Description
Key Technical Specifications
| Parameter | Specification |
|---|---|
| Product Model | |
| Manufacturer | National Instruments (NI) |
| Product Type | 32-Channel Voltage / Thermocouple Input Module |
| System | NI SCXI |
| Analog Input Channels | 32 differential |
| Additional Sensor Channel | 1 cold-junction sensor channel |
| Input Range | ±10 V at gain 1 / ±100 mV at gain 100 |
| Gain | Software-selectable 1 or 100 |
| Filter | Three-pole low-pass |
| Filter Cutoff | 200 Hz (-3 dB) |
| Input Impedance | >1 GΩ, powered |
| Input Bias Current | ±0.5 nA |
| Input Damage Level | ±42 VDC powered / ±27 VDC unpowered |
| Maximum Working Voltage | Each input within ±10 V of chassis ground |
| Output Range | ±10 V |
| Output Impedance | 91 Ω |
| Nonlinearity | 0.005% FSR |
| CMRR, DC, Gain 1 | 75 dB minimum |
| CMRR, DC, Gain 100 | 100 dB minimum |
| System Noise, Gain 1 | 50 µVrms |
| System Noise, Gain 100 | 5 µVrms |
| Operating Temperature | 0 to 50°C |
| Storage Temperature | -55 to 150°C |
| Humidity | 10–90% RH, noncondensing |
| Dimensions | Approximately 115 × 273 mm |
| Rear Connector | 50-pin male ribbon cable |
| Front Connector | 96-pin male DIN C |
The 200 Hz filter, 32 differential channels, selectable gain, input ranges, electrical limits, and environmental ratings are documented by NI for the SCXI-1102/B/C family, with the 200 Hz values specifically applying to the .
Product Introduction
The National Instruments is a 32-channel differential analog input module for the NI SCXI platform, intended for conditioning thermocouple, millivolt, voltage, and process-current signals before they reach the controlling DAQ device. Each channel provides software-selectable gain of 1 or 100, while a three-pole 200 Hz low-pass filter limits signal bandwidth. A dedicated cold-junction sensor channel supports thermocouple measurement applications.
The main distinction between the and the other members of the family is its 200 Hz bandwidth. The original SCXI-1102 uses a 2 Hz filter, while the SCXI-1102C uses 10 kHz, making the 1102B the practical choice when a legacy system needs substantially faster response than the 2 Hz version without moving to the 10 kHz variant.
SCXI-1102B
Application Scenarios & Field Pitfalls — The Engineer’s Perspective
Engineering Pain Point
A common mistake when replacing an old SCXI module is selecting a part from the same family without checking the filter bandwidth. The is not simply an interchangeable revision of the SCXI-1102; its 200 Hz three-pole filter changes the dynamic response of the measurement channel. If the original application depends on slow thermocouple or process measurements, this may be acceptable, but replacing it with the 10 kHz SCXI-1102C or the 2 Hz SCXI-1102 can materially change the measurement behavior.
The module multiplexes its 32 inputs to a single output path connected to the controlling DAQ device. Multiple modules can therefore be used in an SCXI chassis while sharing the DAQ-side acquisition architecture, which was one of the primary reasons the SCXI platform was used for high-channel-count measurement systems.
Typical Applications
- Thermocouple measurement: 32-channel temperature acquisition with cold-junction compensation support.
- Industrial process signals: Conditioning of 0–20 mA and 4–20 mA process-current sources using the appropriate current-loop receiver configuration.
- Low-level voltage measurement: Millivolt and other low-level analog sources using the gain-100 setting.
- Test and measurement systems: Legacy engine, machinery, laboratory, and production-test systems requiring many analog channels through an SCXI chassis.
- Multi-module DAQ systems: Expansion of analog channel capacity where several SCXI modules feed a common DAQ architecture.
Technical Pitfalls to Avoid
1. Do not confuse bandwidth with sampling rate.
The has a 200 Hz analog filter cutoff. A faster DAQ device does not turn the module into a 10 kHz signal-conditioning path. If the application requires fast transient capture, the SCXI-1102C or another architecture may be more appropriate.
2. Check the gain configuration in the acquisition software.
The module provides gain 1 for ±10 V signals and gain 100 for ±100 mV signals. A software configuration intended for one range cannot simply be carried over without confirming the sensor’s actual output level.
3. Verify the thermocouple terminal arrangement.
The includes a cold-junction sensor channel, but the terminal assembly and wiring configuration remain part of the measurement system. Replacing the module while retaining incorrectly configured thermocouple connections can introduce temperature measurement errors.
4. Check current-loop receiver configuration.
The module can condition 4–20 mA and 0–20 mA process-current signals, but these applications require the appropriate current-loop receiver arrangement. Do not assume a standard voltage-input wiring scheme is sufficient for a current-loop transmitter.
5. Treat the software environment as part of the replacement.
The belongs to a legacy SCXI architecture. NI documentation for the family references legacy NI-DAQ and other historical software environments, so compatibility should be checked across the DAQ device, SCXI chassis, interface hardware, drivers, and application software—not just the module itself.
Related Products
- SCXI-1102 — Same 32-channel family with a 2 Hz low-pass filter. Better suited to very slow process and temperature measurements where aggressive bandwidth reduction is intentional.
- SCXI-1102C — Same basic 32-channel architecture but with a 10 kHz low-pass filter. Consider it when the application needs considerably more bandwidth than the .
- SCXI-1100 — General-purpose SCXI analog input module for applications with different voltage/current conditioning requirements.
- SCXI-1120 — Isolated analog input module for applications where channel isolation is required rather than the ‘s primary thermocouple/voltage conditioning function.
- SCXI-1121 — Four-channel universal input module supporting isolated measurement, RTD, strain-gauge, thermocouple, and other low-level signal applications.
- SCXI-1140 — Simultaneous sample-and-hold module for measurement systems where synchronized sampling across multiple channels is important.
- SCXI-1320 — 32-channel terminal block used with applicable SCXI input modules and signal wiring configurations.
- SCXI-1321 — Thermocouple-oriented terminal block option for applicable SCXI installations.
- SCXI-1000 — SCXI chassis platform used to house and interconnect SCXI modules.
- SCXI-1001 — Higher-capacity SCXI chassis for larger multi-module configurations.
Procurement Note
For a replacement , verify the exact module revision, SCXI chassis, terminal block, DAQ interface, gain configuration, thermocouple/current-loop wiring, and software environment before installation. The most important functional check is the 200 Hz filter characteristic; substituting an SCXI-1102 or SCXI-1102C solely because the model numbers look similar can change the analog response of the installed system. NI identifies the as no longer available, so legacy-system replacement should be based on the complete acquisition configuration rather than channel count alone.
