231-E02D

Access PLC Diagnostics

Navigate to MOD function → PLC → Diagnostics → Input/Output Status to view ES.B.HW input states in real-time.

Use the live monitoring feature to observe input state changes during manual activation

Inspect Physical Connections

Check all terminal connections for the ES.B.HW input at the PL/MB modules, ensuring proper torque specifications per Heidenhain documentation.

Power down the system before checking connections to prevent electrical hazards

Verify Cable Continuity

Use a multimeter to test continuity from the input device through to the PLC input terminal, checking for breaks or high resistance.

Check shield connections as poor shielding can cause intermittent signal issues

Test Input Device

Substitute a known good input device or use a jumper wire to simulate the ES.B.HW input signal and verify PLC response.

Ensure voltage levels match PLC input specifications before applying test signals

Access HSCI Configuration

Navigate to MOD function → System → Configuration → HSCI to review the current IOC file configuration for ES.B.HW assignments.

Create a backup of the current IOC file before making any modifications

Verify Input Mapping

Check that ES.B.HW input addresses in the IOC file match the physical wiring and PLC program expectations using the HSCI configuration tool.

Incorrect mapping can cause multiple system malfunctions beyond this alarm

Validate Test Group Settings

Confirm test group parameters in the IOC file correspond to the actual hardware configuration, particularly for dynamic test sequences.

Compare with machine manufacturer's original IOC file if available

Reload Configuration

After corrections, reload the IOC file through MOD → System → Configuration → Load Configuration and perform a complete system restart.

System restart required for IOC changes to take effect

Check Module Status LEDs

Examine the status indicators on the PL/MB modules for error conditions, referring to the module documentation for LED code meanings.

Document LED patterns as they can indicate specific failure modes

Perform Module Diagnostics

Use MOD → PLC → Diagnostics → Module Test to run built-in hardware tests on the suspected PL/MB module.

Module testing may temporarily interrupt normal operation

Swap Module Position

If multiple identical modules are present, swap the suspected module with a known good one to isolate the hardware fault.

Update IOC configuration if module positions are changed

Replace Defective Module

Install replacement PL/MB module ensuring proper seating and secure connections, then reconfigure HSCI settings as needed.

Use only Heidenhain-approved replacement modules to maintain system integrity

Verify Test Output Operation

Access MOD → PLC → Diagnostics → Output Test to manually activate test outputs and verify proper voltage levels at terminals.

Use oscilloscope to check test signal timing and amplitude

Check Test Circuit Wiring

Inspect wiring between test outputs and ES.B.HW input circuits for proper connections and signal routing per electrical schematics.

Verify circuit isolation to prevent feedback loops

Validate Test Sequence Timing

Review PLC program logic for test sequence timing parameters and ensure adequate delay for ES.B.HW input response.

Increase test pulse duration if input response is too slow