Analogue I/O modules offer full isolation

Edited by the Engineeringtalk editorial team Jan 3, 2006

Four new analogue I/O modules join Opto 22's flagship Snap Ethernet systems family, fully supported by ioProject Basic and ioProject Professional software suites.

Opto 22, a developer and manufacturer of hardware and software for industrial automation, remote monitoring, data acquisition and machine-to-machine (M2M) applications, has introduced four new isolated analogue modules: the Snap-AIARMS-i, used for applications involving AC/DC current measurement; the Snap-AIVRMS-i, used for applications involving AC/DC voltage measurement; the Snap-AIMA2-i, used for monitoring very low currents; and the Snap-AOA-23-iSRC, which features built-in, isolated loop sourcing and is used to output current values to industrial devices.

"These new analogue I/O modules offer full isolation between field devices connected to the same module", states Tom Edwards, Senior Application Engineer at Opto 22.

"This electrical isolation eliminates the possibility of any damage resulting from differing operating voltages for the connected devices, and protects against damage to devices that may share a module with an overloaded or otherwise malfunctioning device".

"Also, the built-in, isolated loop sourcing on the Snap-AOA-23-iSRC can significantly reduce troublesome ground loops when installing 4-20mA instrumentation".

The Snap-AIARMS-i offers two channels of 0-10A RMS AC/DC input and is perfectly suited for the 5A secondary input of current transformers used to monitor AC line current in factory power distribution centres.

In these types of applications, the Snap-AIARMS-i enables early detection of spikes in the facility's electrical consumption, often due to malfunctioning compressors, failed bearings or other components.

The Snap-AIVRMS-i provides two individually isolated channels of AC or DC input with a range of 0 to 250V AC/DC.

It is ideal for monitoring the commonly found 120/240V AC and 12/24/48V DC system voltages to powered equipment and the process voltages of that equipment as it operates.

The Snap-AIMA2-i provides two isolated input channels with a range of -1 to +1mA.

It is best suited for measuring very low currents in the microampere range.

The Snap-AOA-23-iSRC provides two channels of current output with a range of 4 to 20mA, and includes built-in, isolated current loop sourcing which saves instrumentation technicians' time and the costs associated with providing required isolated external loop power.

"Users of Opto 22's popular Mistic family of I/O systems - developed in the early 1990s - have found loop-sourcing so valuable, and now it's available in Snap I/O", explains Edwards.

The Snap-AOA-23-iSRC's loop sources are internally connected to the individual outputs.

Additionally, the two channels and their loop sources share no field connections and are isolated from each other.

Each loop source is also current limited so that an external fault on one loop will not affect the other.

All these new modules are part of Opto 22's flagship Snap Ethernet systems family and are fully supported by ioProject Basic and ioProject Professional, comprehensive software suites that include control programming, debugging, human-machine interface development, OPC connectivity and utilities.

The modules are designed for use with Opto 22 Snap B-series mounting racks in control system architectures with Snap Ultimate, Snap Ethernet, or Snap Simple brains as well as the recently introduced Snap PAC-R and Snap PAC-S programmable automation controllers.