Mitsubishi FX0N-8ER PLC Extension Module – FX0N Series

Mitsubishi FX0N-8ER: 8-Point Relay Output Extension Module for Discrete Control Loops

The FX0N-8ER is a dedicated relay output expansion unit engineered for the Mitsubishi Electric FX0N compact PLC family. Within a control architecture, this module occupies the output stage of the discrete I/O loop — receiving execution commands from the CPU base unit via the FX0N backplane bus and driving field-side loads through eight independent relay contacts. Its mechanical relay topology makes it the preferred output interface wherever load-side voltage isolation, mixed AC/DC load compatibility, or high-inrush switching is a hard requirement. The module draws 1.5 W from the base unit’s 5 VDC internal bus, adds no external power supply dependency, and mounts directly to the right side of any FX0N base unit using the standard DIN-rail slide-lock mechanism.

In conveyor sorting systems, the FX0N-8ER drives solenoid valves, motor contactors, and indicator lamps from a single module footprint. In packaging machinery, its 2 A per-point rating handles the inrush of pneumatic valve coils without requiring interposing relays. In HVAC and building automation panels, the AC 240 V switching capability eliminates the step-down transformer that would otherwise be mandatory with transistor output modules. Each of these scenarios exploits the same core characteristic: galvanic isolation between the PLC logic domain and the field power domain, enforced by the relay coil-contact barrier.

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Technical Parameters

Hardware Logical Analysis

The FX0N-8ER interfaces with the FX0N base unit through a proprietary parallel extension bus operating at 5 VDC logic levels. The base unit CPU allocates output addresses Y0 through Y7 to this module during the I/O assignment phase of the scan cycle. When the CPU sets an output coil in the program, the corresponding bit is latched in the output image register and transferred to the module’s output latch circuit at the end of each scan. The relay driver IC then energizes the relay coil, closing the contact within the specified ≤10 ms response window.

EMC Design: The relay contact output architecture provides inherent galvanic isolation — the field-side circuit is physically disconnected from the logic-side circuit when the relay is open. This eliminates conducted noise paths from inductive loads (motor contactors, solenoids) back into the CPU logic supply. The module’s PCB layout routes the relay coil drive lines away from the logic bus traces, and each relay coil incorporates a flyback suppression diode to clamp the inductive kick at coil de-energization. The result is a measured common-mode noise rejection that meets IEC 61000-4-4 (EFT/Burst) Level 3 requirements without additional external filtering.

Output Grouping and Common Architecture: The eight relay outputs are organized into two groups of four, each group sharing a common terminal (COM1 for Y0–Y3, COM2 for Y4–Y7). This dual-common architecture allows the two groups to switch loads at different voltages simultaneously — for example, COM1 connected to AC 220 V for contactor coils while COM2 is connected to DC 24 V for solenoid valves. No cross-group interference is possible because the relay contacts are fully isolated from each other and from the logic domain.

Backplane Bus Load: At 1.5 W internal consumption, the FX0N-8ER imposes a 300 mA load on the base unit’s 5 VDC bus. System designers must verify that the cumulative bus load of all connected extension modules does not exceed the base unit’s rated extension bus current capacity (typically 300 mA for FX0N-14MR, up to 600 mA for FX0N-60MR). Exceeding this budget causes undefined CPU behavior and must be avoided during panel design.

Contact Protection: For inductive AC loads, Mitsubishi recommends installing a CR snubber circuit (typically 0.1 µF + 100 Ω in series) across the load terminals to suppress contact arc and extend electrical endurance beyond the rated 100,000 operations. For DC inductive loads, a freewheeling diode across the load coil is the standard practice. These measures are external to the module but are documented in the FX0N hardware manual and should be incorporated into panel wiring design.

System Integration Benefits

• Deterministic Output Latency: The relay switching response of ≤10 ms is consistent across the full operating temperature range, allowing control engineers to calculate worst-case output latency as a fixed value rather than a temperature-dependent variable.
• Mixed Voltage Load Compatibility: The dual-common group architecture permits simultaneous switching of AC and DC loads at different voltage levels from a single module, reducing panel wiring complexity and eliminating the need for separate output modules per voltage domain.
• Zero External Power Dependency: The module draws all operating power from the base unit’s internal 5 VDC bus. No external 24 VDC supply is required for module operation, simplifying the panel power distribution design and reducing potential single points of failure.
• Transparent Diagnostic Visibility: Each relay output state is reflected in the CPU’s output image register and is directly readable via GX Developer or GX Works2 monitoring. Engineers can verify field-side switching status from the programming terminal without physical access to the panel.
• Scalable I/O Expansion: The FX0N series supports up to 128 total I/O points through cascaded extension modules. The FX0N-8ER can be combined with FX0N-8EX (input) and FX0N-8EYT (transistor output) modules on the same base unit to build a mixed I/O configuration matched precisely to the application’s signal types.
• High Inrush Tolerance: The 2 A rated contact current accommodates the inrush current of small motor contactors and solenoid valves without requiring interposing relays, reducing BOM cost and panel footprint.
• Broad Environmental Compliance: Rated operation from 0 °C to +55 °C with vibration resistance to 9.8 m/s² (57–150 Hz) qualifies the module for installation in machine-mounted control panels subject to mechanical vibration from spindles, conveyors, and press machinery.
• Standardized Wiring Interface: The module uses the same removable screw terminal block format as all FX0N base units, allowing maintenance technicians to replace the module without rewiring field cables — the terminal block transfers intact to the replacement unit.
• CE and UL Dual Certification: Simultaneous CE marking and UL/cUL listing allows the same panel design to be deployed in both European and North American markets without hardware modification, reducing the cost of multi-market machine certification.

Quality Assurance & Global Logistics

Every FX0N-8ER unit supplied by siemensplc.com is sourced directly from Mitsubishi Electric’s authorized distribution network. Each unit ships in original Mitsubishi Electric factory packaging with intact holographic authenticity labels and full traceability documentation. Prior to dispatch, units undergo incoming inspection covering contact resistance measurement, coil energization verification at rated voltage, and visual inspection of PCB and terminal block condition. Units that do not meet Mitsubishi Electric’s published acceptance criteria are quarantined and returned to the supply chain.

Our warehouse is located in Xiamen, China — a major international logistics hub with direct access to Xiamen Gaoqi International Airport and Xiamen Port. Standard export shipments are dispatched within 1–3 business days of order confirmation. Typical transit times are 3–5 business days to Southeast Asia, 5–7 business days to Europe and the Middle East, and 7–10 business days to North and South America via DHL Express, FedEx International Priority, or UPS Worldwide Expedited, depending on destination and customer preference. All shipments include commercial invoice, packing list, and certificate of origin documentation suitable for customs clearance. Export classification and HS code documentation are provided upon request.

A 12-month warranty from the date of shipment covers manufacturing defects and premature component failure under normal operating conditions as defined in the FX0N hardware manual. Warranty claims are processed with a target response time of 48 hours. Replacement units are dispatched before the defective unit is returned, subject to credit authorization, to minimize customer downtime.

Contact Information

Email: [email protected]
WhatsApp: +86 18359268345
Web: siemensplc.com
Location: Xiamen, China
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