Oldham MX 43 Fixed Gas Detection Controller

Fully scalable and designed to functional safety performance level 1 standards, the Oldham MX 43 is an analogue and digital controller that continuously measures and controls gases in the atmosphere.

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  • Overview
  • Features
  • Specifications
  • Applications
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SIL-1 Certified Oldham MX 43 is a Flexible, High Quality, Easy to Use Gas Detection System

The Oldham MX 43 fixed gas detector manages both digital lines and analogue channels, and covers all needs for a wide variety of gas monitoring applications. The Oldham MX 43 fixed gas detection controller allows up to 32 detectors to be distributed on 8 lines for increased cost savings.

The Oldham MX 43 features improved storage capacity by adding an USB module. The USB option provides the user the following benefits:

  • continuous data logging on the USB key at a user defined sampling rate from 2 seconds to 15 minutes,
  • recording in real-time of all events (alarms, faults, alarm resets, calibration etc.)
  • automatic backup of the configuration • automatic backup of the firmware
  • loading a configuration or a firmware file from the USB stick in order to restore or update the system easily.

The 4GB USB drive fitted with the USB kit, provides a recording capacity of more than 2 years (18 months in the worst case for a controller equipped with 32 detectors), a 2 second sampling rate (32 measurements every 2 seconds), and 100 events per day per gas detector (3200 events per day).

The MX 43 is now available with a programming CD that is compatible with any MX 43 controllers already in use. The COM 43 is a simple application that gives user access to the advanced features of the MX 43 controller and makes programming fast and easy to do on one's own. Users save precious time by configuring the controller's parameters on their computer and transferring these parameters directly to the MX 43 using a USB cable. Programming is quick and easy: the COM 43 application can be installed on a computer from a CD and gives access to all of the controller's options:

  • Configuration of measurement channels
  • Simplified relay programming
  • Up to 5 on-board functions: OR, AND, NOR, NAND, VOTING
  • Advanced management of audible alarms with timer options (holding time, automatic acknowledgment, reactivation, evacuation)

COM 43 is equipped with useful features that make programming your MX43 gas detector easy, quick, and secure:

  • Graphic display for easy relay programming
  • Architecture displayed progressively as the programming process is completed
  • Access to an Oldham gas monitor library pre-programmed according to industry standards
  • Highly practical "copy-paste" function saves time by preventing programming errors from one sensor to the next
  • "Verification/validation" feature to ensure correct programming and to flag any programming errors before validating
  • Transfer settings to the controller in just a few seconds The CD also contains the French and English user manuals for the COM 43 and the MX 43 controller.
  • Analogue and digital controller
  • 4 or 8 lines, up to 32 detectors
  • Up to 32 fully programmable relays (OR, AND, NAND, NOR, Voting functions)
  • Large graphic display
  • Remote modules (cost savings on wiring installation)
  • USB Data logging capability
  • RS485 Modbus RTU and multiple analog outputs
  • SIL-1 Certified to IEC/EN 61508 and EN 50402 functional safety standards
Oldham MX 43 Gas Detection Control Panel Specifications
Dimensions (wall-mounted version):
370 x 299 x 109 mm (14.6 x 11.8 x 4.3 inches)
Dimensions (rack): 19", 4U ; 482.8 x 177 x 192.5 mm (19.1 x 7 x 7.6 inches)
Ingress Protection: IP55 (wall-mounted), IP31 (rack)
Cable entries (wall-mounted version):
12 M16 cable glands, 4 to 8 mm2 (8 to 11 AWG) outer diameter cable
 6 M20 cable glands, 6 to 12 mm2 (7 to 9 AWG) outer diameter cable
LCD back-lit display + smart keys
 Display in video inverse in case of fault
 Customizable by user (display 1 to 16 channels simultaneously, fixed or scrolling, on events...)
 Bar graph with alarm threshold
Visual Indicators: 
7 LEDs per line, 1 LED fault indicator
5 smart keys, 1 audible alarm accept/reset button
Oldham MX 43 Gas Detection Control Panel Specifications
Operating Temperature: -20°C to +50°C
Storage Temperature:  -20°C to +50°C
Humidity:  5 to 95% RH
Power:  100-240 Vac 50-60 Hz or 21-28 Vdc, 112 W max
Battery:  Embedded back up power supply in option (0.6 Ah)
Consumption:  500 mA min (without module)
Oldham MX 43 Measurement Lines
Digital Lines: 
8 maximum
RS-485 communication, proprietary protocol, 9600 Baud
2 twisted shielded-pair cable
Analogue Channels:
8 maximum
0-23 mA analog signal input (4 to 20 mA reserved for measurement) 120 Ohm load resistance
2 or 3-core shielded cable
Voltage (typical): 21 to 28Vdc
Maximum current output per line: 1.2 A (1.5 A intermittently)
Maximum current output in total: 2.4 A permanent (3.2 A intermittently)
Oldham MX 43 Alarms
Per Channel: 
5 alarm levels (A1, A2, A3, Overscale, Underscale) + Fault
Non-ambiguity reading option for combustible gases monitoring
Programmable Threshold:  On instantaneous ou averaged values, rising or falling alarms, manual or automatic acknowledgement
On-board Relays: 
5 fully programmable alarm relays
1 fault relay (non-configurable)
Dry contact relay
DPCO relays with contact rating of 250 Vca 2 A (inductive)
Digital Outputs:  RS-485 Modbus RTU serial link
Oldham MX 43 Approvals
EMC:  According to EN50270
ATEX:  EN50271 and metrological performances according to EN60079-29-1
Low Voltage Directive:  According to EN61010
Functional Safety (reliability data): 
SIL1 capability according to EN50271:2010
λdu =2,29.10-6, PFDavg=1,03.10-2, Ti=1 year, MTBF=20 years, SFF 60% (data for 4 channel version, 24 Vdc powered)
MED:  According to Marine Equipment Directive 96/98/EC. Fulfills the EMC requirements for installation in General Power Distribution Zone and/or Deck Zone.


  • Mining
  • Marine
  • Confined Space
  • Fire/Hazmat
  • Utilities
  • Refineries