Electrical amplifier for controlling valves
Contents
1. an amplifier for a particu lar type of valve the amplifier is connected via the inter face to an external processor from which the complete program and data such as the amplifier and valve spe cific data and the program are loaded to the program mable unit and in the read only memory Then the am plifier is programmed for a particular valve type and size Further claims relate to particularly useful embodi ments of the invention For example the interface al lows for a bidirectional data transfer between the ampli fier and an external processor Accordingly the ampli fier may be incorporated in a central control in a plant Further the external computer may use data received from the amplifier to optimize the process The programmable unit further includes digital and analogue inputs The analogue inputs for desired values actual values as feed back of pressures valve piston positions and or current values in the solenoid windings are supplied through an internal multiplexer to an analo gue digital converter Digital inputs allow read out of desired values stored and further allow performance of additional functions for example to vary stored param eters and to vary desired values by actuating a keyboard connected thereto These additional functions determine the embodi ment of the amplifier structure When a subsequent setting is not necessary for example with an amplifier incorporated in a valve or valve sandwich plate the2. unit for controlling any ofa selected one of different fluid power valves comprising a supporting structure associated to the selected valve 20 25 40 45 50 65 6 to be controlled said supporting structure including at least an endstage a power supply a control electronics for generating valve specific positioning signals to ob tain a predetermined operation of said valve and inputs for delivering desired valve parameter value signals to said control electronics and outputs connected to said endstage characterized in that said control electronics comprises a read only memory and a programmable unit including at least a microprocessor a working memory analog and digital inputs and outputs includ ing signal convertors means for loading said read only memory with a program of operation a valve specific program and a plurality of associated data from said programmable unit and said microprocessor via an in terface wherein said supporting structure further com prises a valve code storing means which provides a binary code for a particular type of valve said code being read out in performing a checking mode and wherein said programmable unit includes a number of digital inputs for loading said valve code in order to compare the valve specific program with the valve code stored in the valve code storing means when per forming the checking mode 2 The amplifier of claim 1 wherein the data stored is varied via dig
3. 67 4 754 392 6 1988 Nakashima et al u 364 167 01 4 755 729 7 1988 Gotou u 364 167 01 4 790 233 12 1988 Backe et al 364 167 01 4 816 987 3 1989 Brooks et al 364 167 01 4 879 644 11 1989 Gottshall 364 167 01 4 979 127 12 1990 Mizuno et al 364 167 01 digital inputs desired values actual volues Multiplexer FOREIGN PATENT DOCUMENTS 0094090 11 1983 European Pat Off 0149010 7 1985 European Pat Off 3414378 10 1984 Fed Rep of Germany 3345528 6 1985 Fed Rep of Germany 3410082 9 1985 Fed Rep of Germany 3521075 12 1985 Fed Rep of Germany 3432494 3 1986 Fed Rep of Germany 2952500 7 1987 Fed Rep of Germany 3700353 7 1988 Fed Rep of Germany 3700898 7 1988 Fed Rep of Germany 3828591 3 1989 Fed Rep of Germany 3935937 5 1990 Fed Rep of Germany OTHER PUBLICATIONS Digitale CNC Streckensteuerung Mar 1987 One Axis and Two Axis Controller User s Manual including Appendices A B C and D Index and Supple ment Appendices E and F Feb 1987 List continued on next page Primary Examiner Jerry Smith Assistant Examiner Paul Gordon Attorney Agent or Firm Harness Dickey amp Pierce 57 ABSTRACT Amplifier units for controlling valves in particular proportional solenoid valves comprise a number of components such as an end stage a power supply a control electronics and possibly a closed loop co
4. A 8 KR Huijqoua UONDIIPUI 10133 SS2JPPD JAJDA uoljviado dojS 4D S jno dwo sanjDA pasisap burjjDo 5 172 311 1 ELECTRICAL AMPLIFIER FOR CONTROLLING VALVES This is a continuation of U S patent application Ser No 07 434 370 filed Nov 13 1989 and now aban doned The invention relates to electrical amplifiers for con trolling fluid power valves comprising a supporting structure associated to a valve The supporting struc ture includes at least an end stage a power supply a control electronics for generating valve specific posi tioning signals to obtain a predetermined control or output characteristic of said valve The supporting structure also includes inputs for delivering desired value signals to the control electronics and outputs connected to the endstage The control electronics or respectively the supporting structure may be supple mented by a number of components i e at least a con troller including inputs for at least an actual value a ramp generating unit top modulate desired values in puts for activating desired values and outputs to a dis play and to circuits for failure recognition BACKGROUND OF THE INVENTION Conventional amplifiers and closed loop control am plifiers to drive valves in particular proportional sole noid valves are made up of a number of individual com ponents Thus the current through the solenoid wind ings is controlled by an endstage to which power is supplied by a su
5. United States Patent 9 Reinhart et al HAN a EAN US005172311A 11 Patent Number 45 Date of Patent 5 172 311 Dec 15 1992 54 ELECTRICAL AMPLIFIER FOR CONTROLLING VALVES 75 Inventors Peter Reinhart Lohr Main Karl Hessd rfer Karlstadt Horst Lausch Lohr Rodenbach all of Fed Rep of Germany 73 Assignee Mannesmann Rexroth GmbH Fed Rep of Germany 21 Appl No 865 623 22 Filed Apr 8 1992 Related U S Application Data 63 Continuation of Ser No 434 370 Nov 13 1989 aban doned 30 Foreign Application Priority Data Nov 11 1988 DE Fed Rep of Germany 3838353 151 Int CS ee GO6F 15 46 52 U S Cl 364 140 364 167 01 58 Field of Search 364 167 01 140 141 364 142 188 189 509 510 137 624 11 624 18 624 2 56 References Cited U S PATENT DOCUMENTS 4 134 423 1 1979 Mayer once 137 486 4 523 286 6 1985 Koga et al a 137 551 4 573 114 2 1986 Ferguson et al 364 167 01 4 595 979 6 1986 Arai et al 364 167 01 4 627 009 12 1986 Holmes et al u 364 167 01 4 628 442 12 1986 Isobe et al 364 200 4 628 444 12 1986 Nozawa etal 364 167 01 4 722 044 1 1988 Heiser et al 364 167 01 4 744 022 5 1988 Kumar et al we 364 167 01 4 744 218 5 1988 Edwards et al 60 368 4 745 744 5 1988 Cherry et al 364 1
6. a front plate Eurocard system for controlling a valve and FIG 3 is a block diagram of an amplifier unit DETAILED DESCRIPTION Referring now in detail to the drawings FIG 1 illus trates an amplifier mounted on a supporting plate 2 for connection to a valve 1 The supporting plate 2 carries an endstage 4 and a power supply 5 A daughter plate 3 for accomodating a programmable unit 6 and a read only memcry 7 is mounted on the supporting plate 2 Still further the supporting plate 2 comprises a num ber of terminals for transmitting and or receiving sig nals such as positioning output values actual values data exchange with an external computer and terminals for connecting the power supply unit 5 to a line voltage and for electrical connection of the valve 1 Similar basic supporting plates are provided for all types of valves They distinguish from each other sub stantially by different endstages 4 only By limiting the design to a few embodyments for example incorporat ing endstages with two different output current values the stock required comprises a few different basic units In FIG 1 the amplifier controls a directly actuated directional proportional solenoid valve of a predeter mined rated size The program required for control is transmitted from a computer via the interface to the ROM 7 by means of the programmable circuit 6 Ac cordingly the amplifier for the valve 1 is programmed and ready for operation after being te
7. amplifier is easily mounted in a casing including a few terminals When additional input terminals are needed to perform externally controlled functions of the valve the amplifier unit may be mounted in a module casing When still further input terminals are desired such as a keyboard and a display allowing to vary and display certain values the supporting plate is provided with a 20 30 35 50 55 60 65 4 front plate for accomodation of the key board and the display elements According to the invention a particu lar amplifier plate is associated to a particular valve type To facilitate this association a valve code is pro vided This means that the amplifier plate receives a valve code in which the associated valve type is binary coded when the amplifier unit is associated to a particu lar valve This may be checked by reading out the valve code to make sure that the memory is loaded with the valve specific data only or respectively to make sure that the end stage may be activated only when the proper valve code associated thereto is presented Reading out is performed when the initializing routine is performed i e when the initial stage of the amplifier is reset BRIEF DESCRIPTION OF THE DRAWING FIG 1 is a perspective view of an amplifier unit de signed for mounting on a valve or valve sandwich plate for controlling a proportional solenoid valve FIG 2 is a perspective view of an amplifier unit in cluding
8. e multiplicity of amplifier types referred to above and to simplify the manufacturing process as well as stocking The present invention provides an amplifier which overcomes many of the problems associated with the amplifier types previously known According to a main feature of the present invention a control electronics is defined by a programmable unit The programmable unit is programmed to perform all functions necessary for each valve type to generate a particular positioning signal The unit is connected to a read only memory into which the variable and constant values of the individual valve type and the control pro gram for this valve are loaded Each amplifier thus comprises an endstage a power supply suitable for the associated valve and the programmable unit including an interface and a read only memory in which the valve and amplifier specific data and programs are stored All these data are defined to determine the function of the valve its size and even the manufacturing toler ances as well as different control types and different control gains Furthermore the general operational program for the data processing of the programmable unit is stored in 5 172 311 3 the read only memory These data stored are preferably variable so that input terminals are provided in particu lar for digital values to vary the values desired This may be performed by means of a keyboard The data may further be fed to a display This i
9. er Fluidtechnisches Kolloquium S 303 321 Dr Feuser DE Z 8 Aachener Fluidtechnisches Kolloquium Mar 115 1988 S 323 340 Mauer et al DE Z Scholz D Ventilansteuerung und regelung mit digitaler Signalverabeitung In o p olhy draulik und pneumatik 29 1985 No 1 S 21 24 DE Z Burkel R Romes R Integration von Elek tronik in Bauelemente der hydraulischen Antriebstech nik In o p olhydraulik und pneumatik 32 1988 No 4 S 231 232 234 236 239 240 242 244 246 DE Z Backe W Fluidtechnik im Wandel In o p olhydraulik und pneumatik 32 1988 No 7 S 473 476 479 484 DE Z Anders P Symbiose Mikroelektronik Fluid technik In 0 p olhydraulik und pneumatik 32 1988 No 7 S 487 492 494 497 499 DE Z Burkel R Symbiose Mikroelektronik Fluid technik In o p olhydraulik und pneumatik 32 1988 No 7 S 500 506 Sloan et al IBM Technical Disclosure Bulletin vol 21 No 3 Aug 1978 1987 Elektrohydraulische Sheet 1 of 3 5 172 311 Dec 15 1992 U S Patent s pu is Buiuonsod BE San DA JDNYID a90JJa UI DIA WA J3 SUDJ DIDI U S Patent Dec 15 1992 Sheet 2 of 3 5 172 311 Sheet 3 of 3 5 172 311 Dec 15 1992 U S Patent J0ss390 Jd DUJa xa ol abvis Ayddns Jamo 2 Cc 9 EEE En i 390 Ja u1 Jaxayd yjnW sngssaupy syndu Yoy d p e biJ san DA DN ID San DA paJ sap dWDJ pUJa Xa 6 5 BI ae ee aAJD
10. ertechnik am Beispiel des RH 90 Oct 1987 Auf der 21 Bauma verteilter Prospekt der Firma O and K Aufbruch In Neue Leistungs Dimensionen Zeichnungen zur Darstellung eines Pumpen Managin g Systems angefertigt durch die Einsprechende Dec 1983 Prior use 1983 by Lothar H Pees Propcon 10 Valve amplifier May 1984 System 90 Microcontroller Sundstrand Sauer Apr 1987 Fisher C Systeme der elektrohydraulischen Antrieb s und Steuerungstechnik o p Olhydraulik und pneumatik 31 1987 No 4 pp 354 357 358 VDI Berichte vom Sep 1988 pp 176 177 136 Pelka Was ist ein Mikroprozessor Franzis Verlag 1981 pp 8 9 16 17 Siemens Components 24 1986 Heft 2 p 63 Prior use 1987 by Ottmar Knisch CPS 10 und CPS 20 Aug 1987 7 Kraftfahr Technisches Taschenbuch 1987 pp 63 130 131 Elektronik Lexikon 1974 pp 206 84 86 Schreiben des VDMA an die Mitarbeiter des AK 13 Digitale Reglerkarte Mikrorechner Oct 1986 Catalog Mannesmann Rexroth RD 29943 1 86 pp 306 1 313 7 Jan 1986 Catalog Mannesmann Rexroth RD 29985 10 85 pp 342 6 345 3 Oct 1985 MOOG Datenblatt D 243 01 01 Sep 1986 Hoonhorst Hans Bendix Sequential Fuel Injection Bendix Electronics 1986 Dubbel Taschenbuch fiir den Maschinenbau 1981 p 1085 DE Z NN Impulse fiir Servo fluid Apr 1987 pp 24 26 DE Bosch Hydraulik Regelungstechnik S 57 DE Z 8 Aachen
11. f the valve by means of push button switches which are lo cated at different places of the plant to continuously adjust the valve towards opening or closing Provided the plant comprises a number of identical valves and associated amplifiers the inputs valve ad dress allows to select the valve to be actuated pro vided the input receives a signal whereas the desired values for the other valves are not change thereby The high concentration of processing data in the amplifying unit makes it possible to recognize and to display errors in response to data processing to improve the safe processing of the positioning value The error is indicated through a further digital input error indica tion After processing the error signal or respectively eliminating the error the amplifier provides an en abling signal to reinitiate the control of the valve A number of further digital inputs is connected to a valve code means 8 in which the valve type associated to the particular amplifier is binary coded for example by a number of soldering bridges In order to read the program into the memory 7 the valve code means is checked to make sure that only the software associated to the particular type of valve may be stored Finally the keyboard 9 is connected to the digital input 16 The keys allow selection of increment and decrement values and selection of a predetermined pro gram What is claimed is 1 An electrical amplifier
12. itable power supply The amplifier fur ther receives signals defining a number of desired values such as valve piston positions fluid flow volumes and pressures Additionally desired values are set by poten tiometers and will be supplied to the amplifier by oper ating switches Desired values for the piston position of the valve or the height of the pressure for example are generated in an analogue manner A main component of each amplifier is the control electronics which is con nected between the desired value input and the endstage and which generates the positioning signals for the control and output characteristics of the valve in accor dance with a valve specific program This program will vary in response to the function of the valve and the valve size As an example such control may be em ployed in directly operated or pilot operated directional proportional valves operating with and without feed back directly operated or pilot operated pressure valves pressure limiting valves or pressure reducing valves further flow valves directional servo valves or servo pressure valves Such control amplifier may op erate a variety of valves having a predetermined func tion which requires a certain algorithm for generating positioning signals in the amplifier to obtain a predeter mined interrelationship between setting a desired value and generating a suitable output current in the endstage In addition the size of the valve and thus the s
13. ital inputs of the programmable unit 3 The amplifier of claim 1 wherein the program of operation the valve specific program and the associated data can be transferred in either direction via said inter face 4 The amplifier of claim 1 wherein adjustable de sired value signals for the valve and operational param eters are loaded to and read out from the read only memory 5 The amplifier of claim 1 wherein said programma ble component includes at least an input to activate reading out and varying the desired value signals stored in the read only memory 6 The amplifier of claim 1 wherein said programma ble unit includes at least an input to receive an signal in case of a failure to reset the positioning signal for the valve in a predetermined stage by means of the pro gram 7 The amplifier of claim 1 wherein said programma ble unit includes at least a pair of inputs for a start stop operation to continuously vary the positioning signal for the valve 8 The amplifier of claim 1 wherein said programma ble unit includes inputs for a keyboard 9 The amplifier of claim 1 wherein said programma ble unit includes a multiplexer for analogue signal inputs of desired values and actual values 10 The amplifier of claim 1 wherein said valve is controlled via said interface from an external processor 11 The amplifier of claim 1 wherein the data stored in the read only memory are read out via said interface and wherein
14. ng plate which in turn may be mounted to suit a specific purpose Simple circuit amplifiers having a limited number of terminals and lacking setting means such as desired value setters may be mounted in a casing which is called a module More sophisticated amplifiers which include means for setting valve specific and am plifiers specific parameters such as desired values ramp times etc are mounted on a supporting plate including a front plate to accomodate switches push buttons or display elements A number of amplifiers of this type are combined in magazines Modules and magazines are assembled in a switching board Otherwise it is possible to mount an amplifier directly to a valve adjacent the valve casing or to secure it to a valve sandwich plate A substantial disadvantage of the prior art valve am plifiers is the need for a great variety of individual am plifiers to serve the various types of valves and valve sizes to be held on stock so that a particular amplifier which is associated to a particular valve is available According to the prior art the individual valve types and valve sizes further need specific amplifiers in a variety of embodiments For example one embodiment for each valve integrated assembly the modul assembly or the magazine assembly must be stocked All the vari ous amplifier types must be separately manufactured and held on stock SUMMARY OF THE INVENTION It is an object of the present invention to avoid th
15. ntrol including signal inputs for desired and actual values The control electronics generates a desired positioning characteristic for each type of valve According to the invention the control electronics is replaced by a pro grammable component including a read only memory in which the amplifier is associated to a particular type of valve by loading the read oniy memory with valve specific data which specify a particular type of valve The invention allows to manufacture and to stock non programmed amplifiers of identical structure To make an amplifier unit ready for use a particular program is loaded to suit the amplifier to the valve type 15 Claims 3 Drawing Sheets 5 172 311 Page 2 OTHER PUBLICATIONS Blickley George J Servo Becomes Digital Actua tor Control Engineering Jun 1986 XPERT Linear Actuator XLA User Manual Jul 1986 Dipl Ing Dieter Scholz Aachen Korrektur von Ventilkennlinien mit Hilfe von Mikorprozessoren 1986 pp 209 233 DE Prospekt Digitaregler DR 10 Gesellschaft fiir Antriebs unde Steuerungstechnik mgH and Co KG D 7742 St Georgen Schwarzwald Jul 1985 Prof Dr Ing W D Goedecke Dr Ing R Schwenzer DE Z Fluid Apr 1985 Wenn die All tags Pneumatik nicht reicht Dipl Ing Dieter Scholz Aachen Korrektur von Ventilkennlinien mit Hilfe von Mikroprozessoren 7 Aachener Fluidtechnisches Kolloquium Mar 1986 Verf H Rummel Bagg
16. onverted by the digital analogue unit 19 to an ana logue control signal for the endstage 4 The voltage supply of the electronics and of the endstage is provided by the power unit 5 The control may be performed by an external master processor to which the data gener ated by the amplifier are supplied to optimize the pro cessing control The multiplexer 11 is electrically connected to a num ber of analogue transducers in particular for receiving measuring signals of a variety of actual values such as pressures valve piston positions and or solenoid cur rents as well as an external ramp time modulator The amplifier unit is further connected to an analogue de sired value setter through the multiplexer 11 Now turning to the digital input 16 there is a variety of functions For example any signals defining desired values stored in the ROM 7 may be activated by the input calling desired values A total of 15 desired values may be read from the memory in using 4 keys provided the desired value reading is coded corre spondingly Each desired value is associated with at least a predetermined ramp time during which the de sired value changes The associated ramp times are stored a like in the memory A further input ramp out allows maximization of the ramp time so that the desired value is delivered as a positioning value having a minimum delay which is inherent to the system The inputs start stop operation allow control o
17. s of particular advantage when initially loaded data are manually var ied to optimize the valve characteristic which varied data are then transferred via the interface to a master processor where the data are stored to be ready for delivery This is of use when further valves of the same type are to be programmed According to this embodi ment of the invention there is provided a bidirectional data transfer In a still further embodiment the endstage may be located on a supporting structure together with the power supply to which supporting member the pro grammable unit including the read only memory on a so called daughterplate is soldered or pinned This daughterplate is identical for all types of valves Merely the endstages need a few different embodiments since different output currents are necessary in accordance with the valve size However the invention provides for a substantial simplification in stockholding and man ufacturing by using a programmable unit and read only memory in combination with the non programmable components such as the endstage and the power stage Accordingly the amplifier may be manufactured re gardless of the individual valve types to be controlled Amplifier carrying plates are manufactured which are identical to each other and are different in the endstage only As a rule a variety of two or three different ends tages will be sufficient so that manufacturing and stock are greatly simplified To suit
18. said data are varied 12 The amplifier of claim 1 wherein said supporting member is provided with a supplementary member incorporating said programmable unit and said read only memory 13 The amplifier of claim 1 wherein said supporting member is selectively mounted on said valve to be con trolled or a valve sandwich plate or mounted in a hous ing or provided with a front plate accommodating actu ating and display elements 14 The amplifier of claim 1 wherein specific values of a valve are loaded in the read only memory 15 The amplifier of claim 1 wherein the supporting member is provided with a front plate accommodating actuating and display elements k k k
19. sted for the hard ware valve characteristic FIG 2 illustrates an embodiment of an amplifier unit including a keyboard and display for calling up and changing data and for displaying data This can take place interactively without standstill of the amplifier For changing the the amplifier can be programmed using the keyboard 9 and the display 10 The keyboard further allows to change data in the memory As shown in FIG 2 the keyboard 9 and the display 10 are dis posed on a front plate of the unit FIG 3 illustrates the components of the amplifier The programmable component comprises a multiplexer 11 to which analogue data are applied which are cycli cally scanned in the multiplexer 11 and are transferred via an analogue digital converter 12 to a data bus 15 Additionally a number of digital inputs 16 is provided to the data bus 15 The programmable component further 5 172 311 5 comprises a microprocessor 17 to perform arithmetic calculations a random excess memory 18 and an inter face 13 for a series transfer of data from and to the computer 14 The data transmitted through the inter face 13 to program the amplifier are stored in a random memory 7 In operation the signals defining any desired values as well as the signals defining the actual values are sup plied to the programmable unit 6 in which the corre lated signals for controlling the endstage are read from the memory 7 and processed The digital output signal is c
20. troke and the geometry of the valve piston must be considered to obtain the proper signal These requirements result in control electronics and amplifiers are valve specific This means that each valve type or at least each valve family needs an individual specifically designed amplifier Moreover the control electronics may include further components all known to the artisan For example to obtain a continuous transient of response from a sudden variation of a desired value a ramp circuit may be use ful Components for the recognition of failure for ex 5 20 25 40 45 60 65 2 ample for indicating a broken cable may be helpful As mentioned before the amplifier may be a closed loop amplifier so that additional inputs are provided for the feed back of actual values such as the solenoid current and or the valve piston position or pressures occuring at the valve or adjusted by the valve Still further the endstage is controlled by a pulse width modulated sig nal thus supplying a pulsed current having a fixed or freely selected frequency to the valve solenoid The forgoing enumeration of individual components of a valve amplifier should not be considered to be com plete Further details are found in the handbooks of valve manufacturers for example in MANNESMANN REXROTH RD 29003 3 88 Hydraulic and electronic components for proportional and servo systems The amplifier components are regularly mounted on a supporti
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