Infrared Sensor – Raytek Marathon MR Series


  • One or two-color operation
  • High speed digital signal processor supports smart operation
  • Bi-directional RS-485 communications (networkable)
  • Supports up to 32 Marathon Series sensors in a single multidrop network
  • Programmable relay output (temperature setpoint or “fail safe”)
  • Standard and close-focus versions available
  • Variable-focus optics and built-in interface and display simplify installation
  • Through-the-lens sighting
  • Simultaneous analog and digital output with user-defined alarms
  • Compact, rugged design, IP65 NEMA-4 rated
  • Fast response time down to 10 mSec
  • Provides simultaneous analog and digital outputs
  • Two-way digital communications
  • Superior optical resolution to 130:1
  • Field calibration and sensor diagnostics software included

The Marathon MR infrared sensor measures targets impossible to view with traditional noncontact sensors in harsh, high temperature applications. This ratio IR sensor is designed for targets obstructed by smoke, steam, particulates, or smaller than the instrument’s field of view.

The MR operates in ambient temperatures up to 315°C (600°F) with ThermoJacket enclosure. It supports up to 32 Marathon Series sensors in a single multidrop network. The included Raytek DataTemp Multidrop software enables easy and consistent installation, as well as, configuration and data capture across the following applications:

  • 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


Environmental Rating IP65 (IEC529) / NEMA-4
Ambient Temperature

without cooling

0 to 50°C (32 to 122°F)

with air cooling

0 to 120°C (32 to 250°F)

with water cooling

0 to 175°C (32 to 350°F)

with ThermoJacket

0 to 315°C (32 to 600°F)
Storage Temperature -20 to 70°C (68 to 158°F)
Relative Humidity 10 to 95%, non-condensing
Shock IEC 68-2-27
Vibration IEC 68-2-6
Optical head 480 g (17 oz)
with air/water cooled housing 800 g (28 oz)
Outputs 0/4-20 mA, max. load: 500 W
RS485 full duplex, networkable
Relay, 48 V, 300 mA, response time < 2 ms
Power Supply 24 VDC ± 20%, 500 mA



Raytek Marathon MR Series Infrared Sensor-DpstarGroup