I. Product Introduction

NI SCXI-1305 is an 8-channel AC/DC coupling terminal board for the SCXI platform, without an acquisition module, specifically designed for the SCXI-1120/D, 1121, 1125, 1126, 1140, 1141/1142/1143 high-precision voltage input modules. The core is each channel's independent AC/DC coupling + switchable bias resistor, with 8 BNC + 1 SMB, suitable for high-frequency / AC small signal and floating source measurement. It is now obsolete (Obsolete) and spare parts and maintenance are available.

II. Model and Part Number

Model: SCXI-1305

Part Number: 777687-05

Position: BNC upgrade version of SCXI-1304 (screw terminal), focusing on high-frequency / portable connection

III. Technical Parameters

Electrical Parameters

Channels: 8 differential inputs (compatible with the above SCXI modules)

Connectors: 8×BNC (signal) + 1×SMB (digital / clock / trigger)

Coupling: Each channel 2-bit dip switch, AC/DC selectable

AC: 1μF capacitor + 1MΩ resistor, high-pass filtering, -3dB@0.16Hz, DC resistance ≤ 50VDC

DC: Direct connection, no filtering

Bias resistor: Each channel 2MΩ, switchable ground (floating source reference)

Rated Voltage: ±42VDC (maximum signal)

Common Mode Rejection Ratio (CMRR): ≥100dB (DC–60Hz)

Input Impedance: 1MΩ (AC coupling), high impedance (DC coupling)

Mechanical and Environmental

Size: 173.5×30.3×99.3mm (6.83×1.19×3.91in)

Weight: 412g (14.5oz)

Installation: Standard SCXI front panel, direct-insert module 96-pin connector

Temperature: Operating 0～50℃; Storage - 20～70℃

Humidity: 10%～90% RH, no condensation

Shielding: Full metal shielding enclosure, anti EMI/RFI

IV. Interfaces and Configuration

Front Panel: 8×BNC (differential signal ±), 1×SMB, each channel 2-bit dip switch (AC/DC), bias ground switch

Back Panel: 96-pin DIN connector, direct connection to SCXI-112x/114x front end, no independent bus

Software: Compatible with NI-DAQmx, supports LabVIEW, C/C++, LabWindows/CVI

V. Core Functions

Each channel AC/DC hardware configuration: AC filters DC / low-frequency noise (vibration, acoustic); DC direct connection (DC / slow-changing signal), dip switch without software.

BNC + SMB high-frequency connection: BNC compatible with high-frequency / coaxial cables; SMB provides trigger (HOLDTRIG), clock (OUTCLK/EXTCLK), compatible with 1141/1142/1143.

Floating signal ground reference: 2MΩ bias resistor can be grounded, providing a stable reference for non-grounded sensors (piezoelectric, isolated), reducing common-mode interference.

Full shielding anti-interference: Metal enclosure isolates industrial EMI/RFI, ensuring the accuracy of weak AC signals.

VI. Application Scenarios

High-frequency / AC small signals: vibration, microphone, accelerometer (AC coupling).

Floating / isolated sensors: piezoelectric, non-grounded sensors (bias ground). SCXI-112x/114x Kit: Combined with 1120/D, 1121, 1125, 1126, 1140/1141/1142/1143.

Portable / High-frequency Testing: BNC quick connection, suitable for laboratory / field high-frequency measurements.

VII. Usage and Maintenance Use

Power-off installation: Push the module front end in and lock the 96-pin connector.

DIP configuration: For each channel, set 2 switches to AC or DC; close the floating source and ground the bias.

Wiring: BNC for differential ±, SMB for trigger / clock; shield connected to ground.

Software: Select the module in NI-DAQmx, set the range / sampling rate, no additional driver required. Maintenance

Environment: 0 - 50℃, dry and ventilated, away from strong electromagnetic interference.

Check: Regularly inspect BNC/SMB for looseness and oxidation, as well as terminal cleaning.

Cleaning: Power off and wipe with absolute alcohol, then dry before powering on.

Storage: Power off and remove the board, seal it in an anti-static bag, and store in a cool and dry place.