MTL7728+ MTL Zener Barrier

Eaton Crouse-Hinds series MTL7700 Zener barrier, Analogue/digital, 28 Vdc, 93mA, Polycarbonate, DIN rail mount, + polarity, For controller outputs, solenoids

The MTL7707+ is a 2-channel shunt-diode safety barrier similar to the MTL7787+ but with built-in electronic overvolt protection. It is intended primarily for safeguarding a hazardous-area switch controlling a relay, opto-coupler or other safe-area load from an unregulated dc supply in the safe area. 

The MTL7706+ is a 1-channel shunt-diode safety barrier, with builtin electronic overvolt protection, for energising a 2-wire, 4/20mA transmitter in a hazardous area. It is powered from a positive supply of 20–35V dc and delivers a 4/20mA signal into an earthed load in the safe area. It is proof against short circuits in the field and in the safe area and is extremely accurate. The MTL7706+ will pass incoming communication signals up to 10kHz from a ‘smart’ transmitter, while in the outgoing direction it will pass signals of any frequency likely to be encountered. 

The MTL7707P+ is a two-channel shunt-diode safety barrier similar to the MTL7787P+, but is designed for use with group IIB gases and features built-in electronic overvolt protection allowing use with unregulated power supplies up to 35V dc. It is intended primarily as a low cost solution for driving IIB certified 2-wire 4/20mA transmitters, but can also be used with controller outputs with current monitoring, solenoid valves and switches. To protect the fuse and enable the loop to continue working, the supply current is limited automatically at 50mA should the output be short-circuited or excess voltage applied. 

The MTL7742 is a single channel switch/prox input barrier with an open collector solid state interface to the safe area equipment. The solid state switch is especially useful for high frequency switching apparatus including pulse and rotational sensors. The power bus terminal can be used to connect power to the module and the input power supply range makes the module suitable for use with unregulated supplies. 

The MTL7743 is a dual channel switch/prox sensor input barrier with a relay interface. This module is ideal for applications where high channel packing densities are required for digital inputs. Power is connected using the power bus terminal. 

MTL7744 2 channel proximity sensor or switch inputs with solid state outputs

A dual channel version of the MTL7742. This module provides two solid state interfaces for prox/switch inputs. Power is connected via the power bus. 

The MTL7745 is a single channel switch/prox input barrier providing line fault detection. Proximity detectors or switches fitted with end-ofline resistors may be connected. Short circuit or open ciruit conditions in the field wiring will generate an alarm condition. The LFD relay contacts close when a fault is detected allowing the contacts to be connected in parallel to provide a common alarm. The power bus terminal can be used to connect power to this module. 

The MTL7798 power feed module incorporates both voltage and current sense mechanisms to protect barrier circuits by activating a solid state trip mechanism when fault or overload conditions occur in the power source circuit. Resetting the module after tripping is achieved by interupting the supply to the unit. A red LED indicates a circuit trip condition and a green LED the availability of power at the outputs. Bussed power for other modules is sourced from the top of the unit using the Bus Power Link BPL7700 or via terminals 1 and 2