Honeywell SPXCDALMRFD Sensepoint XCD RFD Gas Detector Transmitter

Product Introduction

The Honeywell SPXCDALMRFD is a remote transmitter from the Sensepoint XCD RFD Series. It interfaces with remotely installed catalytic or infrared flammable gas sensors. The transmitter supports Honeywell 705 and 705HT sensor types.

Its three-wire architecture provides a configurable 4-20mA output for industrial gas monitoring systems. An optional RS485 Modbus RTU interface enables digital communication with compatible controllers. Three programmable relays provide additional alarm and fault signaling.

The transmitter features a backlit LCD and non-intrusive magnetic controls. Operators can configure parameters and perform calibration without opening the enclosure. Its remote sensor arrangement supports installation distances up to 30 meters (100 feet).

The SPXCDALMRFD suits industrial plants, process facilities, and hazardous-area gas detection applications. Its enclosure options support demanding industrial installation environments.

Technical Specifications

Signal Output and Detection Performance

The SPXCDALMRFD transmits sensor-related gas detection signals to the plant control system. Its 4–20mA output supports standard industrial analog input channels.

• Normal Measurement: The 4–20mA range represents the configured gas measurement range.
• Fault Monitoring: Output below 1.0mA indicates a fault condition.
• Configuration Status: The output enters its specified inhibit range during configuration.
• Overrange Indication: A 22.0mA signal indicates maximum overrange.
• Relay Signaling: Three relays support configurable external alarm and control circuits.

Important: The transmitter's measurement range, resolution, sensitivity, and linearity depend on the connected sensor. Confirm these values against the selected 705 or 705HT sensor documentation.

Installation Guidelines

Correct installation ensures reliable gas monitoring and stable signal transmission. Follow the approved project drawings and Honeywell installation instructions.

• Mounting Position: Install the transmitter on a rigid wall or suitable mounting pole.
• Sensor Placement: Position the remote sensor near the potential gas release point.
• Remote Connection: Keep the sensor cable within the specified 30-meter maximum distance.
• Power Supply: Provide a stable 16–32 VDC supply with sufficient power capacity.
• Signal Wiring: Connect the three-wire 4–20mA circuit according to the source or sink configuration.
• Grounding: Follow the approved grounding and shielding requirements.
• Cable Entries: Use compatible 3/4-inch NPT cable glands and suitable sealing components.
• Relay Wiring: Verify contact ratings before connecting external alarm loads.
• Hazardous Areas: Follow the applicable installation rules and certified wiring methods.

Commissioning and Maintenance

The transmitter provides local configuration through its LCD and magnetic interface. Technicians can perform routine adjustments without removing the enclosure cover.

Commissioning Procedure:

1. Verify the transmitter model and connected sensor compatibility.
2. Inspect the enclosure, cable glands, terminals, and mounting hardware.
3. Check the supply voltage against the specified operating range.
4. Confirm the selected 4–20mA source or sink configuration.
5. Configure the alarm relays and communication parameters.
6. Verify the LCD status and fault indications.
7. Perform sensor calibration using the approved calibration procedure.
8. Test analog output, relay operation, and Modbus communication when installed.

Maintenance Recommendations:

• Inspect the enclosure for corrosion, damage, or moisture ingress.
• Check terminal connections and cable gland sealing periodically.
• Perform sensor zero and span calibration at approved intervals.
• Test alarm relays and fault signaling during scheduled inspections.
• Verify Modbus communication and controller readings when applicable.
• Record calibration results and maintenance activities.

Compatibility and System Integration

The Honeywell SPXCDALMRFD operates as a remote transmitter within a compatible Sensepoint XCD gas detection arrangement.

• Sensor Compatibility: Designed for remotely mounted Honeywell 705 and 705HT flammable gas sensors.
• PLC/DCS Integration: The 4–20mA output connects to compatible analog input channels.
• Digital Integration: Optional RS485 Modbus RTU supports compatible communication systems.
• Alarm Integration: Three relay outputs support external alarm and control interfaces.
• Power Compatibility: The system requires a 16–32 VDC supply.

Check the sensor type, wiring arrangement, communication option, and firmware requirements before replacement. Do not assume direct compatibility with other Sensepoint transmitter variants.

Enclosure and Environmental Characteristics

The transmitter supports industrial environments through its enclosure design and specified operating limits.

• Temperature: -40°C to +65°C transmitter operating range.
• Ingress Protection: IP66 enclosure protection against dust and powerful water jets under specified test conditions.
• Aluminum Version: LM25 epoxy-painted aluminum alloy construction.
• Stainless Steel Version: 316 stainless steel construction.
• Installation: Wall or pole mounting options.

Verify chemical exposure, ambient temperature, and hazardous-area requirements before selecting the enclosure material.

Certifications and Compliance

The supplied product information identifies ATEX, IECEx, and cCSAus hazardous-area certification options for the Sensepoint XCD platform.

• ATEX hazardous-area certification.
• IECEx hazardous-area certification.
• cCSAus certification.
• Class I, Division 1 application suitability, subject to the exact certified configuration.

Selection Note: Confirm the transmitter nameplate, enclosure variant, certificate number, and regional approval requirements before installation. Certification details can vary by product configuration.

Packaging and Included Components

The standard product identification is Honeywell SPXCDALMRFD Transmitter Only.

• 1 × SPXCDALMRFD remote gas detector transmitter.
• Standard product enclosure in the ordered material configuration.
• Manufacturer identification and product labeling.
• Additional accessories or documentation, subject to the confirmed supply configuration.

Note: The remote gas sensor, mounting accessories, cable glands, and connection cables are not confirmed as standard inclusions. Please verify the final package contents before ordering.

Frequently Asked Questions

Q1: What is the primary function of the Honeywell SPXCDALMRFD?

The SPXCDALMRFD serves as a remote transmitter for compatible flammable gas sensors. It processes sensor signals and provides analog, relay, and optional digital outputs to control systems.

Q2: Which gas sensors are compatible with this transmitter?

This model supports remotely installed Honeywell 705 and 705HT flammable gas sensors. Confirm the exact sensor technology and connection requirements before purchasing.

Q3: Can the transmitter operate without a remote gas sensor?

No. This transmitter requires a compatible remote sensor for gas measurement. It does not independently detect flammable gases.

Q4: How can engineers diagnose an unexpected 0mA output?

First, measure the DC supply at the transmitter terminals. Then inspect the sensor wiring, terminal connections, and fault indications. An output below 1.0mA indicates a fault condition under the specified output scheme. Check the sensor and configuration before replacing the transmitter.

Q5: What should technicians check when the 4–20mA signal remains abnormal?

Compare the transmitter output with the configured sensor range. Check for inhibit conditions, wiring resistance, incorrect source or sink settings, and sensor calibration errors. Also verify the receiving PLC or DCS input configuration.

Q6: How should buyers select between aluminum and stainless steel enclosures?

Choose LM25 aluminum for suitable general industrial environments. Consider 316 stainless steel for applications requiring greater material resistance to corrosive exposure. Evaluate the actual chemicals, installation conditions, and project specifications before selection.

Q7: Can the SPXCDALMRFD communicate with a PLC or DCS through Modbus?

Yes. The optional RS485 Modbus RTU interface supports digital integration with compatible controllers. Confirm the communication option, baud rate, address, and register mapping during system design.

Q8: What should buyers confirm before ordering a replacement transmitter?

Check the complete model number, sensor compatibility, enclosure material, output configuration, and communication requirements. Also verify hazardous-area approvals and terminal arrangements. These checks help prevent wiring and integration problems during commissioning.

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