Intrinsic Safety Barriers - MTL 7700 Series

The MTL7700 Series of intrinsically safe passive network devices use zener diodes, resistors and fuses to safely divert excess electrical energy to ground and prevent sparking or overheating of equipment in hazardous areas.

The MTL7700 intrinsic safety device provides quick and easy installation and maintenance with removable terminals, the loop can be disconnect by simply unplugging the terminals from the side of the module. Wire entry is also angled to assist wiring within limited space enclosures.

DIN-rail mountable the MTL7700 intrinsic safety devices clamp simply and securely onto standard T-section DIN rail, simultaneously making a reliable intrinsically safe earth connection.

For applications where field device power is required for switch inputs or 2-wire transmitters, the MTL7700 barrier range provides a bussed power feed facility. When used in conjunction with the MTL7798 power feed module the user has a fully protected, electronically fused supply to many barriers with no additional wiring required.

All MTL7700 range zener barriers are based on the same simple principle. Each channel contains two stages of pulse-tested Zener or forward-connected diodes and an ’infallible’ terminating resistor. In the event of an electrical fault in the safe area, the diodes limit the voltage that can reach the hazardous area and the resistor limits the current. A fuse protects the diodes, and the two stages of voltage limitation ensure continued safety if either stage should fail. No active output current limiting circuits are employed. All models are certified ’ia’ for all zones and ’IIC’ for all explosive atmospheres (except MTL7707P+ and MTL7729P+, 'ia' 'IIB').

Note

Power bus facility applicable to MTL7706+, 7741 and 7787+ barriers

Features and Benefits

Intrinsically safe zener barriers
Standard DIN rail mount
Removable, colour-coded terminals
Bussed power feed to other modules
Solid state and relay switch modules
Choice of solid-state or relay output
Dual-channel variants - 6.3mm per channel
Proximity detector inputs
Direct replacement for MTL700 Series
Compatible terminal numbering and safety descriptions
Dimensions: 105 x 90 x 12.6mm