Summary of the invention
The object of the invention is to, for the problems referred to above, propose a kind of PLC control system for plastic floor vulcanizer and control method thereof, to realize system stability and to avoid the advantage of contactor melting welding.
For achieving the above object, the technical solution used in the present invention is:
For a PLC control system for plastic floor vulcanizer, comprise fuse, PLC, touch-screen, pressure sensor, A/D modular converter, control relay, A.C. contactor, thermal overload relay, temperature controller, transistor driving plate and Switching Power Supply,
Described fuse, for the short-circuit protection of control system;
Described touch-screen, is connected with PCL by RS485 communication, realizes the I/O monitoring of optimum configurations, data monitoring and PLC;
Described PLC is whole control system control centre;
Described pressure sensor, realizes the detection of pressure signal;
Described A/D modular converter, is connected with PLC by integrated wire arrangement, and the input point of A/D modular converter is connected with sensor, sends PLC to after the analog signal for pressure sensor feeds back being come changes into data signal;
Described control relay, the coil of this control relay is directly connected with PLC output point, by PLC Direct driver; The normally opened contact of control relay is connected with the normally-closed contact of thermal overload relay;
Described A.C. contactor, for controlling the work of motor; Main contact end of incoming cables is directly opened with sky and is connected, and leading-out terminal is connected with thermal overload relay, and coil is connected with the normally-closed contact of thermal overload relay;
Described thermal overload relay, for the overload protection of vulcanizer motor, end of incoming cables is connected with the leading-out terminal of A.C. contactor, and leading-out terminal is connected with motor, and normally opened contact is connected with PLC input point, and normally-closed contact is connected with the coil of A.C. contactor;
Described temperature controller, for detecting the vapor (steam) temperature of vulcanizer; Input connects K type thermocouple, output switching signal when output reaches control temperature, and the output of temperature controller is connected with the input of PLC, and the switching signal that temperature controller exports is correlated with by PLC control vulcanizer the action of air valve after PLC process;
Described transistor driving plate, the b pole of transistor driving plate is connected with PLC output, and the e pole of transistor driving plate is connected with Switching Power Supply positive pole, and the c pole of transistor driving plate is connected with control relay;
Described Switching Power Supply, provides dc source; The input of Switching Power Supply is connected with fuse, and the output of Switching Power Supply is connected with control relay with touch-screen, PLC, transistor driving plate respectively.
Technical scheme of the present invention also discloses a kind of control method of PLC control system simultaneously, comprises the following steps:
Step 1, to PLC power-up initializing;
Step 2, above-mentioned PLC have judged whether operation requests, as standby in then do not continued, and if any operation requests, then whether be automatically control request, if not being automatic request, then transfer manual operation to if detecting;
Step 3, as above-mentioned PLC is detected as automatic control, then starts operation of oil pump, be pressurized to setup pressure value to master cylinder, described oil pump is divided into speed oil pump and ftercompction oil pump;
Step 4, be pressurized to setting value as master cylinder, then PLC controls the air bleeding valve of plastic floor vulcanizer, draining valve, drain valve, steam enter valve and cooling water enters the opening and closing of valve, PLC controls the running of speed oil pump and ftercompction oil pump simultaneously, thus control master cylinder is pressurized to setting value, completes plastic floor vulcanizer job control;
Step 5, the above-mentioned oil cylinder completing plastic floor vulcanizer job control under PLC controls pressure release to being less than setup pressure value.
According to a preferred embodiment of the invention, the setup pressure value in above-mentioned steps 3 and step 5 is 1Mpa.
According to a preferred embodiment of the invention, air bleeding valve in above-mentioned steps 4, draining valve, drain valve, steam enter the opening and closing that valve and cooling water enter valve and comprise the following steps:
Step 401, control draining valve and drain valve by PLC and open, and set the time of opening, timing while opening draining valve and drain valve;
Step 402, as above-mentioned steps 401 timing time arrives, then by drain shut valve, drain valve continues to open, and steam enters valve and opens, simultaneously setting-up time, and timing simultaneously;
Step 403, timing time as above-mentioned steps 402 arrive, then open air bleeding valve, close drain valve, and steam off enters valve and opens cooling water and enters valve, and setting-up time, timing simultaneously;
Step 404, timing time as above-mentioned steps 403 arrive, then close air bleeding valve, open draining valve, and steam off enters valve and opens cooling water and enters valve, and setting-up time, timing simultaneously;
Step 405, to arrive as above-mentioned steps 404 timing time, then air bleeding valve, draining valve, drain valve, steam are entered valve and cooling water and enter valve and all close.
According to a preferred embodiment of the invention, in above-mentioned steps 4, PLC controls the running of speed oil pump and ftercompction oil pump, thus control master cylinder is pressurized to setting value, completes plastic floor vulcanizer job control and comprises the following steps:
Step 501, control speed oil pump stop, and ftercompction oil pump runs, thus is pressurized to the first setup pressure value, when reaching the first setup pressure value, just control ftercompction oil pump to close, and timing is carried out to the working time of the first force value, judge the working time under the first force value and operating pressure;
Working time under the first force value in step 502, above-mentioned steps 501 and operating pressure all meet the requirements, then start ftercompction oil pump, thus be pressurized to the second setup pressure value, when reaching the second setup pressure value, just control ftercompction oil pump to close, and timing is carried out to the working time of the second force value, judge the working time under the second force value and operating pressure; Repetitive controller ftercompction oil pump, until be pressurized to the 4th setup pressure value, completes master cylinder pressurization.
Technical scheme of the present invention has following beneficial effect:
Technical scheme of the present invention, by replacing the Control of reason with PLC, and discloses a kind of control method, reaches control system and stablize and the object avoiding contactor melting welding.
Below by drawings and Examples, technical scheme of the present invention is described in further detail.
Detailed description of the invention
Below in conjunction with accompanying drawing, the preferred embodiments of the present invention are described, should be appreciated that preferred embodiment described herein is only for instruction and explanation of the present invention, is not intended to limit the present invention.
For a PLC control system for plastic floor vulcanizer, comprise fuse, PLC, touch-screen, pressure sensor, A/D modular converter, control relay, A.C. contactor, thermal overload relay, temperature controller, transistor driving plate and Switching Power Supply,
Fuse, for the short-circuit protection of control system, the device power taking of all use single phase poaer supplies is all through overcurrent fuse (mainly containing PLC, temperature controller, Switching Power Supply), and power taking is in A phase.
Touch-screen, is connected with PCL by RS485 communication, realizes the I/O monitoring of optimum configurations, data monitoring and PLC;
PLC is the heart of whole control system, and all motion action, mode of operation select and oil cylinder limit switch, electric motor protecting detection signal, temperature detection signal are all connected to the input point of PLC; Output point connects the b pole (PNP pipe) or the negative pole of control relay that cause transistor driving plate.Simultaneously PLC also serves as the computing of Stress control data, the process of A/D modular converter data, the monitoring in control time, each action control, is control centre.
The oily trigger that pressure sensor is installed on hydraulic system is connected with hydraulic cylinder, connects by pair twist shielded signal line the detection that the input point causing A/D modular converter realizes pressure.
A/D modular converter is connected with the expansion mouth of PLC by integrated wire arrangement, and the input point of A/D modular converter is connected in sensor, sends PLC to after the analog signal for pressure sensor feeds back being come changes into data signal.
Control relay plays transitional function, and its coil is DC24V, and relay coil is directly connected with PLC output point, by PLC Direct driver; Be connected with the electromagnet of the AC220V normally-closed contact of (mainly steam enters valve etc.) and thermal overload relay of the normally opened contact of control relay is connected.
A.C. contactor is for controlling the work of motor; Main contact end of incoming cables is directly opened with sky and is connected, and leading-out terminal is connected with thermal overload relay, and coil is connected with the normally-closed contact of thermal overload relay.
Thermal overload relay is used for the overload protection of motor, and end of incoming cables is connected with the leading-out terminal of A.C. contactor, and leading-out terminal is connected with motor, and normally opened contact is connected with PLC input point, and normally-closed contact is connected with the coil of A.C. contactor.
Temperature controller is for detecting vapor (steam) temperature; Input connects K type thermocouple (the installation of TC is on jet chimney), export a switching signal, therefore output is connected when output reaches control temperature with the input of PLC.The signal that temperature controller sends is controlled the action of relevant air valve after PLC process by PLC.
Transistor driving plate also plays a transition role; Its function control relay is identical.Its b pole is connected with PLC output, and e pole is connected with Switching Power Supply positive pole, and c pole is connected with hydraulic valve electromagnet, working station indicator, control relay.
Switching Power Supply is used for for the direct current device of DC24V is powered; Input is connected with fuse, and output is connected with touch-screen, PLC, transistor driving plate, control relay, hydraulic valve work of electromagnet status indicator lamp.
A control method for PLC control system, comprises the following steps:
Step 1, to PLC power-up initializing;
Step 2, above-mentioned PLC have judged whether operation requests, as standby in then do not continued, and if any operation requests, then whether be automatically control request, if not being automatic request, then transfer manual operation to if detecting;
Step 3, as above-mentioned PLC is detected as automatic control, then starts operation of oil pump, be pressurized to setup pressure value to master cylinder, described oil pump is divided into speed oil pump and ftercompction oil pump;
Step 4, be pressurized to setting value as master cylinder, then PLC controls the air bleeding valve of plastic floor vulcanizer, draining valve, drain valve, steam enter valve and cooling water enters the opening and closing of valve, PLC controls the running of speed oil pump and ftercompction oil pump simultaneously, thus control master cylinder is pressurized to setting value, completes plastic floor vulcanizer job control;
Step 5, the above-mentioned oil cylinder completing plastic floor vulcanizer job control under PLC controls pressure release to being less than setup pressure value.
Wherein, the setup pressure value in step 3 and step 5 is 1Mpa.
Air bleeding valve in step 4, draining valve, drain valve, steam enter the opening and closing that valve and cooling water enter valve and comprise the following steps:
Step 401, control draining valve and drain valve by PLC and open, and set the time of opening, timing while opening draining valve and drain valve;
Step 402, as above-mentioned steps 401 timing time arrives, then by drain shut valve, drain valve continues to open, and steam enters valve and opens, simultaneously setting-up time, and timing simultaneously;
Step 403, timing time as above-mentioned steps 402 arrive, then open air bleeding valve, close drain valve, and steam off enters valve and opens cooling water and enters valve, and setting-up time, timing simultaneously;
Step 404, timing time as above-mentioned steps 403 arrive, then close air bleeding valve, open draining valve, and steam off enters valve and opens cooling water and enters valve, and setting-up time, timing simultaneously;
Step 405, to arrive as above-mentioned steps 404 timing time, then air bleeding valve, draining valve, drain valve, steam are entered valve and cooling water and enter valve and all close.
In step 4, PLC controls the running of speed oil pump and ftercompction oil pump, thus control master cylinder is pressurized to setting value, completes plastic floor vulcanizer job control and comprises the following steps:
Step 501, control speed oil pump stop, and ftercompction oil pump runs, thus is pressurized to the first setup pressure value, when reaching the first setup pressure value, just control ftercompction oil pump to close, and timing is carried out to the working time of the first force value, judge the working time under the first force value and operating pressure;
Working time under the first force value in step 502, above-mentioned steps 501 and operating pressure all meet the requirements, then start ftercompction oil pump, thus be pressurized to the second setup pressure value, when reaching the second setup pressure value, just control ftercompction oil pump to close, and timing is carried out to the working time of the second force value, judge the working time under the second force value and operating pressure; Repetitive controller ftercompction oil pump, until be pressurized to the 4th setup pressure value, completes master cylinder pressurization.
As follows according to manufacture craft control overflow:
1) whole manufacture craft requires to realize three sections of Stress control and continuously, controlled pressure resolution ratio is 0.1Mpa, oscillatory pressure range ± 0.3Mpa and fluctuation range can set (as: first paragraph: 8Mpa, 25Min between 0.1 ~ 0.3; Second segment: 15Mpa, 45Min; 3rd section: 18Mpa, 12Min);
2) three Stress control periods can set at any time between 0 ~ 99Min99S, and come into force after having set;
3) each pressure setting parameter, time parameter all completes at touch-screen, and will possess power-failure memory;
4) can show board working stage in real time, can send acousto-optic index signal after each operation completes, board also declines automatically;
5) heating-up temperature can on temperature controller free setting.
Vulcanizer machine divides left and right sides two parts and symmetrical.The cylinder diameter of the left and right sides is about 600mm(to be determined according to operating pressure) piston stroke is about 900mm.The working method of left and right two cylinders is identical, but left and right sides oil cylinder can not ftercompction simultaneously.What be in two oil cylinders centres is fuel tank, and speed oil pump motor, ftercompction Oil pump electrical machinery, oil circuit conglomerate and control cabinet are arranged on fuel tank.
Under oil cylinder and fuel tank are all in ground, the ground degree of depth is about 1.2m.Bearing plate, control cabinet are in about 500mm place on level ground.
The operative body of machine divides right side and left side.Primarily of hydraulic cylinder and bearing plate composition.Hydraulic cylinder mainly provides pressing pressure (pressure requirements is more stable), and bearing plate, for holding the product that need suppress, is equipped with circulation pipe bearing plate side in the middle of bearing plate, and circulation pipe bearing plate side has a high steam inlet port and one to be outlet.Circulation pipe bearing plate also must cool except adding the additional cooling water of circulation pipe simultaneously in circulation pipe.Wherein the board top of left side operative body is that high steam enters valve and cooling water enters valve.
Primarily of fuse, PLC and A/D modular converter, control relay, A.C. contactor, thermal overload relay, transistor driving plate, Switching Power Supply composition in control cabinet.
Left side ground edge is air bleeding valve, draining valve, drain valve.
Control cabinet can realize the manual adjustment of left and right two cylinders and automatically control two kinds of working methods, is selected by the selector switch on guidance panel.
Fuel tank and complete machine hydraulic oil store and circulation place, in order to the needs that dispel the heat, so volume should be selected larger.The technical program selects volume to be greater than 1m3.
Be that after the Control System Design of core, installation and programming have been debugged, the function of machine also can realize with PLC, but the oil cylinder working-pressure of machine control to owe accurately.Arrive accurate pressure and control quite difficulty.Usage ratio valve then easily realizes accurate pressure and controls, and in debug process, to have carried out corresponding improvement as follows for this programme:
To the improvement of ftercompction motor
Can in time pressure be filled when occurring needing ftercompction action to the requirement of ftercompction motor.If setting pressure is determined n, master cylinder actual pressure is m.When after ftercompction, m>(n+0.3 appears in pressure) namely actual pressure be greater than the setting pressure upper limit, now should carry out release.When occurring m<(n-0.3 after pressure-relief valve action) actual pressure, now should ftercompction lower than setting pressure lower limit like this.So again and again, contactor frequent movement, motor frequent starting.
In the process of debugging, find that ftercompction motor speed is the key factor affecting pressure controling precision.If ftercompction motor speed is slow, then oil pump capacity is low, and ftercompction is slow, and PLC is long for detection time, then precision is high.Otherwise then precision is low.Just started ftercompction oil pump and adopted 7.5KW4 pole motor, motor speed high oil pump flow is large.Be difficult to during ftercompction control flow, after using 6 pole motors instead, rotating speed reduces flow also step-down, and ftercompction slows, and pressure controling precision significantly improves.
Hydraulic system is improved
Occur in debug process that the phenomenon of release excessive velocities causes because of the reason that pressure-relief valve flow is larger.Adoption rate flow valve is controlled cost and can be uprised, and does not therefore consider to use.Now we have employed following several method and control release speed.
1) depressurized circuit installs choke valve additional; Installing choke valve additional can manual adjustments release speed, and have larger flexibility, release speed can adjust according to actual conditions.
2) damping sheet is installed additional; Namely make under one piece of backing plate is installed at pressure-relief valve, backing plate is separately made a call to a through hole less than through hole on valve body and works as throttling use with this, this way cost is low.But release speed is non-adjustable, flexibility is not high.
3) become backhaul release and work release two parts in hydraulic control partial design, two parts work alone.Release when namely working uses slow release, then can controlled pressure very well.Worked the fast release of rear use, would not affect overall operating efficiency like this.
Above first and second kinds of methods can play good control action to the speed of release, but the work that simultaneously also directly affects complete after time of release, so still impact is created to whole work efficiency.Can consider in this case to adopt third method.
Ftercompction control method is improved
For maintaining metastable pressure, system requirements ftercompction speed, therefore motor understands frequent starting unavoidably, and motor is bringing onto load startup.This is just easy to cause motor damage, also have impact on electrical network and line voltage is often fluctuated.
Because motor needs the regular hour from starting to stable operation.Can consider to be written as electric motor starting when coding and after stable operation, ftercompction magnetic valve just starts action, namely magnetic valve deferred action is not with control contactor synchronization action.So both can alleviate load during electric motor starting, also can reduce the capacity selecting contactor.Certainly situation will see the design of hydraulic system like this, and when design of Hydraulic System becomes bringing onto load to start, then the capacity of contactor will select larger 5 times of being at least rated current.
To the selection of ftercompction electric motor protecting device
Ordinary circumstance can select thermal overload relay to protect motor, but just inapplicable in such occasion.Because motor frequent starting, so we can not ignore probe of contactor welding problems.Just in case occur contact melting welding and ftercompction complete after PLC still control contactor disconnect, now due to motor phase failure, although thermal overload can send overload signal but also be of no avail.Therefore, electric motor protecting part should adopt motor heating magnetic circuit breaker and auxiliary contact to replace the protection device of thermal overload relay as motor.
Last it is noted that the foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, although with reference to previous embodiment to invention has been detailed description, for a person skilled in the art, it still can be modified to the technical scheme described in foregoing embodiments, or carries out equivalent replacement to wherein portion of techniques feature.Within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.