National Instruments SCXI -1122 - Manual (Page 7)

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