MTL TP32 Surge Protectors

The MTL TP32 surge protectors are designed to protect process transmitters and devices on fieldbus systems. The TP32 is a hybrid design consisting of high-power, solid state electronics and a gas discharge tube capable of diverting surges up to 20kA. For hazardous-area use, approvals for both intrinsically safe, flameproof, explosion-proof and non-incendive operation are available in all gas groups and apparatus temperature classifications up to T6.

The terminated TP32-T has the same protection circuit as the standard product, but also includes a Foundation fieldbus termination circuit. This unique combination eliminates the need to purchase and install additional termination circuitry for the FF segment. The TP32-T provides excellent transient protection control and terminates the bus segment in one simple-to-install package. The termination circuit is designed to the requirements described in ANSI/ISA 50.02-2. Note: Two terminators are required per bus segment.

The earth connection is made via the casing of the transmitter, negating the need for a separate earth connection or a ground stake at the transmitter. In operation, the TP32 makes sure that the transmitter electronics are never exposed to damaging transients between the lines and ground. Any surge current appearing as a series-mode or common-mode transient is converted into a common-mode voltage whereupon the transmitter electronics are temporarily raised to some higher voltage level before ‘floating' down automatically and without damage to resume normal operation.

Encased in a 316 stainless steel enclosure, the TP32 exhibits unparalleled mechanical durability providing years of maintenance-free operation in harsh environments. The enclosure is available threaded for all the common conduit entries. Versions are available for 1/2-inch NPT, 20mm ISO, and G 1/2-inch (BSP 1/2-inch) threaded entries.

Installation of the MTL TP32 is simple and can easily be accomplished with existing installations. By connecting in parallel to the transmitter circuit the TP32 does not interfere with the normal operation of the bus, passing AC or DC signals without adding increased voltage drop across the segment while consistently diverting surge currents safely to ground and clamping output voltage to safe levels.