CN2159416Y - Simple and reliable controller for constant pressure water supply - Google Patents

Abstract

The utility model discloses a simple and reliable controller for constant pressure water supply. The controller realizes compact and reliable closed loop control by a self-editing PID regulation subprogram added to an EPROM in a frequency converter and a primary panel frequency setting changed to a pressure setting, and can cooperate with a programmable controller to realize the mutual switching control of a plurality of pumps, thereby, the effect of saving energy is achieved. The utility model spurns conventional external PID controller or PIC with analog input and analog output. The utility model simplifies the hardware design, the installation, and the regulation, and enhances the reliability of products.

Description

Simple and reliable controller for constant pressure water supply

The utility model relates to the power electronics control device, more particularly, relates to a kind of control device of building constant pressure water supply.

Present constant pressure water supply controller mostly adopts PID adjuster or single board computer or has mould goes into the programmable logic controller that goes out with mould, by the processing from the 4-20MA current signal of pressure sensor is removed to control the output frequency of frequency converter, thereby reach the purpose that the control of pump rotating speed is realized constant pressure water supply.Because of PID regulator operations complexity, price is expensive; Though the single board computer cost is low, poor reliability, to go into the PLC that goes out with mould very expensive and have mould, gives to use and popularization brings obstacle.

On the other hand, the VCD frequency converter that prior art adopted is in the open loop state of a control, its panel only has two buttons that make the frequency lifting, the user regulates water system pressure and then must could realize by being located at single board computer or having the control button that mould goes on the PLC that goes out with mould, one operations are not easy, and the two has increased system complexity.

The purpose of this utility model provides and a kind ofly overcomes the cost of prior art and the shortcoming that reliability can not be taken into account, and has structure and use the constant pressure water supply system controller of characteristics such as simple.

The purpose of this utility model is achieved in that a kind of controller that only needs that without external regulator filter a PID adjusting program is added to EPROM in the frequency converter and then realize closed-loop control of structure.The detailed process that the PID program is added in the frequency converter is:

(1) lid of VCD frequency converter is opened, the EPROM program block is dialled down with driver-extractor.

(2) go out whole 16K programs with simulating developer is machine-readable, with 8096 inverse assembler dis-assemblings.

(3) add long call instruction at the 0688H place, make it call 3000H virgin program.

(4) deposit the PID subprogram at the 3000H place.

(5) the original program piece is wiped with eraser, new procedures is solidified into.

Constant pressure water supply controller of the present utility model comprises a VCD frequency converter and a pressure sensor, it is characterized in that, comprise among the EPROM in the described VCD frequency converter that the PID that an initial address is second address regulates subprogram, first address among the described EPROM comprises a PID who points to described second address and regulates the long call instruction of subprogram, and "+" end of described pressure sensor is connected with current input terminal (IV) with the power output end (P24) of described VCD frequency converter respectively with "-" end.

Constant pressure water supply controller of the present utility model, also can comprise a programmable logic controller PLC and a plurality of contactor, described programmable logic controller has 3 sub-X1-X3 of 24V direct-flow input end at least, and 8 sub-Y1-Y8 of relay output end, it is 0 output signal LOW and alarm output signal FLA that the X1 of described programmable logic controller, X2, three input terminals of X3 receive the output signal RCH, the indication frequency that reach the 50HZ power frequency from the indication frequency of described VCD frequency converter respectively; In 8 lead-out terminals of described programmable logic controller PLC, Y1-Y6 receives among 6 contactor JC1-JC6 the control end of each respectively, and the F end that Y7 is connected to described VCD frequency converter just changes in order to control it; Y8 is connected to the RST end of described VCD frequency converter in order to it is resetted, and a link of JC1, the JC3 in described 6 contactors, each of JC5 is connected with the frequency conversion output of described frequency converter; The link of each is received the power frequency input among JC2, JC4 in described 6 contactors, the JC6, another link of JC1 and JC2 is connected to each other and is in the same place in the described contactor, another link of JC3 and JC4 is in the same place each other in the described contactor, and the link that adds of JC5 in the described contact and JC6 is connected to each other.

Described first address in the constant pressure water supply controller described in the utility model can be 0688H, and described second address is 3000H.

Implement constant pressure water supply controller of the present utility model, the user only needs to set operating pressure by the frequency converter panel, do not re-use outside PID adjuster or have mould and go into the PLC that (A/D) phase mould goes out (D/A), simplified hardware design, Installation and Debugging and use, improved product reliability yet.

In conjunction with the accompanying drawings and embodiments, the utility model is described in further detail, in the accompanying drawing,

Fig. 1 is that the PID among the frequency converter EPROM of the present utility model regulates the flow chart of program;

Fig. 2 is the utility model first example structure schematic diagram;

Fig. 3 is the utility model second example structure schematic diagram;

Fig. 4 is the electrical schematic diagram of the controller of the utility model second embodiment.

The PID that Fig. 1 shows according to the frequency converter EPROM of the utility model structure regulates the realization stream figure of subprogram, this PID adjusting program adopts discrete tone of Chinese characters joint algorithm, it is the sampling period at sampling instant T=iT(T), PLD regulates rule can pass through numerical formula (1) expression, at sampling instant T=(I-1) T, with formula (2) expression. By (1)-(2) formula (3), pusher gets formula (4). Its computing block diagram as shown in Figure 1, program is provided with meets limit and weakens integration method, in case the control variable enters the saturation region, stops to increase the calculating of integration item.

Ui＝K［ei＋T／Ti× $\underset{\mathrm{j＝0}}{\overset{i}{\mathrm{\Σ}}}$ ej＋Td／T×（ei－ei－1）］＋Uo …（1）

Ui-1＝K［ei－1＋T／Ti× $\underset{\mathrm{j＝0}}{\overset{\mathrm{i－1}}{\mathrm{\Σ}}}$ ej＋Td／T×（ei－1－ei－2）］＋Uo …（2）

Ui＝Ui－1＋△Ui＝Ui－1＋doei＋dlei－1＋d2ei－2    ……（4）

Wherein: ei is the deviation value of typical set value and sampled value, and Td is the differential coefficient, and Ti is integral coefficient, and Td, Ti can adjust according to concrete frequency converter. Need use the no sign bit multiplication and division subprogram of tape symbol addition and subtraction subprogram and double word joint in the program, since simple, no longer carefully chat.

Fig. 2 illustrates the also promptly the simplest single water pump control example of the utility model first embodiment.VCD frequency converter (VVVF) shown in the figure promptly comprises through revising the PID that adds just like Fig. 1 block diagram illustrations regulates program.As shown in Figure 2, this constant pressure water supply controller is made of the pressure sensor P that VCD variable-frequency governor (VVVF) adds a tandem type 24V power supply, output 4-20MA.Water pump M is directly received in VVVF output.Because the VCD frequency converter itself has 24V power output terminal P24, no longer uses external power source, directly "+" of pressure sensor terminated to the terminals P 24 of VVVF, the current input terminal IV that "-" terminates to VVVF gets final product, and is therefore very succinct.Behind the water supply network, power on the connection to frequency converter, the water pump slow start, by " △ " key on the panel and " " key assignments good berth pressure.After pressure reduces, after PID calculates, frequency converter frequency is raise, otherwise, after increased pressure, after PID calculates, frequency converter frequency is descended, because CPU sampling and calculating are all very fast in the VVVF, pid parameter is again repeatedly preferably to form, and final pressure can be stabilized in the 0.01MP.

Though controller shown in Figure 2 is very simple, can only drive a water pump, and not have peripheral cell control start and stop, work indication, warning when water supply volume changes greatly, the problem of low load with strong power is arranged, power savings is not ideal enough.

Fig. 3 illustrates the utility model second embodiment, can realize switching mutually between three pumps many water pump control examples of the control of supplying water.The controller of this embodiment can only make a pump work when low discharge or zero delivery, and when big flow three pumps is worked simultaneously, thereby reaches energy-saving effect.

As shown in Figure 3, PLC can be any programmable logic controller with following condition: have three 24V direct-flow input end at least, eight relay output end.Among Fig. 3, "+" of pressure sensor, "-" end are connected to P24, the IV end of VVVF, the RCH of VVVF, LOW respectively, FLA is connected to the X1 of PLC, X2, X3 input, RCH is the output signal that frequency arrives 50HZ, and LOW is that frequency is a zero output signal, and FLA is the alarm output signal of VVVF.The Y7 of PLC is connected to the F end of VVVF, the just commentaries on classics of control VVVF.The Y8 of PLC is connected to RST end, and VVVF is resetted in switching and during fault.The Y1 of PLC controls 1#, 2#, the power frequency of 3# water pump, frequency conversion, off-state to the control end that Y6 receives six contactor JC1-JC6.

Suppose that starting mode of pump is 1# in proper order, 2#, 3#, after powering on, JC1 is logical, and the 1# speed change starts slowly, if VVVF is operated in and can stablizes pressure below the 50HZ, does not then need to drop into water pump again.If VVVF has reached 50HZ, and pressure does not reach setting value (signal that PID regulates output has reached maximum), then RCH signal effective (high level) after PLC detects, makes JC1 disconnected through time-delay, JC2 is logical, and VVVF is resetted by Y8, and to delay time after 1 second, releasing resets, make JC4 logical, the 2# speed change starts slowly.In like manner, 2# is after the most at a high speed (VVVF export 50HZ), and pressure does not but reach setting value, will make the 3# connection once more, is operated in the speed governing attitude.

Suppose present 1#, 2# is operated in the power frequency attitude, and 3# is operated in the speed governing attitude, but the speed of 3# has been zero, pressure has but surpassed setting value, and this moment, the FLA of VVVF was effective, after PLC detects, if by " dropping into earlier; withdraw from earlier " principle, the 1# that drops into is at first disconnected, promptly JC2 disconnects, 3# slow start again then is till pressure stability.

The PID program increases the frequency converter output frequency according to setting pressure and current pressure or reduces, and the water pump that is in the speed governing attitude also makes speed increase or reduces, and sampling and adjustment process do not rely on PLC fully, and PLC only is used for the switching of control of pump here.The key of here dealing with problems is ingenious RCH signal and the LOW signal that has utilized VVVF.Can realize easily that according to this basic circuit two switch or four switchings.

Fig. 4 is the detailed electrical wiring diagram of specific implementation Fig. 3 constant pressure water supply controller, the logic control of wherein adopting the American I PM IP1612A of company programmable logic controller to switch as a plurality of water pumps, P1612A itself has 4 tunnel 2 moulds and goes into, 2 tunnel 10 moulds go out, but all not having use in design, adopt the purpose of this PLC, mainly is to utilize its RS232C interface, reach with host computer and communicate by letter, and that its cost adds a communication module again than other PLC is much lower.The composition components and parts of this constant pressure water supply controller are described as follows:

JC1-JC7: A.C. contactor; J1-J7: relay; D1-D7: diode; RJ1-RJ3: thermal relay; M1: ammeter; M2: voltmeter; L1-L3: indicator lamp; DC1-DC2: dc source; KC: air switch; SW1: start stop switch; F: current transformer; P: pressure sensor; XJ: phase failure protector; AL: protect alert device; PLC: programmable logic controller; VVVF: variable-frequency governor.The XJ design is in the entrance, if A, B, the C three-phase has phase shortage, and JC1 will disconnect, thus to motor open-phase protection purpose, KC is used for overcurrent and overheating protection, is convenient to the outage maintenance simultaneously.M2 is contained in and indicates operating voltage on the panel, and M1 is contained in and refers to total current on the panel.SW1 is contained in and controls start and stop on the panel.L1, L2, L3 are contained on the panel as the work indication.

Because of having only a start stop switch, therefore operation is very simple, and it is finished by VVVF and PLC automatically in work; can be unattended; DN1201 has open-phase protection, overtemperature protection, overcurrent protection simultaneously; overvoltage protection; perfect functions such as under-voltage protection can drive three water pumps, and economize on electricity obviously; and be furnished with the RS232C interface, be easy to connect with host computer.Therefore the practicality autgmentability is all very strong.

Claims (3)

1, a kind of constant pressure water supply controller, comprise a VCD frequency converter and a pressure sensor, it is characterized in that, EPROM comprises that the PID that an initial address is second address regulates subprogram in the described VCD frequency converter, and first address among the described EPROM comprises that a PID who points to described second address regulates the long call instruction of subprogram:

"+" end of described pressure sensor is connected with current input terminal (IV) with the power output end (P24) of described VCD frequency converter respectively with "-" end.

2, constant pressure water supply controller as claimed in claim 1 is characterized in that: described VCD frequency converter also is connected with a programmable logic controller PLC; Described programmable logic controller PLC also is connected to 6 contactors; Described programmable logic controller has at least three 24V direct-flow input end X1, X2, three input terminals of X3 to receive the output signal RCH that reaches 50HZ from the indication frequency of described VCD frequency converter respectively, and the indication frequency is 0 output signal LOW and alarm output signal FLA; Y1-Y6 receives each control end of described 6 contactor JC1-JC6 respectively in 8 lead-out terminals of described programmable logic controller PLC, and Y7 is connected to the F end of described VCD frequency converter, just changes in order to control it; Y8 is connected to Y1-Y6 in the RST terminal of described VCD frequency converter and receives each control end of described 6 contactor JC1-JC6 respectively, and Y7 is connected to the F end of described VCD frequency converter, just changes in order to control it; The RST end that Y8 is connected to described VCD frequency converter is used for it is resetted, and each a link of JC1, the JC3 among described 6 contactor JC1-JC6, JC5 is connected with the frequency conversion output of described frequency converter; JC2 among described 6 contactor JC1-JC6, each link is connected to the power frequency input among JC4, the JC6; Each another link of described contactor JC1 and JC2 connects together, and each another link of described contactor JC3 and JC4 is connected together, and another link of each of described contactor JC5 and JC6 connects together.

3, constant pressure water supply controller as claimed in claim 1 or 2 is characterized in that described first address is 0688H, and described second address is 3000H.

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