SMC INR-244-755 Replacement/Upgrade Solution for EX Series

Product Overview

SMC INR-244-755 Replacement/Upgrade Solution for EX Series: Seamless Transition from Legacy Fieldbus Systems

The SMC INR-244-755 is a dedicated power supply unit engineered for the SMC EX Series fieldbus manifold platform, providing stable 24 VDC regulated power to distributed I/O valve manifold assemblies operating under DeviceNet, CC-Link, PROFIBUS-DP, and EtherNet/IP communication architectures. As legacy automation infrastructure ages and OEM support windows close, facilities running older SMC EX120, EX250, or EX500 series manifold systems increasingly face the challenge of sourcing reliable replacement power supply modules without triggering a full system redesign. The INR-244-755 addresses this challenge directly — it is a form-fit-function replacement that preserves existing wiring harnesses, DIN rail mounting footprints, and fieldbus node addressing, allowing maintenance teams to restore system availability with minimal downtime.

In a typical retrofit scenario, a plant engineer managing a pneumatic valve island network discovers that the incumbent power supply — often an earlier SMC INR-244-xxx variant or a third-party 24 VDC rail supply — has degraded due to capacitor aging, voltage ripple, or thermal cycling stress. Rather than replacing the entire EX Series manifold assembly, which would require re-engineering the valve sequencing logic in the host PLC (commonly a Mitsubishi MELSEC Q Series, Siemens S7-300, or Omron CJ2M), the INR-244-755 can be swapped in directly. The module’s output voltage tolerance and current capacity are matched to the EX Series manifold’s internal bus requirements, ensuring that connected solenoid valve drivers, I/O sub-plates, and communication gateway modules such as the SMC EX600 or EX250-SDN1 continue to operate within specification.

Wiring compatibility is a primary concern during any power supply replacement. The INR-244-755 uses the same connector pinout and cable entry orientation as its predecessors in the INR-244 family, meaning that existing 24 VDC supply cables, PE ground conductors, and functional earth connections can be re-terminated without modification. This is particularly valuable in installations where cable lengths have been cut to exact routing dimensions inside compact control cabinets, where re-cabling would require partial disassembly of adjacent terminal blocks, relay modules, or circuit breakers. Maintenance personnel can complete the physical swap in under 30 minutes using standard tools, with no requirement to re-route conduit or modify cable trays.

From a communication protocol standpoint, the INR-244-755 is transparent to the fieldbus layer — it supplies power to the manifold’s internal logic and solenoid circuits independently of the fieldbus communication module. This means that whether the EX Series manifold is integrated into a DeviceNet segment managed by an Allen-Bradley ControlLogix gateway, a PROFIBUS-DP network supervised by a Siemens ET 200S IM151 interface module, or a CC-Link network coordinated by a Mitsubishi QJ61BT11N master module, the power supply replacement does not require any changes to network topology, node addressing, baud rate settings, or GSD/EDS configuration files. The host PLC program continues to execute valve control logic without modification.

Physical installation space is another critical factor in control cabinet retrofits. The INR-244-755 maintains the same DIN rail mounting width and depth profile as the original SMC EX Series power supply, ensuring that adjacent components — including SMC SI unit communication modules, manifold end plates, and blanking plates — remain in their existing positions. In high-density cabinet layouts where every millimeter of rail space is allocated, this dimensional compatibility eliminates the need for cabinet re-layout or the fabrication of custom mounting brackets. The module’s ventilation clearance requirements are also unchanged, preserving existing thermal management arrangements.

For facilities operating mixed-generation SMC manifold systems — for example, combining EX250 manifolds on older DeviceNet segments with EX600 manifolds on newer EtherNet/IP segments — the INR-244-755 can serve as a standardized power supply replacement across both generations, simplifying spare parts inventory management. Stocking a single power supply model rather than multiple variants reduces procurement complexity and ensures that maintenance teams can respond to unplanned failures without waiting for custom-sourced components.

TOPNLMS maintains verified stock of the SMC INR-244-755 with same-day dispatch capability from Xiamen, China. Each unit undergoes pre-shipment functional verification including output voltage accuracy, load regulation, and ripple measurement. All units are supplied with a 12-month warranty covering manufacturing defects and functional failures under normal operating conditions. Replacement support is available throughout the warranty period, with direct technical communication via email and phone to assist with installation verification and commissioning questions.

Compatibility Comparison Table

Seamless Upgrade Solutions

A complete EX Series manifold modernization typically involves more than the power supply alone. When upgrading from a legacy DeviceNet-based EX250 manifold system to a current EtherNet/IP architecture, the SMC EX600-DEN3 SI unit (EtherNet/IP communication module) is the natural companion to the INR-244-755, replacing the older EX250-SDN1 DeviceNet gateway while retaining the existing valve manifold body and solenoid sub-plates. For installations where the manifold I/O sub-plate — such as the SMC EX9-AE4 or EX9-AE8 — has reached end-of-life alongside the power supply, both components can be replaced simultaneously without disturbing the pneumatic tubing or valve body assembly.

In control cabinets where the INR-244-755 replacement is part of a broader electrical upgrade, engineers frequently address the 24 VDC bus infrastructure at the same time. Phoenix Contact or Weidmüller DIN rail terminal blocks adjacent to the manifold power supply are often re-terminated during the swap, and a PULS or Meanwell 24 VDC DIN rail power supply feeding the manifold circuit may be upgraded to a higher-efficiency unit to reduce heat load in the cabinet. Signal isolators — such as Phoenix Contact MINI MCR signal conditioners — are sometimes added between the PLC analog output cards and the manifold’s pressure feedback sensors during the same maintenance window, improving signal integrity on long cable runs.

For sites migrating from older Mitsubishi MELSEC A Series or Q Series PLC platforms to the current iQ-R Series, the INR-244-755 replacement can be coordinated with the installation of a Mitsubishi RJ71DN91 DeviceNet master module or RJ71EIP91 EtherNet/IP module, allowing the manifold network to be re-homed to the new PLC rack without changes to the manifold wiring. Similarly, facilities upgrading Siemens S7-300 systems to S7-1500 can retain the existing PROFIBUS-DP manifold segment by adding a Siemens ET 200SP IM155-6 DP interface module, with the INR-244-755 continuing to power the manifold assembly throughout the transition.

Retrofit Guidance FAQ

Q: Does replacing the INR-244-755 require changes to the PLC program?
A: No. The INR-244-755 is a power supply module only. It does not affect fieldbus communication, I/O mapping, or valve control logic. The host PLC program continues to execute without modification after the swap.

Q: Is the wiring connector compatible with the original INR-244 series?
A: Yes. The INR-244-755 uses the same connector pinout and cable entry orientation as other INR-244 family variants. Existing 24 VDC supply cables can be re-terminated directly without modification or adapter cables.

Q: Will the INR-244-755 fit in the same DIN rail position as the original power supply?
A: Yes. The module maintains the same DIN rail mounting footprint and depth profile as the original EX Series power supply, so no cabinet re-layout or custom mounting hardware is required.

Q: Which fieldbus protocols are supported?
A: The INR-244-755 is protocol-transparent at the power layer. It is compatible with EX Series manifolds operating on DeviceNet, PROFIBUS-DP, CC-Link, and EtherNet/IP communication architectures. No changes to network configuration, node addressing, or GSD/EDS files are required.

Q: What if the manifold’s SI unit communication module also needs replacement?
A: The INR-244-755 can be replaced independently of the SI unit. If the communication module also requires replacement, both can be swapped during the same maintenance window. TOPNLMS can advise on compatible SI unit models for your specific manifold configuration.

Q: How long does physical installation take?
A: A direct swap of the INR-244-755 can typically be completed in under 30 minutes by a qualified maintenance technician using standard tools, without re-routing cables or modifying adjacent components.

Warranty Assurance

Every SMC INR-244-755 unit supplied by TOPNLMS is covered by a 12-month warranty from the date of shipment. Pre-shipment testing includes output voltage accuracy verification, load regulation measurement, and ripple assessment to confirm that each unit meets SMC’s original performance specification before dispatch. Units that do not pass functional verification are quarantined and not shipped.

In the event of a warranty claim, TOPNLMS provides direct replacement support with priority processing for customers experiencing production downtime. Our technical team is available via email and phone to assist with installation verification, commissioning questions, and compatibility confirmation for your specific manifold configuration. Warranty claims are handled directly — no third-party RMA routing — ensuring fast response and clear communication throughout the resolution process.

Same-day dispatch is available for in-stock units ordered before the daily cut-off time, with shipment from Xiamen, China via DHL Express, FedEx International Priority, or customer-nominated freight forwarder. Export documentation including commercial invoice, packing list, and certificate of origin is prepared with each shipment to support customs clearance in destination countries.