SD range

MTL Instruments design and manufacture a wide range of protection solutions for all of your system surge protection requirements. They offer a wealth of over 50 years experience in the surge protection industry. Their surge products embodies the strengths of Telematic, a name synonymous with the water industry, and Atlantic Scientific, which has strong ties in the network, ITS and wireless infrastructure markets.

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The MTL SD range is a series of surge protection devices combining unparalleled packing densities, application versatility, proven reliable hybrid circuitry, simple installation and optional ‘loop disconnect’ facilities – features which make the range the ultimate surge protection solution for process equipment, I/O systems and communications networks. The exceptionally high packing densities are the consequence of an ultra slim ‘footprint’ for individual modules which can thus ‘double-up’  as feedback terminals. Each module provides full hybrid surge protection for 2 and 3 wire loop protection.

SDX units, available in 7V, 16V, 32V and 55V versions (SD07X, SD16X, SD32X and SD55X respectively) are suitable for a wide range of applications including THCs, 4-20mA loops, shut-down systems and fire and gas detectors.

In addition to the many beneficial features offered by SDX devices, the SD variants fuse/disconnect package provides both fused protection against fault currents and a convenient method of isolating field circuitry from protected circuitry without needing additional disconnect terminals. Also provided is a third connection on the field and safe side of the protector in order to terminate screens safely to earth.

The MTL SDR range has been specially designed to meet the requirements for high speed data links with an extremely high bandwidth. SDR units are available in a range of voltage variants enabling a wide range of communication systems to be protected e.g. RS232, RS422, RS485, Bus powered systems etc. These devices are classed as simple apparatus and can therefore be used in hazardous areas without affecting the certification of the circuit.

This range of SD surge protectors offer excellent levels of protection over all three wires in conjunction with minimal footprint requirements. This is the most compact 3-wire surge protector on the market.

  • SD32T3 is a three terminal SPD for 3-wire transmitters or sensors
  • SDRTD is designed specifically for Resistance Temperature Detectors
  • SDR3 is a three terminal SPD for high bandwidth applications


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SD   Surge Protection for Data & Signal applications Datasheet  Manual  Safety Manual