Background technology
DKJ type electric actuator is the performance element in the DDZ type DDZ, and it accepts the control signal of upper instrument, automatically handles topworks and finishes position control such as equipment such as air door, baffle plate, water valve, valves.As shown in Figure 4, DKJ type electric actuator is made up of servoamplifier 1, servomotor 2, speed reduction unit 3 and position transmitter 4.When needs change the aperture of valve, last level controller sends valve position steering order (being generally 4~20mA current signal) and gives servoamplifier 1, the positive input that is servoamplifier 1 has the signal input, the position feed back signal of this signal and the opposite polarity valve position of being measured by position transmitter 4 compares, deviation signal is relatively amplified through servoamplifier 1, make the power level of servoamplifier 1 that enough power output be arranged, form with the 220V alternating current drives two phase servomotor 2 forward or reverse, the output torque of servomotor 2 is transformed into low-speed and large-torque output through speed reduction unit 3, rotates to drive load (valve).The rotation direction of speed reduction unit 3 output shafts is always rotated towards the bias direction that reduces input signal and position feed back signal.When deviation signal is zero (less than the dead band of servoamplifier 1), be that the position feed back signal of valve position is when equaling the valve position control signal, servoamplifier 1 no-output, the forward or reverse control signal of servomotor 2 disappears, this moment speed reduction unit 3 output shafts and load (valve) just be parked in the corresponding position of valve position control signal on, finish once and regulate, the valve position control signal constantly changes, and topworks also just constantly follows adjustment.
Servoamplifier 1 and position transmitter 4 are core components of DKJ type electric actuator, and it is directly connected to the reliability of electric actuator work.But present servoamplifier 1 and position transmitter 4 reliabilities are very poor, and zero point drift is serious, fluctuation of service, and frequent fault, generally be no more than half a year normal working hours, and the use that has is just bad less than one month.In addition, equipment jam phenomenons such as valve, air door often appear in the scene, and there are deviation in the position feed back signal of valve position at this moment and valve position steering order, and servoamplifier 1 is exported the 220V alternating current all the time and driven servomotor 2, and servomotor 2 because of the valve jam by stall, be easy to overcurrent and burnt.
In recent years, traditional DDZ type DDZ control system changes DCS (Distributed Control System, dcs) in succession into, and the unreliable problem of electric actuator is more outstanding, becomes the biggest obstacle that DCS transforms.For solving this type of problem, many enterprises have to eliminate such actuator, give a long price for collection and watch import " electrical header " actuator that is put in one.The price of " electrical header " actuator is more than 3 times of electric actuator, and maintenance cycle is long, the maintenance cost height.Along with the quality of DCS improves and popularization and application, the price of DCS is in continuous decline, and the price of import " electrical header " actuator shared proportion in The whole control system is increasing, even surpasses DCS, causes very big financial burden to enterprise.Therefore, press for the research and development new technology, original electric actuator is used, reduce investment outlay.
Summary of the invention
The objective of the invention is to overcome the insecure problem of electric actuator performance, a kind of servoamplifier and position transmitter of soft servo replacement electric actuator is provided, design a kind of pulse control method of electric activator.
The device that the present invention is based on is made up of controller, servomotor, speed reduction unit and the position transmitter of DCS, the departure of the valve real opening value of opening value that the valve preparation reaches and position transmitter feedback is adjusted outgoing position increment control servomotor forward or reverse servomotor drive speed reduction unit through the controller of DCS and is turned to the respective angles position
Adjusting valve opening in each sampling period may further comprise the steps:
The controller of step a:DCS receives the valve opening control increment du that calculates in the sampling period;
Step b: calculate speed reduction unit output quantity du_out, speed reduction unit output quantity du_out equals the speed reduction unit output quantity that the previous sampling period passes over and adds the valve opening control increment du that calculates in this sampling period;
Step c: judge whether speed reduction unit output quantity du_out satisfies condition | du_out|>SC, wherein SC is the dead band of electric actuator;
Judged result is for being to carry out next step; Judged result is not adjusted aperture for not in this sampling period, the speed reduction unit no-output, and this sampling period finishes;
Steps d: judge speed reduction unit output quantity du_out du_out>0 that whether satisfies condition,
Judged result is for being execution in step e; Judged result is for denying execution in step f;
Step e: judge jam sign flag_ks flag_ks>0 that whether satisfies condition,
Judged result is not adjusted aperture for being in this sampling period, the speed reduction unit no-output, and this sampling period finishes; Judged result is for denying execution in step g;
Step f: judge jam sign flag_ks flag_ks<0 that whether satisfies condition,
Judged result is not adjusted aperture for being in this sampling period, the speed reduction unit no-output, and this sampling period finishes; Judged result is for denying execution in step h;
Step g: the output width is Δ t, amplitude is that the pulse voltage of 220V is given servomotor, and the control servomotor just changes, pulse width Δ t=(| du_out|/100) * T_all, wherein T_all is the omnidistance time of speed reduction unit, i.e. required time when aperture 0 reaches full scale 100 continuously; Execution in step i then,
Step h: the output width is Δ t, amplitude is that the pulse voltage of 220V is given servomotor, the counter-rotating of control servomotor, pulse width Δ t=(| du_out|/100) * T_all, wherein T_all is the omnidistance time of speed reduction unit, i.e. required time when aperture 0 reaches full scale 100 continuously;
Step I: judge whether jam of valve;
Judged result is for being to carry out next step; Judged result is not, and this sampling period is adjusted and finishes;
Step j:DCS warning is exported to operator station and is carried out respective handling, and speed reduction unit output quantity du_out=0 is set,
Step k: whether receive DCS and confirm to dispose instruction,
Judged result is for being, execution in step l, and judged result finishes this adjustment for not,
Step l: jam sign flag_ks=0 is set,
This sampling period finishes.
Advantage of the present invention is:
1, abandons unsettled servoamplifier, significantly improved the stability and the reliability of electric actuator work;
2, stopped the situation that causes the servomotor of electric actuator to burn because of equipment jams such as valve, air doors;
3, saved great amount of investment.
Embodiment
Embodiment one: present embodiment is described below in conjunction with Fig. 1, Fig. 3, present embodiment based on device form by controller 5, servomotor 2, speed reduction unit 3 and the position transmitter 4 of DCS, the departure of the valve real opening value of opening value that the valve preparation reaches and position transmitter 4 feedbacks is adjusted outgoing position increment control servomotor 2 forward or reverse through the controller 5 of DCS, servomotor 2 drives speed reduction unit 3 and turns to the respective angles position
Adjusting valve opening in each sampling period may further comprise the steps:
The controller 5 of step a:DCS receives the valve opening control increment du that calculates in the sampling period;
Step b: calculate speed reduction unit 3 output quantity du_out, speed reduction unit 3 output quantity du_out equal the speed reduction unit output quantity that the previous sampling period passes over and add the valve opening control increment du that calculates in this sampling period;
Step c: judge whether speed reduction unit 3 output quantity du_out satisfy condition | du_out|>SC, wherein SC is the dead band of electric actuator;
The dead band SC of electric actuator is generally between the 1-1.5 aperture.
Judged result is for being to carry out next step; Judged result is not adjusted aperture for not in this sampling period, speed reduction unit 3 no-outputs, and this sampling period finishes;
Steps d: judge speed reduction unit 3 output quantity du_out du_out>0 that whether satisfies condition,
Judged result is for being execution in step e; Judged result is for denying execution in step f;
Step e: judge jam sign flag_ks flag_ks>0 that whether satisfies condition, jam sign flag_ks has three kinds of states, and flag_ks=0 explanation valve does not have jam, flag_ks=+1 explanation valve forward jam, the reverse jam of flag_ks=-1 explanation valve.
Judged result is not adjusted aperture for being in this sampling period, speed reduction unit 3 no-outputs, and this sampling period finishes; Judged result is for denying execution in step g;
Step f: judge jam sign flag_ks flag_ks<0 that whether satisfies condition,
Judged result is not adjusted aperture for being in this sampling period, speed reduction unit 3 no-outputs, and this sampling period finishes; Judged result is for denying execution in step h;
Step g: the output width is Δ t, amplitude is that the pulse voltage of 220V is given servomotor 2, control servomotor 2 is just changeing, pulse width Δ t=(| du_out|/100) * T_all, wherein T_all is the omnidistance times of speed reduction unit 3, i.e. required time when aperture 0 reaches full scale 100 continuously, the omnidistance mechanical angle scope of speed reduction unit 3 operations is 0 °~90 °, represent that with aperture then corresponding numerical value is aperture 0~full scale 100; Execution in step i then,
Step h: the output width is Δ t, amplitude is that the pulse voltage of 220V is given servomotor 2,2 counter-rotatings of control servomotor, pulse width Δ t=(| du_out|/100) * T_all, wherein T_all is the omnidistance times of speed reduction unit 3, i.e. required time when aperture 0 reaches full scale 100 continuously;
Step I: judge whether jam of valve;
Judged result is for being to carry out next step; Judged result is not, and this sampling period is adjusted and finishes;
Step j:DCS warning is exported to operator station and is carried out respective handling, and speed reduction unit 3 output quantity du_out=0 are set,
Step k: whether receive DCS and confirm to dispose instruction,
Judged result is for being, execution in step l, and judged result finishes this adjustment for not,
Step l: jam sign flag_ks=0 is set,
The operator can assign the instruction that an affirmation disposes after having carried out corresponding fault handling and having solved fault, if receive this instruction, means that the valve stuck issue solves, then with jam sign flag_ks zero clearing.
This sampling period finishes.
Need the aperture increment du of the valve of adjustment can once not load to electric actuator, finish but substep experiences several sampling periods, be divided into several sections and depend on step-length, described step-length is set by program, generally speaking, if PID control, then step-length≤4; If Fuzzy controls (fuzzy control), step-length<10, after setting first pulse can not occur and sends like this, electric actuator also not carry out and finishes, and the next sampling period is sent out the phenomenon of another pulse again.The control program of pulse control method of electric activator of the present invention and DCS is used, and has reached excellent control effect.
Because the aperture increment du of the valve that need adjust is divided into plurality of sections according to the step-length of DCS program setting, the valve opening control increment du that calculates in each sampling period might be less than dead band SC, the speed reduction unit 3 output quantity du_out in this sampling period need be accumulated to like this in the next sampling period, can carry out next step in case the absolute value of the speed reduction unit 3 output quantity du_out in sampling period surpasses dead band SC.
Before giving servomotor 2 output pulses, judge the state of jam sign flag_ks earlier, speed reduction unit 3 output quantity du_out>0, read-me is assigned instruction allows speed reduction unit 3 drive valves be rotated in the forward, at this moment need to judge whether valve is in forward jam state, if valve is in forward jam state, then can not give the pulse of servomotor 2 output forwards again, otherwise servomotor 2 can burn because of overcurrent.
Speed reduction unit 3 output quantity du_out<0, read-me is assigned instruction allows speed reduction unit 3 drive the valve reverse rotation, at this moment need to judge whether valve is in reverse jam state, if valve is in reverse jam state, then can not give servomotor 2 outputs reverse pulse again, otherwise servomotor 2 can burn because of overcurrent.
The design of this step of the present invention overcome the conventional electric actuator when the valve jam because there are deviation for a long time in valve position feedback signal and valve position control signal, cause servoamplifier 1 to export the 220V alternating current all the time and drive servomotor 2, and the problem that causes servomotor 2 overcurrents to burn.
Embodiment two: below in conjunction with Fig. 2 present embodiment is described, the difference of present embodiment and embodiment one is, step I judge valve whether the method for jam comprise following step:
Step I-1: time-delay 2 * | Δ t|, calculate valve position variation delta FW=FW-FW_1, wherein FW is the valve position amount of this measurement, FW_1 is the valve position amount of measuring last time,
The purpose of time-delay a period of time is to consider that rotate command that speed reduction unit 3 executive routines are assigned will reach predetermined target and need the regular hour, do not measure at once if do not delay time, the valve position signal that measures is inaccurate, but it is oversize to delay time again, surpass the sampling period as time-delay and then can jump to the next sampling period, it is chaotic that program is taken place, and the length in sampling period is defined voluntarily by program.
Step I-2: judge whether valve position variation delta FW satisfies condition | Δ FW|>0.5|du_out|,
Judged result finishes this adjustment for being, judged result is not, execution in step i-3,
If | Δ FW|>0.5|du_out|, we think that valve position changes, valve does not have jam;
Step I-3: judge whether speed reduction unit 3 output quantity du_out satisfy condition | du_out|>SC,
Judged result is for being, execution in step i-4, and judged result is not for, execution in step i-5,
Step I-4: jam sign flag_ks=+1 is set, is just changeing jam, whether jam is judged end to valve, and redirect is gone out, execution in step j,
Step I-5: jam sign flag_ks=-1 is set, the counter-rotating jam.
If | Δ FW|<0.5|du_out|, judge the valve position no change, valve is in the jam state, need judge that at this moment valve is forward jam or reverse jam, if | du_out|>SC, judgement is a valve forward jam, and jam sign flag_ks=+1 is set, if | du_out|<SC, judgement is the reverse jam of valve, and jam sign flag_ks=-1 is set, the function of jam sign flag_ks set is to use during for follow-up program run.
Other is identical with embodiment one.