17020

Check Position Sensor Status

Navigate to DIAGNOSIS > PLC > I/O Status and verify magazine position sensors in DB31.DBX are switching correctly during manual magazine rotation.

Use Service Display S7-300/400 to monitor real-time I/O states

Verify Sensor Wiring

Check 24VDC supply and signal continuity to position sensors using multimeter. Verify connections at PLC input modules.

Disconnect power before checking wiring connections

Test Sensor Response

Manually trigger each position sensor and confirm corresponding DB31.DBX bit changes state in PLC diagnostics.

Dirty or misaligned sensors often cause intermittent position detection

Check Drive Status

Access DIAGNOSIS > Drives and verify magazine axis drive shows 'Ready' status without fault codes. Check for overcurrent or following error alarms.

Look for drive fault history in the alarm buffer

Verify Motor Movement

Use JOG mode in MACHINE > Manual to command magazine rotation and observe actual movement matches commanded direction.

Ensure magazine area is clear before jogging

Check Motor Coupling

Inspect mechanical coupling between motor and magazine for wear, looseness, or obstruction preventing proper indexing.

Listen for unusual noises during indexing that indicate mechanical binding

Review PLC Program

Open SIMATIC Manager and examine tool change FB logic, particularly position confirmation signals written to DB31.DBX interface.

Check for recent PLC program modifications that may have affected tool change logic

Monitor DB31 Interface

Use PLC diagnostics to watch DB31 data block during tool change sequence, verify position request and confirmation handshaking.

Compare working and non-working tool positions to identify pattern

Verify Position Calculation

Check PLC logic calculates correct magazine position based on tool number and pocket arrangement defined in tool management.

Incorrect position calculation can damage magazine or tools

Check Timeout Parameters

Navigate to COMMISSIONING > Machine Data and review MD18080 value. Compare with actual magazine indexing time using stopwatch.

MD18080 should be 150-200% of actual worst-case indexing time

Adjust Monitoring Time

If timeout is too short, increase MD18080 value incrementally and test tool change operation.

Don't set timeout excessively high as it masks real positioning problems

Verify Related Parameters

Check MD18082 (tool change monitoring) and related magazine-specific machine data for consistency.

Document original parameter values before making changes

Visual Inspection

Examine magazine for chips, coolant buildup, or foreign objects blocking rotation. Check for tool holder interference.

Lock out machine power before accessing magazine area

Manual Rotation Test

With drives disabled, manually rotate magazine to feel for binding, rough spots, or excessive resistance.

Magazine should rotate smoothly with consistent effort throughout full rotation

Lubrication Check

Verify magazine bearing lubrication per maintenance schedule. Check for proper grease type and quantity.

Over-lubrication can attract chips and cause more problems than under-lubrication