National Instruments SCXI-1120 User Manual

Also see for SCXI-1120: Quick start guide User manual CALIBRATION PROCEDURE Instructions for safe use User guide

Contents

ContentsSCXI-1120 User Manual vi © National Instruments CorporationDigital I/O Signal Connections ..............................................................2-26Timing Requirements and Communication Protocol.............................2-28Timing Signal.............................................................................2-28Communication Signals .........................................................................2-28Chapter 3Theory of Operation .......................................................................................................... 3-1Functional Overview ...................................................................................................... 3-1SCXIbus Connector ........................................................................................... 3-2SCXIbus Connector Signal Descriptions ...........................................................3-4Digital Interface .............................................................................................................3-6Digital Control Circuitry ................................................................................................3-7Analog and Timing Circuitry .........................................................................................3-8Analog Input Channels....................................................................................... 3-8Calibration..........................................................................................................3-10Calibration Equipment Requirements ....................................................3-10Offset Null Adjust ..................................................................................3-11Analog Output Circuitry ........................................................................ 3-12Scanning Modes .............................................................................................................3-13Single-Module Parallel Scanning.......................................................................3-14Multiplexed Scanning ........................................................................................3-14Single-Module Multiplexed Scanning ................................................... 3-14Single-Module Multiplexed Scanning (Direct).......................... 3-14Single-Module Multiplexed Scanning (Indirect) .......................3-15Multiple-Module Multiplexed Scanning................................................ 3-15Multiple-Chassis Scanning ....................................................................3-16Chapter 4Register Descriptions ......................................................................................................... 4-1Register Description....................................................................................................... 4-1Register Description Format ..............................................................................4-1SCXI-1120 Registers ......................................................................................... 4-1Module ID Register................................................................................ 4-2Configuration Register ...........................................................................4-3Slot 0 Register Descriptions...............................................................................4-5Slot-Select Register ................................................................................4-6Hardscan Control Register (HSCR) .......................................................4-7FIFO Register.........................................................................................4-8Chapter 5Programming........................................................................................................................ 5-1Programming Considerations.........................................................................................5-1Notation.............................................................................................................. 5-1Register Writes...................................................................................................5-1Register Selection and Write Procedure ................................................ 5-2Initialization ...........................................................................................5-3