F3XC08-0C Yokogawa 8-Point No-Voltage Input Module

F3XC08-0C | Yokogawa No-Voltage Contact Input Module

The Yokogawa F3XC08-0C is an 8-point no-voltage contact input module designed to acquire discrete contact states in compatible FA-M3 PLC systems. It accepts dry-contact signals and uses transformer isolation to separate the input interface from the internal circuitry.

Each input supports configurable sampling periods, while separate commons allow individual input circuits to be wired according to the system design. These features make the module suitable for monitoring relay contacts, mechanical switches, and other compatible potential-free contacts in industrial control panels.

01 | At a Glance: Contact Input Specifications

• Manufacturer: Yokogawa
• Model: F3XC08-0C
• Series: FA-M3
• Product type: No-voltage contact input module
• Input channels: 8
• Input method: No-voltage contact
• Isolation method: Transformer isolation
• Contact rating: 5 V DC, 20 mA maximum
• ON resistance: 200 Ω maximum
• OFF resistance: 100 kΩ minimum
• Maximum simultaneous ON ratio: 100%
• External connection: 18-point terminal block with M3.5 screws
• Common arrangement: Separate commons
• Interrupt setting: Configurable for each input point
• Current consumption: 75 mA
• Weight: 170 g

02 | Contact-State Recognition and Response Timing

The module determines the input state based on the electrical condition of the connected contact. The specified contact ratings and resistance thresholds should be checked when selecting field devices or investigating an unreliable signal.

• ON condition: Contact resistance of 200 Ω maximum.
• OFF condition: Contact resistance of 100 kΩ minimum.
• OFF-to-ON sampling options: Always (0 μs), 62.5 μs, 250 μs, 1 ms, and 16 ms.
• ON-to-OFF sampling options: Always (0 μs), 62.5 μs, 250 μs, 1 ms, and 16 ms.
• Response-time reference: Sampling period plus a maximum of 1 ms.

Sampling time affects how quickly contact transitions are recognized. A short setting may be appropriate when fast state changes matter, while a longer setting can help suppress brief transitions caused by contact bounce or electrical interference. The actual response also depends on the configured sampling period and the controller's processing behavior.

03 | Wiring Design: Eight Inputs, Separate Commons

The F3XC08-0C uses an 18-point terminal block with M3.5 screw terminals. Its separate-common arrangement gives engineers flexibility when wiring individual contact circuits, subject to the module's terminal assignment and system design.

Before commissioning, verify the terminal numbering against the applicable Yokogawa manual. Confirm that the connected devices provide no-voltage contacts rather than externally driven voltage signals. Applying an external voltage to an input intended for a dry contact may produce incorrect operation or damage the interface.

For relay contacts and mechanical switches, check contact resistance, wiring continuity, terminal tightness, and the condition of the field cable. Use the specified contact rating as the reference when evaluating whether a field device is suitable.

04 | Where This Module Is Used

Relay status acquisition: Reads compatible relay contact states used for equipment status and control interlocks.

Mechanical switch monitoring: Monitors limit switches, selector switches, and other potential-free contacts where the electrical interface meets the module's specifications.

Control-panel feedback: Collects discrete contact information from auxiliary contacts and panel-mounted devices in compatible PLC installations.

Machine sequence monitoring: Provides contact-state inputs for sequence conditions, equipment-position feedback, and event detection.

Maintenance and retrofit projects: Can be considered when replacing an existing compatible module or restoring contact-input acquisition in an FA-M3 system.

Confirm the PLC base unit, CPU, module-slot compatibility, terminal assignment, and software configuration before installation. The same input count alone does not establish system compatibility.

05 | Troubleshooting by Symptom

Input remains OFF when the contact closes: Check the contact circuit for continuity and measure the contact resistance. Confirm that the resistance is within the specified ON limit of 200 Ω maximum. Inspect loose terminals, damaged wiring, and incorrect terminal assignments.

Input remains ON when the contact opens: Check for unintended bridging, wiring shorts, contamination, or a contact that has not fully opened. Verify that the open-circuit resistance meets the specified OFF condition of at least 100 kΩ.

Input status changes repeatedly: Inspect the mechanical contact for bounce or wear and check the field cable for electrical interference. If appropriate, test a longer sampling period and compare the input behavior before and after the change.

Only one channel fails: Check the connected contact, individual wiring path, and terminal tightness before suspecting the module. Where permitted by the system procedure, compare the signal path with a known-good channel using the correct terminal mapping.

Several channels behave abnormally: Inspect shared installation conditions, terminal wiring, and the module's seating in the PLC system. Although the module uses separate commons, a common installation or wiring issue can still affect multiple circuits.

Interrupt events are missing or delayed: Verify the interrupt setting for the relevant input and review the selected sampling period. Check the controller program and interrupt-handling configuration as well; the module setting alone does not determine total application response time.

06 | Operating Environment and Handling

• Operating temperature: 0 to 55°C.
• Storage temperature: -20 to 75°C.
• Operating humidity: 10–90% RH, non-condensing.
• Storage humidity: 10–90% RH, non-condensing.
• Atmosphere: Free of corrosive gases, flammable gases, and heavy dust.

Install the module within the specified environmental limits. Before handling or replacing it, follow the applicable FA-M3 system instructions for power isolation, electrostatic precautions, and module insertion. Ensure the terminal block is secure and the field wiring matches the documented pinout.

07 | Global PLC Spare HUB Review

The F3XC08-0C is designed for contact-state acquisition rather than direct measurement of an externally supplied voltage. This distinction is important when replacing a module in an existing control panel. A voltage-input module and a no-voltage contact input module may have similar discrete-channel functions, but their electrical interfaces are not interchangeable by default.

For a reliable replacement, compare the complete model code, input type, contact resistance limits, terminal arrangement, and common configuration. When diagnosing a fault, measure the field contact before changing PLC parameters. This helps determine whether the problem originates in the switch, cable, terminal connection, sampling configuration, or input hardware.

08 | Warranty, Shipping and Quotation

• Warranty: 12-month warranty, subject to the seller's written warranty terms.
• Shipping carriers: FedEx, UPS, and DHL, subject to destination and service availability.
• Dispatch target: 24–48 hours where stock availability and order processing permit. Confirm the actual dispatch schedule when requesting a quotation.
• Quotation support: Provide the model number, required quantity, target PLC configuration, and destination to help verify availability and shipping options.

Contact Global PLC Spare HUB for pricing, availability, and compatibility checks for the Yokogawa F3XC08-0C No-Voltage Contact Input Module.

09 | Frequently Asked Questions

Q1: Can I connect a sensor that outputs 24 V DC directly to this module?

Do not assume it is suitable. The F3XC08-0C is specified for no-voltage contacts, not as a general 24 V DC voltage-input module. Check the sensor's output type and use an appropriate interface if required by the system design.

Q2: How should I evaluate a contact that works intermittently?

Measure its closed-state resistance and verify that it meets the 200 Ω maximum specification. Inspect for worn contacts, oxidation, loose terminals, and unstable mechanical operation. Also confirm that the selected sampling period matches the expected signal behavior.

Q3: What is the benefit of separate commons when planning the input wiring?

Separate commons allow the contact circuits to be arranged according to the module's terminal design instead of assuming that all inputs share one common connection. Follow the official terminal diagram to plan each circuit and avoid incorrect cross-connections.

Q4: Does selecting the 0 μs sampling option mean the complete PLC response is instantaneous?

No. The specification lists an “Always (0 μs)” sampling option, but it also states that response time is the sampling period plus a maximum of 1 ms. Controller scan time, program execution, and interrupt handling can add further delay to the overall application response.

Q5: What should I send a supplier when sourcing a replacement for an older installation?

Provide the complete F3XC08-0C model code, the FA-M3 system configuration, the intended contact-device type, and the required quantity. If possible, include a clear photo of the existing module label and terminal arrangement so the part number and wiring requirements can be checked before ordering.

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