Omron launches modular I/O for deterministic control

A key feature of the Sysmac NX-series I/O system is its use of the distributed clock function of the EtherCAT machine network to achieve deterministic control behaviour. This ensures accuracy and repeatability of timing in the control loop, which is a key requirement of modern machine control. Individual I/O units compensate for signal delays depending on their position in the system, which means that inputs can be latched and outputs set anywhere in the control system with sub-microsecond accuracy. As a result, machines can achieve higher production quality and increased throughput.

Sysmac NX-series I/O has been developed to meet machine builders' and system integrators' requirements for a modular I/O system that can be used with Omron controllers and also with a wide range of open networks, and that combines openness and performance with superior real-time behaviour and ease of use.

To reach the required performance level, Omron has developed a new I/O interconnection bus with exceptional data throughput. As well as offering a data transfer rate far exceeding that of the field network, this bus propagates the EtherCAT distributed clock to individual I/O units, which enables the I/O units to synchronise with the Sysmac machine controller's primary task cycle. And, since each I/O station only counts as a single network node, the cycle times of the EtherCAT network remain low.

In addition, the new bus system will support the development of special inputs with a time-stamp function, which can be used to determine accurately the sequence of events. Complementary time-stamped output units enable users to control precisely the timing of digital output sequences. The total accuracy of timing from inputs to outputs is only limited by the on/off delays of the signals, and is planned to be well within one microsecond.

Wide range of variants

Sysmac NX-series I/O units are offered in a wide range of variants, so users can establish a balance between I/O density and ease of installation, and between performance and cost. The wide variety of units available also helps to meet local market needs when exporting machines globally.

Digital I/O units provide from four to 16 input or output points in just 12mm width. As well as standard models, versions are available with high-speed response and safety inputs and outputs. A full range of analogue I/O is available, with two to eight signals per unit, for current, voltage, thermocouple or RTD signals. High-performance models offer 10us conversion time per channel and 1:30,000 resolution. To support the motion control functions of the Sysmac series controllers, I/O units for encoder inputs and pulse outputs are included in the range. These can be assigned to motion axes in the controller configuration.

Machine safety functions are fully integrated in the Sysmac NX-series I/O. The programmable safety control unit and its safe input and output units can be inserted anywhere in the I/O system. No other special hardware is needed; the safety communication is passed transparently through the standard EtherCAT interfaces of the Sysmac control network, making it easy to add safety functions to any control system.

All Sysmac I/O units have the same height and depth (100mm x 71mm). The standard unit width is 12mm, or 24mm for some special units in the range. All I/O units have a detachable front connector with push-in terminals, which means that I/O wiring looms can be prepared and installed separately, signals can easily be disconnected for testing and commissioning, and units can be replaced without re-wiring. User-defined labelling and keying of the I/O connectors are supported to guard against installation errors.

At the initial market release in the first quarter of 2013, the Sysmac NX-series I/O will consist of approximately 70 types of I/O unit as well as system modules that include power feeds and ground terminals, a safety I/O controller, and the network interface unit for EtherCAT. Bus interfaces for other networks, plus additional I/O units will be released during 2013. For more information go to www.industrial.omron.eu.