Oldham MX 32 Analog and Digital Gas Detection Controller

Overview

The Oldham MX 32 is a compact, low-profile gas detection controller from Teledyne Gas and Flame Detection. It continuously monitors gas detectors connected by 4-20 mA signals, Wheatstone bridge catalytic heads, dry logic inputs or RS485 Modbus digital lines from compatible detectors. Teledyne describes the controller as analog and digital, able to supervise up to eight detectors, fully scalable through add-on modules, and offering SIL1 reliability. In practice, the Oldham MX 32 suits small and medium installations such as plant rooms, boiler houses, car parks, laboratories, pump stations, gas turbine enclosures and skid packages.

Seven Star LLC supplies the Oldham MX 32 controller, its modules and compatible Oldham detectors to industrial, utility and building services customers in Oman and the GCC. We help configure the channels, alarm thresholds and relay logic, and we provide model selection support from Muscat.

Key Features of the Oldham MX 32

• Analog and digital inputs: two measurement lines, each configurable as an analog channel or a digital RS485 line.
• Up to eight detectors: spread over two digital lines for lower cabling cost.
• 4 in. backlit graphic LCD: shows the measured value, an eight-hour average, bar graph with thresholds and detector status; up to eight detectors can be displayed at the same time.
• Grayscale alarm display: the screen switches to grayscale in alarm so the detector concerned is identified immediately.
• Five programmable events per detector: A1, A2, A3, over-scale and under-scale, plus a fault.
• Relays: four fully programmable on-board alarm relays and one fault relay, with up to 16 more relays through external modules.
• Integrated beacon and horn options: red or blue strobe with audible alarm can be ordered with the controller.
• Data logging: stores up to 512 alarm events, 512 fault events and 512 system events by default.

Inputs and Expansion Modules

Each analog channel accepts a 0-23 mA signal (4-20 mA reserved for measurement) or a Wheatstone bridge catalytic detector such as the OLC 10, OLC 10 Twin or OLC 100, with a 120 ohm load resistance and two or three core shielded cable. Each digital line uses RS485 communication with Teledyne’s proprietary protocol at 9600 baud over two twisted shielded pairs, connecting digital detectors such as the OLCT 10N and OLCT 80. Expansion modules add a programmable 4 or 8-relay module that can be placed close to fans or valves, an 8-analog-input module that brings standard 4-20 mA gas or flame detectors onto a digital line, a 16-logic-input module for fire alarms, emergency stops or limit switches, and a 4-analog-output module that repeats detector values, minimum, maximum or average for a recorder, PLC or building management system.

Detectors commonly used with the Oldham MX 32 include explosion-proof 4-20 mA transmitters such as the Oldham OLCT 100 and Oldham OLCT 710. For larger systems with more channels, Teledyne offers the Oldham MX 62 controller.

Relay Logic and Configuration

Oldham MX 32 relays can be programmed on instantaneous or averaged values, rising or falling alarms, with manual or automatic acknowledgement. With the optional COM 32 configuration software, relay logic can combine alarms using OR, AND, NOR, NAND and voting functions, with multiple timers and advanced management of audible alarms including acknowledgement, reactivation and evacuation. Catalytic bead over-range protection is provided per channel. The on-board relays are DPCO dry contacts rated 5 A at 250 VAC or 30 VDC, and the controller provides a Modbus RTU RS485 output for supervision systems and up to eight 4-20 mA analog outputs through modules.

Calibration Support

The Oldham MX 32 displays a calibration curve with cursors for span setting, the measured value and the calibration gas value, enabling a simplified non-intrusive, one-person calibration procedure for connected detectors. This reduces the time needed for routine maintenance of a multi-point system.

Power and Environment

The Oldham MX 32 is powered from 100-240 VAC at 50-60 Hz (35 W) or 22-28 VDC (92 W), with 250 mA maximum consumption without modules or detectors. Maximum current output per line is 0.42 A at 50°C to 1 A at 30°C with internal AC power, or 1.5 A with external DC power. The wall-mounted enclosure is IP55, measures 265 x 266 x 96 mm and has five M16 and two M20 cable glands. Operating and storage temperature are −20 to +50°C with 5 to 95 percent relative humidity. Because the controller is not explosion-proof, it is installed in a safe area such as a control room, guard house or electrical room.

Approvals and Functional Safety

Teledyne lists EMC to EN 50270, low voltage directive to EN 61010-1, metrological performance to EN 60079-29-1 and EN 50271, CSA approval to CAN/CSA-C22.2 No. 0-10 and 61010-1-12 and UL 61010-1, and SIL1 capability according to EN 50271 with an MTBF of 25 to 28 years and SFF of 60 percent.

Typical System Designs (General Guidance)

The following examples are general application ideas rather than manufacturer data. In a basement car park, an Oldham MX 32 can supervise CO and NO2 detectors on a digital line, with one relay starting extract fans at the first alarm and another relay driving warning signs at the second alarm. In a boiler room, a single catalytic methane detector on an analog channel can trip the gas shut-off valve through a relay and send the reading to the building management system through a 4-20 mA output module. On a small chemical dosing skid, two toxic gas detectors and an emergency stop input can be combined with voting logic so the Oldham MX 32 isolates the process only when the condition is confirmed.

Oldham MX 32 Ordering Code

The ordering code MX32-A-B-C-D-E-F selects version (1 channel, 2 channels or Wheatstone bridge), power supply (24 VDC or 100/240 VAC), menu language, strobe and audible alarm (none, red or blue), RS485 output and COM 32 software. Teledyne’s example MX32-1-2-2-2-1-1 is a one-channel unit with 100/240 VAC supply, English menu, blue strobe and horn, RS485 output and COM 32 software.

Technical Specifications

How to Order

To order the Oldham MX 32, send Seven Star LLC the number and type of detectors, the gases, the required relay actions and the power supply. Our Muscat team will propose the controller configuration and any modules, and prepare a formal quotation. The brochure and user manual can be downloaded from this page, and we provide model selection support from Muscat across Oman and the GCC.