Infrared Temperature Sensor – Raytek Marathon MM Series


  • Broad temperature range from -40 to 3000°C (-40 to 5432°F)
  • Superior optical resolution to 300:1
  • Spot sizes down to 0.6 mm
  • Fast response times down to 1 ms
  • Easy adjustment with variable focus optics
  • Through-the-lens sighting, optional with laser aiming or video function
  • Video monitoring and image capture capability
  • Compact, rugged housings with IP65 (NEMA-4) rating
  • Smart, two-way digital communications (RS232/485)
  • Programmable relay output
  • Simultaneous analogue and digital outputs
  • Dirty lens alarm

The new Marathon MM Series platform, which covers a temperature range of minus 40 to 3000°C (minus 40 to 5432°F), consists of six IR temperature sensor models, each with a specific measurement wavelength and temperature range appropriate for either low- (minus 40 to 800°C / minus 40 to 1472°F), medium- (250 to 1100°C / 482 to 2012°F), or high-temperature (300 to 3000°C / 572 to 3273°F) production monitoring.

The Marathon MM now features Precision Variable Focus that allows fast, easy and accurate adjustment of the focus of measurement targets, either by push-button at the rear of the instrument or remotely via an RS232/RS485 PC connection, where adjustments can be seen real-time through video. Sensors with variable focus option can be configured according to each application requirements reducing the installation time and chance for incorrect installation.

All sensors feature identical installation hardware and include Raytek DataTemp Multidrop software to enable easy and consistent installation, configuration and data capture across the full breadth of an application:

  • steel and metals processing (foundry/forging operations & heat treating)
  • glass bending, forming, tempering, annealing, and sealing
  • paper processing (ink drying/curing & lamination)
  • plastics processing and thermoforming; and semiconductor processing


Model Temperature Range Spectral Response Response Time (95% response)
LT -40°C to 800°C 8 – 14 µm 120 ms
(-40°F to 1472°F)
G7 300°C – 900°C 7.9 µm 120 ms
(572°F to 1652°F)
G5L 250°C to 1650°C 5 µm 60 ms
(482°F to 3002°F)
G5H 450°C to 2250°C 5 µm 60 ms
(842°F to 4082°F)
MT 250°C to 1100°C 3.9 µm 120 ms
(482°F to 2012°F)
3M 100°C to 600°C 2.3 µm 20 ms
(212°F to 1112°F)
2ML 300°C to 1100°C 1.6 µm 2 ms
(572°F to 2012°F)
2MH 450°C to 2250°C 1.6 µm 2 ms
(842°F to 4082°F)
1ML 450°C to 1740°C 1 µm 2 ms
(842°F to 2732°F
1MH 650°C to 3000°C 1 µm 2 ms
(1202°F to 5432°F)


Raytek Marathon MM Series Infrared Temperature Sensor-DpstarGroup