Description
NI SCXI‑1127 Multiplexer – High‑Density Reed‑Relay Switching for DMM/DAQ Routing
The National Instruments SCXI‑1127 is a versatile SCXI switch module designed to route dozens of signals to a single measurement device. From my experience, it’s typically chosen when you need clean, repeatable, low‑thermal paths for DMM scanning or DAQ front‑end selection—especially in automated test benches where space and channel count matter. You might notice that the 1127 shines in low‑frequency, precision applications where reed relays help keep offsets and contact noise in check.
Our Order Process & Guarantees
- Warranty period: 365 days
- Delivery time: 1 week for in-stock; no more than one month at the latest
- Payment: 50% advance payment, full payment before delivery
- Express delivery: FedEx, UPS, DHL
Key Features
- High‑density signal routing – Configurable multiplexer topologies up to 64 1‑wire or 32 2‑wire channels for efficient DMM/DAQ scanning.
- Reed‑relay architecture – Typically provides low thermal EMF and fast, consistent switching that’s well suited for precision measurements.
- Break‑before‑make behavior – Helps protect instruments and DUTs by avoiding accidental shorting during channel transitions.
- Tight SCXI integration – Controlled through the SCXI backplane; pairs smoothly with NI‑DAQmx/NI‑SWITCH in LabVIEW, LabWindows/CVI, or .NET.
- Compact, modular footprint – Single‑slot SCXI module that scales easily across multi‑slot chassis for larger systems.
- Built for low‑frequency precision – In many cases preferred for DC to low‑kHz measurements, resistance scans, and guarded routes to NI DMMs.
Technical Specifications
| Brand / Model | National Instruments NI SCXI‑1127 |
| HS Code | 8537.10 (Boards/panels for electric control, ≤1000 V) |
| Power Requirements | Powered via SCXI chassis backplane (no external power on the module) |
| Multiplexer Topologies | Up to 64×1 (1‑wire) or 32×1 (2‑wire); 4‑wire measurements achievable using paired channels |
| Signal Switching Elements | Reed relays (low thermal EMF, fast actuation) |
| Operating Temperature | 0 °C to 50 °C (typical SCXI operating range) |
| Communication / Control | SCXI backplane; software support via NI‑DAQmx / NI‑SWITCH |
| Installation Method | Single‑slot SCXI module; mates to SCXI terminal block and cable per NI guidelines |
| Typical Use Cases | DMM scanning, resistance measurements, sensor bank selection, automated functional test |
Related or Supporting Products
- NI SCXI‑1128 – Similar form factor with armature relays; typically handles higher current at the expense of higher contact resistance.
- SCXI Chassis – SCXI‑1000/1001/1000DC series for housing and powering the module.
- Terminal Blocks – Matching SCXI terminal blocks (SCXI‑133x family) for screw‑terminal or shielded connectivity to the 1127/1128 series.
- NI DMMs – Commonly paired with NI DMMs for scanning (e.g., 6½‑digit models) or routed to DAQ analog inputs for channel expansion.
- PXI Switch Alternatives – If you prefer PXI, consider PXI multiplexers such as PXI‑2530B for a newer platform with similar switching topologies.
Customer feedback from a recent lab retrofit: “We moved 48 temperature/resistance points onto a single NI DMM through the SCXI‑1127. It seems to be the simplest way we found to keep wiring tidy and still scan under 1 second per pass. The reed relays have been stable—no drift issues so far.”
Installation & Maintenance
- Cabinet & environment – Install in a ventilated SCXI chassis within a 19‑inch rack or bench setup. Keep ambient 0–50 °C and avoid high humidity or corrosive atmospheres.
- Wiring practice – Use short, shielded leads where practical. For low‑level measurements, guard sensitive paths and keep high‑energy lines isolated from measurement lines.
- Safety precautions – De‑energize circuits before changing wiring. The module is break‑before‑make; still, treat all unknown lines as energized and observe creepage/clearance best practices.
- Software setup – Configure switching routes in NI‑DAQmx/NI‑SWITCH. From my experience, naming channels/banks early saves time when test sequences grow.
- Routine maintenance – Periodically verify relay health with a quick continuity/self‑test and clean terminal contacts. Keep drivers up to date to maintain stable switching sequences.
Quality & Certifications
- Conformance: CE and RoHS compliant; produced under ISO‑certified quality systems
- Electrical safety: Designed for integration in compliant SCXI systems; UL or equivalent safety listings typically apply at the system level
- Warranty: 365‑day warranty from us; original NI manufacturer coverage applies where available
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