Honeywell XNX XNX-UTSI-MHNNN – no sensor (transmitter body), IR, UL, 316SS, 3/4" NPT
XNX-UTSI-MHNNN is a Honeywell XNX IR-personality transmitter body, UL / cUL, 4 × 3/4" NPT, 316 stainless steel, Modbus RTU + 4–20 mA HART, local HART port on the transmitter, no sensor. It is the junction-box electronics for Searchpoint Optima Plus or Searchline Excel—not an MPD catalytic transmitter.
Same sensor, swap enclosure/approval: aluminium XNX-UTAI-MHNNN, 316SS XNX-UTSI-MHNNN, other approval XNX-AMSI-MHNNN. XNX-UTAI-MHNNN · XNX-UTSI-MHNNN · XNX-AMSI-MHNNN

Part-number decode
| Segment | Meaning | This SKU |
|---|---|---|
| XNX | Honeywell XNX universal transmitter | XNX |
| A / U | Approval A=ATEX/IECEx; U=UL/cUL | U |
| M / T | Entry M=M25; T=3/4" NPT | T |
| A / S | Enclosure A=aluminium; S=316SS | S |
| V / I / E | Personality V=mV(MPD); I=IR Optima/Excel; E=EC | I |
| N / R / M / F | Option N=HART only; R=relays; M=Modbus; F=FFB | M |
| N / H | Local HART port N=no; H=yes | H |
| NNN | no sensor (transmitter body) | NNN |
Same sensor, swap enclosure/approval: aluminium XNX-UTAI-MHNNN, 316SS XNX-UTSI-MHNNN, other approval XNX-AMSI-MHNNN.
Technical specifications
| Category | 变送器本体 |
|---|---|
| Personality | IR personality (Searchpoint Optima Plus / Searchline Excel) |
| Sensor / range | no sensor (transmitter body) |
| Target | body / sensor not fitted |
| Principle | personality board only |
| Output | Modbus RTU + 4–20 mA HART |
| Local HART | local HART port on the transmitter |
| Supply | 16–32 VDC (24 VDC nominal) |
| Enclosure | 316 stainless steel |
| Entries | 4 × 3/4" NPT |
| Display | Backlit LCD, magnetic-wand menus |
| Ingress | IP66 |
| Approvals | UL / cUL |
| Temperature | −40~+65 ℃ |
| Mass | approx. 5.0 kg |
| Mates with | Searchpoint Optima Plus point IR or Searchline Excel open-path IR |
Why this personality / sensor
Optima Plus (point IR) and Excel (open-path) need the IR personality board and a different wiring/power budget than MPD millivolt heads. Ordering an mV body and hoping to hang Excel later will fail at commissioning. This SKU keeps the transmitter certified while the IR head is specified on its own datasheet.
Personality and replaceable parts
XNX-UTSI-MHNNN uses the IR personality (Searchpoint Optima Plus / Searchline Excel) board and mates with Searchpoint Optima Plus point IR or Searchline Excel open-path IR. This SKU ships without a sensor; order the head by gas. Spares live on product-3991. Do not substitute Sensepoint XCD cartridges on XNX.
Typical applications
Use IR bodies on tank-farm open-path runs, compressor-hall Optima points, and LNG boil-off galleries where the path length or window kit is sized after the transmitter is already on the pipe stand.
Selection contrast
| P/N | Gas | Range | Option | Body |
|---|---|---|---|---|
| XNX-UTAI-MHNNN | body | — | Modbus | Aluminium |
| XNX-AMSI-MHNNN | body | — | Modbus | 316SS |
| XNX-UTSI-NHNNN | body | — | HART | 316SS |
| XNX-UTSI-RHNNN | body | — | Relays | 316SS |
| XNX-UTSI-FHNNN | body | — | FFB | 316SS |
Installation and wiring
Wall-mount XNX-UTSI-MHNNN (316 stainless steel, approx. 5.0 kg) on a rigid stand sized for that mass. This SKU uses 4 × 3/4" NPT entries—glands must match; do not retap XNX-UTSI-MHNNN. Land XNX-UTSI-MHNNN 4–20 mA HART per the loop drawing; relays/Modbus/FFB exist only on the matching option board. Magnetic-wand menus on the XNX-UTSI-MHNNN lid stay non-intrusive. XNX-UTSI-MHNNN is a body: wall-mount the transmitter first and mate the head after the personality is confirmed—do not buy a configured SKU until the gas is frozen.
FAQ
- Can I add an MPD sensor to XNX-UTSI-MHNNN later?
- XNX-UTSI-MHNNN ships as a transmitter body. mV personalities accept MPD CB1/IV1/IF1/IC1 heads; IR personalities need Optima/Excel; EC personalities need XNX electrochemical cells. Do not mix those three families on this board.
- Is XNX-UTSI-MHNNN a complete gas detector?
- No. XNX-UTSI-MHNNN is electronics and enclosure only. A configured detector has a three-character sensor code such as CB1 instead of NNN.
- Why is XNX-UTSI-MHNNN 316SS instead of aluminium?
- XNX-UTSI-MHNNN is the marine/sour-service body (~5 kg). Inland dry rooms can take aluminium sibling XNX-UTAI-MHNNN and save mass on the bracket.
- Why is XNX-UTSI-MHNNN NPT instead of M25?
- XNX-UTSI-MHNNN is the UL/cUL body and ships 3/4" NPT. Do not tap M25 on this lid—order ATEX sibling XNX-AMSI-MHNNN if metric glands are mandatory.
- Can I retrofit Foundation Fieldbus on XNX-UTSI-MHNNN after it ships?
- No. XNX-UTSI-MHNNN is the Modbus RTU option board. FFB is a different sales option (XNX-UTSI-FHNNN), not a jumper on this lid.
Documents
Honeywell XNX datasheet / manual · On-site XNX selection matrix
Availability and enquiry
Stock is lot-based. If this box is out, jump to 316SS XNX-UTSI-MHNNN or UL XNX-UTSI-MHNNN rather than a dead SKU.