VXI SVM2608 user manual Scale

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VXI Technology, Inc.

CHnI+

CHn+

CHn–

CHnI–

EXT TRIG

	1x, 2x, 5x, 10x	FILTER	+		MEMORY	DATA &	VMEINTERFACE	DATA	BACKPLANE
	gain0	FILTER	+	16	MEMORY	DATA &	VMEINTERFACE	CONTROLS	BACKPLANE
÷ 1	+		ADC			μP		ADDRESS
÷ 10	–	LPF
	–
	gain1
attn					CHANNEL 0	CONTROLS			VME
attn					TRIG
		DAC	–

						CONTROL&
			FORCE		CHANNEL 1 TRIG	CONTROL&
			FORCE
	TRIG		POL		CHANNEL 2 TRIG	DATA
			POL


					CHANNEL 3 TRIG
GLUE LOGIC
	+	EXT TRIG
		EXT TRIG
DAC	–

FIGURE 1-1: SVM2608 BLOCK DIAGRAM

The acquisition process is controlled by two FPGAs that allow for greater flexibility along with higher speed and precision during the digitizing process. As the data is digitized, it is placed in memory. It is then available to the user through the VME interface. Each channel has its own channel memory that can store up to one million samples of data. This data is also made available to the microprocessor for data processing. The samples are stored as words (16 bits). The first sample of a channel is located at the channel’s base address at Offset 0 (0x000000 for Channel 0, 0x200000 for Channel 1, 0x400000 for Channel 2 and 0x600000 for Channel 3). The next sample is located at Offset 2 (0x000002 for Channel 0, etc.) and the third sample is located at Offset 4, etc.

In order to provide better resolution for the measurement, the input signal is amplified accordingly to generate a ±10 VP-Psignal at the input of the ADC. Thus, on different scales, the weight of a bit of digitized data will be different:

SCALE (V)	Bit Weight (μV/count)
1	30.518
2	61.035
5	152.588
10	305.176
20	610.352
50	1525.879

The following equation is used to determine the bit weight at a specified scale:

Bit Weight = Full Scale / 32,768

For example, the Bit Weight of the 10 V range is:

10.0volts / 32768 = 0.0003051757813 V/count

≈305.176 µV/count

12	SVM2608 Introduction

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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 TriggeringLinear Mode Delayed TriggerPre-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 LocationsExample Divide DecimalMSB 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 Accessing the Registers Description of RegistersSysfailctl Force Trigger, Start Register 0x02 Read & Write INTLVL2HSTRIGSRC2 EXT Trig SlopeTimeoutctl ReservedExternal Trigger Level 0x06 Read & Write 2WIREOHMS 4WIREOHMSLINEAR/FIFO ATTN-GAIN1-GAIN0Sample Rate 0x0C, 0x34, 0x5C, 0x84 Read & Write Sample Rate 0x0E, 0x36, 0x5E, 0x86 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 0x24, 0x4C, 0x74, 0x9C, 0xC4, 0xEC Read Only Fifo Data 0x26, 0x4E, 0x76, 0x9E, 0xC6, 0xEE Read OnlyReserved Registers 0xF8 0xFC Trigger Delay = Microprocessor Commands Measurement CommandsCaptured Data Calculations Self Test Command Resistance Measurement Offset MethodResistance 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