Fireye InSight II Marine Flame Scanner

InSight II Marine Flame Scanner Complete Technical Manual: Dual Sensor Explosion proof Design and Field Engineering Application

In the safety control of marine boilers, offshore platform burners, and various industrial combustion systems, flame detection devices are the "eyes" of combustion management systems. Traditional flame scanners typically consist of independent detection heads, amplifiers, and flame switch modules, with complex wiring and numerous fault points. The InSight II series marine flame scanner (model 95DSS3-1CEXSS) launched by Fireye adopts an integrated design, which integrates flame detection, signal amplification, safety judgment, and flame switch functions into one detection head, and can directly interface with the main combustion management system (BMS) without the need for external amplifiers. This article systematically introduces the dual sensor principle, explosion-proof structure, installation and purging requirements, electrical wiring, parameter configuration, and on-site troubleshooting methods of the scanner from an engineering and technical perspective, helping ship electrical engineers and combustion safety technicians fully utilize equipment performance.

Product positioning and core features

The InSight II Marine Scanner is designed for harsh marine environments, featuring a 316 stainless steel casing with IP66 protection rating and ATEX Ex db IIC T6~T4 explosion-proof certification. Its most prominent feature is its dual sensor architecture: it includes both ultraviolet (UV) and infrared (IR) detectors, which can select the most suitable detection method based on the fuel type (oil, gas, or mixed fuel) and combustion conditions.

Compared with the split flame detection system, InSight II integrates signal conditioning, threshold comparison, relay output, and analog signal output all inside the scanning head. Users only need to provide a 24V DC power supply to directly obtain two independent flame relay contacts, two 4-20mA flame intensity analog signals, and one fault relay output. This integrated design significantly reduces the number of amplifier modules inside the cabinet, simplifies the wiring of the ship's engine room, and reduces the complexity of spare parts inventory.

List of core features:

Dual detectors: UV and IR, can be used independently or in combination

Two independent adjustable flame relays (FR1, FR2), each capable of selecting logic from UV, IR, or both

21 modulation frequency selections (used to distinguish target flames from background flames)

Adjustable sensor gain and relay engagement/release threshold

Two 4-20mA analog outputs (corresponding to the flame intensity of FR1 and FR2)

Fault relay (for self diagnostic alarm)

Four programmable memory files (applicable to different fuels or load rates)

Auto Config and manual override function

Remote communication: via Fireye Explorer PC software (optional)

VFD display screen and keyboard (on-site parameter viewing and modification)

316 stainless steel shell, IP66，ATEX Ex db IIC T6/T5/T4，Ex tb IIIC

Dual sensor technology and frequency selection

2.1 Ultraviolet Sensor (UV)

UV sensors are sensitive to the ultraviolet radiation emitted by flames (usually in the wavelength range of 190-270nm), have a fast response speed, and are insensitive to high-temperature thermal radiation (infrared). Therefore, they can effectively distinguish flames from backgrounds such as burning refractory bricks and furnace walls. The advantage of UV sensors is that they are not affected by high-temperature solid radiation inside the furnace, but the disadvantage is that they may respond incorrectly to external ultraviolet sources such as welding arc light and lightning, and may have insufficient sensitivity to certain low ultraviolet radiation flames (such as low NOx burners).

2.2 Infrared Sensor (IR)

IR sensors are sensitive to the infrared radiation unique to flames (typically in the wavelength range of 1.0~3.5 μ m) and can detect the combustion characteristics of carbon containing fuels. IR has a certain inhibitory effect on high-temperature background, but not as thorough as UV. In some burners that use heavy oil or crude oil, IR signals are often more stable than UV signals.

2.3 Dual sensor collaborative work

InSight II allows users to independently select signal sources for each flame relay:

Only UV: The relay action is based on the radiation intensity detected by the UV sensor.

Only IR: based on IR sensors.

UV+IR (logical AND): When two sensors detect flames simultaneously, it is considered as fire, improving safety.

UV/IR (logical OR): If any sensor detects a flame, it is considered as fire and improves availability.

In marine boilers, when switching from fuel oil to gas, the flame radiation characteristics of the two fuels are different. Users can use four programmable files to pre store the optimal settings (gain, frequency, threshold) for two fuels, and achieve one click adaptation through external signals or manual file switching.

2.4 Modulation frequency selection

Flames flicker at a specific frequency (depending on the aerodynamics of the burner and the fuel injection method), while background radiation is typically direct current or at different frequencies. InSight II offers 21 modulation frequency options (typically ranging from 20 to 1000Hz), allowing users to set the scanner to only respond to signals that are consistent with the target flame flicker frequency, thereby suppressing interference from adjacent burners or reflected light. Choosing the right frequency is a key step in improving the signal-to-noise ratio.

Mechanical specifications and explosion-proof structure

3.1 Shell and Protection

Material: 316 stainless steel, the primer is zinc foundation make-up paint, the intermediate coat is gray epoxy resin, and the finish is polyurethane. This three-layer coating system can resist salt spray corrosion in the ocean atmosphere.

Weight: 21.3 pounds (approximately 9.66kg), stainless steel model.

Protection level: IP66 (completely dustproof, resistant to strong water spray).

Explosion proof certification:

ATEX Ex db IIC T6/T5/T4 (Explosion proof enclosure, suitable for Class II explosive gas environment, temperature group T6~T4)

Ex tb IIIC T85/T100/T135 ° C (dust explosion-proof)

Suitable cable connectors and accessories are required to maintain certification.

3.2 Installing flanges

The scanner needs to be fixed to the observation tube through a separate threaded flange. The flange is made of 316 stainless steel material (excluding insulated threaded inserts) and also adopts a three-layer coating. Provide two thread options:

60-2693-2:1 inch BSP female thread with 3/8-inch BSP female cooling air interface.

60-2693-3: 1 inch NPT female thread with 3/8 inch NPT female cooling air interface.

The flange weighs approximately 1.86 pounds (0.84kg) and needs to be ordered separately. When installing, first screw the flange onto the observation tube, and then screw the scanner into the flange. Cooling air is connected through a 3/8-inch interface for blowing observation windows and cooling scanners.

Cooling and blowing air requirements

The furnace temperature of marine boilers can reach hundreds or even thousands of degrees Celsius, and there may be positive pressure present. The scanner must be ventilated with cooling/blowing air to function properly.

Minimum flow rate: 4 SCFM (approximately 113 liters/minute) enters the observation tube through a 3/8-inch interface or a 1-inch Y-shaped connector. If the ambient temperature is close to the upper limit of the scanner's operating temperature (+65 ° C), or if dirty fuel (such as heavy oil) is used, it may be necessary to increase it to 15 SCFM (425 liters/minute).

Air source quality: clean, dry, and cooled air (instrument air or dedicated fan). Damp or oily gases can contaminate observation windows and corrode internal optical components.

Pressure: It must be sufficient to overcome the positive pressure in the furnace. Usually, it is required that the cooling air pressure be at least 2-5 inches of water column higher than the furnace pressure.

Temperature requirement: The scanner itself allows an ambient temperature of -40 ° F to+150 ° F (-40 ° C to+65 ° C). The inlet temperature of the cooling air should be within this range.

Attention: Never install the scanner on a high-temperature furnace without cooling air, otherwise it will immediately damage the sensor and electronic components.

Electrical specifications and cable selection

5.1 Power Supply

Input voltage: 24 Vdc,+10%/-15% (approximately 20.4~26.4V DC).

Power supply current: 0.35 A (typical), maximum apparent power of 8.5 VA.

Power on setup time: The power output rise time must be ≤ 20 milliseconds to ensure reliable startup of the scanner. Fireye recommends using a dedicated power supply 60-2685.

5.2 Cable Requirements

Due to the fact that the scanner output signal (relay contacts, 4-20mA) and input (24V power supply) are all connected through a multi-core cable, shielded cables must be used to prevent electromagnetic interference.

Fireye offers two specifications of dedicated cables:

Model, number of cores, wire gauge, shielding outer diameter, temperature range, maximum length

59-546 8-core # 18 AWG aluminum foil+braided+drain wire 0.44-0.48 inches -40 ° C~+105 ° C 305 meters

59-547 12 core # 18 AWG as above 0.52~0.56 inches -40 ° C~+105 ° C 305 meters

Cable grade: PLTC-ER (power limited tray cable, exposed operation), flame-retardant PVC sheath, compliant with RoHS.

The drain wire must be grounded at one end (usually on the control cabinet side).

The cable length should not exceed 1000 feet (305 meters), otherwise signal attenuation may affect 4-20mA accuracy.

If the user wires the cables themselves, shielded multi-core cables of the same specifications should be used, and each pair of signals should have independent shielding or overall shielding with interference lines.

Installation and wiring steps

6.1 Mechanical Installation

Confirm the position of the observation tube: The observation tube should point towards the stable area of the flame (usually the root of the flame), avoiding observing the furnace wall or cooling air swirl. The length and inner diameter of the observation tube should be selected according to the flame brightness to ensure that the scanner has sufficient field of view.

Welding or fixing installation flange: Weld the 60-2693-x flange to the end of the observation tube (or connect it through threads), ensuring that the flange surface is perpendicular to the axis of the observation tube.

Introduce cooling air: Connect the 3/8-inch pipeline to the cooling interface of the flange, install a manual ball valve and pressure gauge to adjust the flow rate.

Install scanner: Screw the scanner into the flange and manually tighten until the sealing gasket contacts. Do not use a wrench to apply excessive force.

Blowing: First, turn on the cooling air and blow the observation tube for at least 5 minutes before it can be put into operation.

6.2 Electrical Wiring

Taking an 8-core cable as an example, the typical wiring allocation is as follows (refer to the standard configuration, actual should be based on the product manual):

Core wire color/number signal description

Red+24V DC power supply positive pole

Black 0V/negative pole of common terminal power supply

White FR1 relay normally open flame relay 1 contact

Green FR1 relay public

Brown FR2 relay normally open flame relay 2 contacts

Blue FR2 relay public

Yellow fault relay normally open fault alarm

Orange Fault Relay Public

Shielding/disturbance wire grounding control cabinet side single end grounding

Attention: 4-20mA analog output requires additional core wires, which are included if using a 12 core cable. The analog output is of the current source type and can be directly connected to the analog input module of the PLC (load ≤ 500 Ω).

After the wiring is completed, use a multimeter to check for short circuits or short circuits to ground before powering on.

Detailed Explanation of Configuration and Programming

InSight II is locally configured through the VFD display screen and membrane keyboard on the front panel. It can also be remotely connected through the Fireye Explorer software (requiring a dedicated communication adapter).

7.1 Main Adjustable Parameters

Parameter group parameter range/options

Sensor selection flame relay 1 signal source UV/IR/UV+IR/UV or IR

The signal source of flame relay 2 is the same as above

Gain UV gain 0~100% (usually pre-set to 50)

IR gain 0~100%

Modulation frequency selection 1-21 (corresponding to different Hz)

Flame relay suction threshold 0~100% flame intensity

Release threshold 0-100% (usually below the suction value)

Suction delay 0-10 seconds

Release delay of 0-10 seconds

Analog output 4mA corresponds to intensity 0~100%

20mA corresponds to intensity 0~100%

File management, storage/retrieval of files 1-4

7.2 Auto Config function

For situations where the optimal parameters are uncertain, automatic configuration mode can be used. The scanner will automatically detect the modulation frequency and intensity of the flame, and recommend a set of parameters (gain, frequency, threshold). The operator can accept the recommended values or manually adjust them based on them. Automatic configuration will not overwrite existing relay delay settings.

7.3 Four Programmable Files

Marine boilers typically burn multiple fuels (light diesel, heavy oil, natural gas), and the flame characteristics of different fuels vary greatly. Users can store parameters for fuel mode in file 1, gas mode in file 2, and low load mode in file 3. File switching can be done through external dry contacts (requiring wiring) or manually selected from the keyboard. This greatly facilitates the optimization of flame detection for multi fuel boilers.

7.4 Analog output calibration

Two 4-20mA outputs correspond to the real-time flame intensity (percentage) of FR1 and FR2, respectively. Users can set intensity values corresponding to 4mA and 20mA. For example, if 4mA=0% flame and 20mA=100% flame, then linear output is required. It can also be set in reverse (4mA corresponds to 100%, 20mA corresponds to 0%) for certain special PLC logic.

On site debugging and troubleshooting

8.1 Debugging steps

Pre power on inspection: Confirm that the power supply voltage is correct, the cable connection is not short circuited, and the cooling air is turned on.

Power on: The VFD display screen should light up and show the software version and self-test information. The faulty relay may operate during self inspection and return to normal after a few seconds.

View real-time flame intensity: Go to the menu and select "Live Reading", while observing the raw intensity values of UV and IR (0~100%).

Auto Configuration: Start Auto Config, and the scanner will automatically analyze the current flame. After completion, check the recommended frequency and gain.

Manual optimization: If the automatic configuration effect is not ideal (such as large fluctuations in flame signals), manually adjust the gain to achieve a flame intensity of 70-90% at full load, while the background (without fire) intensity is below 10%. When selecting the modulation frequency, you can try observing the stability of intensity readings at different frequencies and choose the frequency that maximizes the signal.

Set relay threshold: The pull in threshold should be set to be higher than the maximum background intensity when there is no fire, with margin left; The release threshold should be lower than the suction value to prevent shaking. The usual suction threshold is set at 30-40%, and the release threshold is set at 15-20%.

Test flame failure response: Manually turn off the fuel or block the scanner's line of sight while the boiler is running, confirm that the flame relay disconnects after a release delay, and the 4-20mA output drops to the corresponding value of 0%.

Analog output verification: Measure the 4-20mA loop current with a multimeter and compare it with the intensity percentage displayed on the screen. If there is no match, you can perform analog output fine-tuning (by entering the service menu).

8.2 Common faults and troubleshooting

Possible causes and solutions for the fault phenomenon

The display screen does not light up. The 24V power supply is missing or the polarity is reversed. Check the power supply, fuse, and wiring terminals

Fault relay action internal self-test failure (sensor, memory, etc.) Record fault code, refer to manual; Try restarting or replacing the scanner

Low flame signal intensity, dirty observation window; Insufficient cooling air causes condensation on the lens; The gain setting is too low; Frequency mismatch cleaning observation window; Increase the cooling air flow rate; Increase gain; Reconfigure frequency automatically

When there is no fire, there is still flame signal (false alarm) and furnace wall radiation interference; Interference between adjacent burners; Improper frequency selection to switch to UV+IR logic and mode; Change the modulation frequency; Check if the observation tube is aligned with the furnace wall

When there is a fire, the relay does not engage and the threshold for engagement is set too high; Low gain reduces the suction threshold; Increase gain

The 4-20mA output remains unchanged or experiences abnormal circuit disconnection; PLC input module overload; Scan the analog output for damage and check the wiring; Measure circuit current; Attempt to restore factory settings

Communication failure (Explorer software) Communication cable error; Confirm the use of the correct adapter for baud rate mismatch; Check the COM port settings in the software

8.3 Maintenance and Calibration Cycle

Daily: Check the cooling air pressure/flow rate and observe the display screen for any fault codes.

Every 3 months: Remove the scanner and clean the observation window (using lens paper and specialized cleaning agent). Check if the sealing gasket is aging.

Every 6 months: Use a flame simulator or a known flame source to verify the pull in/release threshold of the flame relay. Calibrate 4-20mA output.

Every 12 months: Conduct comprehensive functional testing, including flame failure response time and fault relay action.

Long term shutdown: If the boiler is shut down for more than a month, the scanner should be removed, stored in its original packaging in a dry environment, and the opening of the observation tube should be blocked to prevent moisture from entering.

Alternative selection and compatibility recommendations

The InSight II Marine Scanner is an ideal upgrade and replacement solution for the Fireye 95UV, 95IR, or early InSight models still in use on older ships. Attention should be paid when replacing:

Mechanical adaptation: Old models may use different installation flanges. InSight II requires the use of a 60-2693-x flange, which may require on-site modification of the observation pipe threads.

Electrical interface: Old systems may use independent amplifiers (such as Fireye E110, E220, etc.). After replacing with InSight II, the amplifier and flame switch module can be removed, and the relay output of the scanner can be directly connected to the BMS. This greatly simplifies the wiring.

Cable: Old cables may have insufficient cores. Suggest replacing with a new Fireye 59-546 or 59-547 cable to ensure shielding and signal integrity.

Configuration migration: Record the flame frequency and gain settings of the old system, manually input them in the new scanner or use the automatic configuration function to re optimize.