VXI SVM2608 user manual Option

Page 16

VXI Technology, Inc.

sets. (See Microprocessor3Commands for more details on available commands.) The command is sent to the microprocessor via the Command register. Since there are four independent channels on the board, each of them can take a different command and each of them has its own command register. The result of the microprocessor calculation is returned in the Result register for the corresponding channel.

The data stored in the channel memory is raw data. When the microprocessor performs a resistance calculation, it uses calibrated data, meaning that the microprocessor takes the calibrations for the Local Current Sources (see above) values into consideration. The raw data the user downloads from the board represents calibrated voltage measurements. The result calculated by the microprocessor and placed in the Result register when a Resistance Measurement command is issued is based on calibrated Current measurements. While the user can perform calibrated voltage measurements by simply reading the raw data, the calculations for resistance cannot be accurately performed by the user as they do not have the calibrated current values (the exact values injected in the resistance under test by the board’s current source). Although it is possible for the user to read the calibration values (see the Calibration Commands section) and use the raw data to perform all the calibrated measurements on their own, the manufacturer encourages the use of the microprocessor’s capabilities to perform all calibrated resistance calculations.

Option -01

With the addition of the SVM2608-01 option, two additional channels are available with a sample rate of 20 MHz and 12-bits of resolution. This option may be purchased at the same time as the SVM2608 or is factory upgradeable.

The high-speed channels available on Option -01 function independently. The front end of each channel has both a variable gain amplifier and an attenuator, similar to the low-speed channels. A 5 MHz low-pass filter (LPF) is available on these channels, as opposed to the 20 kHz LPF found on the low-speed channels. The ADC converter is a 12 bits converter capable of taking as many as 20 MSamples/s on a scale of -2 V to +2 V. To compensate for offset and gain variation in the ADCs, each channel has two 12 bits DACs that are used to calibrate the offset and the gain on each ADC channel. These calibrations are performed at the factory using precision voltage reference sources. A block diagram for Option -01 is provided on the following page.

16

SVM2608 Introduction

Page 15 Page 17
Image 16
Page 15 Page 17
Contents SVM2608 VXI Technology, Inc Table of Contents Self Test Command Warranty Limitation of WarrantyCertification Restricted Rights LegendEMC Steve Mauga, QA ManagerService should only be performed by qualified personnel Terms and SymbolsUse Proper Power Cord Use Proper Power SourceAvoid Electric Shock Ground the ProductOperating Conditions Improper UseVXI Technology World Headquarters VXI Technology Cleveland Instrument DivisionVXI Technology Lake Stevens Instrument Division Technical SupportVXI Technology, Inc SVM2608 Preface Introduction OverviewScale Acquiring Data TriggeringDelayed Trigger Linear ModePre-Trigger Fifo Mode CommandsCalibrations Test BusOption SVM2608 Block Diagram SVM2608 Environmental Specifications Physical DescriptionFront Panel Interface Wiring GND CH1I CH3IGND CH1I+ GND CH3I+ Exttrigin CH0I CH2ISVM2608 Specifications MtbfOption 1 SVM2608-01 VXI Technology, Inc SVM2608 Introduction Calculating System Power and Cooling Requirements Setting the Chassis Backplane JumpersSetting the Base Address Rotary Switch LocationsDivide Decimal ExampleMSB LSB Switch to C and the front switch to Module INSTALLATION/REMOVALDevice Memory Maps Function OffsetReserved Register OffsetSVM2608 A32 Register MAP MS = Most Significant LS = Least Significant0x72 Command Register Channel 0x74 Databyte Ordering Determining the Register Address Description of Registers Accessing the RegistersSysfailctl Force Trigger, Start Register 0x02 Read & Write INTLVL2HSTRIGSRC2 EXT Trig SlopeReserved TimeoutctlExternal Trigger Level 0x06 Read & Write 2WIREOHMS 4WIREOHMSLINEAR/FIFO ATTN-GAIN1-GAIN0Sample Rate 0x0E, 0x36, 0x5E, 0x86 Read & Write Sample Rate 0x0C, 0x34, 0x5C, 0x84 Read & WriteKHz Channels 0-3/5 MHz Channels 4-5 LPF Control This bit Sample Rate, High-Speed 0xAC, 0xD4 Read & Write Sample Rate, High-Speed 0xAE, 0xD6 Read & WriteTimeout 0x1C, 0x44, 0x6C, 0x94, 0xBC, 0xE4 Read & Write Fifo Data 0x26, 0x4E, 0x76, 0x9E, 0xC6, 0xEE Read Only Fifo Data 0x24, 0x4C, 0x74, 0x9C, 0xC4, 0xEC Read OnlyReserved Registers 0xF8 0xFC Trigger Delay = Microprocessor Commands Measurement CommandsCaptured Data Calculations Resistance Measurement Offset Method Self Test CommandResistance Measurement Dynamic Method Preset Setting Measurement Commands ExampleCalibration Commands Sample PointsSample Rate Trigger Event Forced TriggerPage Error Processing There are no errors in the queue Diagnostic Commands Changes become effective the next time the module powers up Example 2 Setting Channel 2 to Acquire 200,000 Samples ExamplesExample 3 Setting Channel 2 to Pre-acquire 100,000 Samples Timeout Counter = Timeout / Timeout Base Clock Timeout Register = Timeout Base * 213 + Timeout CounterVXI Technology, Inc SVM2608 Programming Appendix a Data Swapping ExampleVXI Technology, Inc SVM2608 Appendix a Index
Top Page Image Contents