Honeywell SPXCDXSCXSS Carbon Monoxide Gas Detector

Honeywell SPXCDXSCXSS Sensepoint XCD Carbon Monoxide Sensor Transmitter

The Honeywell SPXCDXSCXSS is a fixed-point toxic gas transmitter used for the continuous detection of Carbon Monoxide CO in hazardous industrial and marine situations. This device is part of the industry standard Sensepoint XCD product family, combining an electrochemical Surecell™ sensor and a 316 Stainless Steel transmitter enclosure. It has an intuitive tri-color backlit LCD display, a non-obtrusive single operator magnetic wand setup, and full output signaling including 4–20mA, RS485 Modbus RTU, and three fully adjustable 5A relays.

Designed for harsh ambient conditions, high humidity and vibration on offshore platforms, chemical process plants and shipboard engine spaces, the SPXCDXSCXSS provides continuous ambient air monitoring and instantaneous visual and relay activated emergency response during toxic CO buildup events.

Model Details

• Manufacturer: Honeywell Analytics
• Full Model Part Number (MPN): SPXCDXSCXSS
• Series: Sensepoint XCD
• Gas Type: Carbon Monoxide
• Housing Material: 316 Stainless Steel (Ex d explosion-proof enclosure)
• Sensor Technology: Plug-in Surecell™ Electrochemical Cell with Reflex® automated sensor health diagnostic check

Key Features

1. Tri-Color Backlit Status LCD: Instant status identification via traffic-light color coding—Green for normal operation, Flashing Yellow for fault/warning, and Flashing Red for alarm states.
2. Non-Intrusive One-Man Magnet Calibration: Fully adjustable configuration, zeroing, and span calibration using a magnetic wand through the glass window without opening the explosion-proof enclosure or requesting hot-work permits.
3. 316 Marine-Grade Stainless Steel Construction: Maximum protection against saltwater corrosion, chemical washing, and physical shock in offshore, marine, and heavy industrial environments.
4. Comprehensive Signal Outputs: Supports 3-wire 4–20mA (sink/source selectable), RS485 Modbus RTU digital bus communication, and 3 onboard SPDT relays rated 5A @ 250VAC.
5. Hot-Swappable Plug-In Sensor Cell: Intrinsic Safety (IS) barrier design allows rapid replacement of the pre-calibrated toxic sensor cartridge with minimal system downtime.

Key Applications

• Marine Machinery Spaces & Engine Rooms: Monitoring incomplete combustion gas build-up near boilers, main engine exhaust trunks, and auxiliary diesel generators.
• Inert Gas Systems (IGS) & Cargo Pumprooms: Continuous air monitoring on oil tankers, chemical carriers, and gas transport vessels.
• Boiler Rooms & Thermal Fluid Heater Enclosures: Atmospheric monitoring in industrial utility plants and commercial HVAC facilities.
• Chemical & Petrochemical Processing Facilities: Process area toxic gas monitoring in refineries, tank farms, and enclosed gas turbine bays.
• Enclosed Parking Structures & Transport Hubs: Continuous monitoring of vehicle exhaust toxic emissions.

Power Supply Connections

• Terminals 1 & 2: +24VDC Power Input (12–32VDC range) and 0V Common ground connection. Ensure voltage drop across long cable runs does not bring terminal voltage below 12VDC under maximum load (3.7W).

Signal Outputs & Jumpers

• Terminal 3 (4–20mA Output): Linear analog output proportional to 0–Full Scale CO range.
• Sink / Source Selection: Controlled via internal slide switch on the main PCB. Configure to “Source” when driving passive PLC/DCS input cards; select “Sink” for powered external loops.
• Terminals 4 & 5 (RS485 Modbus RTU): Terminal 4 (RS485 A +) and Terminal 5 (RS485 B -). Install 120-ohm bus termination resistors at the physical end-of-line unit on multi-drop networks.

Compatible Controllers & Systems

• Honeywell Controllers: Touchpoint Plus, Touchpoint Pro, Unipoint, and System 57 gas detection control systems.
• Third-Party Automation: Works with any standard PLC, DCS, SCADA, or Marine Integrated Automation System (IAS) supporting 4–20mA analog inputs or Modbus RTU over RS485.

Replacement Sensor Cartridges & Spare Parts

• Replacement Sensor Element: Honeywell Sensepoint XCD CO Sensor Cell Cartridge (P/N: SPXCDXSCXSS / S3KCO).
• Calibration Kit: Honeywell Magnet Wand Assembly (P/N: S3KRMK) and Calibration Flow Cap (P/N: S3KCAL).
• Pipe Mounting Kit: Optional 2″ vertical/horizontal pipe mounting kit (P/N: S3KSMK).

Marine Engineering Installation Advice

When retrofitting or installing the Honeywell SPXCDXSCXSS in marine machinery spaces, positioning is critical. Carbon Monoxide has a vapor density of 0.968 relative to air, making it slightly lighter than dry air, but in engine spaces with high thermal currents, it mixes rapidly with ambient air.

Mount the sensor head at respiratory height (1.5 to 1.8 meters above deck level) in primary operator walkways, near potential leakage points such as boiler uptake joints, exhaust manifold expansion bellows, and auxiliary diesel engine enclosures.

Frequently Asked Questions

What is the full span measuring range of the SPXCDXSCXSS Carbon Monoxide sensor?

The SPXCDXSCXSS comes factory set to a default range of 0–300 ppm CO. However, using the magnetic wand interface, users can field-configure the full scale range between 100 ppm and 1,000 ppm in steps of 100 ppm.

Can I change the sensor cell without opening the main enclosure?

Yes. The Sensepoint XCD sensor assembly incorporates an intrinsically safe (IS) design, allowing technicians to replace the plug-in sensor cartridge in a hazardous area without requesting a hot-work permit or powering down the main enclosure.

How do I configure the 4–20mA output between Sink and Source modes?

Output mode is set via a physical switch located on the internal terminal board. Move the switch to “Source” if supplying power to the receiver loop, or “Sink” if the receiving system provides loop power