Until very recently, there has been a very vocal group of people insisting that safety and control networks should remain separate in all instances to guarantee timely delivery of safety communications. Though this group has not disappeared, it seems they are growing quieter as an increasing number of manufacturers deploy combined safety and control networks without incident.
A few well-known examples of integrated safety and control systems include Honeywell’s Process Knowledge System and Emerson Process Management’s DeltaV and DeltaV SIS (which offers a separate, but integrated approach) for the process industries, and Siemens’ Simatic safety integrated controllers and Rockwell Automation’s GuardLogix controllers for the discrete manufacturing industries.
A new addition to this list are Bosch Rexroth’s SafeLogic and SafeLogic Compact controllers, which feature CIP Safety on Sercos. The company says it is offering these controllers, which integrate safety technology into the Sercos automation network, as a way to “simplify the development of complex machines” for OEMs.
In its announcement of the SafeLogic controllers, Bosch Rexroth says, “The CIP Safety on Sercos safety protocol ensures safe communication from the control unit to the drive with no additional wiring. The SafeLogic and SafeLogic Compact controls cover all complexity levels of safety-based automation in connection with Rexroth'sdrive-integrated SafeMotion functions. The user can program standard and safety functions in the same engineering environment.”
The safety function module of the SafeLogic controllers can also be used with Bosch Rexroth’s IndraMotion and IndraLogic product lines, in effect turning them into control solutions with integrated safety functions. The company says that any customer-specific modifications made in the standard control’s program sequence will have no feedback effects on the safety functions.
In addition, Bosch Rexroth says that SafeLogic’s multi-safety master functionality enables the integration of decentralized safety peripherals from various manufacturers.
For less complex applications, Bosch Rexroth offers SafeMotion for its IndraDrive series. The SafeMotion functions are suitable for requirements up to Cat 4 with PL e (ISO 13849) and SIL 3 (IEC 62061). SafeMotion monitors up to 16 safe and certified motion functions, such as speed, direction of rotation, and position. New logic elements like safety door monitoring are said to reduce the risk of manipulation.
While it’s clear that integrated safety and control applications are expanding, there will continue to be companies looking to optimize safety at any cost, notes Grant LeSeur and Phil Knobel of Schneider Electric in their white paper: “Integrated Control and Safety: Assessing the Benefits, Weighing the Risks”. LeSeur and Knoble point out that such companies will likely continue to maintain separate safety and control systems.
The video below shows a demonstration of Bosch Rexroth’s IndraMotion MTX CNC with SafeLogic Compact.