XNXXSM1SS – Honeywell Smart Sensor for Nitric Oxide (NO)
Description
The Honeywell XNXXSM1SS is an isolated Modbus RTU smart sensor for nitric oxide (NO) detection. It delivers reliable RS485 output for multi-drop networks. This module fits field or factory installations. It supports up to 254 XNX-compatible transmitters. The default range is 100 ppm with a lower detectable limit of 3 ppm. Response time T90 is under 30 seconds. Accuracy stays within ±2 ppm. Operating temperature ranges from -20 °C to 55 °C (-4 °F to 131 °F).
Technical Specifications
| Brand | Honeywell |
| Model | XNXXSM1SS |
| Series / Type | Smart Sensor for Nitric Oxide (NO) – Modbus RTU Output |
| Measurement Range | Default 100 ppm (selectable range N/A) |
| Lower Detectable Limit | 3 ppm |
| Accuracy | ±2 ppm |
| Response Time | T50 < 15 sec | T90 < 30 sec |
| Resolution & Steps | N/A (continuous signal) |
| Linearity / Sensitivity | Linear response per Modbus RTU protocol |
| Temperature Range | -20 °C to 55 °C (-4 °F to 131 °F) |
| Environmental Tolerance | Industrial grade; isolated RS485 for noise immunity |
| Interference Rejection | Isolated physical layer, common-mode rejection |
| Communication | Modbus RTU, RS485+, RS485-, Drain |
| Baud Rate | 1200 to 19.2 Kbaud |
| Max Nodes | 254 XNX compatible transmitters |
| Calibration Gas Range | 30 to 70 % of selected full scale |
| Default Cal Point | 50 ppm |
| Physical Layer | Isolated RS485 |
Installation & Maintenance
- Factory installed in display module or field-installed by qualified engineer.
- Connections: RS485+, RS485-, and Drain terminal.
- Mutually exclusive with relay or Foundation Fieldbus options.
- No special tools required for routine check.
- Diagnostic alerts via Modbus for predictive maintenance.
Compatibility & Certification
- Compatible only with XNX series transmitters (max 254 nodes).
- Supports Modbus RTU functions as per Foundation Fieldbus module (optional).
- Designed for Modicon Quantum and other industrial PLC systems.
- CE marked, industrial EMC compliant.
- Isolated RS485 ensures robust communication in harsh plants.
Typical Applications & Diagnostic Capability
- Continuous NO monitoring in combustion exhaust.
- Chemical plant safety and emission control.
- Environmental monitoring stations.
- Diagnostic data: real-time concentration, calibration status, and fault flags.
- Auto-diagnostic cycle with Modbus error reporting.
Package, Warranty & Shipping
- Package includes: XNXXSM1SS sensor module, terminal block, quick-start guide.
- Warranty: 12 months against manufacturing defects.
- Shipping carriers: FedEx, UPS, DHL – worldwide express.
- All units are tested before shipment for verified performance.
Frequently Asked Questions (FAQ)
- Q: Can I use this sensor with non-XNX transmitters?
No, it only supports XNX compatible transmitters. - Q: What is the default calibration point?
Default cal point is 50 ppm (30-70% of full scale adjustable). - Q: Does it support Foundation Fieldbus?
No, Modbus and Fieldbus are mutually exclusive. - Q: What is the operating temperature limit?
From -20 °C to +55 °C. - Q: Is the RS485 port truly isolated?
Yes, isolated RS485 for reliable multi-drop networks.
Why Buy From Oiltech Controls?
- Over 15 years of experience in industrial automation spares.
- Global shipping support – quick delivery worldwide.
- Tested industrial surplus and refurbished options available.
- Every unit backed by a 12-month warranty.
- Technical verification performed prior to shipment.
- Expert support for obsolete control systems, including Modicon Quantum.
Contact Information:
Email: info@oiltechcontrols.com
WhatsApp: +86 158 8020 0923
Copyright © 2026 Oiltech Controls Limited. All rights reserved.
Original Source: https://www.oiltechcontrols.com/
Engineering note: The XNXXSM1SS provides a true isolated RS485 interface with Modbus RTU framing.
Its measurement bridge is temperature-compensated from -20°C to 55°C.
The default 100 ppm NO range suits most combustion and environmental applications.
Calibration gas adjustment (30–70% of range) allows flexible field setup.
The response time (T90 < 30 s) supports real-time control loops.
Diagnostic & maintenance: The Modbus register map includes live concentration, sensor health, calibration due flag, and hardware fault codes.
Periodic self-test ensures integrity.
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