Touches the screen and PLC in the closed-loop
control frequency conversion energy conservation system application
Chen Hao
Abstract: This article introduced touches the
screen and PLC and touches the screen page design and the PLC
programming in the frequency conversion energy conservation system
application.
Key word: Touches the screen PLC frequency conversion
energy conservation closed-loop control
1st, introduction
Touches the screen is one kind of new programmable
control terminal, is the new generation of high tech man-machine
contact surface product, is suitable to the scene control, the
reliability high, programming simple, the use maintenance is
convenient. More needs the man-machine when the craft parameter
alternately uses touches the screen, may enable the entire production
the automated control function to obtain big strengthening.
PLC has the operating speed high, the instruction rich, the
function formidable, the reliability high, the easy to operate, the
programming nimble, the antijamming ability is strong and so on the
characteristic. In recent years, along with the science and
technology unceasing progress, various professions is more and more
high to its production equipment and the system automaticity request,
uses the modern automation control technology to reduce labor
intensity, optimized production craft, the enhancement labor
productivity and reduces the production cost to play the very vital
role. Touches the screen to unify PLC in the closed-loop control
frequency conversion energy conservation system application is one
kind of automatic control tendency.
Touches the screen and PLC in the closed-loop control frequency
conversion energy conservation system use, may let the operator in
touch in the screen the direct hypothesis target value (pressure and
temperature and so on), (sensor observed value) carries on the
comparison operation through PLC and the actual value, directly sends
out the operational command to the frequency conversion energy
conservation system (simulated signal), adjusts the frequency changer
the output frequency. And may the real-time monitoring control
the system actual value in the size and frequency changer many
parameters, the realization reports to the police, function and so on
record. The general PLC union touches the screen the closed loop
adjustment frequency conversion energy conservation system following
chart to show.
2nd, the closed-loop control frequency conversion
energy conservation system use is very broad, each kind of situation
frequency conversion energy conservation system drives the way and the
control mode respectively has the difference, when concrete
application should act according to the actual situation choice
design. Under enumerates some:
Central air conditioning energy conservation: The freezing
pumps, cooling pumps, the main engine, actually the tower air blower,
the air blower plate tube and so on.
Constant pressure water supply: The water works one, two
levels pump, supply water the pipe network booster pump, the building
water supply water pump and so on
Boiler: The drawing fan, the air feeder, the feed
pump and so on, the frequency conversion energy conservation system
control adjustment pretreatment signal by the boiler automatic control
system, DCS or the multi- impulses control system produces.
Steam turbine: The circulating pump, the condenser pump
and so on, its control adjustment pretreatment signal produces by the
steam turbine automatic control system and DCS.
Pure water processing system: Softens the water pump, the
booster pump and so on.
Pure room: Turbo-charged air blower, FFU group control and
so on.
3rd, entire closed-loop control frequency
conversion energy conservation system composition equipment and its
function:
(1) PLC selects SIEMENS Corporation the S7-200 series: By
CPU224XP, the DI/DO module, the AI/AO module are composed. PLC
took the control unit, is the overall system control core. Its
main function must manifest following several aspects:
(1) completes to system each kind of data gathering as well as
the digital quantity and the simulation quantity interconversion.
(2) completes to the overall system logical control and the PID
adjustment operation.
(3) to touches the screen to provide gathers and the processing
data, and the execution touches each kind of instruction which the
screen sends out.
(4) transforms the PID operation data result the simulated
signal, the achievement adjusts the frequency changer the output
frequency control signal.
(5) completes through the communications cable and the USS4
agreement to the frequency changer interior parameter read-write and
the control.
(2) touches the screen to use SIEMENS Corporation MP370:
Its main function as follows:
(1) may the real time display equipment and the system running
status.
(2) through touches sends out the instruction and the data to
PLC, again completes through PLC to the system or the equipment
control.
(3) may make many many kinds of monitorings picture, has
substituted the traditional electrical control panel and the
demonstration recording meter and so on, also the function is more
formidable.
(3) frequency changer: Uses the SIEMENS Corporation 440
series, may by touch the screen through the USS4 agreement to
establish its internal through PLC the partial parameters, transmits
the data according to PLC (simulation quantity) the value adjustment
water pump or the air blower rotational speed, and feeds back its
internal movement parameter PLC.
(4) sensor and so on pressure, temperature: By control
system (aqueous system or wind system) the actual parameter value
transforms on the electrical signal to pass on to PLC.
(5) electrical part: For PLC, touches power supply and so
on screen, frequency changer and sensor, completes each kind of
operation and the actuation and so on. 4th, touches the screen picture design
Touches the screen picture and so on special-purpose
software to carry on the design by ProTool, then through the
programming computer debugging, after is first qualified downloads
again to touches the screen. Touches the screen picture total to
be supposed in its storage space permission scope, between various
pictures achieves as far as possible may mutually and forces to cut.
(1) host picture design
General, may use the welcome picture or is controlled
the system the main system picture to do primarily the picture, this
picture may enter to each minute picture. Each minute picture
can step return to the main picture. If is controlled the host
system picture to do primarily the picture, then should in the picture
demonstrate is controlled the system some to live wants the parameter,
in order to entire is controlled in this picture the system to have
approximate bringing to completion. (2) controls the picture the design
This kind of picture mainly uses for to control is
controlled the equipment to open stops and demonstrates the frequency
changer interior the parameter, also may suppose the frequency changer
parameter the custom make in among. This kind of picture
quantity in touches in the screen picture to occupy are most, its
specific picture quantity by actual is controlled the equipment
decision.
(3) the parameter establishes the page the design
This picture mainly is carries on the hypothesis to the
frequency changer internal parameter, meanwhile should demonstrate the
parameter hypothesis completes the situation, actually makes when also
should consider the encryption the question.
(4) real-time tendency page design
This picture lives if by the curve recording form
demonstrated is controlled the value, the frequency changer main
operational parameter (for example output frequency) and so on the
real-time condition.
(5) the information records the page the design
This picture mainly is the equipment damage, the
overload, the value ultra scope and the system which the recording
possibly appears anxiously stops and so on the breakdown.
Moreover this picture also may record various equipment to open
stops the operation, takes the certificate.
(6) conserves energy the picture the design
This picture mainly is records and demonstrated the
frequency changer the accumulation uses electricity the number and the
real-time electricity saving condition, in order to user demonstration
frequency conversion energy conservation advantage, also may use for
with other electricity saving surveys to do compares. 5th, PLC programming
The PLC procedure carries on the design by S7-200
special-purpose programming software, then through programs the
computer to download to PLC carries on the debugging on-line, after is
qualified then uses. PLC should first carry on the plan before
the programming to various functions segment address, in order to
avoid duplicates uses the identical address, creates moves by mistake.
(1) logical function design
This subprogram mainly is completes various frequency
changers, the water pump (or air blower) the start stops, the linkage,
the interconnection and automatically throws cuts and so on the
function, generally in leaves under the striation condition to be able
to complete the software logic function the test.
(2) PID function design
May complete the PID adjustment procedure through the
S7-200 in PID guide, when concrete application must act according to
actual is controlled the equipment and the sampling equipment decides
its disposition.
(3) sampling procedure design
When sampling part use standard disposition, should pay
attention to sampling A/D to transform after the concrete data whether
with procedure and so on PID and demonstration necessary, actually
makes when also should consider the sampling is a situation which
multichannel also is connected.
(4) PLC and frequency changer signal procedure design
SIEMENS S7-200PLC and SIEMENS 430 and so on the
frequency changer correspondence generally uses the USS4 agreement
procedure to complete, this procedure main goal is monitors the
frequency changer the real-time running status.
(5) other auxiliary programs designs
The PLC procedure in the actual programming process,
must consider carries on patching to some procedures, reduces the
procedure loophole as far as possible, repeatedly deliberates,
unceasing summary consummation. Concluding remark
Uses in the closed-loop control frequency conversion
energy conservation system touches the screen to be allowed to cause
the user simple direct-viewing monitoring entire central air
conditioning frequency conversion energy conservation system and the
equipment and the system which if is connected, enhanced entire has
been controlled the system as well as enterprise's automaticity and
the hardware scale. Along with the microcomputer technology
unceasing development, touches screen itself the cost also in
unceasing reducing, again used with PLC in the system, realizes entire
has been controlled the system automaticity the quantitive leap, this
will will certainly to cause to touch the screen and PLC by more
applications in the future each kind of production system, and became
the automated control development a luminescent spot.
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