Multi-Channel Monitor and Controller for Distribution Transformer Applications

The LumaSHIELD® is a multi-channel signal conditioner compatible with any of LumaSense’s GaAs-based fiber optic temperature sensors. At the heart of the LumaSHIELD® is the LumaSense Semiconductor Band Gap (SCBG) technology which performs measurements using the temperature-dependent bandgap shift of a Gallium Arsenide (GaAs) crystal.


Key Features

  • Up to 16 measurement channels
  • Total system accuracy (± 0.8 °C)
  • Internal reference to guarantee reliability
  • No drift, no calibration required
  • IEC 61850 compliant
  • Light source lasts the life of the transformer
  • Local and remote data acquisition
  • RS-232, RS-485 and Ethernet1 output with SCPI, Modbus, DNP3 protocols
  • Relays and analog output options available
  • LCD display with user-definable description for each optical channel
  • Use with LumaSense Gallium Arsenide (GaAs) Semiconductor Band Gap (SCBG) fiber optic temperature sensors


The LumaSHIELD®, designed for Smart Grid integration, is fitted with an internal reference that allows regular self-verification and correction of its fully traceable calibration. The internal reference provides long- term accuracy in the adverse conditions encountered in a distribution transformer environment, such as temperature variations, component aging, mechanical shocks and transformer vibrations.

The LumaSHIELD® is equipped with a simple LCD display. Communication options include IEC61850/Ethernet¹, DNP3/Ethernet¹, SCPI and Modbus over RS-232 or RS-485 interface. SPDT-type relays and analog outputs (one per optical channel) are optionally available. A PLC controller is also available to offer extended control capabilities through a wide range of input/outputs.

The LumaSHIELD® has a channel sampling rate of 50 Hz. It is used with standard 62.5/125 micron optical fiber temperature sensors (The LumaSense OTG-T /OTG-TC2 sensors). It also has the ability to read Neoptix, Fiso and Nortech fiber optics. A version is available for 200/230 micron optical fiber sensor models, as well.

¹Ethernet for IEC61850 or DNP3 communication

Typical Applications

  • Distribution Transformers and Small Power Transformers
  • Smart Grid Temperature Monitoring
  • EMI, RFI and Microwave Environments
  • Nuclear and Hazardous Environments
  • Multi-point long-term monitoring


The Best-in-Class GaAs-Based Solution for Winding Hot Spots

The Best-in-Class GaAs-Based Solution for Winding Hot Spots


Technical Data



Number of Channels

3 up to 16

Temperature Range -40 to +230°C (other ranges available upon request)
Accuracy ± 0.8°C (Total system accuracy at typical transformer temperatures including signal conditioner and sensor errors)

Response Time

0.5 s Typical

Measurement Resolution 0.1ºC
Light Source Life Span Life of the transformer
EMI/RFI Susceptibility Complete immunity
Display LCD screen display standard
Probe Signal Strength Readout User-definable description for each optical channel
Calibration Fully Traceable
Environmental Specifications
Operating Temperature -40 to +75 °C
Operating Humidity 0 to 100% non condensing
Analog Output

4-20 mA or 0-1 mA

Serial Output RS-232 and RS-485 standard, Ethernet optional


6 C-Form SPDT relays, 5 A @ 250 VAC or 30 VDC, 6 relay status indicators


SCPI and Modbus standard, DNP3 and IEC61850 optional

Probes OTG-T, OTG-T+ and OTG-A fiber optic sensors

T° Data Storage

> 2,000,000 temperature measurement points

Input Power 12 to 24 VDC
Surge Protection 3000V (1EEE C37.90.1-2002)
Consumption 2.5 W typical

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