Overview
IO-Link is replacing hardwired analog and discrete I/O in modern automation systems. Instead of running individual wires from every sensor back to the panel, IO-Link uses a field-mounted master that communicates with sensors digitally over standard 3-wire cables, then sends all data back to the PLC over EtherNet/IP. The result is less wiring, richer diagnostics, and faster commissioning.
This guide covers the IFM AL1322 master — an 8-port IO-Link master with EtherNet/IP connectivity — paired with an Allen-Bradley CompactLogix processor. This is our standard field I/O architecture.
What You'll Need
- Allen-Bradley CompactLogix processor (5069-L310ER or equivalent)
- IFM AL1322 IO-Link master
- Studio 5000 Logix Designer (v30+)
- IFM AL1322 EDS file (download from ifm.com)
- Ethernet cable (shielded, industrial-rated)
- 24VDC power supply for the IO-Link master
Step-by-Step
Install the EDS File
Download the AL1322 EDS file from IFM's website. In Studio 5000, go to Tools → EDS Hardware Installation Tool. Click Add, browse to the downloaded .eds file, and complete the wizard. The AL1322 will now appear in your I/O catalog.
Restart Studio 5000 after EDS installation. The module may not appear in the catalog until you do.
Add Master to I/O Tree
Right-click the Ethernet port in your I/O tree → New Module. Search for "AL1322" in the catalog. Configure the IP address to match what you've set on the physical unit (default is typically 192.168.1.250). Give it a descriptive name like IOL_Master_Line4.
Configure Connection Parameters
This is where most people get stuck. The AL1322's default connection parameters need to be set correctly:
| Parameter | Value | Notes |
|---|---|---|
| RPI (Requested Packet Interval) | 20ms | Don't go below 10ms |
| Input Size | 232 bytes | Fixed — contains all 8 port data |
| Output Size | 232 bytes | Fixed — contains all 8 port commands |
| Connection Type | Exclusive Owner | Standard for most applications |
If the input/output sizes don't match 232 bytes, the module will not come online. This is the #1 commissioning issue with AL1322 units.
Understand the I/O Data Structure
The 232-byte input array contains data from all 8 ports. Each port has a defined byte range within the array. The structure follows IFM's documentation, with process data for each port at predictable offsets.
Key concept: Each IO-Link port can transfer up to 32 bytes of process data. The master packs all 8 ports into the 232-byte block that gets sent to the PLC every RPI cycle.
Configure Port Settings
Each of the 8 ports can be configured independently via the IFM web interface (browse to the master's IP address). Port modes:
- IO-Link: Full digital communication with IO-Link sensors
- SIO (Standard I/O): Simple digital input — treat it like a regular discrete point
- Disabled: Port is off
For IO-Link mode, the master will automatically detect the connected sensor and negotiate communication parameters (this is called "auto-negotiation").
Map Data in the PLC
Create a User-Defined Type (UDT) in Studio 5000 that matches the IO-Link data structure. This makes your code readable instead of accessing raw byte offsets.
// Example UDT for a temperature sensor on Port 1
UDT_IOL_TempSensor
Temperature : REAL // Bytes 0-3 of port data
Status : INT // Bytes 4-5
DiagCode : DINT // Bytes 6-9Use COP (Copy) instructions to move data from the raw input array into your UDT instances. This gives you named, typed access to every sensor value.
Verify Communication
Check the following to confirm everything is working:
- Module status LED: Solid green = connected to PLC
- Port status LEDs: Green = IO-Link communication active
- Studio 5000: Module should show no faults in I/O tree
- Tag values: Process data should update at the RPI rate
Common Problems
Module shows "Connection Request Error" in Studio 5000
Input/output sizes are wrong. Must be exactly 232 bytes each. Re-check module properties in the I/O tree.
Port LED is flashing orange
IO-Link negotiation failed. Check that the sensor supports IO-Link (not all sensors do). Verify cable wiring (Pin 1 = 24V, Pin 3 = 0V, Pin 4 = C/Q data).
Data reads as all zeros despite sensor being connected
Port may still be in SIO mode. Access the IFM web interface and switch the port to IO-Link mode.
Intermittent communication drops
Check cable length (max 20m for IO-Link), cable quality (use shielded M12 cables), and RPI setting (increase to 50ms if network is congested).
Can't access the IFM web interface
Verify your PC is on the same subnet. Default IP is typically 192.168.1.250. Try a direct Ethernet connection if going through a switch doesn't work.
Pro Tips
- Label every port — Use the IFM web interface to assign descriptive names to each port. When troubleshooting at 2 AM, "Line4_InfeedProx" beats "Port 3."
- Use IODD files — IO-Link Device Description files give you parameter names and ranges for each sensor. Import them into the IFM configuration tool for easier setup.
- Monitor diagnostics — IO-Link provides sensor health data that traditional I/O can't. Wire counts, signal quality, temperature warnings. Build HMI screens to display this data.
- Standardize your UDTs — Create a library of UDTs for each sensor type you use. Reuse them across projects for consistent code structure.
📋 Our Standard IO-Link Configuration
This is our go-to field I/O architecture for new installations:
| Component | Model | Notes |
|---|---|---|
| Processor | 5069-L310ER | CompactLogix, EtherNet/IP |
| IO-Link Master | IFM AL1322 | 8-port, NEMA 4X rated |
This architecture reduces panel wiring by 60-70% compared to traditional I/O and puts diagnostics right at the sensor level. The NEMA 4X rating means the master mounts directly on the machine — no panel required for field I/O.
Need Help With IO-Link Integration?
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