12 January 2010
Until now, the machine integrity required to meet safety requirements is met with simple logic – for example if a guard door is open, the logic stops the machine completely.
The newer programmable safety systems can interact intelligently with people, and increase human protection as well as enhance machine productivity.
Control Techniques says it can provide this new drive safety with SM-Safety, a programmable option module that plugs into a Unidrive SP AC drive or the Digitax ST servodrive. It provides programmable parameters for the key nine safety functions required for machine safety.
“Design engineers of high volume OEM machinery, system integrators and maintenance engineers all have safety responsibilities,” says product manager Imad Rajraji, “and all find it complex and expensive to meet all of the relevant safety standards.
“The SM Safety module, which is effectively a mini safety PLC, simplifies the whole process.” He said it is “a fraction of the price” of a Safety PLC.
The module is used in conjunction with Control Techniques’ software, CTSafeLite – or for more advanced applications, CTSafePro. With the software, designers or users can build a “comprehensive bespoke safety protection zone to meet the precise safety needs of the machinery.”
SM Safety meets international safety standards; EN 61508, EN 62061, EN ISO 13849-1 and, most important with respect to drives, EN 61800-5-2 adjustable speed electrical power systems – Part 5-2: Safety requirements – functional.
The module has a total of 18 I/O ports: four redundant digital inputs, one single digital input, three safe digital outputs, two additional digital outputs, two inputs dedicated to incremental or absolute encoders, and pulse outputs.
Another plug in module for registration control
Another new plug-in module provides high-speed motion and registration control for applications such as printing, packaging and cutting machinery.
The module, called SM-Register, provides motion programming using PLCopen or Control Techniques’ own Advanced Position Controller (APC).
It is programmable in logical user-defined units with two fully independent register capture channels. It has storage for 256 events per channel – microseconds apart – pattern recognition, the ability to filter unwanted marks such as splashes, dirt or text and can handle speeds in excess of 1,000m/min.
Users will find the programmable filter function invaluable in eliminating reaction to random marks or patterns in a web, says Mr. Rajraji. Minimum or maximum pulse width and distance from previous edge are both programmable.
There are a total of seven modes of position capture – positive edge, negative edge, both edges, positive pulse, negative pulse, and patterns of positive pulses and negative pulses.
It connects to a range of standard fieldbus and Ethernet protocols including EtherCAT, Profibus and CANopen as well as feedback from virtually any feedback device including resolvers, and incremental, Sin/Cos and SSI encoders.
Like the SM-Safety module, SM-Register is compatible with Control Techniques’ Unidrive SP AC drive range as well as the Digitax ST family of servo-drives.
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