Current loop isolators

Omniflex has introduced three signal isolators in the Omniterm LZ series with integrated 10 kA 8/20 µs surge arrestors to cater for applications that require both loop isolation and surge protection. The LZ series combines both functions in under 12 mm per channel of DIN rail space.

The Omniterm LZI and LZD are current loop interface modules designed to interface field-mounted transmitters in remote applications such as RTUs and PLCs. These devices provide 1500 VAC signal isolation and fully specified 10 kA surge protection. The LZI is a single channel device with additional flexibility and support for both 2-wire and 4-wire 4-20 mA transmitters. The LZD is a dual channel device for increased packing density suitable for multiple 2-wire transmitters.

In addition, the LZ series incorporates a stabilised 24 V loop supply for the field-mounted 2-wire current transmitters, allowing supply voltages in the range 10-30 VDC to be used.

The Omniterm LZB is a dual-input field contact interface module designed to protect RTU and PLC installations from external factors such as lightning surges, ground loops and wiring faults. This module includes a fully specified surge arrestor and a high side output driver allowing users to combine all these functions into a single module.

These modules utilise advanced electronic techniques to achieve high accuracy and low power consumption with zero field calibration, saving on installation and commissioning time. Reliability figures in accordance with IEC61508 (SIL1) are available to allow inclusion of these devices in safety systems.