IO link gains momentum

The "IO Link" working group is developing the specification for a fieldbus-independent communication interface for intelligent sensors / actuators in factory automation

Profibus International (PI) together with currently 14 manufacturers of sensors, actuators and automation systems in the "IO Link" working group is developing the specification for a fieldbus-independent communication interface for intelligent sensors / actuators in factory automation.

Their work comprises the transmission physics (electrical and mechanical properties, topology), sensor/actuator communication with the IO modules, a neutral data interface to the higher-level communication system and the engineering.

IO Link integrates conventional and intelligent actuators and sensors in automation systems.

The mixed operation of conventional and intelligent sensors is possible at no additional cost.

IO Link uses existing communication systems (fieldbusses or Ethernet-based systems).

The last few metres to the actuators and sensors are connected in a point-to-point connection with off-the-shelf, unshielded standard cables, thereby contributing to the reduction of interfaces and multiple variants.

Typical intelligent actuators / sensors include valves, motor starters, optical sensors, light curtains, analogue signals, RFID or actuators.

These devices can have application-specific parameters and data (eg diagnostic data) which are transmitted via a serial communication procedure.

Flexible telegram lengths are possible, enabling the transmission of even comprehensive data records (eg RFID or light curtains).

Communication is based on a standard UART protocol with a 24 V pulse modulation.

The standard modules used are already being utilised for parameterising and are very cost effective.

Process, service and diagnostic data can be cyclically transmitted in 2 ms typically.

Additional parameters and data can be transmitted acyclically.

IO Link makes central fault diagnosis and tracing to the sensor and actuator level possible.

Exact fault tracing or maintenance requirements reduce machine downtimes.

The exchange of devices is much simpler via central parameter storage.

IO Link thus brings about a cost-optimised solution of the information from actuators/sensor level up to integration into the automation system.

Protection of investment for manufacturers and users is achieved, as all sensors currently available can be connected via the standard IO mode and mixed operation with enhanced intelligent products is possible.

As a result, IO Link has high acceptance from the outset.

IO Link will establish itself as the communication standard among traditional fieldbusses.

Fieldbus-independent transmission with IO Link has already been specified.

The integration of IO Link into the fieldbusses will be specified in fall 2006.

A prototypical solution for Profibus, Profinet and Interbus will be shown at SPC/IPC/DRIVES 2006.

Initial standard products should be available at HM 2007.

Standardisation of IO Link in the IEC is on-going.

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