Retrofitting small medium enterprises for Industry 4.0 with IO-Link

Introduction

In the current business landscape, small and medium-sized businesses lag in digitalization compared to their larger counterparts. Global industrial manufacturing is rapidly moving towards digitalization, and modern manufacturing processes are constantly monitored, analyzed, and optimized. However, a significant gap continues to exist between the few production sites that are fully digitalized and the rest still reliant on analog practices. Building a new smart factory is capital-intensive, so retrofitting the existing infrastructure with digital capability is more pragmatic than replacing it. This article discusses how to retrofit small and medium enterprises to Industry 4.0 using I/O link technology.

I-O Link Technology

IO-Link is a standard interface for 1:1 (point-to-point) connections with sensors, actuators, or other devices as defined in international standard IEC 61131-9. It operates through a three or four-wire unshielded standard cable to establish a connection between the IO-Link device and the IO-Link master. The IO-Link master is essentially a gateway, facilitating communication using field buses or product-specific backplane buses, thus transforming the IO-Link devices into Fieldbus I/O nodes. An IO-Link device can be connected to each port. Hence, IO-Link is a point-to-point communication and not a fieldbus. IO-Link master can be installed either in the control cabinet if it is a component of the I/O system or directly in the field as a remote I/O with IP65/67 protection. The master can have IO-Link channels, known as ports. Each port of the master connects to a unique IO-Link device, which can operate in either SIO (standard I/O) mode or bidirectional communication mode. IO-Link can seamlessly integrate with existing industrial architectures such as Fieldbus or Industrial Ethernet and connect to existing PLCs, HMIs, sensors, or actuators, facilitating rapid adoption of this technology.

Figure 1: IO-Link compatibility with existing industry protocols(Source: Banner Engineering)

IO-link network uses unshielded 3-wire or 5-wire standard cables, using M8 and M12 connectors. These cables have a maximum length of 20 meters. The communication between master and agent devices is half-duplex with three transmission rates (baud rates): COM 1 = 4.8 kbaud , COM 2 = 38.4 kbaud, and COM 3 = 230.4 kbaud.

Figure 2: Pin assignment of IO-Link device(Source: SIEMENS)

In an IO-Link system, the supply range for the master ranges from 20V to 30V, and for the device, 18V to 30V. The IO-Link device must function within 300ms after L+ exceeds the 18V threshold. IO-Link system operates in two communication modes: standard I/O (SIO) and single-drop digital communication interface (SDCI). In SIO mode, backward compatibility is maintained with existing sensors in the field, using 0V or 24V to signal OFF or ON to the IO-Link master. In IO-Link mode, communication is bidirectional at one of three data rates. The IO-Link device only supports one data rate, while the IO-Link master must support all three data rates.

During IO-Link mode, 24V pulses are employed using a nonreturn-to-zero (NRZ) format on the C/Q line where a logic 0 is 24V between CQ and L- and a logic 1 is 0V between CQ and L-. In IO-Link mode, pin 2 can be in DI mode as a digital input.

IO-Link masters specify two types of ports: Class A (Type A) and Class B (Type B). In class A port, pins 2 and 5 functions are not assigned. The manufacturer defines this function.

Generally, an additional digital channel is assigned to pin 2. An extra supply voltage in Class B is offered, which is suitable for connecting devices with an increased power requirement. In this case, an additional (galvanically isolated) supply voltage is made available by pins 2 and 5. A 5-wire standard cable is required to use this additional supply voltage.

I-O link retrofitting solutions from banner engineering

In a packaging unit, the labels are applied automatically to the products placed on the conveyor belt with the help of a machine. As shown in Figure 3, the machine peels the labels from their adhesive backing paper and loads them onto a tamp head. This head presses the labels onto the packages as they pass on a conveyor. However, this process has a challenge: the height of the tamp head must be manually readjusted whenever labeling needs to be run on boxes of a different size, which takes up valuable production time.

Figure 3: IO-Link Technology in Packaging Application (Source: Banner Engineering)

To overcome this challenge, a compact photoelectric sensor (Q2XKLAF Laser Sensor) is fitted onto the tamp head of the labeling machine. This sensor senses targets at a fixed distance. As a product moves on the conveyor, the tamp head receives a label and indexes downward. When the product comes within range of the fixed field sensor, it slows the tamp head down until it makes contact, where it then presses down with the appropriate pressure to apply the label and then rises to repeat the process.

This compact photoelectric sensor is connected to IO-Link Master (DXMR110), which replaces traditionally expensive input cards. The IO-Link Master can communicate with higher-level control systems via EtherNet/IP, Modbus/TCP, and PROFINET. IO-Link Master can send data to a higher-level control system or a supervisory device like a PLC, DCS, HMI, cloud platforms, or any other compatible device to process and interpret the IO-Link data. The specific destination depends on the system architecture and the intended application of the IO-Link communication.

Conclusion

The challenge of upgrading small and medium enterprises to Industry 4.0 can be overcome by retrofitting using IO-Link technology. Farnell offers comprehensive solutions including IO-Link evaluation boards, signal Indicator accessories,temperature sensors,ipressure sensors,proximity sensors/ switches,Current Sensors,motor protection accessories,Input / Output modules for retrofitting an existing application using the IO-Link protocol. This helps optimize machine maintenance, diagnose problems without making much investment, and replace the entire line or equipment.