Fiber-Optic Multiplexer Handles Multiple Nodes

Oct. 27, 2014
Ultra Electronics' EOTec 2000 Multi-Node MX Multiplexer Provides an Economical Alternative to PLCs

Ultra Electronics, Nuclear Sensors & Process Instrumentation (NSPI) traces its roots to 1968 and the founding of Weed Instrument Co., which built its reputation on temperature and pressure sensors for demanding applications including nuclear power, military aircraft and advanced weapons systems. Recognizing the need for highly reliable, high-bandwidth and secure communications led to the acquisition of Apec Electronics Inc., a pioneer of industrial fiber-optic networking for industrial automation, in 1991, and of the 3M Industrial Communications product line in 1994, further strengthening the company's position in the industrial fiber-optic networking market.

"We started our multiplexer product family with a point-to-point solution more than 10 years ago with 4-20 mA, 0-10 VDC, RS-232/485 and dry contacts, but without industry certifications or approvals," says Nick Verlenich, senior product engineer, Ultra Electronics. "Back then, hazardous approval ratings weren't a requirement. Three years ago, we introduced the MX Series multiplexer, which includes Class I, Div. 2, Groups A,B,C and D (U.S. and Canada), ATEX and CE approvals. These newer point-to-point multiplexers support 16 channels, rather than the previous eight channels.

Simple, secure, reliable and economical

Figure 1. Ultra Electronics' EOTec 2000 Multi-Node MX Multiplexer provides an economical alternative to PLCs by transmitting up to 16 input channels and unlimited output channels at each of up to 256 nodes over a pair of fiber-optic cables.

"The new EOTec 2000 Multi-Node MX Multiplexer supports multiple nodes, so users can build daisy chain or self-healing ring topologies, which provide fault tolerance and greater network reliability."

The EOTec 2000 is designed to transmit up to 16 input channels and unlimited output channels of bi-directional electrical information at each of up to 256 nodes, over a pair of single or multimode fiber-optic cables.

The new base module provides input/output module selections that include 4-20 mA, 0-10 Vdc and contact closure. It connects directly to the fiber-optic cable via small form-factor pluggable (SFP) transceivers, and provides visual indicators for power, global alarm and module status, as well as the fiber link status. Each base unit has two transceiver ports, supporting both 1300-nm and 1550-nm wavelengths for either multimode or single-mode optical fiber.

An integrated backplane allows for communications from the base unit to the input/output modules with no need for external inter-modular connections. No programming is required, as input/output configuration is derived via a one-time DIP-switch configuration. Power is supplied through redundant external 24-VDC power supply terminals.

The Multi-Node MX Multiplexer offers an economical alternative to using PLCs or Ethernet to bring low counts of widely distributed I/O into a control system network. "I call it the poor man's PLC, for people who are only using the PLC to send or receive I/O," says Mike Wightman, senior account manager, Ultra. "A PLC is feature-rich, even at the low end."

Compared to a PLC or managed or unmanaged Ethernet switches, which Ultra also offers, "the Multi-Node MX doesn't require a subject matter expert to commission or maintain," Wightman says. "The installation instructions are straightforward and easy to follow. The product is commissioned by setting a few DIP switches."

I/O modules are available in two- and four-channel versions, and all modules mount on 35-mm DIN rail. Applications include remote data acquisition, emissions monitoring, data and signal transmission in lightning-prone locations, hazardous areas, tank gauging and conveyors.

"Many refineries and other critical industries want to limit Ethernet use due to security concerns," Wightman says. The fiber-optic signal is meaningless to anyone who taps into it, and the built-in diagnostics will detect any intrusion. "This multiplexer is a low-cost, high-reliability solution. It gets you inexpensively and quickly into communicating over fiber."

For more information, visit