Contents
© National Instruments Corporation vii SCXI-1122 User Manual
FiguresFigure1-1. The Relationship between the Programming Environment, NI-DAQ, and
Your Hardware................................................................................................... 1-3
Figure2-1. SCXI-1122 Parts Locator Diagram.................................................................... 2-2
Figure3-1. SCXI-1122 Front Connector Pin Assignments.................................................. 3-3
Figure3-2. Ground-Referenced Signal Connection with High Common-Mode Voltage.... 3-6
Figure3-3. Floating Signal Connection Referenced to Chassis Ground for Better SNR..... 3-6
Figure3-4. Floating AC-Coupled Signal Connection Referenced
to Chassis Ground for Better SNR..................................................................... 3-6
Figure3-5. AC-Coupled Signal Connection with High Common-Mode Voltage............... 3-7
Figure3-6. Avoiding Relay Wear by Sampling and Averaging Rather Than
Single-Sample Channel Scanning...................................................................... 3-8
Figure3-7. Connecting a Quarter-Bridge Strain Gauge to Channel 0.................................. 3-9
Figure3-8. SCXI-1122 Rear Signal Connector Pin Assignments........................................ 3-10
Figure4-1. SCXI-1122 Block Diagram................................................................................ 4-2
Figure4-2. Series Connection with Current Excitation........................................................ 4-6
Figure4-3. Four-Wire Scan Connection with Multiplexed Current Excitation................... 4-6
TablesTable2-1. Digital Signal Connection Jumper Settings....................................................... 2-3
Table2-2. Jumper W1 Settings........................................................................................... 2-4
Table2-3. User-Defined Current Receiver Resistors.......................................................... 2-4
Table3-1. Maximum Load per Excitation Channel............................................................ 3-9
Table3-2. SCXIbus to SCXI-1122 Rear Signal Connector to DAQ Board Pin
Equivalences...................................................................................................... 3-13
Table4-1. Sense/Current Output Channel Associations..................................................... 4-4
Table4-2. Pros and Cons of Two-Wire and Four-Wire Connections
with Current Excited Transducers...................................................................... 4-7
Table5-1. Maximum Allowable Error Ranges................................................................... 5-4