IO-Link (Smart Sensor Master)
IO-Link (IEC 61131-9) is a single-wire, bidirectional serial communication standard that connects industrial sensors/actuators to a master. The master connects to higher-level systems (PLC, SCADA, Edge) via PROFINET / EtherNet/IP / Modbus TCP / OPC UA, and transmits process data (PD), identification data (ISDU), and events.
The IOLINK driver of this gateway is a stub. Since IO-Link uses a 3-wire serial (24V / GND / C/Q) physical layer, a PC cannot directly generate/decode signals.
Recommended Integration Path: Register the upper interface of the IO-Link master (PROFINET / Modbus TCP / EtherNet/IP / OPC UA / REST) with another PlantPulse driver.
Why Is Master Hardware Needed?
IO-Link devices are inherently connected to the outside world only through a master. The master groups multiple IO-Link sensors in configurations such as 8 ports or 16 ports and exposes the results over industrial Ethernet.
| Master Category | Representative Products | Upper Interface |
|---|---|---|
| 8-port PROFINET master | ifm AL1100 / AL1xxx, Balluff BNI008x | PROFINET, OPC UA |
| 8-port EtherNet/IP master | Balluff BNI EIP, ifm AL13xx | EtherNet/IP, REST |
| 8-port Modbus TCP master | Pepperl+Fuchs ICE3-8IOL, Murr Cube67 | Modbus TCP |
| Hybrid (multi-protocol) | Turck TBEN-S2, Banner R90C | PROFINET / EIP / Modbus / REST |
Recommended Integration Path
| Interface Provided by Master | PlantPulse Driver to Use | Page |
|---|---|---|
| OPC UA Companion Spec for IO-Link (cleanest option) | OPCUA | OPC-UA |
| Modbus TCP | MODBUS | Modbus TCP |
| EtherNet/IP | EIP | AB EtherNet/IP |
| PROFINET | PROFINET | Siemens Profinet |
| JSON REST | HTTP | HTTP Push |
Masters that support the OPC Foundation's IO-Link Companion Spec (e.g., recent firmware from ifm / Balluff) represent the PD/ISDU of each port as OPC UA nodes. By registering them directly with the PlantPulse OPCUA driver, you can poll sensor values port by port, making this the cleanest option.
Example Register Map for Modbus TCP Registration (ifm AL1100)
Since register maps vary by master, always consult the vendor manual.
| Data | Typical Location (e.g., ifm AL1100) | PlantPulse Notation |
|---|---|---|
| Port 1 PD-In (Process Data In) | Holding Register 0x1000+ | 4096 (decimal) |
| Port 2 PD-In | 0x1100+ | 4352 |
| Per-port status bit | 0x0000 area | 0 + bit number |
| Per-port PD-Out (write) | 0x2000+ | 8192 |
Stub Registration (For Reference)
| Input Field | What to Enter |
|---|---|
| IP Address | (Not used) |
| Port | (Not used) |
| Auto Collection | Recommend disabling |
Common Issues
| Symptom | Possible Cause | Solution |
|---|---|---|
| No value arrives after IOLINK registration | Stub driver | Register again with one of OPCUA / MODBUS / EIP |
| PD values received via Modbus appear corrupted | 16-bit / 32-bit endianness | Apply DW / RDW conversion in the format helper |
| OPC UA node tree is too deep | Standard structure of the Companion Spec | Register aliases for frequently used nodes only |
| Stale values after sensor disconnect | Differences in master fail-safe policy | Recommend changing master fail-safe setting from Last value to Zero |
| RFID reader response appears corrupted | ISDU is byte-array — truncated by Modbus 16-bit units | Use OPC UA Companion Spec or the master REST API |
Next Steps
- Obtain the register map or OPC UA node tree from the IO-Link master manual
- Refer to OPC-UA Registration / Modbus Registration / EIP Registration pages
- Technical background: IO-Link Driver (Advanced)