IO-Link Spy – Communication Analysis Between Master & Device

The IO-Link Spy, also known as the IO-Link Sniffer, functions as an IO-Link analyzer that enables the logging and analysis of IO-Link communication: for example, between an IO-Link master and an IO-Link device. To do this, the IO-Link Spy is simply clipped onto the IO-Link cable. It is an indispensable tool for engineers and users of IO-Link technology during commissioning and field operation, allowing them to identify any kind of issue in IO-Link communication without affecting operation or communication in any way. This also makes it possible to analyze and resolve sporadically occurring faults.

Quickly identify and resolve IO-Link issues?

The IO-Link Spy gives you full transparency into the process, diagnostic, and service data of your IO-Link system

Product Datasheet

Description

The IO-Link signal is tapped via capacitive coupling. Through amplification, filtering, and digital signal processing, the original signal is finally restored. The measured data is transmitted via USB to a software application running on a Windows PC.

IO-Link communication can be seamlessly analyzed at the byte level, M-sequence level, protocol level, and even application level. In the latter case, IO-Link communication is visible in plain text. Filter and search functions simplify the identification of problems. Since the IO-Link Spy is simply connected to an IO-Link cable, the ongoing IO-Link communication does not need to be interrupted. This is particularly useful for analyzing problems during operation or for errors that occur only very sporadically. If necessary, an additional grounding plug can be used to improve signal quality, although in most cases it works perfectly without it.

User benefits of the IO-Link Spy

Logging of IO-Link communication without interrupting ongoing communication
Quick and easy analysis of IO-Link problems
Detection of logical problems
Suitable for development and application
Grounding cable for noise suppression in rare use cases
In progress: automatic COM detection
Also in progress: command-line interface (also for Linux) for test automation and AI-assisted development

User restrictions of the IO-Link Spy

There should be little to no other (digital) signals present on the line (aside from IO-Link communication).
Excessive electromagnetic interference in the environment can lead to problems in restoring the original IO-Link signal.

IO-Link Spy or IO-Link Diagnosis Tool – which fits when?

Both tools analyze IO-Link communication at the byte, M-sequence, protocol, and application level, including precise UART timing. The difference lies in the use case: the IO-Link Diagnosis Tool connects via cable and offers the broader feature set – analog signal display, eye diagrams, SD recording, and an integrated IO-Link master. It operates reliably even in EMC-heavy environments and remains unaffected by digital signals on the I/Q line. The IO-Link Spy, on the other hand, clips wirelessly onto the IO-Link cable and can passively sniff ongoing communication without interrupting it – ideal for troubleshooting directly during operation, when intervening in the wiring isn’t possible.

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	Diagnosis Tool	Spy
Type of connection for capturing IO-Link communication	Wired	Wireless (clipped on the IO-Link cable)
USB connection to the PC	yes	yes
Analysis of IO-Link communication (on byte/ M-Sequence/ protocol/ application level)	yes	yes
Analysis of the precise timing of each UART byte	yes	yes
Recording IO-Link byte streams to SD card	yes	no
Analog features (analog signal view for UL+, IL+, UCQ and ICQ, eye diagrams, analog triggers, calibration, …)	yes	no
Capturing an ongoing IO-Link communication (without interrupting it)	no	yes
Integrated IO-Link Master	yes	no
Works without any issues in environments with electromagnetic disturbance.	yes	no
Digital signals on the I/Q line do not affect the analysis of the IO-Link communication.	yes	no

Contact

Use our contact form for further questions about the Diagnosis Spy. Our team will be happy to help you.