• DIN-rail mounting for easy installation and automatic earthing
  • 20kA maximum surge current per line
  • ±32Vdc working voltage
  • Capacitance
    • Line to line: 40pF
    • Line to earth (ground): 80pF
  • Plug connectors for quick and easy connection or rewiring
  • IEC61158-2:2004 for Foundation fieldbus
  • 10-year product warranty


The MTL FP32 surge protector prevents surges and transient over-voltages, conducted along the trunk or spurs of fieldbus systems, from damaging the associated electronics such as terminators, spur blocks and the bus control equipment. The FP32 is designed to be used at both ends of the trunk where a spur is connected to safely divert any surges to earth.

The multi-stage hybrid surge protection network at the heart of the FP32 uses a combination of solid-state electronics and a gas-filled discharge tube (GDT) to provide surge protection up to 20kA. This surge protection circuit is designed to exhibit exceptionally low line resistance, and adds only a tiny voltage drop to the bus. As a result, no matter how many FP32 devices are connected to a trunk or spur, the system will still be able to support up to 32 transmitters as specified by IEC 61158-2.

In operation, the MTL FP32 surge protector does not adversely affect the performance or operation of the fieldbus or connected equipment. It allows signals to pass with very little attenuation while diverting surge currents safely to earth (ground) and clamping output voltage to safe levels.

Fully automatic in operation, FP32 devices react immediately to make sure that equipment is never exposed to damaging surges between lines or the lines and earth (ground). Reacting instantaneously, the FP32 redirects surges safely to earth and then resets automatically. The FP32 meets IEC 61158-2:2000 for 31.25kB/s systems such as Foundation fieldbus, PROFIBUS-PA and WorldFIP.

DIN-rail mounting and a small footprint allow the FP32 to be conveniently located near terminators and spur blocks, while plug connectors for trunk or spur cables and the earth (ground) and shield of the cable make removing a device or re-patching a simple operation.