23A-0082

Identify the Faulty Device

Record the device number from the %2 parameter in the alarm message. Cross-reference this with the system configuration in MOD > System Setup > Hardware Configuration to identify the specific PLCcore or PLC module.

Take a photo of the full alarm message including timestamp and device number for service documentation.

Perform Visual Hardware Inspection

Power down the control completely via the main disconnect. Open the control cabinet and locate the identified PLC module. Check for physical damage, discoloration, swollen capacitors, or burnt components.

Ensure main power is locked out and verify zero voltage before opening cabinet or touching components.

Reseat the PLC Module

Remove and firmly reseat the PLCcore or PLC expansion module in its slot. Ensure locking mechanisms and all connectors are properly engaged. Check adjacent modules for proper seating as well.

Clean module edge connectors with contact cleaner if corrosion or oxidation is visible.

Test After Restart

Restore power and boot the control. Monitor for alarm recurrence. If alarm returns immediately, the module has likely failed and requires replacement.

Document alarm behavior in the service log including whether it occurs during boot or after specific operations.

Replace Defective Module

If reseating does not resolve the issue, replace the identified PLC module with a Heidenhain-approved spare. After replacement, restore configuration from TNCbackup and verify all PLC functions.

Use only Heidenhain original parts with matching firmware versions to avoid compatibility issues.

Check Software Version Consistency

Enter MOD mode (key switch to position 2), navigate to System Information, and verify the NC software version matches the PLC firmware version. Look for inconsistencies or unusual version strings.

Write down all version numbers including build dates for comparison with Heidenhain documentation.

Review Recent Update History

Check the control's service log and update history to determine if the alarm appeared after a software update. Access via MOD > Service > Log Files.

Look specifically for incomplete or aborted update processes in the log timestamps.

Reload PLC Firmware

Using TNCopt or TNCbackup software, connect via Ethernet and perform a complete firmware reload to the affected PLC device. Select 'Install Firmware' and choose the correct version matching your NC kernel.

Do not interrupt power during firmware installation as this can cause permanent damage to the PLC module.

Perform Complete Software Reinstallation

If firmware reload fails, perform a complete control software reinstallation from Heidenhain installation media. Use the latest compatible software package for your control model.

Always create a complete backup using TNCbackup before major software operations.

Verify PLC Program Compilation

After firmware reload, ensure the PLC program recompiles without errors. Check in MOD > PLC > Compile for any compilation failures that might indicate persistent firmware issues.

If compilation fails repeatedly, the PLC module itself may have corrupted memory requiring hardware replacement.

Check System Bus Status

In MOD mode, navigate to Diagnostics > Bus Systems and check the status of the internal PL bus or X116 communication link. Look for communication errors, timeout counters, or device not responding messages.

Document error counters and compare after a power cycle to see if they increment.

Inspect Internal Cabling

Power down and inspect all internal ribbon cables and communication bus connections between the main CPU board and PLC modules. Check for loose connections, damaged cables, or bent pins.

Handle ribbon cables carefully by the connector bodies only to avoid damaging fragile conductors.

Test Bus Termination

Verify that bus termination resistors are properly installed if required by your control configuration. Check termination settings in MOD > System Setup > Bus Configuration.

Improper termination can cause intermittent communication errors that appear as internal device faults.

Isolate the Communication Path

If multiple PLC devices are present, temporarily disconnect non-essential PLC expansion modules to isolate whether the fault is in the specific device or the communication infrastructure.

Only disconnect expansion modules; never disconnect the main PLCcore during diagnostics.