KEYENCE FS-V34P PNP Fiber Amplifier with 33 μs Fast Response and Dual Digital Display for FUJI NXT II A10398

The KEYENCE FS-V34P is a high-speed digital fiber amplifier designed as a cable-type PNP expansion unit within the FS-V30 sensor series. It is commonly cross-referenced under FUJI part number A10398 for selected FUJI NXT II conveyor or track sensing positions. The unit combines two PNP control outputs, one external input, a red 640 nm four-element LED light source, and selectable response speeds ranging from 33 μs to 16 ms.

Its dual digital monitor displays both preset and current light-intensity values, helping maintenance personnel identify unstable detection, contamination, fiber misalignment, or insufficient sensing margin. Multiple detection and timer functions allow the amplifier to be configured for different production conditions, component colors, PCB surfaces, conveyor speeds, and machine control requirements.

The FS-V34P is an expansion unit rather than a standalone main amplifier. Therefore, buyers should confirm the existing main unit, PNP electrical architecture, wiring arrangement, fiber head, installation position, and machine configuration before ordering.

FUJI A10398 is commonly listed in the SMT spare-parts market as a KEYENCE FS-V34P fiber amplifier used in FUJI NXT II track or conveyor sensing applications. Exact installation positions may vary according to machine generation, module configuration, conveyor specification, and previous maintenance modifications. Buyers should verify the old amplifier label and wiring before replacement.

Modern SMT placement equipment depends on stable conveyor and position-detection signals. When the fiber amplifier, fiber head, wiring, or mounting position becomes unstable, the machine may receive an incorrect board-presence or transfer-position signal.

The amplifier should not be replaced only because a machine displays a sensor alarm. The complete detection circuit should first be inspected to determine whether the problem comes from the amplifier itself or another component.

1. The digital display is damaged, incomplete, or unreadable.
2. The control output cannot switch even when the received light value changes normally.
3. Threshold settings cannot be stored or adjusted correctly.
4. The unit has suffered electrical damage, contamination, overheating, or physical impact.
5. The cable or housing is damaged beyond practical repair.
6. The machine repeatedly reports the same sensor error after the fiber head and wiring have been checked.
7. The existing unit has an incorrect output type or was replaced previously with a mismatched model.
8. The production line requires restoration using the original FS-V34P and FUJI A10398 cross-reference.

The KEYENCE FS-V34P provides a compact digital platform for receiving and processing the optical signal supplied through a compatible fiber unit. It converts changes in received light intensity into PNP control signals that can be read by the machine control system.

Its digital display and adjustable functions support both replacement maintenance and detailed sensing optimization.

The amplifier offers six selectable response modes:

A faster setting is not always the best setting. HIGH SPEED mode supports rapid detection, but slower modes may offer better sensing stability when the target produces a weak or inconsistent optical signal.

The dual digital monitor displays the preset value and current received-light value at the same time. This helps technicians compare the actual signal with the switching threshold without repeatedly changing display pages.

The visual difference between the two values provides useful information about:

• Available sensing margin.
• Fiber alignment.
• Optical contamination.
• Target reflectivity.
• Threshold suitability.
• Signal fluctuation.
• Maintenance requirements.

The FS-V34P has two control outputs. Depending on the machine circuit and amplifier configuration, the outputs may support separate detection conditions, alarm logic, window evaluation, or related machine functions.

The total output load and wiring arrangement must remain within the specified electrical limits. The two outputs should not be treated as independent high-current power outputs.

One external input is provided. Its exact function depends on the selected amplifier settings and machine circuit. It may be used for supported remote functions such as teaching, preset control, or other configured operations.

Before connecting an external signal, confirm the wiring diagram and existing machine configuration.

The amplifier supports standard light-intensity evaluation and additional detection functions. These features help adapt the sensor to different targets and inspection requirements.

Available detection-related functions include:

• Light-intensity detection.
• Area detection.
• Automatic sensitivity tracking.
• Limited light-intensity detection.
• Count checking.
• Abnormality detection.

Not every function is required for a FUJI conveyor application. The replacement unit should normally be configured according to the settings recorded from the removed amplifier.

The timer can help stabilize control signals or adapt short optical events to the PLC input requirements.

The timer duration can be selected from 0.1 ms to 9,999 ms.

The FS-V34P has a narrow housing measuring approximately 30.3 mm high, 9.8 mm wide, and 71.8 mm deep. Its expansion-unit design allows multiple amplifiers to be grouped with a compatible main unit, reducing control-panel space and simplifying multi-point sensing systems.

The following specifications are based on the manufacturer’s published FS-V34P technical data. Electrical loads, grouped installation temperature, wiring, fiber compatibility, and control configuration should be checked before installation.

When multiple units are installed together, heat accumulation must be considered.

For grouped installation, use the appropriate mounting arrangement and keep output current within the manufacturer’s specified limits.

The FS-V34P is designed for industrial fiber-optic sensing systems where limited installation space, fast response, remote fiber-head positioning, or detailed digital adjustment is required.

For FUJI equipment, A10398 is commonly associated with an NXT II track or conveyor fiber-amplifier position. The exact sensing task depends on the machine configuration and connected fiber unit.

The FS-V34P can also be used in compatible PNP fiber-sensor systems for:

• Small-part presence detection.
• Edge detection.
• Label detection.
• Product counting.
• Component passage monitoring.
• Position confirmation.
• Hole or slot detection.
• Packaging equipment.
• Assembly machines.
• Automated inspection stations.
• Electronics production equipment.
• Semiconductor-related handling equipment.
• Compact robotic work cells.
• Material transfer systems.
• High-speed production lines.

Actual sensing distance, spot size, target suitability, and optical performance are determined mainly by the connected fiber unit and target condition, not by the amplifier alone.

The amplifier supplies a red LED light source with a wavelength of approximately 640 nm. The light is transmitted through the connected fiber-optic cable toward the sensing point.

Depending on the fiber-head design, the target either interrupts the transmitted beam or reflects light back toward the receiving fiber.

Common arrangements include:

• Through-beam sensing.
• Reflective sensing.
• Coaxial reflective sensing.
• Small-spot sensing.
• Side-view sensing.
• Area sensing.

The received light returns to the amplifier through the fiber unit. The amplifier converts the optical intensity into a digital value.

The current light value is shown on the red display, while the selected threshold or preset value is shown on the green display.

The amplifier continuously compares the received-light value with the configured threshold or detection condition.

When the selected condition is satisfied, the amplifier changes its output state.

The FS-V34P uses PNP open-collector outputs. When activated, the output supplies a sourcing-type signal to a compatible machine input circuit.

The machine controller then uses this signal to perform the programmed operation, such as:

• Starting or stopping the conveyor.
• Confirming PCB arrival.
• Confirming PCB departure.
• Enabling the next transfer step.
• Generating a sensor alarm.
• Preventing unsafe mechanical movement.
• Checking a production sequence.

Response-mode and timer settings can be adjusted to balance speed and stability.

For example:

• HIGH SPEED mode may be selected for a rapidly moving board edge.
• FINE or TURBO mode may improve stability during standard conveyor detection.
• ULTRA TURBO or MEGA TURBO may improve sensitivity where received light is weak.
• ON-delay can ignore extremely short unwanted signals.
• OFF-delay can maintain output long enough for the control system to register it.

The digital value, gain bar, hold function, and threshold display help maintenance staff evaluate whether the sensor has a sufficient operating margin.

A stable sensor should normally show a clear difference between the detected and undetected conditions. When the two values become too close, cleaning, alignment, threshold adjustment, or fiber replacement may be required.

Before removing the old amplifier, check:

• Manufacturer label: KEYENCE.
• Model number: FS-V34P.
• FUJI reference: A10398, where applicable.
• Output type: PNP.
• Unit type: Expansion unit.
• Cable configuration.
• Connected main amplifier.
• Fiber-head model.
• Current threshold values.
• Response mode.
• LIGHT-ON or DARK-ON setting.
• Timer settings.
• Output wiring.

Take clear photographs of:

• Front display.
• Wiring.
• Unit arrangement.
• Fiber connection.
• DIP switches or buttons.
• Parameter values.
• Amplifier position.
• Main-unit model.

Recording the original configuration reduces installation time and prevents accidental parameter differences.

Switch off and isolate electrical power according to the machine maintenance procedure.

Do not install or remove the amplifier while the circuit is energized.

Check the fiber head and cable for:

• Cracks.
• Tight bends.
• Broken sections.
• Dirty optical surfaces.
• Loose mounting.
• Incorrect alignment.
• Excessive tension.
• Contamination by oil, dust, flux, or adhesive.

Replacing the amplifier will not solve a problem caused by a damaged fiber unit.

Mount the FS-V34P in the same orientation and expansion-unit position as the original unit. Confirm secure mechanical engagement and correct electrical connection with the associated main unit.

Enter or teach the recorded threshold, output logic, response mode, and timer values.

Do not assume that the factory-default settings are correct for the machine.

Move a representative PCB or target into and out of the sensing position. Confirm:

• Stable current-value change.
• Correct output indication.
• Correct LIGHT-ON or DARK-ON operation.
• Adequate sensing margin.
• No unexpected signal fluctuation.

Run the conveyor at normal production speed and observe multiple transfer cycles.

Check for:

• Missed boards.
• Double triggering.
• Delayed signals.
• False alarms.
• Intermittent output.
• Unstable received-light values.

Only return the equipment to production after repeated successful transfer cycles and confirmation that safety and interlock functions operate correctly.

Selecting the correct fiber amplifier requires more than matching the physical appearance. FS-V30 series models can differ in output architecture, unit role, cable type, connector arrangement, number of outputs, and input functions.

PNP and NPN outputs use different current-flow arrangements. A PNP amplifier normally supplies current to the machine input when the output is active, while an NPN amplifier normally sinks current.

Installing an NPN model in a circuit designed for PNP operation may result in:

• No PLC input signal.
• Permanently active signal.
• Incorrect voltage level.
• Wiring damage.
• Machine alarm.
• Unreliable detection.

Always match the output type shown on the removed unit.

The FS-V34P is an expansion unit. It is designed to operate as part of an amplifier group connected to a compatible main unit.

Before purchasing, confirm:

• A compatible main unit is already installed.
• The maximum number of expansion units is not exceeded.
• The two-output unit counting rule is considered.
• The grouped operating temperature is acceptable.
• The main unit and expansion contacts are clean and undamaged.

The FS-V34P is a cable-type model. A connector-type amplifier may have similar sensing functions but cannot necessarily be installed using the existing machine harness.

Compare:

• Cable exit direction.
• Wire colors.
• Cable length.
• Connector type.
• Terminal arrangement.
• Control-panel space.
• Mounting orientation.

The amplifier processes the optical signal, while the connected fiber unit determines much of the physical sensing performance.

The fiber head influences:

• Sensing distance.
• Spot diameter.
• Target size.
• Installation angle.
• Reflection characteristics.
• Heat resistance.
• Chemical resistance.
• Bending radius.
• Through-beam or reflective operation.

For replacement maintenance, retaining the correct existing fiber model is normally safer than selecting a new fiber head without machine testing.

Using both KEYENCE FS-V34P and FUJI A10398 in the inquiry helps suppliers identify the correct component more accurately.

A complete inquiry containing the label photograph, machine model, quantity, and destination reduces repeated confirmation messages.

The dual digital display allows maintenance staff to compare actual and preset values during setup and troubleshooting.

Multiple response and timer settings allow the sensing system to be adjusted according to conveyor speed, PCB surface, detection margin, and process stability.

The narrow amplifier housing makes the unit practical as a maintenance spare for factories operating multiple FUJI NXT II production modules.

For an accurate quotation, please provide the following information:

Product: KEYENCE FS-V34P Fiber Amplifier
FUJI Reference: A10398
Machine: FUJI NXT II
Quantity: ___ Pieces
Required Condition: ___
Delivery Country: ___
Old Unit Photo: Attached
Fiber Model: ___
Required Delivery Date: ___

Q1: Is KEYENCE FS-V34P the same reference as FUJI A10398?

A: A10398 is commonly used in the SMT spare-parts market as a FUJI reference for the KEYENCE FS-V34P amplifier installed in selected NXT II track or conveyor sensing positions. Because equipment configurations may differ, confirm the FS-V34P label, PNP output, wiring, main unit, and installation photograph before ordering.

Q2: Can the FS-V34P operate without another amplifier?

A: FS-V34P is an expansion unit, not a standalone main unit. It normally requires connection to a compatible FS-V30 series main amplifier. Confirm the existing amplifier group, available expansion capacity, unit arrangement, and power configuration before replacement.

Q3: What is the fastest response time of the FS-V34P?

A: The fastest selectable response is 33 μs in HIGH SPEED mode. Additional modes include 250 μs, 500 μs, 1 ms, 4 ms, and 16 ms. Select the mode according to target speed, optical signal strength, sensing margin, and required production stability.

Q4: Can an NPN amplifier replace the FS-V34P?

A: An NPN model should not be treated as a direct electrical replacement for the PNP FS-V34P. PNP and NPN outputs operate differently and may not match the FUJI control input. Always verify the old unit label, machine wiring diagram, and PLC input architecture.

Q5: What should be checked when the machine still reports an alarm after replacement?

A: Inspect the fiber head, optical surface, fiber cable, mounting alignment, amplifier threshold, LIGHT-ON/DARK-ON setting, response mode, timer, wiring, main-unit connection, output load, and machine PLC input. A sensor alarm is not always caused by the amplifier.

Contact SMT PARTS SUPPLY LTD. for availability, quotation, lead time, replacement confirmation, and international shipping information for the KEYENCE FS-V34P fiber amplifier and FUJI A10398 cross-reference.

To receive a faster and more accurate quotation, please send:

• KEYENCE model number.
• FUJI part number.
• FUJI machine model.
• Required quantity.
• Front and side photographs.
• Wiring photograph.
• Fiber-head model.
• Required product condition.
• Delivery country.
• Required delivery date.

Our sales team will review the identification details before quotation to reduce the risk of receiving an incorrect PNP/NPN model, main-unit variant, connector variant, or incompatible expansion amplifier.

KEYENCE and FS-V30 are trademarks or product references of their respective owner. FUJI, NXT, and associated part numbers are trademarks or product references of their respective owner. These names are used only for product identification and compatibility reference. This listing does not imply authorization, sponsorship, or affiliation unless specifically confirmed in the commercial quotation.