PLC development review
On the century 60's later periods, according to at
that time the auto market demand and the computation technology
development, in American Massachusetts Bedford Bedford Associates, to the american automobile manufacturing
industry proposed develop one kind of Modular Digital Controller (MODICON) to substitute continue the
electricity control panel. Other some companies also suggest
take the computer as the foundation plan. Its core thought is
uses the software programming method to replace continues the
electricity control the hard wiring way, and has produces the scene
massive uses the input sensor and the output execution connection, in
order to carries on the large-scale production line the flow control.
This will be is later been called Programmable Logic Controller the origin. MODICON 084 is in the world first kind of investment commercial
production PLC.
The 70's are PLC rise, first obtain the massive applications in
the automobile industry, also start the application time in other
industrial departments. The 80's are it move towards maturely,
comprehensively use the micro electron and the microprocessor
technology; The massive promoted application, and establishes it
in the industry control the unshakeable status time. In this
stage PLC sale throughout by two figures percentage points speed
growth, previous six years rate of increment surpasses 35%, the latter
four years stably develop, yearly rate approximately 12%. The
90's started its third development time. Along with PLC
international standard IEC 61,131 officially promulgated,
impels PLC to start the new breakthrough in the technology:
In system system structure, from traditional single plane to
multi- CPU and distributional and long-distance control system
development; In the programming language, the text and the graph
language multiplicity, created has had the expression control
request, the language processing, the traffic capacity programming
environment.
From the application scope and the application level, besides
continues to develop the machine-finishing automatic production line
control system, then is the development take PLC as the foundation DCS
system, the monitoring and the data picks the SCADA system, the
flexible manufacture system (FMS), the security interconnection
protection (ESD) the system, the movement control system and so on,
the omni-directional real estate enhances PLC the application scope
and the level.
Enters the 90's later periods, as a result of user to open
intense request and pressure, as a result of information technology
vigorously impetus, PLC if also pauses in original special-purpose and
also seals up in the system concept, it will sit waiting for death.
Thereupon PLC entered its development fourth stage. Its
characteristic is:
In retains the PLC function under the premise, uses face the
field bus network system structure, uses the open correspondence
connection, like ethernet, high speed string mouth and so on.
Uses each related international industry standard and a series
of in fact standards.
The worth noting is PLC and DCS these originally is in the
different hardware platform the system, along with the computation
technology, the communication and the programming technology
development, tends to the establishment identical hardware platform,
the utilization identical operating system, the identical programming
system, carries out different DCS and the PLC function. This is
in the true significance EIC three electricity integration. Or
said DCS and the PLC shape will be able to change, but their function
still will exist. Essential technology should be inserts the
type PC system and supports the field bus I/O (hardware) , as well as 61161-3 systematic and is strong real-time take IEC as the foundation
programming (hard real-time) the operating system.
PLC in China's development
In China, approximately from 1,974, 75 years
starts in Beijing and Shanghai to develop uses the position piece to
decline the processing chip the programmable sequence controller, and
has the application. But has not been able to form the volume
production. In 1979 just started which in the reform and open
policy, in under then machinery department measuring appliance
bureau's impetus, started from the American MODICON introduction 584
PLC, and first like lost in the power plant auxiliary engine the coal,
except the ash except control system in and so on the dregs, water
disposal system as well as cement plant succeeds the application, thus
greatly impelled PLC in the our country industry large-scale
utilization. 遗憾.?? spend very great foreign exchange
this project certainly not once to form benignly has the following
development.
Started from 1985, small PLC first was Japanese Mitsubishi
electrical machinery company's MELSEC-F, entered the Chinese market
through the non- government channel. To three, four years time,
small PLC has not formed the big area promoted application aspect.
After 1990, Siemens, Allen Bradley as well as other
well-known brands start on a large scale to enter the Chinese market,
occupies, a large-scale PLC bigger share. After 1995 has formed
large-scale PLC by Europe and America primarily, the medium PLC Europe
and America and Japan shares half and half, small PLC the pattern
which by Japan primarily, Siemens also presses on step by step.
Until now does not have the very big change.
May know by on brief review, PLC has already formed
the scale huge application market in China, but establishes the volume
production by no means, has continues to develop the development
ability the PLC manufacturing industry.
Should point out:
In domestic, PLC application level or not low, the independent
design, the system integration and the scene throw the ability which
transports, may say with the international mainstream horizontal
synchronization;
The PLC application domain very is also widespread, industry and
so on cover metallurgy, electric power, chemical industry, petroleum
chemical industry, machinery, light industry, electron, electrician,
building materials cement, as well as modern farm machinery and other
applications. In recent years the environmental protection
industry also had the widespread application, the development tendency
is very fierce.
In domestic has a huge PLC sale, the service, the application,
the system integration troop, proliferates besides Tibet each place.
Has the sufficient reason to say that, PLC has become the
industry control in China one kind to be suitable the technology.
Therefore, PLC, soft PLC as well as the IEC 61131-3
development, indisputably became extremely made the matter which one
paid attention.
IEC 61,131 international standards in
China
After 1992, the programmable foreword controller
international standard IEC 61,131 each parts announce the
execution one after another. China's commercial run survey and
control standardization committee according to and IEC international
standard equivalent principle, organization translation publication
work. To GB/T15969.1,15969.2,15969.3,15969.4 has promulgated the
PLC national standard to December 29, 1995. This
standard only involves IEC 61131 first, second, third and
the fourth part, has not bought into line with the fifth part of
correspondence, the seventh part of fuzzy control programming software
tool, the eighth part of IEC 61131-3 language realization which in 1995 later will publish leads then.
Promulgates since the standard, certainly has not had the very
tremendous influence. The reason lies in: China does not
have the true presentable PLC manufacturing industry; Certainly not positively recommends in the Chinese
domestic influential PLC brand; Including this standard
department responsible for the work, very little has the organization
the advancement activity. Until 1998 after, because IEC 61131-3 is more and more big in the international control
field influence, starts in the Chinese domestic influential PLC brand
to mention own brand to conform to or compatible IEC 61131-3; Certain newly promotes the DCS system also
publicly declared that, conforms to or compatible IEC 61131-3. Thereupon, the people only then pay
attention to this standard. Has the special article in the
related specialized magazine to introduce this standard the making
background, important, the standard main content. The Chinese
integration of machinery technology application association organized
to translate the monograph which two German author K
arl-Heinz John and Miachael Tiegelkamp wrote: "IEC 61131-3: Industrial automation system programming
". Already distributed by this association's interior.
Recently, the Chinese integration of machinery technology
application association (CAMETA) with developed based on the IEC 61131-3 programming was general designation Germany KW
Corporation far east General Manager Mr. Robert Champoud
is cooperating, the organization coordinated the related IEC 61,131 projects the seminar activities, obtained Siemens,
Phoenix, the Fuji electrical machinery vigorously support. This
regarding promotes its promotion, has the profound significance.
Soft PLC in China
So-called soft PLC actually is in the PC machine
platform, under the Windows operating environment, realizes the PLC
function with software. This concept later only then was
probably introduced in 1996 domestic comes. Because this kind of
technology still was not mature, therefore only had in the academic
circles minority people pays attention regarding this. Although
Interllution and Wonderware HMI and SCADA software
promotes in our country very is all successful, but their soft logic,
soft PLC product P-31 and the InControl actually unusual person asks
about. Certainly, these two companies' not once sedulously
developed this market.
Think&Do and Steeperchase VLC all is 1,998, in 1999
enters the Chinese market, Think&Do has specially spend the very
great endeavor, until now still not entirely as desired.
Certainly has some success applications, if the mail sorts the
system. I felt that, this how many does not use IEC with them 61131-3, but is the initiative uses the flow chart
programming language not without the relations.
German KW Corporation later on will set up the office in 1998 in
Beijing, wore the strength to promote it to conform to IEC 61131-3 programming system MULTIPROG and control procedure ProConOS.
Siemens starts from 2001 in domestic recommendation its soft PLC
series product WinAC, already had some applications. They have
the strategic judgement very much. German Inforteam
Corporation's openPCS in domestic also
started market development, in June, 2002 once has conducted the
technological exchange at Shanghai's automated exposition.
Our country voluntarily develops DCS system, if Shanghai from
meter company's SUPMAX-800, selects French CJ International Corporation to conform to IEC 61131-3 IsaGraf and US'S strong real-time operating
system Vxworks. When Beijing and principle has used Inforteam
OpebPCS to develop new DCS.
Analyzes the world control device the development
situation
Looking from the world scope that, soft PLC/ the PC control took the emerging industry is developing.
Facing this kind of challenge, PLC still was developing.
According to American Venture Development Corp. The report, in 2000 the world altogether
sells the DCS system, the PLC system and the PC control system amounts
to 22 billion US dollars. DCS 40.5%; PLC 46.3%; PC controls 13.2% . These three kind of
control system uses the disperser/long-distance I/O market sales
volume also is 22 billion US dollars. The yearly rate is 6.6%.
To 2005 estimated amounts to 30 billion US dollars.
Looking from the application domain that, DCS still firmly
grasped the large-scale continual flow industry (I/O to reach several
thousand) the process control application. PLC already supported
into the batch to control the market, still occupied the absolutely
dominant position in its traditional separate manufacture industry.
The soft PLC/PC control uses the labor to control PC machine (or
inserts type PC machine) and strong real-time OS, may realize the PLC
function and the movement control. Until now, the PC control in
aspect and so on reliability, security has not obtained the
widespread approval.
According to American Venture Development Corp. Below the report, PLC and the soft PLC/PC
control compares has the merit:
The service and the service system perfect, the experienced
attendant troop is huge.
The power failure cannot have the tremendous influence.
To the low end application, PLC has the enormous performance
price to compare the superiority.
Reliability incomparable, the breakdown engine off are least.
The reinforcement structure, suits the industry environment
application.
Too quickly compares with the PC machine development, the PLC
product may supply goods for a long time, provides the technical
support for a long time.
PLC in factory automation status therefore is so stable, the
reason lies in:
The PLC technology has the long-term stability, the software and
hardware applies conveniently, namely inserts namely uses, the price
is moderate, mays be called the industry control the suitable
technology.
May say now the industry control requests the performance, PLC
may satisfy 85% to 90%. Its insufficiency are partial may use
other means to supplement. In the last few years PLC also
unceasingly is enhancing its technical connotation, fused the IT
technology (to include ethernet, Internet, non- wire technology, field
bus technology, as well as promoted PLC using software engineering
method the programming language, developed brand-new programming
system, and so on).
PLC also had the substantive breakthrough in the open aspect.
First more than 10 year PLC an important aspect which attacks is
its appropriation, now had enormous having a new look. PLC has
used each industry standard, like IEC 61,131, IEEE802.3
ethernet, TCP/IP, UDP/IP and so on, each in fact industry standard,
like Windows NT, OPC and so on.
PLC also has on the hardware makes great strides. The
micro electron technology progress all utilizes in PLC, the primary
device integration rate is more and more high, urges the PLC cost drop
and the reliable enhancement. Specially is PLC CPU the design
PLC-on-a-chip chip already is published many years. The PLC high
end product all had the archery target change on the system structure
and the operating system, the performance largely enhanced. On a
rack may install many CPU module. Also appeared take Web as the
foundation PLC series product.
PLC, soft PLC, IEC 61,131 in China's
future
The traditional PLC manufacturing industry will
not be able in to be possible to foresee future in the domestic
establishment and the development. But does not remove soft PLC
the future which and might foresee in the near future, completely will
have the possibility in domestically to form the certain climate.
Soft PLC I/O definitely may and some has the vitality using the
mainstream the field bus series product. The strong real-time
operating system may use Windows CE, NTE, VenturCom RTX
as well as other; So long as they can realize the control time
determinism, namely the guarantee can by the time highly consistent
way execution control command sequence, and has the result or the
behavior which may forecast. Joins after WTO, China becomes the
"world to make factory" the advancement to accelerate. We have
the enough reason to believe that, PLC, soft PLC can remarkably be
higher than the world in China's sale yearly rate average annual rate
of growth. Therefore, to PLC, soft PLC as well as the IEC 61,131 promotions applications, specially the high level
technical support changes extremely importantly.
Along with the modern industry scale production development, for
enhances the enterprise the market competition strength, the lead-in
tube controls integrated system structure ERP/MES/PCS, in domestic
mentioned the agenda. Underlie automation PCS level main tool
-PLC should to the method, should be rapidly strengthens the PLC
networking and the correspondence development ability, as well as
information preliminary working ability. In domestic, speaking
of the average level, is skilled in or thoroughly understands the PLC
networking correspondence, PLC and the computer correspondence
technical personnel, with next will need to compare, but also will
have many disparities. Therefore, the urgent need takes the
measure, strengthens training. CAMETA also should have an
achievement in this aspect.
IEC 61131-3 is at present only controls the
programming language about the labor the international standard.
Widely applies to PLC, DCS, SCADA, even movement control.
Definitely can develop one's ability to the full in the domestic IEC 61131-3 promotion application.
The key question lies in uses these measures to speed up the
advancement.
Brief conclusion and suggestion
PLC, the soft PLC/PC control, IEC 61131-3 and its correlation software (strong real-time
operating system, programming system platform and so on), still was
the industry controls in the stage in the next ten years the lead.
This requests us to grasp the opportunity, clearly recognizes
the direction, seizes takes the initiative.
Along with the field bus technology rapid development and the
field bus product universal use, besides strengthens the IEC 61131-3 propaganda promotion, but also should many
propagandize IEC 61,499 this to make up IEC 61131-3 not to be able to adapt the distributional
system disappointment new standard.
After passes through the first turn of IEC 61131-3
tour lecture activity, should propagandize through each kind of tool,
lets be engaged in the technical personnel which the labor controls,
specially the PLC programmers all knew, does not grasp the IEC 61131-3 programming language, will be able to fall
behind, cannot follow the development.
CAMETA should key prop up 12 to develop the soft PLC/PC control
the company, grasps several to have the typical significance the
application project, if the scale bigger manufacturing industry
production line, the success add-on summarizes the promotion, lets the
professional realize to the soft PLC/PC control superiority.
|
