Description
NI SCXI-1125 Product Specifications
- Origin: United States / Mexico
- Weight: 1.45 lbs (0.66 kg)
- Form Factor: SCXI Chassis-based module
- Number of Channels: 8 isolated analog inputs
- Isolation Voltage: 300 Vrms (Channel-to-Channel and Channel-to-Ground)
- Bandwidth: Programmable (4 Hz or 10 kHz per channel)
- Gain Settings: Programmable (1, 2, 5, 10, 20, 50, 100, 200, 500, 1000, 2000)
- Input Ranges: ±5 mV to ±300 V (depending on gain and attenuation)
The NI SCXI-1125 is a high-performance analog input module designed for signal conditioning and isolation of millivolt, volt, and thermocouple signals. It is primarily used within an SCXI chassis to provide high-voltage isolation and noise rejection before data reaches a DAQ device. Each of its 8 channels features independent programmable gains and a selectable low-pass filter (4 Hz for high-resolution DC measurements or 10 kHz for faster dynamic signals). This architecture makes the SCXI-1125 an ideal choice for industrial test environments where transducers are located near high-voltage sources or in areas prone to significant ground loops and common-mode interference.
NI SCXI-1125
NI SCXI-1125
Model Comparison: SCXI-1125 vs. Similar Models
The SCXI-1125 is the successor to the SCXI-1120, offering several key upgrades including software-programmable gain and filter settings, whereas the 1120 relies on manual jumpers. While the SCXI-1126 is specialized for frequency and strain measurements, the SCXI-1125 is a more versatile general-purpose voltage and thermocouple module. Compared to the SCXI-1102, which offers 32 channels but only shared isolation (bank-to-bank), the 1125 provides true channel-to-channel isolation. This makes the 1125 the superior choice for safety-critical applications where individual sensors must be protected from high-voltage transients affecting neighboring channels.
Operational Guidelines
- Software Configuration: Use NI-DAQmx in Measurement & Automation Explorer (MAX) to configure the gain and filter settings. Ensure the software settings match the expected physical signal range to avoid “Saturation” or “clipping” errors.
- Cabling and Terminal Blocks: For thermocouple measurements, it is highly recommended to use the TC-2095 or SCXI-1328 terminal blocks, which feature integrated Cold-Junction Compensation (CJC) sensors required for accurate temperature conversion.
- Isolation Integrity: To maintain the 300 Vrms isolation rating, ensure that the field wiring is properly rated for the working voltage and that the terminal block cover is securely fastened to prevent accidental contact with exposed conductors.
- Calibration: The SCXI-1125 supports self-calibration. It is recommended to perform this routine within the chassis environment to compensate for thermal drift and gain errors caused by the specific chassis power supply and ambient conditions.
