231-6016

Check Power Supply Voltage

Navigate to MOD > SYSTEM > DIAGNOSIS > VOLTAGE and verify 24VDC supply reads between 21.6V-26.4V under load conditions.

Check voltage during spindle acceleration when power demand peaks

Measure at Terminal Strip

Using DMM, measure 24VDC at X116 terminals (typically pins 1-2) on the TNC control cabinet terminal strip during machine operation.

Ensure proper lockout/tagout procedures before accessing electrical panels

Load Test Power Supply

Connect temporary load resistor across 24VDC output and verify voltage stability. Replace power supply if voltage drops below 21.6V under rated load.

Use 24V/10W automotive bulb as quick load test

Access Safety Module Diagnostics

Navigate to MOD > SYSTEM > DIAGNOSIS > SAFETY and check X116 module status. Look for internal fault codes or voltage monitoring errors.

Document all displayed fault codes before clearing for service report

Swap Safety Modules

If available, swap X116 with identical spare module. Clear alarm using CTRL+CE and test STOP2 function to verify fault follows module.

Only qualified personnel should handle safety-rated components

Verify Module Firmware

Check X116 firmware version in MOD > SYSTEM > VERSION and compare against latest Heidenhain safety module updates for known issues.

Keep safety module firmware separate from TNC updates for traceability

Measure Voltage Drop

With STOP2 circuit energized, measure voltage at power supply output vs. X116 input terminals. Voltage drop should not exceed 0.5V.

Use separate DMM leads to avoid measurement errors from probe resistance

Check Terminal Connections

Inspect all terminals in STOP2 circuit path for corrosion, loose connections, or burned contacts. Torque terminals to specification (typically 0.8-1.2 Nm).

De-energize circuit before terminal maintenance

Test Wire Continuity

Perform continuity test on 24VDC supply wiring from source to X116. Replace any wiring showing resistance >0.1 ohms per 100 feet.

Check for intermittent connections by flexing wire harnesses during testing

Check EMI Filtering

Verify 24VDC supply has proper EMI filter installed and grounded. Navigate to MOD > SYSTEM > DIAGNOSIS > EMC to check interference levels.

EMI issues often correlate with specific machine operations like rapid traverse

Separate Power and Signal Cables

Ensure 24VDC power cables maintain minimum 6-inch separation from encoder cables, communication lines, and high-current motor cables.

Never run safety circuit wiring in same conduit as variable frequency drive cables

Install Line Conditioning

Add ferrite cores or LC filter to 24VDC supply lines near X116 module. Set machine parameter MP7300 (EMC filter level) to higher setting if available.

Snap-on ferrite cores provide quick EMI suppression test without rewiring