Valve Expert 2.x (user manual) - English
Contents
1. Type of coil configuration Polarity of the control signal This knob sets a value of control signal Switches between Fine and Rough control modes This button starts the Degaussing Digital value of the control knob Range of Control Manual Control Hardware Feedback Picture 23 Valve control panel is shown 4 Pressure Gauges PA PB and DP Valve pressure drop Pressure on the control port A Pressure on the control port B ta 2100 1750 Ph 2450 A x05 k 2500 pai 2800 gt k 350 psi 3450 gt E 7 e AE 5 3500 3500 gt kh o 3500 z a Yo hor p ll Picture 24 The gauges show pressure on the control ports of a servovalve under testing Valve pressure drop is close to zero i e the control signal is near the null bias if control ports blocked and control flow is zero 19 DIETZ automation GmbH March 2004 5 Supply Pressure Gauge Flowmeter Servovale Control Signal and Spool Position Measuring Instruments Oil Level Indicator Load Valve see Picture 25 Supply pressure gauge A servovalve This device shows the real control under testing signal applied to the servovalve Spool position transducer Type of the spool position signal This flowmeter shows total valve flow l Mone 10 10mA 4 20m24 The load valve opens or blocks the control ports A and B2. Analyze the results after test or loading data Close the Automatic Test dialog box Picture 19 Automatic test dialog box The test process usually takes some minutes After that you will be able to produce the analysis or save the data using the corresponded buttons of the Automatic Dialog Box Note that Load Save and Analysis buttons exactly duplicate the functions of the corresponded items from File submenu of the main dialog menu see above Note also that you will not be able to switch on the motor if an alarm is indicated or power supply 380V is absent In such a situation you have to fix the problem and reset the alarm states using the button Reset 17 DIETZ automation GmbH March 2004 Manual Test The item Manual Test of submenu Tests see Picture 18 calls Manual Test Dialog Box see Picture 20 Namely this dialog box should be the starting point of your test process The intuitively understandable interface of Manual Test Dialog Box shows a structural schema of the teststand and gives a possibility to manually check your valve We strongly recommend you to check type and value of rated signal polarity maximal total flow type of spool position signal value of null bias and maximal leakage before starting the automatic test for your valve Notes the Manual Test Dialog Box contains also indicators of power supply 380V and alarm states of the stand Below we desc
3. This device shows electrical signal from the spool position transducer Oil level indicator Picture 25 The main attachments of servovalve are shown Please do not forget to close the load valve before starting the test This will restrict the total valve flow and therefore speed up the pressure installation process and save the hydraulic energy In opposite case the energy of the control flow will heat oil of the teststand Moreover the motor will not be able to install a pressure if the total valve flow will be grater 15 L min 6 Power Supply Indicator Reset Button and Alarms from Emergency Switch High Flow and High Temperature Sensors see 7 Picture 26 Green light indicates the presence 380 V power supply 3 380 The emergency switch was ai activated if this lamp lights There was an overflow if this mm Emergency indicator lamp lights Em High flow In order to clear the alarm states m High temp please fix the problem and then The oil temperature increased click the reset button m Reset 60 C if this lamp lights Picture 26 Power supply indicator reset button and alarm indicators are shown Note also that you will not be able to switch on the motor if an alarm is indicated or power supply 380 V is absent 20 DIETZ automation GmbH March 2004 Manual Test Sequence Example 1 2 EN 8 9 First of all you have to be sure that a servovalve you want to test is installed proper
4. Knowledge of the model allows to exclude the dynamical effect which certainly arise at fast measurements For more details see or http arxiv org abs math DS 0202070 Internal Leakage The total internal flow from supply port Ps to return port T with zero control flow Normally it is measured with control ports blocked Null Leakage The leakage at the null bias control signal Usually this is a maximal value of the internal leakage 28 DIETZ automation GmbH March 2004 Leakage Curve The graphical representation of the dependence of an internal leakage from the control signal An example of such a plot is shown on Picture 39 LEAKAGE DIAGRAM Leakage flow L min iil Hysteresis jj ___ _ 15 10 5 5 10 15 20 Control mA Picture 39 Leakage diagram for a real servovalve Maximum of the leakage flow is about 2L min Leakage Hysteresis The difference in the valve input signals required to produce the same internal leakage during a single cycle of control signal inside the rated control interval Leakage hysteresis is normally specified as maximum difference It is expressed as percent of rated signal Total Valve Flow The sum of the control flow and internal leakage flow Spool Position Signal An electrical signal from a spool position transducer of servovalve Normally this signal is proportional to the mechanical position of the spool Note the most popular servovalves use transducers wit
5. ValveExpert Automatic Teststand for Checking Maintenance and Adjustment of Servovalves User Manual DIETZ automation GmbH March 2004 Contents US DO EE ets sett O O RE vases ANETE AAT E AEA aceon Saute E EEEE E E E A eeiaas l CO E E E EE T E I T 2 MOUE A E A E a AEE 4 Review Ol SPECICATION Sipi TA A A ii 5 APP CAT OM ii a E EEA E A ENE 5 Control sional Tor Sery OV Al VE A 5 Spool Position Siomal Feedback Vorea a EE E eee 5 Power SUPPLY TO SSN OV Al VES SAA AAA AE AAA A TE TAS 5 shit Lge BIE Teg gh b GG PR a mene nein Tarn eA Ne NTN en nee ee a a ee 5 Pxtermal Power Supply Or Val Vel x Pella ea a E E cele 5 ST AUN AA E LE e EE ac E EE O sence ee 6 NS II a a a IN II 7 AA A A R T Standard C aD leS dido I Adapter Man Hold ibas 8 COVE Pri rii 8 Unmyersal Control Board sier iS 9 Servovalve Connector Stand VIEW tr A 10 AU o AAA A sence G 11 SOL Ware ISO dai ias 11 Mam DaO e e e e tl e 12 Menm Descarta AA alain tol 12 B Weer me ere coer neva en RE Peete RT 12 Lada E AE vee T E co 12 BA PRO RO CPE OE O PO O RO E A A ds oot 13 A O sgueas tesa teen ale echt atau Caen E E lta cn cetaceans Sac lanr eee teteas 13 PP ee Sa Nr OE EE eke A E TANE DEEE E E NEA EEE E AETA ae ae ere ee 16 TES ME PE SEO E II A dameee 16 AM do 16 Manual Toni Ri Aia 18 Manual Test Sequence Example liada 21 Special futures of the Manual Test Dialog BOX occcnnnnnnnnininininononinenininoninnnnncnncnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnininenos 22 D
6. Ss Picture 27 Top view of ValveExpert Special futures of the Manual Test Dialog Box The Test Dialog Box is powered by the following abilities 1 Exact Value This ability allows to read the exact value from any analog device see Picture 21 Picture 22 Picture 24 Picture 25 of the system Use the mouse to point out a device and left click it The exact value will be shown in a small window see Picture 28 for an example The measurement device shows the real control signal Use left mouse click to see the exact value Picture 28 Left mouse click shows the exact value 2 Range settings You can choose the range settings of the gauges and other analog devices yourself In order to modify it point out a device and right click it The range setup dialog will appear see Picture 29 Please specify the values of ranges and ticks and click OK The device range settings will be changed according your request Note that you can use the Default button to reset the range settings by default The Cancel button cancels the changes Range Setup Dialog Range Minimum 0 Maximum 250 Minor Major 10 Picture 29 Range Setup Dialog 22 DIETZ automation GmbH March 2004 3 Accumulator Settings This ability is used to check the load pressure of the hydraulic accumulator and correct the corresponding software parameter The right mouse click on the accumulator executes the corresponding dialog see
7. five buttons for fast call of the main functions Menu Description File This submenu see Picture 10 allows to work with data which were obtained at the testing process lt can be used also to close the program MAA File Tests Database Settings Load Picture 10 Submenu File Load Select this item to execute a standard Windows open file dialog see Picture 11 By this dialog you can load the saved test data for analysis and printing results iZ DIETZ automation GmbH March 2004 Select data file to be loaded Look in 3 Last Data 4WRSE 2 055 PMDO72 10D DSS AWRSE 3 D5S PMlipo72 10 Dss awrse pss Mipo72 10F 0ss Filter for files Do72 103 055 MEM to be shown pov2 108 08s Mpo72 10H Ds5 Do72 10c Dss fjoo72 101 0ss Selected file Load the selected file File name Open Files of type Test results dss Cancel Cancel the loading F Open as read only E Picture 11 Windows open file dialog The filter DSS is used by default for data files Save Select this item to save data of a test in a file A standard Windows file dialog will be open see Picture 12 If test data are saved you are able to load the data and produce the analysis Enter the new filename for data Save in Q Last Data 4WRSE 2 085 PMDO72 10F DSs 4wRse 3 0ss PMipO72 106 DSS awrse pss PMlipo72 10H4 Dss p072 10a 088 fjpo72 101 0ss DO072 108 D55 Name for D072 100
8. gives the equivalent dynamical description and can be obtained from the linear differential equation by the Laplace transformation An example of a linear dynamical model and the corresponding transfer function are shown below Ax Bx Cx u t K p p Ap Bp C Here u t control signal x t output flow 4 B and C are some constants Frequency response The relationship between no load control flow and harmonic sinus type input signal Frequency response expressed by the amplitude ratio and phase angle which are constructed for harmonic signals from a specific frequency range Below we give definition of the amplitude ratio and phase lag more precise Let x t be the control flow corresponding to input signal u t Asin t Here v 27f frequency of the test signal After some transition time Ar the output signal x t will be a periodic function with the same frequency a In this case x t can be represented by the following Fourier series x t y R sin kat q 0 k 0 For any k the amplitude R w and initial phase y w expressed by the formulas R K ia y o arg K iw At 22 K io gt edr At The graph of the function amp R 0 represents the amplitude ratio of the valve The graphical representation of the function g is the phase lag Examples of phase lag and amplitude ration is shown below on Picture 41 We must note that valve frequency
9. has build in switches to change polarity of control and coil configurations series parallel or single coil Spool Position Signal Feedback Many modern servovalves have build in electronics These valves are usually equipped with position transducers used for internal feedback of the spool position ValveExpert can check a signal from the spool position transducer The standard signal ranges 10 V 10 mA 4 20 mA are supported Power Supply for Servovalve Servovalves with build in electronics require external power supplies In most cases it is 15 V DC or 24 V DC with current 1 2 A Such power suppliers are built in the teststand Hydraulic Fluid The teststand ValveExpert was developed and tested for a mineral oil with viscosity about 30 We recommend you to use Mobil DTE24 Shell Tellus 29 MIL H 5606 or oil with the similar parameters We must note that these requirements are needed basically to satisfy the requirements of a pump and a flowmeter which are built in the teststand So you should ask the producers of the pump and flowmeter before using another hydraulic fluid The integrated filtration system achieves a cleanliness level 5 of NAS1638 level 14 11 of ISO4406 or better The filtration is controlled by an operator of the stand and depends evidently on the contamination level of the servovalves been tested External Power Supply for ValveExpert The teststand does not require an external hydraulic power supply b
10. little amount of oil will be spread outside Nevertheless our recommendation is to avoid using this feature Database This item of the main menu see Picture 10 opens the Database Dialog Box Picture 32 This dialog is intended for visual modification of test parameters of servovalves Currently the database consists of two tables series table and valve table The dialog shows this database structured in the tree control on the left side This tree is very similar to a tree of Windows Explorer The folders are series and the files are valves The right side of Database Dialog Box shows parameters of a selected item of the tree You can modify them using the keyboard and mouse Please do not forget to save your parameters using the corresponding button after any changes of database records In the opposite case the changes will be lost Note that most of parameters will be disabled if you select a series they are for valves only Notes also parameters from the dynamic group will be hidden if the corresponded box for the settings dialog see below is unchecked Use New Series and New Valve buttons to create a new item of the database and Delete button to erase it You can create a new valve with the same parameters you already have In order to do that just point out a servovalve with parameters you need and press New Valve You can use technology Drag amp Drop to change series of servovalve 23 DIETZ automatio
11. 055 test data file DO072 100 DS5 D072 10E D55 File name Save as type Test results dss Picture 12 Windows save file dialog Note the DSS extension is used by default to save the data Analysis If the automatic test is done or test data are loaded you can select item Analysis to show results of the test Note that you can execute the analysis also from Automatic Test Dialog Box see Picture 19 below We must note that standard modification of the test stand allows checking most of the static characteristics of servovalves e pressure curve flow curve leakage curve spool position diagram and some other parameters The pictures Picture 13 Picture 16 below give an example of the analysis In order to print or save pictures operator shall use the corresponded items of the picture menu The item Save involves saving of the picture on the Desk Top of the computer The item Print opens a standard Windows dialog see Picture 17 In order to check the dynamic characteristics the so called Measurement Piston must be installed This option allows to obtain the frequency response and find the best linear dynamical model see Picture 41 13 DIETZ automation GmbH March 2004 Differential Pressure Print Save Differential Pressure DIETZ GmbH automation DIFFERENTIAL PRESSURE DIAGRAM 80 cooooooooo cece eee ececcee eoomoooooooo conoser Rd commons sososo ee GENERAL
12. INFORMATION Customer Cusfomer Valve model 51 2W4RCE Serial number 00 Principe nozale fapper type Norrunal flow rate at 70bar 40 Ln Norninal signal 30 30m4 60 TEST CONDITIONS System pressure 0bar Test amplitude 154 50 of rated signal Oil temperature 37 C 20 TEST RESULTS Null bias 1 20m4 4 0 of rated signal Hysteresis by pressure curve 2 2 Differential pressure bar 40 Date 12 39 24 102 003 Operator Operator a E f 3 15 10 5 0 5 10 15 20 Control ru Picture 13 Pressure curve Leakage Test Print Save Leakage Test DIETZ cmbn automation LEAKAGE DIAG 5 coom ooooo i cesssececoooon eooooooooooo a ia common conssoo como nroooo GENERAL INFORMATION Customer Customer Valve model 51 2WRCE Serial number 00 Principe nozzle flapper type Norrunal flow rate at 70bar 40 Ln Norninal signal 30 30m4 TEST CONDITIONS System pressure 0bar Test amplitude J5mA 50 of rated signal Oil temperature 37 C TEST RESULTS Null bias 1 20mA 4 0 of rated signal Maximal leakage 2 0Lmin Hysteresis by leakage curve 2 6 Leakage flow Lirain Date 12 39 24 102 003 Operator Operator 15 10 5 0 5 10 15 20 Control rog Picture 14 Leakage curve 14 DIETZ automation GmbH March 2004 J Flow Test Print Save Flow Test DI ETZ GmbH automation FLOW DIAGRAM 25 ceseeosoooooo cece ec ceccceee e
13. Picture 30 The button Auto executes the test program which starts the motor for a short time This implies a small loading of the accumulator and in this case the supply pressure will be very close to the initial load pressure of the accumulator Namely this value will appear in the edit box after the testing Of course this value can be corrected manually We must note that the pressure must be installed to zero before the test Please regular check the load accumulator pressure It should be about 30 40 bar Too small or big load pressure may be a reason of mistakes Accumulator Settings x Load accumulator pressure 35 bar Cancel Auto Picture 30 Accumulator Settings Dialog 4 Impuls Flow Test This future gives a possibility to find the total valve flow for any fixed control signal The right mouse click on the load valve Picture 25 opens it for a short time about 0 2 sec This time is enough to identify the flow The blue arrow will point out the found value see Picture 31 Flowmeter a5 10 Picture 31 Expressed Flow Test is produced Read arrow shows the total valve flow if the control ports are blocked The blue arrow fixed the maximal flow during the expressed flow test 5 Valve Absence Checking The teststand checks the installation pressure process every time you install the pressure The stand will be switched off after 0 2 sec if you forgot to install a valve on the test stand Only a
14. Z automation GmbH March 2004 Introduction ValveExpert is an automatic teststand for checking maintenance and adjustment of servovalves It is a high performance test equipment based on the latest achievements in hydraulic servocontrol systems ValveExpert was designed mainly to provide complete analysis of four way flow control servovalves with flow up to 80 L min and pressure up to 210 bar Nevertheless we must note that ValveExpert can be used successfully also to test some other types of servovalves proportional valves and other hydraulic devices ValveExpert is a completely autonomous teststand with hydraulic power inside and with a computer subsystem for control and powerful mathematical analysis To start measurement with ValveExpert you just need the electric power supply 380 V Small dimensions of the stand and the fact that ValveExpert does not require an external hydraulic power supply and cooling water allows using it as a portable high performance test equipment Note that the computer subsystem allows to print or save all results and test data You can immediately send out the results using a computer network connection The stand allows testing the most standard static and dynamic parameters In addition to such traditional characteristics as static flow curve and frequency response ValveExpert allows to obtain a mathematical model of a servovalve under test The knowledge of the dynamical system which describes the servovalve obv
15. curve is shown on Picture 38 FLOW DIAGRAM Hysteresis Va id Flow L min F 1 i 15 10 5 0 5 10 15 20 Control mA Picture 38 Flow curve for a real servovalve Rated signal is 15mA null bias is about 1 2mA and rated flow is about 24L min Hysteresis Flow Hysteresis The difference in the valve input signals required to produce the same control flow Flow hysteresis is normally specified as the maximum difference occurring in a region of rated control interval It is expressed as percent of rated signal Normal Flow Curve The locus of the mid points of the complete cycle flow curve This locus is the zero hysteresis flow curve However valve hysteresis is usually quite low such that one side of the flow curve can be used for the normal flow curve Flow Gain The slope of the control flow versus input current curve at any specific point or in any specific operating region The incremental flow gain may vary from point to point due to valve nonlinearities The nominal flow gain will generally show three operating regions 1 the null region 2 the region of normal flow control and 3 the region where flow saturation effects occur When this term is used without qualification it is assumed to mean normal flow gain DSS Method A method which allow to identify the flow curve by a short time experiment The main idea of the DSS method is based on the identification of nonlinear dynamical model of servovalve
16. d pressure drop The null bias control signal will be shown on the control signal measurement instrument see Picture 25 An example of settings to find null bias is shown on Picture 20 We must note that our electronic uses a special adaptive control schema to find the null bias Nevertheless we are not able to guarantee the 100 efficiency of the electronics First of all problems can arise if you test a proportional valve with extra slow dynamics In such a case please use the manual control knob to find the null bias Note also that there exist valves which do not have null bias points as well as such valves which have two or more null bias points In the last situation the electronics obviously can not identify the proper choice 17 You can use the left mouse click to open or close the load valve Picture 25 Note the flowmeter will always show the total valve flow i e the sum of the control flow and the internal leakage flow We strongly recommend you do not open the load valve for longer time because the energy of the control flow will heat the oil fast Therefore use the right mouse click to open this valve for a short interval of time In this case a blue arrow on the flowmeter will indicate the maximal flow during this short subtest see the Express Flow Test of the next section zos DIETZ automation GmbH March 2004 Lamp indicates the presence of pressure Servovalve EN ea A y g Cover plate Adapter manifold
17. e a shortcut combination of keyboard keys The following table summarizes all these possibilities Toolbar Keyboard Menu Description Alt F L File gt Load Load a File with Test Data Alt F S File Save SaveTestDatatoaFiley KAItF A File gt Analysis Produce Analysis of a Test Data Alt H A Help gt About Display About Box KAIt H D Help gt Dietz Automation Web Open the Home Page in Internet Picture 35 Three possibilities to call the subsystems of the program are shown The computer must have access to internet 25 DIETZ automation GmbH March 2004 Definitions Electrohydraulic Flow Control Servovalve A device designed to produce hydraulic flow output continuously depending from electrical input signal Usually the dependence is close to proportional one but there are kinds of servovalves where the output flow is not linear function of control Rated Control Interval The interval of possible input electrical signals which specified by a producer of the valve as a nominal control Rated Minimum and Maximum of Control The minimum and maximum of the rated control interval Predefined Bias The mean of the rated maximum and minimum It is expressed as half of sum of rated maximum and rated minimum of control signal Rated Signal The amplitude of the input control signal which is expressed as half of difference between rated maximum and minimum of cont
18. ecause it is inside ValveExpert does not need a water connection for cooling because it does not take much energy The only three phase 380 Volt 50 Hz power supply is required to start measurements with ValveExper 5 DIETZ automation GmbH March 2004 Hydraulics Main manifold with minimess access pressure transducers and valves Hydraulic Oil tank with accumulator pump inside 1e S Picture 2 Hydraulic schema for automatic teststand ValveExpert M brushless servomotor PU gear pump T temperature transducer L oil level sensor F1 10u oil filter F2 3y oil filter F3 air filter PA PB PS pressure transducers for 0 250bar AC 4L hydraulic accumulator VS1 high precision gear principle flowmeter K1 pressure filtration valve K2 load valve K3 security valve SV manifold for servovalve D1 throttle to restrict return flow from accumulator AC All components inside of the dotted box are mounted on the main manifold 6 DIETZ automation GmbH March 2004 Accessories Measurement Piston Most of industrial applications do not require the knowledge of the exact dynamical properties of servovalves Nevertheless they are absolutely necessary to know for most of military science and other high precision and high frequency applications Our firm has developed a special so called Measurement Piston see Picture 3 which in combine with teststand is a
19. erator Operator 4 3 2 1 0 1 2 3 Control Y Picture 16 Spool position diagram 15 DIETZ automation GmbH March 2004 Properties Type HP LaserJet 2100 PCL6 Where LPT Comment Print to file Print range Copies Number of copies 1 All Pages From fo f Selection CEEE Picture 17 Standard Windows print dialog Exit Select this menu item to cancel the program Tests This submenu allows to select the Automatic Test and Manual Test see Picture 18 below ValveExpert x File Tests Database Settings Picture 18 Submenu Tests Automatic Test Select this item to execute Automatic Test Dialog Box see Picture 19 below Data for the future analysis will be accumulated during namely this automatic test process Before starting the Automatic Test Dialog Box you have to be sure that a servovalve is installed electrically connected with the test stand and which works properly Therefore we strongly recommend you to execute the Manual Test Dialog Box see below and check the type and value of rated signal polarity rated flow type of spool position signal null bias and maximum value of leakage After the checking please verify that the valve parameters in your database are close to these which you found see Database Dialog Box Note if the database parameters are very far from reality the automatic test program will not work correc
20. h output signal 10V 10mA and 4 20mA SPOOL POSITION DIAGRAM 0 8 0 6 f 0 4 i 0 2 Spool position V 4 3 2 1 0 Control V b3 Picture 40 Spool position diagram of a real servovalve The red point shows the null bias which does not coincide with the zero of the spool position transducer 29 DIETZ automation GmbH March 2004 Spool Position Diagram The graph of a function which represents dependence of the spool position signal from control signal Servovalves with spool transducers normally have very small hysteresis Nevertheless the spool position diagram can be not uniquely defined An example of a spool position diagram is shown on Picture 40 Spool Position Hysteresis The difference in the valve input signals required to produce the same spool position signal Spool position hysteresis is normally specified as the maximum difference occurring in a region of rated control interval It is expressed as percent of rated signal Dynamical Model of Servovalve A differential equation or system of differential equations which describe basic dynamical properties In practice people usually use linear dynamical models i e they assume that dynamical behavior of valve can be well described by a linear differential equation or system In this case and only in this case the dynamical model can be represented by a transfer function This is a complex function K p from a complex argument p The transfer function
21. he device View or change device properties Picture 8 Measurement amp Automation Explorer 3 Start CD ValveExpert Setup exe program to begin setup the DIETZ automation software for ValveExpert Follow the program instructions to complete the installation 4 Copy your private configuration file ValveExpert cftg with installation specific settings to directory with MS Windows usually c windows The installation program must be run under a valid administrative account Here CD is the drive letter of your CD ROM Please note that you can use ValveExpert software on a separate computer This can be useful to analyze saved test data or correct your database file DBAccess mdb By default this file is located in C Program Files DIETZ Automation GmbH ValveExpert In any case the NI Device Drivers must be installed 11 DIETZ automation GmbH March 2004 Main Dialog By default the program ValveExpert is installed in C Program Files DIETZ Automation GmbH ValveExpert ValveExpert exe You can execute it using the following icon WM from start menu Start Program gt DIETZ automation gt ValveExpert gt ValveExpert The following dialog will appear Wy ValveExpert File Tests Database Settings Toolbar Picture 9 Main dialog of the program ValveExpert This dialog includes menu line and toolbar Menu is used for access to all dialogs of the program Toolbar contains
22. iada nai is cols E E 23 SEM AA AAA A 24 A 23 COMEN Sc o acia 25 DIE TZ AO MALO WE Dis tos 25 A A e e aaa eel eee 25 Menu Description noc a E eatin anid ethene 25 DETAIL AAA AD AAA AAA 26 Electrohydraulic Flow Control Servovalve ccccccnnnnnonooooooooonnnnnnnnnnncnnnnnnnnnnnnn nono nnnnnnnnnnnnnnnnnnnnnnnnnnnnn nono nnnnnnnss 26 MEAT A A e e id 26 Rated Minimum and Maximum of Control TA T A E 26 AAA II A 26 Rated Taba a a a a a 26 Four Way SerVOVal V until A dadas 26 SUPP PSS UO dc 26 PRS CUT SS SUE a eS eck i ca dM ced hi A de inetd 26 Load eg esi oes Diao 26 Valve Pressure A ne ee are 21 Pres Ure CUE oral 2 PISSSULS Elorrio bie 27 MESS cia a 5 DIETZ automation GmbH March 2004 Control Flow Load Plow OF Flow Opus ida 27 A O 21 A o CR 5 AI 27 A a cia nae ec scapes cutee Recreate RO 2 A RR Zi FOW CU nic oia mer rer er peer ener 28 PL VStete sis CE LOW Ely SUC S15 ait 5 ace e A O 28 Norma LO Wy CUNO seeren A AAA E As 28 FOW Gata 28 a AA EE A II A II A 28 ermil Ec 28 NL e edad 28 DETRAS CU SNA AAA AA SATA AE AAA 29 Leakage y y SECU AA o o A 29 RIDE o A O A O A 29 POOL OSO DI SNA Merrie ant ete nee sn es ne reve en ne eve ne ede 29 Sa POsiti m1a ea opie hence Aa ee hanes ene eka ee ied iba cecil ee Garkcs 30 POOL POS iO Ty SUCECSIS A A 30 Dynamical Model 0t Sehy OV aN Cositas 30 Frequency response add 30 Natural RC QUCIICY naea E ios 30 Di ata Bo o AAA o e A er eeer ere erence 30 NES tico tits 32 3 DIET
23. ialog box see Picture 33 The dialog allows to change settings for measurement units DSS correction at the static analysis and some other options of the program Option Show dynamics gives access to the settings dynamical parameters in the Database dialog box and gives a possibility to produce dynamical testing Mark Show logo implies appearance of your logo on the output forms The setting Normalizing pressure predicts the results for the system pressure entered below Program Settings x Measurement Units bar Pressure Lmin Flow r E Temperature 055 Correction Automatic f DoDSS correction C Bypass D55 correction Advanced Options M Show dynamics M Show logo M Normalizing pressure fi od bar Picture 33 Program Settings Dialog Box 24 DIETZ automation GmbH March 2004 Help This submenu see Picture 34 gives you access to the help system ValveExpert Fie Tests Database Settings Picture 34 Submenu Help Contents Select this item to show contents of the help system DIETZ automation Web This item directs you to the main page of DIETZ automation GmbH site in the internet About This dialog contains information about authors version of the program and so on Menu Description Shortcuts There are three ways to call most of dialog boxes which were described above 1 Select an item from menu 2 Click a toolbar button 3 Us
24. iously opens new possibilities for designers and developers of control systems They can use the obtained model for fast computer simulations as well as for complex mathematical analysis We believe ValveExpert will give you best possibilities for checking maintenance and adjustment of your servovalves The developers and designers will find ValveExpert as a good tool to construct excellent control systems General Manager of DIETZ automation GmbH Joachim Dietz ye DIETZ automation GmbH March 2004 Review of Specifications Application The teststand is developed for checking maintenance and adjustment of four way servovalves with rated flow up to 80 L min and supply pressure from 60 to 210 bar Control Signal for Servovalve Using ValveExpert you can check servovalves controlled by current as well as voltage There are four ranges with 12 bit resolution for current control 10 20 50 and 100 mA We must note that in reality the electronics covers about 120 of these ranges e for instance maximal control current for 100 mA range is about 120 mA This extension is made for 20 possibility to correct the null bias of the servovalve i e teststand is able to produce tests with amplitude 100 mA and control shift 20 mA Note also that 20 mA range is used for the popular standard control 4 20 mA There is one range Voltage control signal 10 V The real output signal can be also 20 more i e 12 V Note that ValveExpert
25. ly and the corresponded electrical cable connects the servovalve and teststand Check the alarm indicators Picture 26 Picture 22 Picture 25 and the Emergency switch see Picture 6 They should not be activated If an indicator is light you have to correct the corresponded problem and then reset the indicator using the reset button Picture 26 Switch on the power supply Picture 21 After that the green lamp 380V Picture 26 should indicate the presence of power supply In the opposite case please verify that your teststand is properly connected to 380V Install the Manual Control Hardware Feedback switch in the manual mode and choose the proper values for polarity control range and type of coil configuration Picture 23 Note you should use the parallel mode of the coil configuration switch for servovalves with build in electronics Set up the type of spool position signal see Picture 25 Switch on the motor Picture 21 Switch the Pressure Filtration valve Picture 22 in the filtration mode if you have to produce a preliminary clearing of the oil and after that install the knob in a middle position Note to save your servovalve as well as the teststand you should regularly filter the oil Please do it every time when you add new oil in the tank We recommend 40 minutes filtration for new oil Switch the Pressure Filtration valve Picture 22 in the pressure mode Close the load valve Picture 25 10 Install pressure usi
26. n GmbH March 2004 Select a series ora servovalve from this Type of servovalve Static parameters of a selected servovalve tree view to modify it Database Edit Diak List of Series and Serva E Specification Type i MNozzle Flapper Rated Signal 20 00 m s F DeflectorJet Rated Flow 20 00 L min control Direct Drive 7 Two Stage gt Tolerance of Rated Flow i 5 E 7 JetPipe ServoJet Pressure Drop 0 00 bar Aa DES2E 2004 Three stage i Not Specified Defined Bias m at 0760 25684 Servovalve Control Polarity of Cmca 2 hs control Voltage re 3 Positive PA Negative po Tolerance of Bias lt B Hysteresis of Flow 0 00 E 00 Po E Dynamic Internal Leakage lt Lmin parameters of Amplitude of static test F a selected 0 2 3 2 20 i 10m4 4 20 m of servovalve Connection Dynamic servovalve Serial Supply Pressure 70 00 bar Parallel el Natural Frequency gt so Hz Spool position Natural Amplitude Ratio gt 200 dE None i i f 10 Maximal Amplitude Ratio lt 2 00 dE mn Coil configuration j Amplitude Dinamic test 40 da Signal from spool Comments o comments iC position transducer of servovalve Hew seres New valve Delete Exit the dialog Picture 32 Database Dialog Box Create a new series Settings This item of the main menu see Picture 10 opens the Program Settings d
27. ng the knob or edit box Picture 22 The lamp on the top cover of the stand 11 will indicate the presence of pressure Please do it by small steps and verify absence of the external leakage from the servovalve Note in order to remove the pressure you can switch off the power supply switch off the motor switch the Pressure Filtration valve in the filtration mode set the zero pressure close the program or activate the emergency switch Picture 6 on the teststand The real pressure will be indicated on the supply pressure gauge PS see Picture 25 The flowmeter will indicate internal leakage 12 The gauges DP PA and PB Picture 24 will indicate load pressure drop and pressures at the control ports A and B correspondingly 13 Use the control knob Picture 23 to control the servovalve A reaction of the valve will be reflected by the gauges Picture 24 Picture 25 Note you will see motion of the spool Picture 25 if your valve has a spool transducer 14 For accurate tuning of the control you can switch the control knob in Fine mode Picture 23 15 The button Degaussing Picture 23 is used to start and stop the degaussing process with zero shift The valve control knob sets the amplitude of the degaussing 16 Switch on the Feedback mode Picture 23 if you want to find the null bias In this case a special electronic will try to find the null bias i e a control signal which corresponds to zero loa
28. ntrol Flow Load Flow or Flow Output The fluid flow passing through the valve control ports A and B Polarity The relationship between the direction of control flow and the direction of the input signal It can be positive and negative Usually it is assumed that polarity is positive if positive in some sense control signal opens port A to supply port Ps and control port B to return port T Null Bias The input control signal where the valve supplies zero control flow at zero load pressure drop Note null bias may depend of operating conditions and environment Due to the hysteresis effect null bias depends also on initial state of servovalve Null Shift The maximal change in null bias resulting from changes in operating conditions or environment It is usually expressed in percents of rated signal Rated Flow The specified maximum of control flow for input signals from the rated control interval The flow usually expressed in L min lpm in sec cis or gal min gpm 2 DIETZ automation GmbH March 2004 This value corresponds to specified valve and load pressure conditions Normally it is assumed that the load pressure drop is zero Note usually rated flow corresponds to rated minimum and maximum of control Flow Curve The graph of a function which represents dependence of control flow from control signal Note due to the hysteresis effect the function usually is not uniquely defined An example of a flow
29. oomoooooooo cooononooo ias des coco osoroso O GENERAL INFORMATION i E Custoraer Customer 20 Valve model 51 2W4RCE Serial number 001 Principe nozale fapper type 15 Nominal flow rate at 70bar 40L min Nominal signal 30 7 0mA 10 TEST CONDITIONS 5 System pressure 70bar Test amplitude J5mA 50 of rated signal E Oil temperature 37 C 2 0 TEST RESULTS En Null bias 1 20m4 4 0 of rated signal DSS correction no correction Flow at 14 0ru amp 24 5 L min Flow at 16 0mA4 24 OL min Hysteresis by flow method 2 2 Date 12 39 24 102 003 Operator Operator 25 15 10 5 0 5 10 15 20 Control ru Picture 15 Flow curve J Spool Position Print Save Spool Position DIETZ GmbH automation SPOOL POSITION DIAGRAM 1 cooo ooooo i ceseseceooooon eonooooooooo e bi e cece cece cceee cono noooo GENERAL INFORMATION Customer Customer Valve model 4WRDE 16 Serial number 00 Principe nozzle flapper type Norrunal flow rate at 70bar 300L nin Norninal signal 0 10Y 08 0 6 0 4 TEST CONDITIONS System pressure 0bar Test amplitude 34 30 of rated signal Oil temperature 49 C 0 2 TEST RESULTS Null bias 0 174 1 7 of rated signal Spool position at 0 17V 0 04 Spool position at 3 5 1 04 Spool position at 2 5V 0 9 Hysteresis by spool position curve 0 1 spool position Y p to 0 4 Date 17 34 23 102 003 Op
30. powerful test equipment for dynamical response The Measurement Piston allows to obtain the complete knowledge on dynamics of your servovalve We must note that in addition to traditional frequency response curves you will obtain the best liner dynamical model of your servovalve see Picture 41 Picture 3 The Measurement Piston and a servovalve are installed on the teststand Standard Cables In order to connect servovalves with ValveExpert a number of cables can be delivered on your request Each of the cables contains two connectors One is for the teststand and the other one is for the servovalve Schema of the teststand connector is shown on Picture 6 teststand side view Below we show the most popular connectors for servovalves cable side view 15V GND 24V GND Spool position Spool position 24V GND OV Spool position 7 DIETZ automation GmbH March 2004 OV A Control A Control OV Spool position Adapter Manifolds With the standard equipment come two of the most popular mounting plates 1 Norm ISO 10372 06 05 0 92 for Moog series 72 MTS 252 3x Ultra 4550 2 Norm ISO 10372 04 04 0 92 for Alpha series BOO20010 Atchley 209 Moog 62 Moog 73 Moog 76 Moog 760 Moog 761 Moog 765 MTS 252 2x Pegasus 122A Ultra 4653 Vickers SM4 20 Voskhod UG 176 Additional adapter plates can be delivered on request Picture 4 Adapter Manifolds Cover Cap A co
31. response may vary with the input amplitude temperature supply pressure and other operating conditions Note also that for linear systems K i K i and K i 0 k 2 3 0 Natural Frequency Such frequency that g 7 2 A T f T Degaussing Control The input control signal like u sin ot u Here 4 amplitude T duration frequency of the degaussing Degaussing is used mainly before checking of average parameters of servovale for the control u Below a degaussing curve is shown Picture 42 R 0 is a formal notation for R where is small enough Usually is less 5Hz 30 DIETZ automation GmbH March 2004 General Information Valve Model E760 012 Serial Number Customer Date 05 Jan 2002 11 52 Operator gp oney Test Conditions O A Coil Configuration Series Coils 12 Connections A B and C tied D System Pressure 2000psi 14 Temperature 3800 Frequency Hz Amplitude 8mA 40 of the Rated Signal Results of the Dynamic Response Frequency of 90 Phase Point 95Hz 8 7dB Amplitude Ratio at 95Hz u t Uy Closest Linear Dynamical Model A amp ylot B 0 y o C dy ot Dy A 2 5e 010 B 2e 006 C 0 0033 D 0 71 6aq eseud 0 3mA Null Bias uy u Control Signal mA y Output Flow L min Frequency Hz Picture 41 Frequency response of a real servovalve Green points on the graphics
32. ressure usually expressed in kg cm bar or Ib in psi 26 DIETZ automation GmbH March 2004 Valve Pressure Drop The sum of the differential pressures across the control orifices of the servovalve Valve pressure drop will equal the supply pressure minus the return pressure and minus the load pressure drop Pressure curve A graph which represents dependence of the load pressure drop from control signal at zero control flow i e with control ports blocked An example of such a curve is shown on Picture 37 DIFFERENTIAL PRESSURE DIAGRAM 80 3 SSS SSS See 20 Hysteresis eM Differential pressure bar e E 40 mS L L L mka e ant 15 10 5 0 5 10 15 20 Control mA Picture 37 Pressure curve for a real servovalve Red point shows the null bias of the valve Pressure Hysteresis The difference in the valve input signals required to produce the same load pressure drop at zero control flow i e with control ports blocked Pressure hysteresis is normally specified as the maximum difference occurring in a region between 40 of maximum load pressure drop It is expressed as percent of rated signal Pressure Gain The change in load pressure drop per unit of control with zero control flow control ports blocked Pressure gain is usually specified as the average slope of the curve of load pressure drop versus input current in the region between 40 of maximum load pressure drop Co
33. ribe the basic control elements of the dialog 380 y Emergency High flow High temp EEEL Reset Mone 410 410m 4 2bm4 A i 100 1 150 nt 100m4 ant Vera dE 175 50m4 4 20m6 20m4 Ee of 10m4 EN an fe oo are g cS pls gt Paralel 2 a a 1 Pt 1 qm nl A Pi ra im l i Pai JI 4 B 20 70 bar y Stand Motor 0 0 mA z 1 10 L r Picture 20 Manual Test Dialog Box An example how to check null bias is shown Supply pressure is installed 70bar Rated Control Interval is 20mA 20mA polarity is positive coil connection is serial Valve is controlled by feedback signal from the valve pressure drop transducer at control ports blocked i e at zero control flow Flowmeter shows a small leakage Milliamperemeter shows 1 4 mA null bias 1 Power Supply Motor Switch Frequency Pressure Knob and Temperature Indicator Picture 21 Swith On Off 380V Power Supply Swith On Off Motor Knob to control the motor frequency at the Filtration mode or 100 125 150 ee i 752 175 l Oil Temperature in the tank of power d hydraulic station aby e F a 0 995 Digital control by the knob 0 250 70 bar J Stand Motor Picture 21 The main hydraulic station controls Note that you are not able to switch the motor until 380V is not switched on Note also that high temperature will immediately stop the motor 18 DIETZ a
34. rol signal Let us consider an example Assume that rated control interval is 4mA 20mA i e rated minimum and maximum of control are equal to 4mA and 20mA correspondingly In this case the predefined bias will be 4 20 2 12mA Rated signal is 20 4 2 8mA It is necessary to note that maximal and minimal signals predefined bias and rated signal depend of mode you use to control a servovalve For instance for servovalves with two or more lead coils the rated current must be associated with a specific coil connection series single or parallel Four Way Servovalve A servovalve with supply port Ps return port T and two control ports A and B The ports are arranged so that valve action in one direction simultaneously opens control port A to supply port Ps and control port B to return port T Reversed valve action opens control port A to return port T and control port B to supply port Ps Schematically such a valve is shown on Picture 36 below Picture 36 Control signal implies moving the spool from left to right and back At the left position the port A is connected to Ps and B to T If the spool is on the right side A is connected to return T and B is connected to supply Ps Supply Pressure Pressure on the port Ps Return Pressure Pressure on the port T Load Pressure Drop The differential pressure between the control ports A and B Normally the control is expressed in milliamperes mA or volts V The p
35. show the real data obtained by the Fourier analysis Blue lines are phase lag and amplitude ration of the closest linear dynamical model of servovalve Red point shows the natural frequency a EIS A e weet ee a e i i aS A EEEE EES Sa E eee eee eet A R moe i A o o A i A i gt a f H H 3 ER Oo H A ATA RNA eS eee BOTENG A ARPA AAA cd Ar H H aa H f f PE 1 i ot f gt ee ee t h gt i H _ mm 4 pa a n i p 4 H o_o n i ot A f _ _ H 7 i r f __ Be AAA i 1 gq w o wo o e o wo q gt y y q gt wv Picture 42 An example of the control to produce degauusing March 2004 DIETZ automation GmbH 31
36. the NI Device Drivers installation program Picture 7 Please follow the program instructions and NI documentation to install the drivers for PCI 6025E card inserted in the computer of your teststand Mos Install Device Drivers View ReadMe File Browse CD Exit NI Device Drivers ni com downloads 2003 National Instruments All rights reserved Picture 7 NI Device Drivers installation program 2 Please execute the Measurement amp Automation Explorer Start Program National Instruments Measurement amp Automation and check that your NI PCI 6025E card works properly see Picture 8 Note by default Measurement amp Automation Explorer is located in C Program Files National Instruments MAX NIMax exe Y PC1 6025E Device 1 Measurement amp Automation Explorer i E oj x File Edit View Tools Help lt Hide Help Configuration A Properties glDelete A Test Panels Back fl Y E 8 My system Attribute Value DAQ Device Basics 1 Data Neighborhood os 1 5 8 Devices and Interfaces FY Serial Number 0x 101E137 1 8 Traditional NI DAQ Devices Mm NI DAQmx Devices PXI PXI System Unidentified What do you want to do Ports Serial amp Parallel 9 Scales 33 Software E Aa IVI Drivers amp Remote Systems Runthe DAQ Test Panels Remove t
37. tly In order to start the automatic test we recommend the following sequence 1 Select a servovalve model you plan to test from your database 2 Fill Serial No Customer and Operator These edit boxes are optional Fill them if you need this information on the output forms of the Analysis 3 Select the type of test using tests settings Notes there are three types of tests Static with Flow Test Static without Flow Test Dynamic Test 4 Switch on the power supply 380V 5 Switch on the motor Start the testing using the Test button 16 DIETZ automation GmbH March 2004 Automatic Test List of Seres and Servovaly Hardware alarm states 0b661 42743 OE 004 Choose a valve from database for the automatic test 0 760 25b05 0760 2716 060 3604 060 6384 NS 0761 232 E760 0 Additional information supplied for the test 380V power supply indicator Serial Mo E 106 380V power supply switch 380 Y High flow Power motor switch High temp Filter 12 mk Filter 3 mk Oil Emergenci gt Reset the alarm states Reset L Date Static Test settings Static test I Flow test Dynamic test e Find bias Test type Test data Model E 760 012 you prefer to do Load data from disk Customer Zimmermann Operator Dietz Start the testing Test Analysis Save data E sil
38. utomation GmbH March 2004 value of the pressure at the Pressure mode 2 Frequency Pressure Knob Oil Level Indicator 3mk and 12mk Filters Filtration Pressure Valve and Hydraulic Accumulator see Picture 22 This tube is filled by blue it the system at the Pressure mode It indicates the level of oil in the accumulator This valve switches the hydraulic system in the Pressure of Filtration mode This tube is filled by blue it the system at the Filtration mode ali These indicators become red if It is necessary to exchange the corresponding filter The indicator becomes red if 1400 1750 2100 the oil level is too low 10505 Cc 2450 Knob to control the motor uy frequency at the Filtration 03150 mode or value of the 2 pressure at the Pressure 1000 psi 7005 Digital control by the E Filtration Pressure knob mode Picture 22 The system is in the Pressure mode Pressure 1000 psi is installed Filters and oil level are OK The accumulator is about 50 loaded Note that you will not be able to switch on the motor if the oil level indicator or filters indicate an alarm In such a situation you have to fix the problem and reset the alarm states using the button Reset see Picture 26 below 3 Control Signal Knob Degaussing Button Rough Fine Feedback Manual Polarity Control Range and Coil Configuration Switches see Picture 23
39. ver cap shown on Picture 5 can be delivered with ValveExpert Unfortunately nobody can guarantee that there will not be external leakage from a valve during a test A lot of oil can be outside in such a situation The cover cap will save you and your room from the oil shower Picture 5 Cover cap 8 DIETZ automation GmbH March 2004 Universal Control Board Servovalve 10 15V Power supply 9 15V 8 24V T GND 6 Spool position 5 Spool position 4 D 3 C 2 B Control 1 A Control Temperature transducer Sua 4 Pressure transducer PA i y 4 j Mmm n Pressure transducer PB eae ag Computer PCI 6025E E 1 1 Measurement piston Pressure transducer PS 9 DIETZ automation GmbH March 2004 Servovalve Connector You may construct a special cable for your servovalve according this schema of the stand connector A Control 3 B Control GND E a dE fe Not used A wee Spool position OV Spool position ValveExport F D Picture 6 Serovalve connector 10 DIETZ automation GmbH March 2004 Software ValveExpert Software Installation 1 Insert the DIETZ automation disk with ValveExpert software in your CD ROM This CD is supplied also by National Instruments software Autorun exe will start
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