HONEYWELL Sensepoint XCD Gas Detector

Load resistance: maximum 250 Ω

Special current state:

≤ 1mA: System malfunction

2mA: Start or inhibit state (Inhibit)

3.5mA: Below the lower range limit

4-20mA: Normal measurement

22mA: Over range

3. Wiring terminals

The internal terminal module of the transmitter provides 15 wiring positions, mainly including:

Terminal 1, 2:24V+, 0V power supply

Terminal 3: 4-20mA signal output

Terminal 4: Common Terminal (COM)

Terminals 5 and 6: Modbus RTU (RS485) A/B line (optional)

Terminal 7-15: The normally open, normally closed, and common terminals of three sets of relays

4. Cable selection and distance calculation

For a 24Vdc power supply system, it is necessary to ensure that the minimum voltage reaching the transmitter meets the requirements. The cable length is affected by the wire diameter and resistance. The example calculation is as follows:

Controller output voltage 24V, detector minimum voltage 16V (ATEX version), allowable voltage drop 8V

Detector working current=5W/16V ≈ 312.5mA

Maximum circuit resistance=8V/0.3125A=26 Ω (13 Ω per core)

Taking a 1.5mm ² cable (resistance 12.7 Ω/km) as an example, the maximum single core length is approximately 13 Ω/12.7 Ω/km, which is approximately 1023 meters.

5. Grounding and shielding

The equipment is equipped with grounding terminals both inside and outside, with internal grounding as the main grounding and external grounding as the auxiliary connection

The cable shielding layer should only be grounded at a single point at the controller or detector end to avoid the formation of ground loop interference

Installation and mechanical structure

1. Installation method

The Sensepoint XCD transmitter is integrated with a mounting plate, which can be directly fixed to the wall or installed on a 40-80mm diameter riser or horizontal pipe through a pipe mounting bracket (SPXCDMTMB). Ensure that the sensor sinter is facing downwards during installation to maintain an IP66 protection level.

2. Environmental adaptability

Temperature range: -40 ° C to+75 ° C (slightly different depending on certification and sensor type)

Humidity range: Continuous 20-90% RH, intermittent 10-99% RH (non condensing)

Pressure range: 80-120kPa (electrochemical sensor) or 90-110kPa (catalytic and infrared sensor)

Protection level: IP66 (weather protection cover must be installed correctly)

3. Explosion proof sealing requirements

When using conduit installation, each cable entry must have a seal fitting installed within 18 inches (457mm). If the sensor is installed remotely, additional sealing components need to be added at the sensor wiring entrance.

Display interface and magnetic rod operation

Sensepoint XCD is equipped with a high brightness LCD display with backlight color indication:

Green constantly on: normal operation

Red flashing: gas alarm

Yellow flashing: device malfunction

The display screen can simultaneously show gas concentration (numbers and bar charts), range units, alarm status, and menu information.

Magnetic rod operation is achieved through three sensing areas:

Short press (≤ 2 seconds): Enter the menu or confirm the option

Long press (≥ 3 seconds): return to the previous level or exit

Three operating modes:

Monitoring Mode: Normal measurement state

Configuration Mode: Set parameters such as range, alarm value, relay action, and suppression current, which can be password protected

Review Mode: View current configuration parameters and cannot be modified

Calibration and maintenance

1. Calibration frequency

Honeywell recommends conducting a gas response test (Bump Test) or comprehensive calibration every 6 months, with the specific frequency determined based on on-site gas exposure, sensor type, and regulatory requirements.

2. Zero point calibration and range calibration

The calibration process requires the use of specialized calibration caps (Gassing Cap, P/N: S3KCAL) and standard concentration gases. The recommended flow rates for different gas types are as follows:

Flammable (catalytic): 1.0-1.5 L/min

Flammable (infrared): 0.4-0.6 L/min

Toxic gas: 0.5-1.0 L/min

Oxygen: 0.5-1.0 L/min

Special precautions:

For hydrogen sulfide sensors, zero calibration must use 20.9% Vol oxygen compressed air, and nitrogen or background air must not be used

The infrared methane/carbon dioxide sensor must undergo range calibration immediately after zero calibration

After calibration is completed, the device will automatically reset the "calibration expiration" warning counter

3. Sensor lifespan and replacement

Catalytic combustion sensor: typical lifespan of 36 months (may be shortened due to toxic substances)

Infrared sensor: with a typical lifespan of over 5 years

Electrochemical sensor: Typical lifespan ≥ 24 months (depending on application)

When replacing the sensor, the transmitter power must be disconnected to ensure that the new sensor model and range are consistent with the original sensor.

Fault codes and diagnosis

Sensepoint XCD provides fault diagnosis information through display screen and current output:

Code Description Suggested Actions

Perform zero and range calibration upon expiration of W-01 calibration

The temperature of the W-02 transmitter exceeds the limit and will be cleared after the temperature is restored