PRIO-020

Verify I/O Link cable connections

Power down the controller and physically inspect all I/O Link cables from the controller CPU rack to each distributed I/O module. Check the RJ45 or dedicated I/O Link connectors on both ends. Ensure cables are fully seated and locking tabs are engaged. Pay special attention to the FROM LINK and TO LINK ports on daisy-chained modules.

Always perform CONTROLLED STOP and disconnect main power before disconnecting or reconnecting I/O Link cables to prevent damage to communication circuits.

Check cable routing and physical damage

Inspect the entire cable run for pinch points, cuts, excessive bending (minimum bend radius is typically 10x cable diameter), or damage from robot motion. Check that cables are properly secured in cable tracks and not routed near high-voltage lines or servo motor cables which can cause EMI interference.

I/O Link cables should never exceed 50 meters total length in a daisy-chain configuration. If you have multiple drops, calculate cumulative length from controller to the last device.

Test cable continuity if fault persists

With power removed, use a cable tester or multimeter to verify continuity on all conductors in the I/O Link cable. For shielded cables, verify shield continuity and proper grounding at both ends. Replace any cable showing intermittent or open circuits.

Keep a known-good I/O Link cable in your service kit for quick swap testing. This can immediately identify cable faults versus module issues.

Inspect I/O module LED status indicators

Examine each I/O module for status LEDs. Normal operation shows steady green POWER LED and steady or blinking green COMM LED. Red LEDs, no LEDs, or rapidly flashing patterns indicate faults. Note which specific rack slot or module address shows abnormal status - this identifies the faulty device.

On DeviceNet and CC-Link I/O modules, the COMM LED blinks at different rates depending on network activity. Consult the specific module manual, but generally steady green or slow blink is normal, while red or no light indicates the problem device.

Verify DC power supply to I/O modules

Using a multimeter, measure DC voltage at the power input terminals of each I/O module. Verify 24VDC ±10% (typically 21.6V to 26.4V). Check for blown fuses in the power distribution. If voltage is low or absent, trace back to the power supply and check circuit breakers, fuses, and wiring.

Maintain proper lockout/tagout procedures when checking live DC power circuits. Even 24VDC can cause equipment damage if shorted.

Check I/O configuration against physical modules

From the teach pendant, navigate to MENU > I/O > I/O Link to view configured I/O Link devices. Compare the configured addresses and module types against the physically installed hardware. Access System > Variables > $IOC_LINK to view I/O Link configuration details and verify each module's expected address matches the physical DIP switch or rotary switch settings on the modules.

Press the Detail softkey on the I/O Link screen to see real-time communication status for each configured module. A module showing 'Not Responding' indicates that specific address is the problem.

Isolate faulty module by elimination

If multiple modules are on the I/O Link chain, power down and physically disconnect modules one at a time starting from the furthest device from the controller. Power up after each removal. If the alarm clears when a specific module is removed, that module is faulty and should be replaced. If alarm persists with all modules removed, the controller I/O Link interface may be faulty.

Before replacing an I/O module, verify the exact catalog number and firmware version. R-30iA and R-30iB have specific compatible module versions listed in the Controlled Start-up documentation.

Verify physical address settings on all modules

Power down the system and physically inspect each I/O module's address selector (DIP switch or rotary dial). Record each address setting. Common addressing schemes start at 0 or 1 and increment sequentially. Ensure no two modules share the same address and that addresses are within the valid range (typically 0-15 or 0-31 depending on system).

Take photos of all DIP switch settings during initial installation or after changes. This documentation is invaluable for troubleshooting and reduces errors during module replacement.

Compare physical addresses to controller configuration

From teach pendant: MENU > NEXT > System > Config > I/O, then press the I/O Link Config softkey. Review the assigned addresses and module types. Each entry must match a physical module at that address. Check parameters: $IOC_LINK[x].$SLOT for address assignment, $IOC_LINK[x].$TYPE for module type, and $IOC_LINK[x].$NUM_RACKS for number of configured devices.

On R-30iB controllers, you can use MENU > I/O > I/O Link > Diagnostics to see a visual map of expected versus detected devices, making mismatches immediately obvious.