JPS59225411A - Digital valve controller - Google Patents

Abstract

PURPOSE:To eliminate flow error by detecting a differential pressure across a valve so as to correct the controlled flow from table information deciding the opening of a digital valve. CONSTITUTION:An output of a programmable sequencer 2 setting the control procedure of a valve 6 is given to a control unit 1 driving a pulse motor 7 of the digital valve 6 based on the table information and switch groups A1-An comprising digital switches 3a-3n for setting flow and digital switches 4a-4n for setting moving pattern are connected to the sequencer 2. The flow is controlled by a flow setting signal and a moving pattern setting signal via a driver 5. Further, the unit 1 is provided with a differential pressure correcting adaptor 12 to correct flow based on a differential pressure DELTAP across the digital valve 6. The differential pressure DELTAP is detected by a differential pressure detector 15 and the opening correcting amount is operated by the adaptor 12.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Industrial Application Field The present invention relates to a digital valve control device that adjusts the flow rate of fluid by driving a pulse motor based on table information. The present invention relates to a digital valve control device that detects and corrects a controlled flow rate.

b. Prior Art Conventionally, the flow ffi common to hydraulic equipment 1. II III
Generally, an analog control force type using feedback control is adopted, but with the analog control method, it is difficult to obtain high control accuracy due to noise, temperature drift, etc. This required complex control, and of course, since it was feedback control, sufficient attention had to be paid to oscillations in the control system.

Therefore, in order to solve the problems of conventional analog control methods,
The inventors of the present application use a so-called digital valve in which the opening degree of the drive c of a pulse motor is adjusted, and the table information that determines the opening degree of this digital valve and the movement pattern until it moves to the setting device Iσ. We have proposed a digital valve control device that can control the flow rate according to the movement pattern determined by the viscosity determined by the number of stubs. (For example, Japanese Patent Application No. 58-45057).

By the way, in this digital valve control device, the flow Δ for the opening degree according to the number of control pulses is uniquely determined based on the flow rate characteristics under certain predetermined conditions. , even when the opening is changed, the controlled flow rate changes due to fluctuations in the differential pressure across the valve due to the hot stones in the fluid.

That is, the viscosity of the fluid is high in the ribs where the temperature is low, making it difficult for the fluid to flow, creating a large pressure difference, and the planned flow IJ,
On the other hand, when the temperature is high (the viscosity of the fluid decreases and it becomes easier to flow, the differential pressure decreases, resulting in a flow rate that is higher than the planned flow rate even if the opening is the same). , the viscosity of only the controlled opening of the digital valve is iα
First, there was a problem in that actual control accuracy caused errors depending on the magnitude of temperature change.

C1 Purpose of the Invention The present invention has been made to solve the above-mentioned problems of the conventional art, and to prevent control errors due to differential pressure across the valve caused by fluid flow. The purpose of the present invention is to provide a digital valve control device that achieves the following.

d0 Structure and operation of the invention In order to achieve this object, the present invention provides a set flow rate based on table information that determines the opening degree of the digital valve and table information that determines the movement pattern of the digital valve until the control amount shifts to 1 odor. In a digital valve control device that drives a pulse motor of a digital valve to control the flow, a differential pressure detector detects the differential pressure across the valve due to the fluid passing through the digital valve. The control flow rate of the digital 4-r controlled based on the no-pull information is corrected based on the detected differential pressure.
The flow rate can be precisely controlled to the specified flow rate.

e. Embodiment FIG. 1 is a block diagram showing an embodiment of the present invention. First, to explain the configuration, 1 is a control unit 1 which generates a pulse signal to drive a pulse motor of a digital valve based on the data pulse information. The output of the programmable sequencer 2 that sets the control procedure of the digital valve is detected for the unit 1, and the programmable sequencer 4) 2 has a digital switch 38 for setting the flow rate. 311 and digital switches 4a to 411 for movement pattern setting, switches liY A 1 to 80 are connected to the digital switches 3a to 3n of each switch group A1 to A11. Set the flow m according to the control procedure, and set the digital switch lJa~411 to J.
By setting the movement pattern until transition to the set flow rate, when the device is started, the flow ω setting signal and the movement pattern setting function are converted into two according to the control procedure predetermined by the programmable sequencer 2: It is converted into an I-code signal and output to the control unit 1-1.

On the other hand, the output stage of the control unit 1 has a driver 5.
is connected to a signal line, and the output of this driver 5 is supplied to a flow rate control digital valve 6, which is controlled by a throttle 8 by the speed-up rotation of a pulse motor 7.
The opening degree of the valve is adjusted to perform flow control.

Of course, the driver 5 uses the pulse signal from the control unit 1 to generate a rotating magnetic field in the pulse motor 7!
,: Converts the current into the current, and then outputs the right function.

Next, we will explain the control unit ~1.
The command equal sign from the programmable sequencer 2 externally connected via the interface 10 is input to the second pin 1 to the roller 9, and according to the command signal from the programmable sequencer 2. The valve is actuated according to a predetermined operating procedure. Further, the controller units 1 to 1 are provided with a differential pressure correction adapter 12 for correcting the flow rate based on the differential pressure ΔP across the digital valve 6. is the detected pressure ρ1. of the pressure detectors 13 and 14 provided on the inlet and outlet lines of the digital valve 6 for flow rate control. The difference ΔP of P2 is ΔP-・1
] The output signal of the differential pressure detection 115 detected as 1-P2 is digitally converted by the A, -'D converter 16 and input manually, and the differential pressure correction adapter 12 is controlled to the set opening degree based on the detected differential pressure ΔP. Calculate the opening correction amount when the
-〇-A is output to the controller 9, and the control 1''-A 9 generates the correction pulse of the pulse Tanabata 7 based on the correction amount from the differential pressure correction adapter 12. It is a block diagram showing an example of the controller 1-+:1-ra 9 in the embodiment, in which the setting opening degree M given by the programmable sequencer is input via the interface and the corresponding table information is read. The pulse interval generator 1 inputs the movement pattern K from the programmable sequencer and reads out the corresponding table information.
8.

The divided pulse number generator 17 stores the number of divided pulses oO~n9 in each divided division when the number of pulses corresponding to the set flow rate set by the digital switch is divided into N=10 as AC table information.

A memory 17a is provided.

As the AC data in the memory 17a, if the number of driving pulses of the pulse motor 7 for which the maximum flow rate is reached by the digital valve 6 for flow control is, for example, 255 pulses, each of the digital switches 3a to 3n has -U1= 25
Since 5 types of flow rate settings are possible, one block is the number of pulses nQ - n9 in 10 divisions obtained by dividing each set flow Φ into N = 10 for 255 types of set flow rates.
It is composed of five types of Unisol blocks.

On the other hand, the pulse interval generator 18 has a set flow rate N =
Pulse interval To-T corresponding to each divided pulse number n Q-n9 for each division divided into 10? A memory 18a is provided that stores 1S table information consisting of a plurality of blocks in which TS7-pull information tlJ is stored.
The pulse interval TO-1°9 determines the shape of the movement pattern of 1) that drives the pulse motor toward the set flow rate, and is composed of, for example, 31 types of block tables. The designation of the setting flow ff1M and movement pattern of the grammable sequencer J:2 is to designate the block number of the A'CC table information 0 in the memory 17a and the block number of the TS table information in the memory 18a.

The output of the divided pulse number generator 17 is supplied to an AC counter 19 using an up/down counter.
9 is the number of divided pulses 110 to 19 read out from the designated table 1 of the memory 17a in the divided pulse number generator 17, and is preset sequentially. Count the output pulses, and when the preset number of divided pulses is reached, the next stage 1
A count output is generated in the FR counter 20. When the PR counter 20 counts the number of divisions N-10 of the boosol information in the main channels 17a and 18a, it outputs the output and outputs it to the division pulse number generator 17 and the inter-pulse sunlight 41-(reset 1-1 in '18).
Right function to apply.

On the other hand, the output of the pulse interval generator 18 is supplied to the tine 21, and the timer 21 outputs the pulse interval TO output from the pulse interval generator 18 to 1 at T9. ↓Outputs pulse motor drive pulses with one-sided pulse width and pulse interval.
3. The output of this timer 21 is supplied to the multiplexer 22, and the multiplexer υ22 has a divided pulse number generator 1.
A signal is supplied from 7 that determines the rotation direction of the pulse motor, that is, the opening and closing direction of the valve. 114 rotates in the clockwise direction to output a CCW pulse that reduces the flow rate, and the output of this pulse generator 22 becomes the pulse output from the control unit 1-1, and the driver 5 shown in FIG. is supplied to.

Furthermore, the output of the tie 721 is supplied to the AC counter 19, and this pulse resistance value is used as the preset number of divided pulses 1.
)0 to n9, the AC counter 15 outputs an output to the PR counter 20.

Next, we will specifically explain the AC table information in the memory 17a set in the divided pulse number generator 17 of the controller 9 shown in FIG. explain.

FIG. 3 is an explanatory diagram showing the principle of AC and TS doubles of the present invention, in which the number of control pulses corresponding to the set flow rate is divided into N==10 as shown on the vertical axis, and the number of divided pulses in each division is calculated. 00 to 9 is determined, and this divided pulse number n
Q~1] Store the value of the divided pulse MinQ~n9 in 〇 to address AO~ of the memory corresponding to 9, and store this in one table block so that the maximum number of pulse motors that correspond to the maximum set flow rate is, for example If it is found that there are 255 pulses, 255 types of block tables from 1 to 255 are created.

FIG. 4 is an explanatory diagram showing the AC sol created in this way, and shows A(, 255f!, which is -1 to 255).
I! A table block of the type is created in advance and stored in the memory 17.
It is stored in a.

-j), -T' S 't-Pull information is the pulse interval T O-T 9 of each 9311 division as shown on the horizontal axis corresponding to the divided pulse number nO ~ 119 shown on the vertical axis of the gi53 diagram. The values of pulse interval '1-0 to T9 can be created by storing the pulse interval '1-0 to T9 at address a 0 = -a 9. For example, in this embodiment, 31 types of movement patterns are determined.

FIG. 5 is an explanatory diagram showing the AC table information determined in this way, and 31 types of block tables indicated by blocks of TS-1 to TS-31 are stored in the memory 18a. , In FIG. 5, [J1 pulse interval 1-0-T'9 is stored as a value in units of 10 μs.

As is clear from the AC and 1" S-7 pulls in Figures 4 and 5, the control number of the digital valve according to the present invention is as follows. Then, 111 pulses are generated with a pulse interval of 1, and finally 09 pulses are generated with a pulse interval of T9. As a result, control within the shaded area in Fig. 3 The characteristics are determined and these control characteristics are continuously connected to obtain the control characteristics of the digital valve for flow rate control, which has a polygonal line approximation.

Next, the control operation of the flow rate control valve by controller 1-0-59 shown in FIG. 2 will be explained in accordance with the program flow shown in FIG.

First, start the device with the large control pulse number N and movement pattern K set according to the set flow rate using the switch group A1 to A n shown in FIG. Then, in block a, the controller 9 reads the number of control pulses M input through the intuno 1-base 10 into the movement pattern, and proceeds to block b, where it reads the PR counter 20ePl'<=O, preseller l-L, and so on. and select block C (this aj selects 1 block M in the AC double block and 1 block L1 in the l-5-j-pull. Then, in block d selects the ACj-pull block [)
The number of divided pulses 110 stored in the first address 80 of the block M is transferred to the AC counter 19, and the first address AOI is stored in the specified block of the next block cr'l-S table. Memorized pulse interval - 1
-0 to the tine 21 by 1 to 1". In this way, the pulse interval T.

Thailand that was let? 21 generates a pulse having a pulse interval To as shown in block J, and the output pulse from this timer 21 is supplied to the driver 5 shown in FIG. 1 via a multiplexer 22, and is used for flow control. The pulse motor 7 of the gagetal valve 6 is driven to rotate in the direction set by the programmable sequencer 2, for example, in the opening direction. At the same time, the number j of tie v-21 is AC counter 19
is supplied to AC counter 1 as shown in block L1.
9 is incremented. Next, in the determination block 11, it is determined whether the counted value of the ΔC counter 19 matches the number of divided pulses in the block d'' (the divided pulse number no. The next pulse is output at TO. Therefore, blocks f to h
In this case, the pulse output by the timer 21 is repeated until the number of pulses equal to the number of divided pulses nQ preset by the ACC counter 19 block d is output.

Subsequently, when it is determined in the determination block h that the h1 value of the AC counter 19 matches the preset number of divided pulses 110, the AC counter IL7. The PR counter 20 is incremented as shown in block 1 when the %iil number is output. Next, in the discrimination program 1-1 check, the PR counter 2
It is determined whether the count value of 0 matches the number of divisions N-10 η or not, and if the 51 value of the PR counter 20 is less than 10, it means that control is in progress, so proceed to block k and address A.
O is incremented from 1 to 1, and then returns to block d, and pulse 1 to the AC counter 19 with the number of divided pulses 1+1 of the next address A1 and address Δ are incremented to block C.
1) (let the timer 21 with a pulse interval T1), and similarly generates 111 pulses with a pulse interval T1 in blocks [...11!L].

Thereafter, the pulse output from the timer 21 corresponding to U is performed at the addresses Δ2 to Δ9 that fall on the designated doubles M and K in the same way, and the pulse output at the address A9 ends.
Since the count value of the PR counter 20 is PR=10 when reaching the determination block L) tsukuj, the pulse Tanabata control based on the specified PR and TSS table is terminated,
Select /V for blocking to perform differential pressure correction, which will be explained later.

FIG. 7 is a block diagram showing an embodiment of the differential pressure correction adapter 12 that is similar to the embodiment shown in FIG.

First, to explain the configuration, the differential pressure correction adapter 12 is composed of a microcomputer that performs correction calculations under program control, and is connected to the computer 1 shown in FIG. ~ The motor drive pulse Ni output to the roller 9J and the digital valve 6 and the differential pressure ΔP across the throttle 8 are input to the digital valve 6, and further obtained by the correction calculation of the central processing unit 1-25. A number of correction pulses ΔN are output. The central processing unit 1-25 has a table memory 20 storing table information for selecting the aperture area Ai of the aperture that goes to the digital valve based on the number Ni of motor drive pulses, and a table memory 20 that stores data for selecting the aperture area Ai of the aperture that goes to the digital valve based on the number Ni of motor drive pulses.
An artmeter 27 is connected to temporarily store the number of pulses Ni and the differential pressure ΔP manually applied.
□ Next, the arithmetic processing performed by the doubler 12 (differential pressure correction) in FIG. 7 will be explained. First, the control flow ff1Q of the digital valve 6 for controlling the flow m is obtained by the following equation.

Q = CAm mouth 7 fu 00. (1) However, C:
Flow coefficient Δ: Valve opening area [am] ΔP: Differential pressure across the valve [kg/cm] ρ: Oil density [
k(+・S/CIII) It is clear from this equation (1) that the control flow (a) Q is the flow coefficient C2, which is the opening surface g of the valve.
tA, oil density ρ;

The opening area of the valve is determined by -L [ΔF) before and after the valve, and the opening degree of the aperture depends on the number of pulses J to the pulse motor of the digital valve. The area is uniquely determined, and for this frontage area, each pulse with the number of driving pulses N1 to Nn as the address as shown in FIG.
Therefore, by storing the corresponding frontage area AI-An as table data, the opening surface MA of the corresponding valve can be determined as table data by addressing based on the number of driving pulses N.

On the other hand, the flow coefficient C is a value that changes depending on the Reynolds number, and the oil density ρ is also a value that changes according to the oil equation 1i, but in this example, the flow coefficient C and the oil density ρ are
is treated as a constant.

Therefore, the above equation (1) is expressed as Q == K −A m −(2)(11L
, K = C-rTT75te constant f&, and by calculating this equation (2), the set opening of the digital valve for flow rate control performed according to flowchart 1- in Fig. 6 can be changed to LJ. The actual flow rate can be calculated. Therefore, there is a difference in pressure difference ΔP after l1iJ of the valve between the actual lift of the digital valve calculated by the above equation (2) and the flow rate reset by the digital switch, which depends only on the number of drive pulses. Since an IC error occurs according to become.

Next, the arithmetic processing by the differential pressure correction adapter shown in FIG. 7 will be explained with reference to the flowchart in FIG. 9.

First, as shown in Nos. 1 and 1-1 of FIG. The tI differential pressure correction routine shown in FIG. 9 is executed.

In this differential pressure compensation routine (υ), first, block A
The pulse of the digital valve 6 output from the controller I/roller 9 is calculated from the number Ni of drive pulses for 7 to 81 yen.
The aperture area △i is determined by l−
Pull selection. Continuing - (, block 1) In block B, read the detected difference "Δ[)I" through the input/output interface 24, and in block C -3, set the predetermined constant 1<, opening area Ai, and detected differential pressure ΔPi. The actual flow rate Q of the digital valve 6 corresponding to the number of driving pulses Ni of the pulse motor is calculated using
Calculate r.

Next, in block D, the corrected flow rate ΔQ is calculated from the difference between the set flow rate ff1Q of the digital switch and the actual flow rate Qr.
-ru. Of course, the correction flow n) ΔQ& has a positive and negative fraction.

Next, in block E, from the corrected flow rate ΔQ obtained in block l), the number of driving pulses of the pulse motor required to obtain the corrected flow rate ΔQ is calculated as ・1Ili, iJ−number of pulses Δ
When the number of corrected pulses ΔN is 1 or more in judgment block F, the process proceeds to block G and outputs a corrected pulse. On the other hand, when the number of corrected pulses ΔN is in the decimal place, the pulse motor is driven. Since the meteor GX correction cannot be performed, the arithmetic processing is ended without performing the meteor correction.

FIG. 10 shows the pulse motor rotation part of the digital valve with respect to the axis 11h, which is the time axis 11h on which the differential pressure correction of the present invention is applied. -, and if the flow rate control by the controller 9 is completed according to the specified movement pattern at time Tn, then the processing shown in FIG. The motor is driven for correction, and an actual flow rate that matches the flow rate set by the digital switch is obtained by removing the error caused by the differential pressure Δ[] across the digital valve.

In addition, in the embodiments described in (1) and (2), the flow coefficient C and the oil density ρ are treated as constants as shown in equation (2), but in order to further improve the control efficiency, All you have to do is perform the following performance.

Therefore, the flow coefficient C is a function of the modified Reynolds number R111 as C==f ([n) ...<2) However,
R1111 is given by the modified Reynolds number, where the modified Reynolds number R111 is the ratio of the Reynolds number Re modified by a coefficient that varies with the displacement of the valve, i.e. the opening area A, i.e. Rm = k - Re - (3) 11j L...
R (U: Reynolds number k: It is given by a coefficient that changes with the displacement of the valve, and the Reynolds number Re is RO-V A/ν...(4) However, V: Oil flow velocity [cm/s] C: Viscosity Since it is given by the coefficient (varies with the epidemic T), it is sufficient to calculate the flow rate coefficient C by Jζ in these calculations.

Furthermore, since the density ρ of oil changes depending on the temperature, the dryness 1i of the oil flowing through the digital valve is detected to determine the density ρ according to the temperature of the hot melon. Then, the flow coefficient C and the density ρ obtained by the above calculation are substituted into the above-mentioned equation (1), and the actual flow flQr is calculated using the opening area A and the front-to-back difference ΔP.

In addition, in the above embodiment, the flow rate control of the digital valve based on the double information is completed, and the flow rate correction is performed based on the detected differential pressure ΔP, but this differential pressure The timing of the flow rate correction based on [Delta]1] may be performed at an arbitrary timing during control by the controller 59.

r1 Effects of the Invention Next, a detailed explanation of the present invention will be given based on the seal pull information that determines the opening degree of the digital valve and the shift to the set opening degree. A digital valve control device W that drives the digital valve pulse motor to obtain the set flow rate.
J3 at J3, the digital valve's 1) pressure after IJ is detected, and the control amount of the digital valve 1, which is controlled based on the sheeple information, is corrected according to this detected differential pressure. ? By eliminating the flow rate error that varies depending on the differential pressure across the digital valve, it is possible to control the flow rate with extremely high viscosity.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing a specific configuration of the controller shown in FIG. Figure 4 is an explanatory diagram showing the principle of table information used in the roller. Figure 4 is an explanatory diagram showing an example of AC table information used in the controller. T.S.
An explanatory diagram showing an example of table information, FIG. 6 is a flowchart diagram showing the control process of the digital valve of the controller in FIG. 1. A block diagram showing a specific example of the 1-rl supplementary adapter. Fig. 8 is an explanatory diagram showing the table information used in the differential pressure correction adapter shown in Fig. 7. Fig. 9 is an explanatory diagram showing the differential pressure correction adapter shown in Fig. 7. Flow block p -1- showing correction calculation processing by the adapter
10 are time charts showing flow rate control according to the present invention. 1: Control unit] 2: Programmable sequencer 3a to 3n: Opening degree setting digital switch 48 to 4n
:Pattern setting circle digital switch f5:Driver 6:Flow 11i77Ill ico11kawa digital valve 7
:Pulse motor 8:Aperture 9:Controller 10:Interface 1-S 12:Differential pressure correction 7Double 13.1/l:Moon-force detector 15:Differential pressure detector 16:Δ/''D *Converter 17: Divided pulse number generator 18: Pulse-to-pulse dual light '1 unit 19: △0 counter 20: pH counter 21: Tie? 22: Multi-break 24: Input/output interface 25 Knee central processing unit 26: Double memory Patent applicant Yu Takeuchi, Patent Attorney, Tokyo Keiki Co., Ltd.

Claims (1)

[Claims] The pulse motor of the digital valve is driven so as to obtain the set flow rate based on the table information that determines the pajtx of the digital valve and the table information that determines the movement pattern of the digital valve until it shifts to the set opening. A digital valve control device that controls the flow includes a differential pressure detector that detects the differential pressure after assistance by the fluid passing through the digital valve block, and a differential pressure detector that detects the differential pressure detected by the differential detector. - A digital valve control device*, characterized in that it is equipped with differential pressure correction means for correcting the control opening degree of the digital valve that is controlled according to the pressure.