Wireless: An important step to critical control
One of the most promising things about wireless control is the potential for a walk-around HMI to free operators from the control room. The practical aspects of making that a reality just took a critical step with Siemens’ introduction of their Simatic Mobile Panel 277 Wireless, which the company points out has an emergency stop function that has been tested and certified to SIL 3. Don’t underestimate the importance of this simple sounding feature.
(SIL 3 is considered the highest risk reduction level achievable using one programmable electronic system. SIL 4 exists, but only in exceptional applications such as nuclear power plants. Read an article online that explains SIL classifications.)
The Simatic Mobile Panel 277 Wireless can interface with PLCs and other larger scale systems via wireless Ethernet. The unit features a 7.5 in. TFT touch display with integrated e-stop functions. This allows an emergency shutdown via the device from wherever the operator is. This capability offers users the potential to allow more control outside a control room, which is an understandable objective of wireless system designers.
The panel can have its range limited for safety and security reasons through the use of predefined active zones. The use of Profinet enables the use of safety technology over wireless Ethernet networks.
—Edited by Peter Welander, process industries editor, PWelander@cfemedia.com ,
Control Engineering Weekly News