Gebruiksaanwijzing /service van het product 1142 van de fabrikant National Instruments
Ga naar pagina of 86
SCXI TM SCXI-1141/1142/1143 User Manual SCXI-1141/1142/1143 User Manual May 2007 371748E-0 1.
Support Worldwide Technical Support and Product Info rmation ni.com National Instruments Corporate Headquarters 11500 North Mopac Expressway Aust in, Texas 78759-3504 USA Tel: 512 683 0100 Worldwide O.
Important Information Warranty The SCXI-1141, SCXI-1142, and SCXI-1143 modules are warranted ag ainst defects in materials and workmans hip for a period of on e year from the date of shipment, as evidenced by receipts or other document ation.
Conventions The follo wing con v entions are used in this manual: < > Angle brackets that cont ain numbers s eparated by an ellipsis represent a range of v alues associated with a bit or signal name—for example, AO < 3 . . 0 > . » The » symbol leads you through nested menu items and dial og box options to a final action.
© National Instrument s Corporation v SCXI-1141/ 1142/1143 U ser Manual Contents Chapter 1 About the SCXI-1141/1142/1143 What You Need to Get Started .............. .............. ........... ............ .............. ........... .......... 1-2 National Instruments D ocumentatio n .
Contents SCXI-1141/1142/1 143 User Manual vi ni.com Chapter 4 Theory of Operation Power-Up State ................. ........... .............. ........... .............. ............ .............. ........... ...... 4-1 Digital Control Circuitry .....
Contents © National Instruments Corporation vii SCXI -1141/1142/ 1143 User Manual Appendix B Removing the SCXI-1141/1142/1143 Module Appendix C Common Questions Glossary Index Figures Figure 2-1. Ground-Referenced Signal Conn ectio n................ .
Contents SCXI-1141/1142/1 143 User Manual viii ni.com Tables Table 1-1. Accessories Available for the SCXI-1141/1142/1143 .............. ............ 1-4 Table 2-1. Front Signal Pin Assignments ...... ...... ........... ........... ............... ...
© National Instruments Corporation 1-1 SCXI -1141/1142/ 1143 User Manual 1 About the SCXI-1141/1142/1143 This chapter describes the SCXI-1141/1142/11 43 module, and explains how to install and remove the hardw are and software. The SCXI-1141/11 42/1143 module has eight lowpass f ilters and eight differential-input amplifiers.
Chapter 1 About the SCXI-1141/1 142/1143 SCXI-1141/1142/1 143 User Manual 1-2 ni.com What Y ou Need to Get Started To set up and use the SCXI-1141/1142/ 1143 module, you need the following: ❑ Hardwa.
Chapter 1 About the SCXI-1141/1142/1143 © National Instruments Corporation 1-3 SCXI -1141/1142/ 1143 User Manual DAQ . Select the appropriate informat ion for you r application in the remaining drop-down menus and click Go .
Chapter 1 About the SCXI-1141/1 142/1143 SCXI-1141/1142/1 143 User Manual 1-4 ni.com • The follo wing help file for software information: – Start»Programs»National Instruments»NI-DAQ» NI-DAQmx.
Chapter 1 About the SCXI-1141/1142/1143 © National Instruments Corporation 1-5 SCXI -1141/1142/ 1143 User Manual V erifying the SCXI-1141/1142/1143 Installation in Software Refer to the SCXI Quick Start Guide for inform ation on verifying the SCXI installation.
Chapter 1 About the SCXI-1141/1 142/1143 SCXI-1141/1142/1 143 User Manual 1-6 ni.com • If you get a Verify SCXI Chassis message box showing the SCXI chassis model number, Chassis ID: x , and the mes.
© National Instruments Corporation 2-1 SCXI -1141/1142/ 1143 User Manual 2 Connecting Signals This chapter describes input and output sign al connections to the SCXI-1141/1142/114 3 module through the fron t and rear signal connectors.
Chapter 2 Connecti ng Signals SCXI-1141/1142/1 143 User Manual 2-2 ni.com Table 2-1. Front Signal Pin Assignments Front Connect or Diagram Pin Number Column A Column B Column C 32 AI 0 + NC AI 0 – 3.
Chapter 2 Connecting Signals © National Instruments Corporation 2-3 SCXI -1141/1142/ 1143 User Manual Front Connector Si gnal Descriptions Analog Input Channels The SCXI-1141/1142/1143 module instrum.
Chapter 2 Connecti ng Signals SCXI-1141/1142/1 143 User Manual 2-4 ni.com analog ground. The inputs are protect ed against maximum input voltages of up to ±15 V po wered of f and ±30 V po wered on. Caution Exceeding the differential or common-mode input v oltage limit s distorts input signals.
Chapter 2 Connecting Signals © National Instruments Corporation 2-5 SCXI -1141/1142/ 1143 User Manual Figure 2-2 illustrates how to connect a non-referenced (floating) signal source to an SCXI channel. Figure 2-2. Floating Signal Connection For A C-coupled signals, connect an ex ternal resistor from the A C-coupled input channel to ground.
Chapter 2 Connecti ng Signals SCXI-1141/1142/1 143 User Manual 2-6 ni.com Figure 2-4. Ground Offset AC-Coupled Signal Connection Figure 2-5. Floating AC-Coupled Signal Connection Digital Input and Out.
Chapter 2 Connecting Signals © National Instruments Corporation 2-7 SCXI -1141/1142/ 1143 User Manual Rear Signal Connector Note If you use the SCXI-1141/1142/1143 module with a National Instruments DA Q device and SCXI cable assembly , you do not need to read the remainder of this chapter .
Chapter 2 Connecti ng Signals SCXI-1141/1142/1 143 User Manual 2-8 ni.com T able 2-2 shows the pin assignments for the SCXI-1141/ 1142/1143 module rear signal connector .
Chapter 2 Connecting Signals © National Instruments Corporation 2-9 SCXI -1141/1142/ 1143 User Manual In parallel output mode, chan nel 0 is selected at the out put multiplexer and is connected to AI 0. The se ven othe r channels are directly connected to AI 1 through AI 7, respectively , on the rear connect or .
Chapter 2 Connecti ng Signals SCXI-1141/1142/1 143 User Manual 2-10 ni.com The signals on the rear signal connect or are classif ied as analog output, digital I/O, or timing I/O signals. 26 SER D A T OUT P0.4 Out put Serial data out—th is signal taps into the SCXIbus MISO line to accept serial output data from a module.
Chapter 2 Connecting Signals © National Instruments Corporation 2-11 SCXI-1141/114 2/1143 User Manual Analog Output Signal Connections Pins 3 through 17 of th e rear signal connector are analog out put signal pins. Pin 3 is the main output, and pin 4 is its reference signal.
Chapter 2 Connecti ng Signals SCXI-1141/1142/1 143 User Manual 2-12 ni.com The digital output signal is pin 26. Pin 26 is SER DA T OUT and is equiv alent to the SCXIb us MISO serial data output line. The digital I/O signals of the SCXI-1141/11 42/1143 module correspond to the digital I/O lines of an E/M Series D A Q device.
© National Instruments Corporation 3-1 SCXI -1141/1142/ 1143 User Manual 3 Configuring and T esting This chapter discusses configuring the SCXI-1141/1142/1143 in MAX using NI-DAQmx, creating and testing a virtual channel, glob al channel, and/or task.
Chapter 3 Configur ing and T esting SCXI-1141/1142/1 143 User Manual 3-2 ni.com Input Selection The front end of the SCXI-1141/1142/ 1143 includes a software configurable switch that allows you to program matically connect the inpu t channels of the SCXI-1141/1142/114 3 to either the front connector or internal ground.
Chapter 3 Configurin g and T esting © National Instruments Corporation 3-3 SCXI -1141/1142/ 1143 User Manual NI-DAQmx Using NI-DAQmx, you can configure software settings, such as sensor type and gain.
Chapter 3 Configur ing and T esting SCXI-1141/1142/1 143 User Manual 3-4 ni.com 6. If you are creating a task, you can se lect a range of channels by holding do wn the <Shift> key while select ing the channels. Y ou can select multiple individual channels by holding do wn the <Ctrl> key while selecting channels.
Chapter 3 Configurin g and T esting © National Instruments Corporation 3-5 SCXI -1141/1142/ 1143 User Manual 4. Select the channel(s) you want to v erify . Y ou can select a block of channels by holding down the <Shift> ke y or multiple channels by holding down the <Ctrl> key .
© National Instruments Corporation 4-1 SCXI -1141/1142/ 1143 User Manual 4 Theor y of Operation This chapter contains an ov erview of the SCXI-1141/1142/1143 module and explains the operation of each functional unit of the module. The SCXI-1141/1142/1 143 module has eight software-controlled input channels that amplify and f ilter signal s.
Chapter 4 Theory of Operation SCXI-1141/1142/1 143 User Manual 4-2 ni.com Figure 4-1. SCXI-11 41/1142/1143 Module Block Diagram External Clock Analog Bus Rear Signal Connector Analog Switch Analog Swi.
Chapter 4 Theory of Operation © National Instruments Corporation 4-3 SCXI -1141/1142/ 1143 User Manual Digital Control Circuitr y The digital control circui tr y contains a Module ID (i dentification) register, a configuration register for the m odule, a gain register, and an EEPROM for storing gain-calibration constants.
Chapter 4 Theory of Operation SCXI-1141/1142/1 143 User Manual 4-4 ni.com In general, to provide optimum measurement resolution and noise rejection, you can select as high a g ain as will not cause the output to exceed this limit.
Chapter 4 Theory of Operation © National Instruments Corporation 4-5 SCXI -1141/1142/ 1143 User Manual Lowpass Filters The SCXI-1141/1142/1143 module filters are 8th-order elliptic, Bessel, and Butterworth lo wpass filters, respec tively.
Chapter 4 Theory of Operation SCXI-1141/1142/1 143 User Manual 4-6 ni.com As Figure 4-2b sho ws, a real f ilter has ripple (an uneven v ariation in attenuation versus frequency) in the passband, a transition region between the passband and the stopband, and a stopband with finite attenuation and ripple.
Chapter 4 Theory of Operation © National Instruments Corporation 4-7 SCXI -1141/1142/ 1143 User Manual As Figure 4-4 sho ws, the SCXI-1141/1142/1143 module provides 80 dB attenuation abov e 1.5 times the cu tof f frequenc y for the SCXI-1141 module, six times for the SCXI-1142 module, and 3.
Chapter 4 Theory of Operation SCXI-1141/1142/1 143 User Manual 4-8 ni.com Figure 4-5. T ypical Passband Re sponses of the SCXI-1141/1142/1143 Module Phase Response Figures 4-6 thro ugh 4-8 i llustrate the ph ase response characteristics of the SCXI-1141/1142/114 3 module filters.
Chapter 4 Theory of Operation © National Instruments Corporation 4-9 SCXI -1141/1142/ 1143 User Manual Figure 4-6. Phase Response Characterist ics of the SCXI-1141/1142/1143 Module Filters Figure 4-7 shows the adv a ntages of the SCXI-1142 Bessel f ilter .
Chapter 4 Theory of Operation SCXI-1141/1142/1 143 User Manual 4-10 ni.com Figure 4-7. Ph ase Error of the SCXI-1141/1142/1143 Module The most common effect of phase nonlinearity is ringing in response to a step input.
Chapter 4 Theory of Operation © National Instruments Corporation 4-11 SCXI-1141/114 2/1143 User Manual Figure 4-8. Unit Step Response of the SCXI-1141/1142/1143 Module Setting the Cutoff Frequency The cutoff frequencies of the filters in the SCXI-1141/1142/114 3 module are set internally by dividing a base frequency of 100 kHz by an integer.
Chapter 4 Theory of Operation SCXI-1141/1142/1 143 User Manual 4-12 ni.com than the signal frequency range of interest. At frequencies much lo wer than the cutof f f requenc y , passband r ipple and phase nonlinearity are much less noticeable.
Chapter 4 Theory of Operation © National Instruments Corporation 4-13 SCXI-1141/114 2/1143 User Manual Because the SCXI-1141 module stopba nd begins at 1.5 times the cutof f frequency , the Nyquist frequency should be at least 1.5 times the cutoff frequency .
Chapter 4 Theory of Operation SCXI-1141/1142/1 143 User Manual 4-14 ni.com Using the External Clock Input You can set the cutoff frequencie s of filters in the SCXI-1141/1142/11 43 module by using the.
Chapter 4 Theory of Operation © National Instruments Corporation 4-15 SCXI-1141/114 2/1143 User Manual For bes t results, the cutof f frequenc y of a particul ar f ilter should rem ain within this range.
Chapter 4 Theory of Operation SCXI-1141/1142/1 143 User Manual 4-16 ni.com Filter Bypass Mode You can bypass the fil ter of any channel thro ugh software control, thus making the unfiltered signal available at the output. The input am plifiers are not bypassed.
Chapter 4 Theory of Operation © National Instruments Corporation 4-17 SCXI-1141/114 2/1143 User Manual channel 0 and continues. Y ou can program the SCXI-1141/1142/114 3 module to start scans with any channel.
© National Instruments Corporation 5-1 SCXI -1141/1142/ 1143 User Manual 5 Using the SCXI-1141/1142/1143 Module This chapter makes suggestions for developing you r application and provides basic info rmation regarding cal ibration. Developing Y our Application in NI-DAQmx Note If you are not using an NI ADE, using an NI ADE prior to version 8.
Chapter 5 Using the SCXI-11 41/1142/1143 Modul e SCXI-1141/1142/1 143 User Manual 5-2 ni.com Figure 5-1. T ypical Program Flowchart for Voltage Measurement Channels Ye s Create Channel Adjust Timing S.
Chapter 5 Using the SCXI-1 141/1142/11 43 Module © National Instruments Corporation 5-3 SCXI -1141/1142/ 1143 User Manual General Discussion of T ypical Flowchart The following sections b riefly discuss some considerations for a few of the steps in Figure 5-1.
Chapter 5 Using the SCXI-11 41/1142/1143 Modul e SCXI-1141/1142/1 143 User Manual 5-4 ni.com When programmat ically adjusting tim ing settings, you can set the t ask to acquire continuously , acqui re a buf fer of samples, or acquire one point at a time.
Chapter 5 Using the SCXI-1 141/1142/11 43 Module © National Instruments Corporation 5-5 SCXI -1141/1142/ 1143 User Manual Analog Input»General Properties»Advanced»Gain and Offset»Gain Value AI.Gain Specifies a g ain factor to apply to the signal conditioning portion of the channel.
Chapter 5 Using the SCXI-11 41/1142/1143 Modul e SCXI-1141/1142/1 143 User Manual 5-6 ni.com Table 5-3. NI-DAQmx RTD Measurement P roperties Property Short Nam e Description Analog Input»Temperature» RTD»Type AI.R TD.T ype Specifies the type of R TD connected to the channel.
Chapter 5 Using the SCXI-1 141/1142/11 43 Module © National Instruments Corporation 5-7 SCXI -1141/1142/ 1143 User Manual Note This is not a complete list of NI-DA Qmx properties and does not include ev ery property you may need to configure your application.
Chapter 5 Using the SCXI-11 41/1142/1143 Modul e SCXI-1141/1142/1 143 User Manual 5-8 ni.com Table 5-6. Pro gramming a T ask in LabVIEW Flowchart Step VI or Program Step Create T ask in D A Q Assistan.
Chapter 5 Using the SCXI-1 141/1142/11 43 Module © National Instruments Corporation 5-9 SCXI -1141/1142/ 1143 User Manual Using a NI-DAQmx Channel Property Node in LabVIEW You can use property no des in LabVIEW to ma nually configure the channels. To create a LabVIEW prope rty node, complete the following steps: 1.
Chapter 5 Using the SCXI-11 41/1142/1143 Modul e SCXI-1141/1142/1 143 User Manual 5-10 ni.com 6. Right-click ActiveChans , and select Add Element . Left-click the ne w ActiveChans box. Navigate through the m enus, and select the property you wish to define.
Chapter 5 Using the SCXI-1 141/1142/11 43 Module © National Instruments Corporation 5-11 SCXI-1141/114 2/1143 User Manual LabWindows/CVI LabWindows/CVI work s with the DAQ Assistant in MAX to generate code for an voltage measurement task . You can then use the appropriate function call to modify the task.
Chapter 5 Using the SCXI-11 41/1142/1143 Modul e SCXI-1141/1142/1 143 User Manual 5-12 ni.com T o actually create and configure the channel, you would enter something resembling the following example code: Task myTask = new NationalInstruments.DAQmx.Task(“myTa skName”); MyTask.
Chapter 5 Using the SCXI-1 141/1142/11 43 Module © National Instruments Corporation 5-13 SCXI-1141/114 2/1143 User Manual Calibration The SCXI-1141/1142/1 143 is shipped with a calibration certificate and is calibrated at the factory to the speci fication s described in Appendix A, Specifications .
© National Instruments Corporation A-1 SCXI-1141/ 1142/1143 U ser Manual A Specifications This appendix lists the specifications for the SCXI-1141/1142/114 3 module. These specif icati ons are typical at 25 ° C unless otherwise noted. Amplifier Characteristics Number of channels .
Appendix A Specifications SCXI-1141/1142/1 143 User Manual A-2 ni.com DC gain error ........................ .............. ....±0.6% before calibration, ±0.02% after calibration 1 DC input offset ........................ .............. . mV max Filter Characteristics Filter type SCXI-1141 module .
Appendix A Specifications © National Instruments Corporation A-3 SCXI-1141/ 1142/1143 U ser Manual Bandwidth and response time System Noise THD 1 kHz ............... ........... ............ ......... –70 dB 0–25 kHz .............. ........... ..
Appendix A Specifications SCXI-1141/1142/1 143 User Manual A-4 ni.com Stability DC gain temperature coef ficient.............20 ppm/ ° C Input offset drift .................. .............. ...... µV/ ° C typ µV/ ° C max AC gain temperature coef ficient.
Appendix A Specifications © National Instruments Corporation A-5 SCXI-1141/ 1142/1143 U ser Manual Physical Figure A-1. SCXI-1141/1142/1143 Dimensions Weight SCXI-1141 and SCXI-114 3 ............ 623 g (22.0 oz) SCXI-1142 ....................... ....
Appendix A Specifications SCXI-1141/1142/1 143 User Manual A-6 ni.com Environmental Operating temperature ............. ........... ....0 to 50 ° C Storage temperature ................. .............. .–20 to 70 ° C Humidity .............. .......
Appendix A Specifications © National Instruments Corporation A-7 SCXI-1141/ 1142/1143 U ser Manual CE Compliance This product meets the essential re quirements of applicable European Directi ves, as .
© National Instruments Corporation B-1 SCXI-1141/ 1142/1143 U ser Manual B Removing the SCXI-1141/1142/1143 Module This appendix describes how to remov e the SCXI-1141/1142/1143 mod ule from an SCXI chas sis and from MAX.
Appendix B Removing the SCXI -1141/1142/1143 Module SCXI-1141/1142/1 143 User Manual B-2 ni.com 2. If the SCXI-1141/1142/1143 is the mod ule cabled to the E/M Series D A Q device, disconnect the cable. 3. Remov e an y terminal block that connects to the SCXI-1141/1142/ 1143.
© National Instruments Corporation C-1 SCXI-1141/ 1142/1143 U ser Manual C Common Questions This appendix lists common questions rel ated to the use of the SCXI-1141/1142/ 1143. Which version of NI-D AQ w orks with the SCXI-1141/1142/1143, and how do I get th e most curr ent version of NI-D A Qmx? NI recommends that you hav e NI-D A Qmx 8.
Appendix C Comm on Questions SCXI-1141/1142/1 143 User Manual C-2 ni.com Can I conf igure the SCXI-1141/1142/1143 for use in parallel mode? Y ou can configure the SCXI-1141/1142/1143 for parallel mode using either NI-DA Qmx or T raditional NI-DA Q (Legac y).
Appendix C Common Questions © National Instruments Corporation C-3 SCXI-1141/ 1142/1143 U ser Manual In LabVIEW , can I use differen t inpu t limits f or the same SCXI-1141/1142/1 143 channel if I re peat the channel in the SCXI channel string array? No.
Appendix C Comm on Questions SCXI-1141/1142/1 143 User Manual C-4 ni.com Which accessories can I use to conn ect signals to the front of the SCXI-1141/1142/1 143 module? For information reg arding av ailabl e accessories, refer to Chapter 1, About the SCXI-1141/1142/1143 .
© National Instruments Corporation G-1 SCXI-1141/ 1142/1143 U ser Manual Glossar y Symbol Pref ix V alu e pp i c o 1 0 –1 2 nn a n o 1 0 –9 μ micro 10 –6 m milli 10 –3 k kilo 10 3 Mm e g a 1.
Glossary SCXI-1141/1142/1 143 User Manual G-2 ni.com A A amperes A GND analog ground signal A OUT analog output signal A C alternating current ADE application dev elopment en vironment aliasing the co.
Glossary © National Instruments Corporation G-3 SCXI-1141/ 1142/1143 U ser Manual DIG GND digital ground signal DIN Deutsche Industrie Norme (German Industrial Standard) DMM digital multimeter E EEPR.
Glossary SCXI-1141/1142/1 143 User Manual G-4 ni.com L lowpass filter a filter that passes signals belo w a cutoff frequenc y while blocking signals abov e that frequency M max maximum MB megab ytes m.
Glossary © National Instruments Corporation G-5 SCXI-1141/ 1142/1143 U ser Manual R rms root mean sq uare rolloff the ratio that a system attenuates signals in the stopban d with respect to the passb.
Glossary SCXI-1141/1142/1 143 User Manual G-6 ni.com T THD total harmonic distortion TTL transistor-transistor logic V Vv o l t s VI virtual instrume nt (a LabV IEW progr am) V rms vo lts, root mean s.
© National Instruments Corporation I-1 SCXI -1141/1142/ 1143 User Manual Index A A GND signal front connector (table), 2-3 rear connector (table), 2-9 A OUT signal (table), 2-9 A C-coupled signal connections floating (figure), 2-6 ground-offset (f igure), 2-6 ground-referenced (figure), 2-5 adjusting tim ing and triggeri ng, 5-3 AI+<0.
Index SCXI-1141/1142/1 143 User Manual I-2 ni.com settings in MAX NI-D A Qmx, 3-3 creating a global channel or task, 3-3 troubleshooting self-test verification, 1-5 verifying signal, 3-4 NI-D A Qmx, 3.
Index © National Instruments Corporation I-3 SCXI -1141/1142/ 1143 User Manual signal desc riptions (tab le), 2-3 front signal connector pin assignments (figure), 2-2 functional overvie w of SCXI-1141.
Index SCXI-1141/1142/1 143 User Manual I-4 ni.com Measurement Studio, 1-2 creating code for using SCXI-11141/1142/11 43, 5-11 Module ID register, 4-3 modules, installing, 1-4 multiple x ed mode, an al.
Index © National Instruments Corporation I-5 SCXI -1141/1142/ 1143 User Manual removing modules from M AX, B-1 SCXI-1141/1142/ 1143 from SCXI chassis, B-1 requirements for getting started, 1- 2 rippl.
Index SCXI-1141/1142/1 143 User Manual I-6 ni.com specifications amplifier characteristics, A-1 CD compliance, A-7 digital I/O, A-4 electromagnetic comp atibility, A-6 en vironmental characteristics, .
Een belangrijk punt na aankoop van elk apparaat National Instruments 1142 (of zelfs voordat je het koopt) is om de handleiding te lezen. Dit moeten wij doen vanwege een paar simpele redenen:
Als u nog geen National Instruments 1142 heb gekocht dan nu is een goed moment om kennis te maken met de basisgegevens van het product. Eerst kijk dan naar de eerste pagina\'s van de handleiding, die je hierboven vindt. Je moet daar de belangrijkste technische gegevens National Instruments 1142 vinden. Op dit manier kan je controleren of het apparaat aan jouw behoeften voldoet. Op de volgende pagina's van de handleiding National Instruments 1142 leer je over alle kenmerken van het product en krijg je informatie over de werking. De informatie die je over National Instruments 1142 krijgt, zal je zeker helpen om een besluit over de aankoop te nemen.
In een situatie waarin je al een beziter van National Instruments 1142 bent, maar toch heb je de instructies niet gelezen, moet je het doen voor de hierboven beschreven redenen. Je zult dan weten of je goed de alle beschikbare functies heb gebruikt, en of je fouten heb gemaakt die het leven van de National Instruments 1142 kunnen verkorten.
Maar de belangrijkste taak van de handleiding is om de gebruiker bij het oplossen van problemen te helpen met National Instruments 1142 . Bijna altijd, zal je daar het vinden Troubleshooting met de meest voorkomende storingen en defecten #MANUAl# samen met de instructies over hun opplosinge. Zelfs als je zelf niet kan om het probleem op te lossen, zal de instructie je de weg wijzen naar verdere andere procedure, bijv. door contact met de klantenservice of het dichtstbijzijnde servicecentrum.
