IO-Link: Did You Know?

  • Post category:TECH TIPS
  • Reading time:2 mins read

Did you know that IO-Link can transmit up to 32 bytes in one cycle?

The IO-Link interface standardized in IEC 61131-9 is based on simple serial data transmission via conventional connecting cables. With IO-Link, it is over exactly this cable that data packets are exchanged cyclically between the IO-Link master and an IO-Link device packed in one protocol. These data packets are called M-sequences in ‘IO-Link language’. The information contained in these data packets is defined for IO-Link but can be scaled to a large degree. Process data are completely transmitted cyclically with each data packet to guarantee deterministic response times in an application. Parameter and event data, on the other hand, are subject to less time-critical requirements These are transmitted distributed among multiple data packets.

Data widths of 1 bit to 32 bytes (256 bits) can be defined in each case for process input data (e.g., sensor signals) and process output data (e.g., actuator control signals). This enables the cycle time to be optimized for a fixed transmission rate. This applies regardless of the transmission involved – whether a single inductive sensor that supplies only 1 bit of switching information as process data, a light array that transmits a detection state of each individual channel of its over 200 channels, or a combined sensor-actuator device that generates or requires pressure measurements, status information and valve control data.

Even at a maximum process data width of 32 bytes, cycle times of less than 3 milliseconds can be realized with IO-Link – and over simple, 3-wire unshielded connecting cables.