Honeywell Sensepoint XCD SPXCDULNO1 – Fixed O₂ Detector (0-25.0%Vol, Electrochemical (Surecell™), UL, LM25, 3/4" NPT)
SPXCDULNO1 is the Sensepoint XCD oxygen deficiency / enrichment transmitter, fixed 0–25.0 %vol electrochemical cell, LM25 epoxy-coated aluminium, 2 × 3/4" NPT, UL / CSA. It is the dedicated O₂ SKU for nitrogen-purged vessels, confined plant rooms and inerting skids.
Same gas, swap enclosure/approval: aluminium SPXCDALMO1, 316SS SPXCDASMO1, UL SPXCDULNO1. SPXCDALMO1 · SPXCDASMO1 · SPXCDULNO1
Part-number decode
| Segment | Meaning | This SKU |
|---|---|---|
| SPXCD | Sensepoint XCD series | SPXCD |
| A / U | Approval A=ATEX/IECEx/GB; U=UL | U |
| L / S | Enclosure L=LM25 aluminium; S=316SS | L |
| M / N | Entry M=M20; N=3/4" NPT | N |
| O1 | Gas oxygen, Electrochemical (Surecell™) | O1 |
Same gas, swap enclosure/approval: aluminium SPXCDALMO1, 316SS SPXCDASMO1, UL SPXCDULNO1.
Technical specifications
| Target gas | O₂ / oxygen |
|---|---|
| Principle | Electrochemical (Surecell™) |
| Default range | 0-25.0%Vol |
| User FSD window | Fixed 25.0%Vol |
| Resolution | n/a |
| Output | 4–20 mA sink/source + optional Modbus RTU |
| Supply | 16–32 VDC (24 VDC nominal) |
| Power | 3.7 W |
| Enclosure | LM25 epoxy-coated aluminium |
| Entries | 2 × 3/4" NPT |
| Display | Tri-colour backlight LCD |
| Relays | 3×5A@250VAC |
| Ingress | IP66 |
| Approvals | UL / CSA |
| Temperature | −40~+65 ℃ |
| Mass | approx. 2.0 kg (4.4 lb) |
Why this principle for this gas
Oxygen is neither heavier nor lighter in a meaningful way for siting—the risk is displacement by N₂ or enrichment from leaks. A Surecell™ O₂ cell is used because catalytic and IR channels cannot report %vol oxygen. Mount at the height where personnel breathe or where the purge first enters; do not hide it behind a vessel skirt.
Sensor and replaceable parts
OEM cartridge SPXCDXSO1SS. Calibration cap S3KCAL. Collecting cone follows buoyancy—see installation. Pipe/duct kits: SPXCDMTBR / SPXCDDMK.
Typical applications
Nitrogen-inerted tanks, analyser houses and bottle stores need a latched O₂ trip, not a walk-around reading. XCD gives 4–20 mA plus relays so the purge skid can hard-interlock; a portable cannot hold that permit.
Selection contrast
| P/N | Gas | Range | Principle |
|---|---|---|---|
| SPXCDULNO1 | O₂ | 0-25.0%Vol | EChem |
| SPXCDULNHX | H₂S | 0-50ppm | EChem |
| SPXCDULNCX | CO | 0-300ppm | EChem |
| SPXCDULNFX | LEL | 0-100%LEL | Catalytic bead |
| SPXCDALMO1 | O₂ | 0-25.0%Vol | EChem |
| SPXCDASMO1 | O₂ | 0-25.0%Vol | EChem |
Installation and wiring
Wall-mount SPXCDULNO1 (oxygen, LM25 epoxy-coated aluminium) through the one-piece plate with M8 bolts sized for that mass. This SKU uses 2 × 3/4" NPT entries: pipe kit SPXCDMTBR covers Ø1.5–3″, duct kit is SPXCDDMK, and glands must match—do not retap SPXCDULNO1. Land SPXCDULNO1 4–20 mA as three-wire and set Modbus address from the menu only. Magnetic wand calibration on the SPXCDULNO1 lid stays non-intrusive. Aim the SPXCDULNO1 O₂ head at the purge inlet or the breathing line.
FAQ
- SPXCDULNO1: Can I change the 25 %vol O₂ FSD?
- SPXCDULNO1 — No. The O1 cell is fixed at 25.0 %vol. If you need a different span you are specifying the wrong platform.
- SPXCDULNO1: How often is an oxygen cell replaced?
- SPXCDULNO1 — Plan 12–18 months in continuously powered service. Keep SPXCDXSO1SS on the shelf; oxygen cells age even in the box once the foil is broken.
- LM25 or 316SS for SPXCDULNO1 (oxygen)?
- SPXCDULNO1 ships in LM25 epoxy aluminium (~4.4 lb). For oxygen in salt spray, caustic CIP or sour-water splash, switch to 316SS sibling SPXCDASMO1 instead of painting this lid.
- Why is SPXCDULNO1 NPT instead of M20?
- SPXCDULNO1 is the UL/CSA oxygen body and ships 3/4" NPT. Do not tap M20 on this lid—order ATEX sibling SPXCDALMO1 if metric glands are mandatory.
- Can I retrofit Modbus on SPXCDULNO1 after it ships?
- Modbus RTU on SPXCDULNO1 is a transmitter sales option, not a jumper on the oxygen lid. Confirm the option before the box leaves; 4–20 mA sink/source is already on this SKU.
Documents
Honeywell Sensepoint XCD datasheet / manual · On-site XCD selection matrix
Availability and enquiry
Stock is lot-based. If this aluminium ATEX box is out, jump to 316SS SPXCDASMO1 or UL SPXCDULNO1 rather than a dead SKU.