CN101488009A

CN101488009A - System for transferring frequency convertor PID function by PLC/DCS single-channel correcting feedback

Info

Publication number: CN101488009A
Application number: CNA200810300127XA
Authority: CN
Inventors: 宦述晓
Original assignee: Guiyang Aluminum Magnesium Design and Research Institute Co Ltd
Current assignee: Guiyang Aluminum Magnesium Design and Research Institute Co Ltd
Priority date: 2008-01-16
Filing date: 2008-01-16
Publication date: 2009-07-22
Anticipated expiration: 2028-01-16
Also published as: CN101488009B

Abstract

The invention discloses a system with a PLC/DCS single channel frequency converter used for with a PID function. The system comprises the frequency converter with an internal PID function, a PLC/DCS module and an electric motor speed adjustment module, wherein a virtual process parameter set value Y1 is set in internal parameters of the frequency converter with the internal PID function and an actual process parameter feedback value X is output; the PLC/DCS module is connected with the frequency converter with the internal PID function, receives the actual process parameter feedback value X, generates a revision process parameter feedback value X1 and inputs the feedback value X1 to the frequency converter with the PID function; the electric motor speed adjustment module is connected with the frequency converter with the internal PID function and receives actual process parameter X and changes the rotate speed of the electric motor connected with the speed adjustment module depending on the actual process parameter X. With the internal PID function of the frequency converter adopted, the system of the invention can examine the working condition of the electric motor, thus ensuring smooth adjustment curve, simplified PLC/DCS process, stable use of the frequency converter, high speed of execution, low cost and good use effect.

Description

PLC/DCS single channel correction feedback is called the system of frequency convertor PID function

Technical field

The present invention relates to a kind of parameter setting system of aluminium frequency converter hardware, especially a kind of PLC/DCS single channel correction feedback is called the system of frequency convertor PID function.

Background technology

At present, the aluminium industry is regulated at present usually the output frequency of frequency converter by the output of the analog quantity of PLC/DCS, to regulate the rotating speed of variable frequency drive motors, thereby make certain technological parameter satisfy technological requirement, for example: the rotating speed of regulating blower fan, regulate the top hole pressure of blower fan, it is remained on about setting value; Regulate the rotating speed of batcher, regulate feeding coal, it is remained on about setting value; Regulate the rotating speed of shurry pump, regulate the flow of slip, it is remained on about setting value.The frequency converter working stability is regulated fast, and energy-conservation characteristics adopt in a large number in the aluminium industry.Technological parameter input PLC/DCS, the processing parameter setting value is set on host computer, and all need show on host computer.The mode that aluminum current industry PLC/DCS regulates frequency converter has following two kinds: (0～10V) single channel analog quantity speed-regulating signal is directly regulated frequency converter to a kind of PLC/DCS of being output 4～20mA, its execution is regulated and is finished by program, PID module arithmetic program execution time is long, if particularly many or PID of frequency converter regulates more in the control system, will cause program execution time long, the control system corresponding speed is slow, adjustment curve is unsmooth, when value of feedback and setting value differed big, the adjusting time was corresponding longer; Another kind is that (0～10V) road analog signals is to frequency converter for PLC/DCS output two-channel 2-4 a 4～20mA, utilization frequency converter in-built PID function is regulated the output of frequency converter, an analog signals is the feedback signal of technological parameter, one is setup parameter, utilization frequency converter in-built PID function is regulated the output of frequency converter, this method characteristics are to carry out to regulate to be finished by frequency converter, though decentralized adjusting control, simplified process, the PLC/DCS program does not have the PID module, program execution speed is fast, and adjustment curve is level and smooth; But increased a signal cable more, increased cost.And above-mentioned PLC/DCS list/binary channels frequency converter control method all has a shortcoming, at motor on the spot under the manual control mode, owing to there is not the output of PLC/DCS control and analog quantity, frequency converter does not have the input of speed conditioning signal and setting signal, operating personnel start frequency converter and motor on the button box on the spot at motor, motor speed is zero, does not rotate, and can't check whether motor work is normal.

Summary of the invention

The objective of the invention is to, provide a kind of PLC/DCS single channel correction feedback to call the system of frequency convertor PID function.The frequency converter working stability of this system, adjustment curve is level and smooth, and the PLC/DCS process is simplified, and execution speed is fast, and is with low cost, can check whether motor work is normal, to overcome the deficiencies in the prior art.

Technical scheme of the present invention is: PLC/DCS single channel correction feedback is called the system of frequency convertor PID function, comprising:

The frequency converter of internal PID function is provided with a virtual processing parameter setting value Y1, and exports an actual process parameter feedback value X in the inner parameter of the frequency converter of internal PID function;

The PLC/DCS module is connected with the frequency converter of described internal PID function, receives actual process parameter feedback value X, and produces a correction process parameter feedback value X 1, is entered in the frequency converter of internal PID function;

The motor speed adjustment module is connected with the frequency converter of internal PID function, and receives actual process parameter X, changes connected rotating speed of motor by actual process parameter X.

Described correction process parameter feedback value X 1, calculate by formula X1=(Y1-Y)+X in the PLC/DCS module, wherein Y1 is virtual processing parameter setting value Y1, and Y is actual process parameter setting value Y, actual process parameter X is identical with actual process parameter feedback value X, is X.

Described correction process parameter feedback value X 1 calculates by formula X1=(Y1-Y)+X in the PLC/DCS module, and wherein Y is actual process parameter setting value Y.

The range limit value that described virtual processing parameter setting value Y1 is a technological parameter.

The frequency converter of described internal PID function is connected with a Frequency Converter Control dish.

Compared with the prior art, the present invention utilizes frequency converter in-built PID function, under motor is on the spot manual control mode, the PLC/DCS module is the control of conversion device not, and the value of feedback that exports frequency converter to is 0, frequency converter always acceleration motor to maximum speed, motor moves with rated speed like this, can check the working condition of motor, guarantee that adjustment curve is level and smooth, the PLC/DCS process is simplified, frequency converter uses stable, execution speed is fast, and is with low cost, and result of use is good.

Description of drawings

Fig. 1 is a structured flowchart of the present invention.

Embodiment

Embodiment: PLC/DCS single channel correction feedback is called the system of frequency convertor PID function, comprise: the frequency converter of internal PID function, in the inner parameter of the frequency converter of internal PID function, a virtual processing parameter setting value Y1 is set, Y1 is the range limit value of technological parameter, and be connected the Frequency Converter Control dish by one with it virtual processing parameter setting value Y1 is input in the frequency converter of internal PID function, and export an actual process parameter feedback value X; The PLC/DCS module is connected with the frequency converter of internal PID function, receive actual process parameter feedback value X, in the PLC/DCS module, calculate one of generation and revise process parameter feedback value X 1 by formula X1=(Y1-Y)+X, wherein Y is actual process parameter setting value Y, is input in the frequency converter of internal PID function revising process parameter feedback value X 1; The motor speed adjustment module is connected with the frequency converter of internal PID function, and receives actual process parameter X, changes connected rotating speed of motor by actual process parameter X again.

Certain engineering AB-PLC control system needs to regulate blower speed by the ABB-frequency converter and regulates blower fan top hole pressure (sensor measurement scope 0～10000Pa, scope of design 0～7200Pa), (3000～6000Pa), the motor rated speed is 2950rpm to make it remain on working set value; The PLC/DCS module has only an analog output channel to frequency converter.Requirement shows actual blower fan top hole pressure X on host computer, set actual blower fan top hole pressure Y on host computer, and the actual blower fan top hole pressure X of record, draws pressure X-time curve.

When converter parameter is set, call the PID function of frequency converter, setting the motor maximum speed is 2950rmp, the virtual pressure parameter setting value Y1 of frequency convertor PID is imported by the Frequency Converter Control dish, be set at 80% (Y1=80%, corresponding 6000Pa), will revise pressure parameter feedback value X 1 by among the frequency converter A I1 mouth input converter PID; The time constant of frequency convertor PID, proportion integration differentiation constant are set according to actual conditions.

The artificial blower fan top hole pressure setting value Y that sets (can change on host computer, such as Y=66.7%, corresponding 5000Pa), with blower fan outlet pressure sensor signal X (4500～5500Pa, corresponding 60%～73.3%) input PLC/DCS module, in the PLC/DCS modular program, carry out computing, following formula:

X1＝(Y1-Y)+X

The PLC/DCS module inputs to single channel analog signals X1 (72.3%～85.6%) in the frequency convertor PID by frequency converter A I1 mouth; Frequency convertor PID is regulated motor speed according to virtual pressure set points Y1 and correction pressure feedback value X1, makes and the actual pressure feedback value X approaches actual pressure setting value Y; According to the actual debug results of engineering, the frequency converter working stability, adjustment curve is level and smooth, and the PLC/DCS process is simplified, and result of use is fine.

The feedback value X 1 that frequency converter obtains is revised, has compared a recruitment (Y1-Y) with the actual process feedback value X, and this recruitment just includes actual process parameter setting value Y, and formula is become:

(Y-X)＝(Y1-X1)

Virtual as can be seen setting value is identical with the difference of the difference of revised value of feedback and actual set value and actual feedback.

If actual process setting value Y=75%, actual process feedback value X=70%, frequency converter obtain to such an extent that modification process feedback value is X1=75%, virtual technique initialization value is Y1=80%, the PID of frequency converter heightens motor speed, makes X1 near Y1=80%, and X also just approaches Y=75% simultaneously.

If actual process setting value Y=75%, actual process feedback value X=80%, frequency converter obtain to such an extent that value of feedback is 85%, setting value is 80%, and the PID of frequency converter turns down motor speed, makes X1 near Y1=80%, and X also just approaches Y=75% simultaneously.

Under motor is on the spot manual control mode, the PLC/DCS module is the control of conversion device not, export frequency converter X1=0 to, frequency converter always acceleration motor to maximum speed (generally being set at the rated speed of motor) by frequency converter, motor moves with rated speed like this, can check the working condition of motor.

Claims

[claim 1] a kind of PLC/DCS single channel correction feedback is called the system of frequency convertor PID function, comprising:

The frequency converter of internal PID function is provided with a virtual processing parameter setting value Y1, and exports an actual process parameter feedback value X in the inner parameter of the frequency converter of internal PID function;

The PLC/DCS module is connected with the frequency converter of described internal PID function, receives actual process parameter feedback value X, and produces a correction process parameter feedback value X 1, is entered in the frequency converter of internal PID function;

The actual process parameter feedback value of on-the-spot input is given PLC/DCS, and PLC/DCS is last to set actual setting value Y, and process parameter feedback value X 1 is revised in output; Frequency converter is according to setting value Y1, and feedback value X 1 is regulated motor speed and regulated feedback value X, and it is remained on about setting value Y.
[claim 2] PLC/DCS single channel according to claim 1 correction feedback is called the system of frequency convertor PID function, it is characterized in that: revise process parameter feedback value X 1, in the PLC/DCS module, calculate by formula X1=(Y1-Y)+X, wherein Y is actual process parameter setting value Y, actual process parameter X is identical with actual process parameter feedback value X, is X.
[claim 3] PLC/DCS single channel according to claim 1 and 2 correction feedback is called the system of frequency convertor PID function, and it is characterized in that: virtual processing parameter setting value Y1 is the range limit value of technological parameter.