Making use of IO-Link in industrial applications
Figure 2: The type of connector used with the connecting cable depends on the type of port. IO-Link class-A primary ports accept M8 or M12 (like the AL1120 from ifm efector shown here) connectors with up to four pins, while class-B counterparts accept connections with devices having five-pin M12 connectors (for bidirectional data communication). Image source: ifm Efector
■ Optimizing operations ■ Reducing downtime and streamlining maintenance ■ Trimming raw material costs and making strategic operational decisions. The harmonized IO-Link interface is defined by the IEC 61131- 9 standard and supported by Siemens, Omron Corp., ifm Efector, Balluff, Cinch Connectivity, Banner Engineering, Rockwell Automation, SICK, Pepperl+Fuchs, and dozens of other component and system manufacturers. No wonder IO-Link connectivity is widely leveraged in operations involving assembly automation, machine tools, and intralogistics. Its three main uses in these and other industrial settings include status communications, machine control, and rendering devices intelligent. IO-Link controller modes correlate to uses Recall from previous digikey. com articles that the IO-Link communication protocol renders each connector port on an IO-Link high-level primary (controller) capable of four communication modes. These include a fully deactivated mode as well as IO- Link, digital input (DI), and digital output (DQ) operating modes. The modes loosely correlate to the three main IO-Link uses listed above. The IO-Link operating mode supports bidirectional data
diagnostics and monitoring data from the sensor is requested by the primary.
IO-Link application 1 of 3: actionable status communications Machine monitoring is possible with IO-Link devices set up to report status that can, in turn, inform the system of necessary adjustments and corrections. Consider one use in the machine- tool industry — that of IO-Link pressure sensors which verify workpieces are clamped with a pressure appropriate for damage- free yet secure holding during material-removal operations. Here, IO-Link sensors essentially support the optimization of machine tasks for fewer rejected workpieces. IO-Link devices can also make actionable status communications to support enhanced maintenance routines for minimized downtime. For example, IO-Link position sensors on an assembly machine might continually report the locations of end effectors to ensure none are out of range or alignment.
communications with field devices and is typically used during data collection for monitoring, testing, and diagnostics. A primary’s port in DI mode accepts digital inputs and works when the port is connected to sensors — in this context, acting as input devices. In contrast, a port in DQ mode acts as a digital output, typically when the port is connected to an actuator (in this context, effectively an output device) or when a system PLC is set up to directly send instructions to another IO-Link device. Though beyond the scope of this article, it’s worth noting that the ports on an IO-Link primary can readily switch between modes. For example, a primary’s port connected to a sensor can run in DI mode — and then switch to IO- Link communication mode when
fieldbus or Ethernet ports for such connections. Devices in advanced control applications involving IO-Link systems integrate in one of three ways: ■ They directly connect to the host computer or PLC ■ They connect to an IO-Link primary and communicate via the IO-Link protocol ■ They use IO-Link compatible communications and connect to an IO-Link primary via an IO-Link hub The latter essentially acts as an intermediary to connect non-IO- Link devices to the primary.
Figure 3: IO-Link facilitates the creation of highly advanced control and automation systems. The machine-tool industry makes copious use of IO-Link sensors to verify appropriate workpiece clamping and milling end-tool pressures and positions. Image source: Getty Images
provided by IO-Link devices, a plant’s machine technicians can predict and correct errors and potential breakdowns before they happen. Technicians can also identify weak links in a machine or plant — to inform enterprise-level operational changes, purchasing decisions, and captive machine designs in the future.
application functions supported by IO-Link. Where an IO-Link installation supports functions that run sans intervention of personnel, the IO-Link primary often connects to a host system or higher-level PLC that processes received data and then directly or indirectly commands actuators in the design to the appropriate coordinated responses. Such automated control requires that the IO-Link system connect to a higher-level controller via standardized fieldbus or Ethernet protocols and cabling. In fact, most IO-Link primaries have
IO-Link application 2 of 3: advanced control and automation
An added benefit of IO-Link
Control and automation are other
By analyzing diagnostics data
we get technical
16
17
Powered by FlippingBook