merge less than nonjoinder packing call duration time expense.

Known parameter Tp, Ts, V are measured value, and by step, 2-1 measures,

V＝1200byte／s，Ts＝0.003s，Tp＝0.002s。

Known parameter Z s, A, F, St, Sa, Sc, P, Ze are the data of arranging in communication message form, by Fig. 6 A and the described common communication message form of Fig. 6 B, can be obtained,

Zs＝1byte，A＝1byte，F＝1byte，St＝1byte，Sa＝2byte，Sc＝2byte，P＝2byte，Ze＝1byte.

So by above known parameters substitution inequality:

Dmid＜(Tp+Ts)*V+2Zs+2A+F+St+Sa+2Sc+2P+2Ze：

Dmid＜[(0.002+0.003)*1200+2*1+2*1+1+1+2+2*2+2*2+2*1](byte)；

Dmid＜24(byte)。

Namely, being Fig. 6 A and Fig. 6 B when communication message, when Dmid is less than 24 bytes, merging is less than nonjoinder packing call duration time expense, meets the Rule of judgment merging, so carry out merging data bag, must operate.

Step 2-4: judge the current splitting datagram that whether needs, namely judge whether Dbase > L, because Dbase is QB1QB2QB3, therefore Dbase=3byte, again because step 2-1 measures to obtain L=64byte, so do not meet the packet splitting condition of Dbase > L, do not carry out splitting datagram.

Step 2-5: judge the current merging data bag that whether needs, first, after merging, the size of packet can not be greater than the maximum number of byte of the error rate held stationary of can guaranteeing to communicate by letter, and namely must meet Dbase+Dmid+Dafter≤L, otherwise not allow to merge.Because Dbase is QB1QB2QB3 (note QB1～QB3), Dafter is QB5QB6QB7QB8 (note QB5～QB8), so Dmid is QB4, Dbase+Dmid+Dafter=3+1+4=8 (byte), known parameter L is measured value, by step, 2-1 measures, L=64byte, therefore, Dbase+Dmid+Dafte < L, meets the precondition merging.

Continue to judge whether Dmid < 24 (byte), because current Dbase is QB1QB2QB3 (note QB1～QB3), Dafter is QB5QB6QB7QB8 (note QB5～QB8), Dmid is QB4, Dmid=1 (byte) < 24 (byte), so meet the Rule of judgment of merging data bag.

Step 4: merging data bag, this step realizes two adjacent packet combinings is become to one, namely Dbase and Dafter are merged, as shown in Figure 7, the value of new Dbase is Dbase=Dbase+Dmid+Dafter, and new Dmid and the value of Dafter can be released by the value class of new Dbase.

Because current Dbase is QB1QB2QB3 (note QB1～QB3), Dafter is QB5QB6QB7QB8 (note QB5～QB8), Dmid is QB4, so QB1～QB3 and QB5～QB8 are merged to formation QB1QB2QB3QB4QB5QB6QB7QB8 (note QB1～QB8), new Dbase is QB1～QB8, new Dafter is QB53QB54, and new Dmid is QB9～QB53.

Step 2-5: judge the current merging data bag that whether needs, first, after merging, the size of packet can not be greater than the maximum number of byte of the error rate held stationary of can guaranteeing to communicate by letter, and namely must meet Dbase+Dmid+Dafter≤L, otherwise not allow to merge.Because current Dbase is QB1～QB8, Dafter is QB53QB54, Dmid is QB9～QB53, Dbase+Dmid+Dafter=8+44+2=54 (byte), known parameter L is measured value, by step, 2-1 measures, L=64byte, therefore, Dbase+Dmid+Dafte > L, does not meet the precondition merging.

Step 2-6: the Rule of judgment judgement of deriving according to step 2-2 and 2-3 can obtain, and current data packet had not both met yet do not meet-splitting condition of merging condition.

Step 5, notebook data bag have been packed, and the data of this bag are QB1～QB8, judge whether to have not packaged data, through observation shows that data QB53QB54 is also not packaged, so continue to beat next bag.

Step 2-4: judge the current splitting datagram that whether needs, namely judge whether Dbase > L, because Dbase is QB53QB54, therefore Dbase=2byte, again because step 2-1 measures to obtain L=64byte, so do not meet the packet splitting condition of Dbase > L, do not carry out splitting datagram.

Step 2-5: judge the current merging data bag that whether needs, there is no adjacent valid data and its merging due to after QB53QB54, so do not meet the precondition merging.

Step 2-6: the Rule of judgment judgement of deriving according to step 1-2 and 1-3 can obtain, and current data packet had not both met yet do not meet-splitting condition of merging condition.

Step 5: notebook data bag has been packed, the data of this bag are QB53QB5, judge whether to have not packaged data, through observation shows that all packings of all data, so packing all completes.Finish institute in steps.

The data handling procedure that above step is described is as shown in Figure 7:

Obviously, those skilled in the art can carry out various changes and modification and not depart from the spirit and scope of the present invention the present invention.Like this, if of the present invention these are revised and within modification belongs to the scope of the claims in the present invention and equivalent technologies thereof, the present invention is also intended to comprise these changes and modification interior.

Claims (3)

1. a communication data packaging method of monitoring programmable logic controller (PLC), is characterized in that, step is:

Step 1, generation need the data of description of monitoring address, programmable logic controller (PLC) memory block, be designated as valid data, all valid data are divided into groups with successional feature according to address, memory block, continuous valid data are divided into one group, form continuous effective data packets, continuous effective data packets is arranged with address, memory block order from small to large, form the Rankine-Hugoniot relations of effective data packets;

If step 2, effective data packets meet splitting condition, enter step 3; If effective data packets meets merging condition, enter step 4; If effective data packets had not both met merging condition and had not met splitting condition yet, enter step 5, wherein:

Splitting condition is: the size of effective data packets is greater than the maximum number of byte of the error rate held stationary of can guaranteeing to communicate by letter;

Merging condition is: the size after adjacent two effective data packets merge is not more than the maximum number of byte of the error rate held stationary of can guaranteeing to communicate by letter, and the estimation call duration time of adjacent two effective data packets after merging is less than the estimation call duration time before a plurality of effective data packets merge;

Step 3, fractionation effective data packets:

The byte number that note Dbase is current effective data packets, the maximum number of byte that note L is the error rate held stationary of can guaranteeing to communicate by letter, effective data packets is divided into two, the first can guarantee the to communicate by letter maximum byte fractional part of error rate held stationary, be designated as L part, it two is that effective data packets is removed remaining part after the maximum number of byte of the error rate held stationary of can guaranteeing to communicate by letter, be designated as (Dbase-L) part, L part and (Dbase-L) part are broken into respectively to a bag, enter step 5;

Step 4, merging effective data packets:

Note Dafter is the byte number of the effective data packets adjacent with current effective data packets, note Dmid is the invalid continuous data byte number between adjacent two effective data packets, two adjacent effective data packets are merged into one, the value of the master data byte number of new packing is Dbase+Dmid+Dafter, master data byte number with new packing breaks into a bag by adjacent two effective data packets, enters step 5;

After step 5, current effective data packets have been packed, judge whether that all effective data packets have all packed, if also have not packaged effective data packets, return to step 2 and continue to beat next bag, otherwise packing end.

2. a kind of communication data packaging method of monitoring programmable logic controller (PLC) as claimed in claim 1, is characterized in that, described step 2 comprises:

Step 2.1, start to monitor programmable logic controller (PLC) before, first send the communication frame of some regular lengths, measure 4 parameters, comprise v, L, Ts, Tp, wherein, v is communication Mean Speed, Ts is the interval time of the equipment transceiving data of monitoring programmable logic controller (PLC), the interval time of the transceiving data that Tp is programmable logic controller (PLC);

If during step 2.2 Dbase > L, meet the condition that splits effective data packets, enter described step 3, otherwise do not meet the condition that splits effective data packets, enter step 2.3;

If step 2.3 Dbase+Dmid+Dafter > is L, do not meet the condition that is associated with effect packet, enter described step 5, otherwise judge whether the estimation call duration time after adjacent two effective data packets merge is less than the estimation call duration time before a plurality of effective data packets merge, if, enter described step 4, otherwise enter described step 5.

3. a kind of communication data packaging method of monitoring programmable logic controller (PLC) as claimed in claim 2, it is characterized in that, in described step 2.3, judge that the step whether estimation call duration time after adjacent two effective data packets merge is less than the estimation call duration time before a plurality of effective data packets merge is:

The call duration time Tuc that step 2.3.1, estimation need before merging:

The call duration time Tc that step 2.3.2, estimation need after merging:

Step 2.3.3, be combined front and merge after the call duration time that needs compare: if Tc-Tuc < 0 enters described step 4, otherwise enter described step 5.

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