Surge protective devices for MCR technology

Surge protection for MCR technology

In measurement and control technology (MCR technology), surge protection ensures interference-free signal transmission. The high quality and availability of the transmitted signals is essential for smooth operation. Our surge protective devices offer an ideal solution for all applications in MCR technology. System failures can thus be avoided.

Product List

Your advantages

  • Protection to suit your needs, with a complete range of surge protective devices for all common MCR signals
  • Versatile use: designs and connection technology adapted to the application
  • Easy testing with pluggable surge protective devices
  • Worldwide use in potentially explosive areas with ATEX and IECEx approvals
  • Surge protection for MCR technology is part of the COMPLETE line system
TERMITRAB complete product range

TERMITRAB complete product range

TERMITRAB complete – the product range starting from 3.5 mm

TERMITRAB complete is the world's narrowest surge protection solution for MCR technology. This product range provides you with a complete system. It ranges from simple, single-stage surge protection to multi-stage, pluggable versions with knife disconnection, signaling, and remote signaling option.

The narrowest surge protective devices are just 3.5 mm wide. This represents space savings of up to 50% compared to installations with a 7 mm overall width.

The protective devices in the TERMITRAB complete range provide mechanical signaling that displays the status of the protective devices without the need for additional auxiliary power. Optional remote signaling modules visually monitor up to 40 protective devices. In the event of a thermal overload, the remote signaling modules notify the control room, for example, of the status in the form of a group message via a floating contact.

Surge protection for MCR technology – PLUGTRAB PT-IQ

Clear signal colors for the status of the protective device

PLUGTRAB PT-IQ – always know what is going on

PLUGTRAB PT-IQ provides multi-stage monitoring of the installed surge protective devices. At the same time, all voltage limiting components of the protective circuits are monitored. The controller supplies power to up to 28 protective devices. At the same time, it safeguards the group remote signaling function. A yellow status signal indicates that the performance limit has been reached as a result of frequent overvoltages. The surge protection system continues to function and your system is still protected. When the status is yellow, replacement is recommended in order to avoid unnecessary service call-outs.

  • Green: protective device OK
  • Yellow: performance limit reached, replacement recommended
  • Red: overloaded, replacement required
Surge protection for direct connection to sensor heads

SURGETRAB S-PT: surge protection for direct installation on the field device

SURGETRAB S-PT – installation directly on the field device

SURGETRAB surge protective devices are designed for all common standard signals that are directly attached to the sensor head via their connecting threads. This type of mounting saves time and money, and there is no need for an additional connection box for installing the surge protection.

Connection versions for through and parallel wiring are available. This enables you to connect the protective circuit in series or in parallel to the interface of the measuring element. Versions with parallel wiring require a second connecting thread on the sensor head.

Typical applications in MCR technology

Surge protective devices for isolated signal circuits

Surge protective devices for isolated signal circuits

Isolated signal circuits

Analog measured variables such as speed, pressure, flow, etc. are recorded by sensors and converted into current or voltage values by measuring transducers. They are transmitted to the controller or the isolator module within a standardized value range. The “1x2 circuit” is typically used for this type of analog transmission method.

Transient coupled-in overvoltages can cause damage both on the field device and centrally. You should therefore equip both of these end points with surge protection for MCR technology.

Surge protective device for signals with common reference potential

Surge protective device for signals with common reference potential

Signals with common reference potential

Switching states and signal contacts are typical signals that are recorded with the binary inputs of controllers. The controllers also switch actuators such as solenoid valves. Use suitable surge protection to protect the sensitive inputs and outputs of controllers. The individual binary signals are often connected against a common reference potential. Typical arrangements that take into account this common reference potential are provided by so-called 2x1 or 4x1 circuits.

Surge protective device for resistance-dependent measurements

Surge protective device for Pt 100 measurements, for example

Resistance-dependent measurements

If a measured variable is determined directly based on the resistance value of an electrical component, the additional impedances within the measuring loop play a special role. This affects, for example, temperature measurements with platinum resistance detectors (Pt 100, Pt 1000) as well as strain gauges with two-wire technology. As a rule, MCR surge protection products contain impedances in the common mode paths. If the impedances are introduced into the circuit without recalibration, the measurement result will be falsified due to the change in the total impedance. Circuit versions without additional longitudinal resistances simplify the installation of surge protection in applications of this kind.

Narrow TERMITRAB complete surge protection for Ex applications

Surge protection for Ex applications

Potentially explosive applications

Explosive atmospheres repeatedly arise in the chemical and petrochemical industries due to industrial processes. They are caused, for example, by gases, fumes or vapors. Explosive atmospheres can also occur, however, in mills, silos, sugar and fodder factories due to the dust present there.

The surge protective devices for the Ex area are subject to specific conditions. The products therefore meet the specific requirements for intrinsic safety protection. Since all surge protective devices are assigned to the “Ex ia” category for intrinsically safe circuits, they provide maximum safety. In this category, the equipment must not be capable of causing ignition, even in the event of two independent faults.

It can be installed in Ex zone 1, Ex zone 2 or in the non-Ex area. The connected signals can be forwarded through to Ex zone 0. Some products also meet the requirements of pressure-tight encapsulation protection. Approvals are granted in accordance with ATEX and IECEx.

TERMITRAB complete surge protective device with single-stage protective circuit

TERMITRAB complete surge protective device with single-stage protective circuit

Single-stage protective devices

Ideally, a surge protection concept should have a multi-stage design. This involves the optimum arrangement of components that respond quickly such as suppressor diodes and powerful protective devices such as gas discharge tubes. The gap between these two protection stages is closed by varistors. They take longer to activate than diodes but have a higher discharge capacity.

Single-stage protective devices are only equipped with one component. They are suitable, for example, for the additional protection of long cables from the field, at the building entrance or at the transition between different protection zones. Single-stage protective devices with common mode voltage protection provide protection against overvoltages between the individual signal wires. Versions with normal mode voltage protection provide protection for the wires and ground.