At its 2012 Automation Fair in Philadelphia, Rockwell Automation has announced a pair of micro-PLCs (programmable logic controllers) with embedded motion capabilities for controlling up to three axes. The Allen-Bradley Micro850 and enhanced Micro830 PLCs are aimed at machine-builders and are said to optimise the performance and cost of standalone machines.

“To be profitable, machine-builders around the globe demand world-class micro-PLCs,” says Co Gia Nguyen, vice-president and general manager of Rockwell’s Asia-Pacific business centre. “But these controllers must meet machine-builders’ requirements for economical, just-enough control, while providing additional options and features that enable machine-builders to differentiate their machines from the competition. The new Micro850 and enhanced Micro830 controllers balance those needs and help machine-builders compete more profitably.”

The Micro850 micro-PLC (above) offers the same form factor, plug-in support, instruction/data size and motion capabilities as Rockwell’s 24-pt and 48-pt Micro830 controllers, with the addition of expansion I/O and an embedded Ethernet/IP port for connecting to Allen-Bradley PanelView HMIs (human-machine interfaces). Tags created while configuring the HMI screens can reference the variable names in the Micro850 program.

The PLCs support for up to five plug-ins, allowing OEMs to customise their machines using extra I/O, special functions, and serial ports, without increasing the size of the controller. If more I/O or higher-performance analogue I/O are needed, the Micro850 controller supports up to four 2085 I/O expansion modules – including high-density digital I/O and high-accuracy analogue I/O – for a total of 132 I/O points.

The Micro850 and Micro830 (enhanced via a firmware and software upgrade) controllers support up to three motion axes using pulse outputs to stepper or servo drives. OEMs can use motion function blocks, such as Home, Move Velocity, Move Absolute, and Move Relative to simplify single-axis moves. For applications where precise positioning is needed at high speeds, a Touch Probe function block has special hardware to achieve exact-position registration.

Rockwell’s Connected Components Workbench software simplifies the installation, configuration, connectivity, and maintenance of machine devices, including the Micro800 controllers, Allen-Bradley PowerFlex AC drives, and PanelView graphic terminals. The integrated software saves time and costs compared to using a different programming tool for each device.