What is the difference between the MX4-R2 and MX5-R2 expansion modules?

The MX4-R2 is a temperature-focused expansion module, adding up to 18 J/K-type thermocouple inputs and up to 9 three-wire 100-ohm Pt RTD inputs, along with one magnetic pickup input. It is designed for applications requiring extensive temperature monitoring such as multi-stage gas compressors with multiple cylinder temperature points. The MX5-R2 is an analog and digital I/O expansion module, adding 10 analog inputs (0–24 mA or 0–5 VDC), 6 FET digital outputs, 4 analog outputs (4–20 mA), and one magnetic pickup input. It suits applications that need extra pressure, flow, or level transmitter inputs and additional analog control outputs.

How are the MX Series modules configured?

Configuration is performed through the PC-based Centurion Configuration Software, which runs on a Windows computer and connects to the C5 system via USB or serial port. All I/O points on the MX Series modules are software-selectable — no physical jumpers are required to change channel assignments, input types, or output modes. The software provides point-and-click configuration of all I/O, alarm setpoints, shutdown thresholds, and control loop parameters. No programming experience is needed to commission the system using the provided configuration templates.

What communication protocols do the Centurion C5 MX Series modules support?

Communication is handled through the C5 main I/O module, which the expansion modules connect to directly. The C5 supports Modbus RTU via two RS232 ports and two RS485 ports, Modbus TCP/IP and EtherNet/IP (CIP) via two Ethernet 10/100 ports with Device Level Ring (DLR) support, J1939 via CAN for electronic engine ECU integration, and optional Wi-Fi on the C5-1 variant. This extensive communications capability allows the C5 and MX module system to interface with HMIs, PLCs, PCs, SCADA systems, and radio/satellite communications equipment.

What temperature range do the MX Series expansion modules support?

Both the MX4-R2 and MX5-R2 modules are rated for an operating temperature range of -40°F to +185°F (-40°C to +85°C). This wide range supports installation in outdoor industrial enclosures across arctic, temperate, and hot-climate environments without the need for additional heating or cooling provisions in most standard applications. Power input for both modules is 10–30 VDC, consistent with the C5 main module and typical industrial DC power supplies.

Centurion C5 MX Series expansion I/O modules MX4-R2 and MX5-R2 for compressor and pump control systems in hazardous area industrial installations

MX Series I/O Modules

MX4-R2 & MX5-R2 | Expansion I/O | Centurion C5

Compressor Control · Expansion I/O · Hazardous Area Certified

Centurion C5 MX Series I/O Modules – MX4-R2 & MX5-R2 Expansion I/O for Industrial Control Systems

The Centurion C5 MX Series I/O Modules — comprising the MX4-R2 and MX5-R2 — are plug-in expansion modules designed to extend the signal capacity of the Centurion C5 configurable controller. The MX4-R2 adds thermocouple and RTD temperature monitoring capability for multi-point temperature measurement, while the MX5-R2 expands analog and digital I/O for broader process monitoring and control. Both modules are software-configured, require no hardware jumpers, and are certified for Class 1 Division 2 and ATEX/IECEx Zone 2 hazardous environments — making them the go-to solution for reciprocating and screw compressors, pump packages, and complex multi-stage industrial applications where the base C5 module I/O count needs to be increased.

18 T/C Inputs (MX4-R2)

10 Analog Inputs (MX5-R2)

-40°C to +85°C

Cl.1 Div 2 Haz. Area Rated

Key Features

The Centurion C5 MX Series expansion I/O modules are engineered to grow with the demands of your control application. When a gas compressor, pump system, or industrial process requires more thermocouple inputs, additional analog measurement channels, or extra digital switching capacity than the C5 main module provides on its own, the MX4-R2 and MX5-R2 slot directly into the system without special cables or complex wiring changes. Configured entirely through the Windows-based Centurion Configuration Software — with no jumper settings required — these modules bring certified hazardous area I/O expansion to three-to-four-stage compressor packages, engine-driven pump systems, and multi-loop process control panels. With an operating range of -40°C to +85°C, 10–30 VDC power supply compatibility, and internationally recognized ATEX and IECEx Zone 2 approvals, the MX Series modules deliver proven reliability in even the most challenging field environments.

Seamless Plug-In Expansion for the Centurion C5 System: The MX4-R2 and MX5-R2 modules connect directly to the Centurion C5 main I/O module, extending its I/O count without requiring special interface cables or additional hardware. The system automatically synchronizes with the connected expansion modules, recognizing their channel types and integrating all signals into the unified Centurion configuration environment. This plug-and-play architecture makes it straightforward to add capacity when compressor stages are added or when process monitoring requirements increase over the life of the installation.
MX4-R2: Extensive Thermocouple and RTD Temperature Input Capacity: The MX4-R2 adds up to 18 J-type or K-type thermocouple input channels, with up to 9 channels reconfigurable for three-wire 100Ω Platinum RTD measurements. Each temperature input includes automatic open-circuit, short-to-DC+, and short-to-DC− wire fault detection, as well as cold junction compensation for thermocouple accuracy. This level of temperature monitoring capacity is essential for multi-stage gas compressors where cylinder discharge temperatures, intercooler outlet temperatures, and aftercooler temperatures must all be tracked simultaneously for process safety and efficiency management.
MX5-R2: Versatile Analog and Digital I/O Expansion: The MX5-R2 adds 10 analog input channels accepting 0–24 mA or 0–5 VDC signals at 15-bit resolution, 4 analog outputs at 4–20 mA with 16-bit resolution for control valve or variable speed drive signals, and 6 FET digital outputs for switching loads. A magnetic pickup / AC run signal input is also included. This makes the MX5-R2 ideal for applications requiring additional pressure transmitter inputs, flow meter signals, level sensor inputs, or proportional analog control outputs beyond what the main C5 module provides.
Software-Selectable I/O — No Jumpers Required: All input and output channels on both expansion modules are individually configured through the PC-based Centurion Configuration Software. There are no physical jumpers to set for input type selection, voltage range, or output mode — every parameter is defined entirely in software. This eliminates wiring errors caused by jumper misplacement during installation or maintenance, and makes it possible to reconfigure a channel remotely or in the field without opening the module enclosure, significantly reducing commissioning and troubleshooting time.
Comprehensive Hazardous Area Certifications: Both the MX4-R2 and MX5-R2 carry third-party certifications for installation in areas classified for flammable gases and vapors. Approvals include Class 1, Division 2, Groups A, B, C, and D for North American applications, Class I Zone 2 per NEC/CEC, ATEX Zone 2 (DEMKO, II 3G Ex ec [ic] IIC T4 Gc) for European installations, and IECEx Zone 2 for global projects. All digital inputs, analog inputs, and temperature inputs are intrinsically safe and non-incendive, allowing connection to field devices in hazardous zones without additional barriers in most configurations.
Wide Operating Temperature Range for Harsh Environments: Both expansion modules are rated for continuous operation from -40°F to +185°F (-40°C to +85°C), making them suitable for outdoor industrial panel installations across arctic, desert, and tropical climates. Combined with a 10–30 VDC wide-range power input and robust industrial terminal block connectivity, the MX Series modules are built to maintain reliable signal accuracy and switching integrity under the vibration, temperature cycling, and electrical noise conditions typical of engine rooms, compressor packages, and outdoor process skids.
Magnetic Pickup Input for Speed and Run Signal Monitoring: Each MX Series module includes one magnetic pickup input capable of accepting AC run signals in the range of 4.5 VAC to 120 VAC at frequencies from 30 Hz to 10 kHz. This input supports speed sensing from engine flywheels, compressor crankshafts, and pump shafts, enabling the Centurion C5 system to monitor rotational speed for over-speed and under-speed protection on the expanded system — directly from the expansion module without consuming the main C5 module's magnetic pickup channel.

Applications

Multi-Stage Reciprocating and Screw Gas Compressors: Multi-stage gas compression packages generate large volumes of temperature and pressure data from cylinder discharge points, interstage coolers, and aftercoolers that must be continuously monitored. The MX4-R2 expansion module provides the additional thermocouple and RTD channels required to cover all temperature measurement points on three-to-four-stage compressors, while the MX5-R2 supplies the extra pressure transmitter inputs needed to monitor every stage — enabling the C5 controller to enforce stage-by-stage alarm and shutdown protection from a single integrated control system.
Engine and Electric Motor-Driven Pump Systems: Pump packages driven by natural gas engines or electric motors often require temperature monitoring of bearings, mechanical seals, and process fluid alongside analog measurement of suction and discharge pressures and flow rates. The MX4-R2 handles the bearing and seal temperature points via RTD inputs, while the MX5-R2 accommodates additional 4–20 mA transmitter signals for pressure and flow — giving the Centurion C5 system complete visibility of the pump package without the need for a secondary controller.
Oil and Gas Production and Processing Facilities: Surface production equipment such as gas lift compressors, wellhead boosters, and gas gathering systems operates in classified hazardous areas and requires robust, certified I/O expansion to handle the sensor-dense nature of the process. The MX Series modules' ATEX Zone 2 and Class 1 Div 2 certifications make them directly installable in classified area control panels, simplifying the system architecture and avoiding the cost and complexity of adding separate certified transmitters or barriers for each additional measurement point.
CNG and LNG Compression Stations: Compressed and liquefied natural gas stations demand high-density temperature and pressure monitoring across multiple compressor units and compression stages. The MX4-R2's thermocouple and RTD capacity supports the temperature-intensive requirements of CNG and LNG processes, while the MX5-R2's analog inputs and outputs support pressure control valves and variable speed drives — enabling the Centurion C5 to function as the central control and monitoring platform for the entire station from a compact, integrated hardware set.
Industrial Process Control Panels Requiring Expanded I/O: In general industrial applications — including chemical processing, power generation auxiliaries, water injection systems, and HVAC for critical facilities — the C5 with MX Series expansion covers process monitoring needs that exceed the built-in I/O of the base module. System integrators can use the MX5-R2 to add analog measurement and control channels without redesigning the panel around a different controller platform, protecting the existing C5 investment while scaling the system to meet new process requirements.
Remote and Unmanned Field Installations with SCADA Integration: Where compressor stations and pump systems operate remotely with minimal staffing, the Centurion C5 with MX Series expansion modules connects to SCADA systems via Modbus RTU, Modbus TCP/IP, or EtherNet/IP. All additional sensor signals handled by the expansion modules are available on the same communication bus as the main C5 module, providing the remote control room with a unified data feed from every I/O point across the system — simplifying SCADA integration and reducing communication infrastructure costs at unmanned sites.

Technical Specifications

Specifications are listed below for the Centurion C5 Main I/O Module, MX4-R2 Expansion I/O Module, and MX5-R2 Expansion I/O Module for engineering reference and procurement purposes.

Parameter	C5 Main I/O Module	MX4-R2 Expansion	MX5-R2 Expansion
Operating Temperature	-40° to +185°F (-40° to +85°C)	-40° to +185°F (-40° to +85°C)	-40° to +185°F (-40° to +85°C)
Power Input	30 W max, 10–30 VDC	14.1 W max, 10–30 VDC	16.5 W max, 10–30 VDC
Configuration Method	PC-based Centurion Configuration Software	PC-based Centurion Configuration Software	PC-based Centurion Configuration Software
Analog Inputs	12 × (0–24 mA or 0–5 VDC, 15-bit); 4 configurable for potentiometer	—	10 × (0–24 mA or 0–5 VDC, 15-bit hardware)
Digital Inputs	32 × NO or NC, optically isolated with LED indicators; intrinsically safe; wire fault detection	—	—
Temperature Inputs	8 × J/K thermocouple or 3-wire 100Ω Pt RTD; cold junction compensation; wire fault detection	18 × J/K thermocouple (up to 9 convertible to 3-wire 100Ω Pt RTD); cold junction compensation; wire fault detection	—
Digital Outputs	10 total: 4 relay (Form C, dry contacts), 4 FET (source), 2 FET (sink); LED indicators	—	6 × FET (sink)
Analog Outputs	4 × 4–20 mA, 16-bit hardware	—	4 × 4–20 mA, 16-bit hardware
Magnetic Pickup / AC Run Signal	1 × 30 Hz–10 kHz, 4.5 VAC rms min, 120 VAC rms max	1 × 4.5 VAC–120 VAC, 30 Hz–10 kHz	1 × 4.5 VAC–120 VAC, 30 Hz–10 kHz
Communication Ports	2 × RS232 Modbus RTU; 2 × RS485 Modbus RTU; 1 × USB Host Type A; 1 × USB Server Type B; 2 × CAN (proprietary + J1939); 2 × Ethernet 10/100 DLR (Modbus TCP/IP, EtherNet/IP CIP); 1 × Wi-Fi (C5-1 only)	Via C5 main module	Via C5 main module
Real-Time Clock	Battery backed; ~10 years unpowered service life	—	—
I/O Selection	All I/O software selectable; no jumpers required	All I/O software selectable; no jumpers required	All I/O software selectable; no jumpers required
Hazardous Area Rating (North America)	Class 1, Div 2, Groups A, B, C, D; Class I Zone 2	Class 1, Div 2, Groups A, B, C, D; Class I Zone 2	Class 1, Div 2, Groups A, B, C, D; Class I Zone 2
ATEX Certification	Zone 2, II 3G Ex ec [ic] nC IIC T4 Gc; DEMKO 18 ATEX 1926X	Zone 2, II 3G Ex ec [ic] IIC T4 Gc; DEMKO 18 ATEX 1926X	Zone 2, II 3G Ex ec [ic] IIC T4 Gc; DEMKO 18 ATEX 1926X
IECEx Certification	Zone 2, Ex ec [ic] nC IIC T4 Gc X; IECEx UL 18.0072X	Zone 2, Ex ec [ic] IIC T4 Gc X; IECEx UL 18.0072X	Zone 2, Ex ec [ic] IIC T4 Gc X; IECEx UL 18.0072X
Input Safety Classification	All digital/analog inputs intrinsically safe and non-incendive	All temperature inputs intrinsically safe and non-incendive	All analog inputs intrinsically safe and non-incendive

Technical FAQ

Common Questions Answered

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The MX4-R2 and MX5-R2 are expansion I/O modules that plug into the Centurion C5 configurable controller to increase its signal handling capacity. The MX4-R2 adds thermocouple and RTD temperature inputs for multi-point temperature monitoring on compressors, engines, and pump systems. The MX5-R2 adds analog inputs, analog outputs, digital outputs, and a magnetic pickup input for applications requiring additional analog and digital I/O beyond the C5 main module's built-in capacity. Both modules are widely used on three-to-four-stage compressor packages and complex pump systems where the base C5 module channel count is insufficient for all required measurement and control points.

The MX4-R2 is a temperature-focused expansion module, adding up to 18 J/K-type thermocouple inputs and up to 9 three-wire 100Ω Pt RTD inputs, along with one magnetic pickup input. It is the right choice for applications requiring extensive temperature monitoring such as multi-stage gas compressors with numerous cylinder and cooler temperature points. The MX5-R2 is an analog and digital I/O expansion module, adding 10 analog inputs (0–24 mA or 0–5 VDC), 6 FET digital outputs, 4 analog outputs (4–20 mA), and one magnetic pickup input — suited to applications needing extra pressure transmitter inputs, flow signals, or additional proportional control outputs.

Yes. Both the MX4-R2 and MX5-R2 carry third-party hazardous area certifications covering Class 1, Division 2, Groups A, B, C, D for North America; Class I Zone 2; ATEX Zone 2 for Europe and international projects; and IECEx Zone 2 for global installations. All digital inputs, analog inputs, and temperature inputs are classified as intrinsically safe and non-incendive, making the modules suitable for installation in control panels serving natural gas compressor stations, offshore production platforms, refineries, and similar classified locations.

Configuration is carried out through the PC-based Centurion Configuration Software, which connects to the C5 system via USB or a serial port. All I/O channels on both MX modules are software-selectable — no physical jumpers are needed to define input types, signal ranges, or output modes. The software provides a graphical point-and-click interface for setting alarm thresholds, shutdown setpoints, control loop parameters, and display options. Configuration templates for common applications are included, and no programming experience is required to commission the system.

All communications are handled through the C5 main I/O module, which the MX expansion modules integrate with directly. The C5 supports Modbus RTU via two RS232 ports and two RS485 ports, Modbus TCP/IP and EtherNet/IP (CIP) via two 10/100 Ethernet ports with Device Level Ring (DLR) support, J1939 via a dedicated CAN port for electronic engine ECU communication, and optional Wi-Fi on the C5-1 variant. All expansion module I/O points are accessible on this unified communication interface, simplifying SCADA and HMI integration for the complete system.

Both the MX4-R2 and MX5-R2 are rated for continuous operation across -40°F to +185°F (-40°C to +85°C). This wide operating range supports installation in outdoor industrial enclosures across arctic, temperate, and high-ambient-temperature environments without requiring supplemental heating or cooling in most standard applications. Both modules accept 10–30 VDC power input, consistent with the C5 main module and most industrial DC power supply standards.