190

Visual Inspection of E-Stop Buttons

Check main control panel E-stop (red mushroom button), pendant E-stop if equipped, and any external E-stop stations for pressed or stuck condition.

Do not bypass or disable E-stop buttons - they are critical safety devices

Release E-Stop Buttons

Twist and pull out any pressed E-stop buttons clockwise until they pop out to the released position. Ensure all buttons move freely without binding.

E-stop buttons should have a distinct 'click' when released and should spring back firmly

Reset Alarm and Test

Press RESET on the control panel to clear Alarm 190, then press POWER UP to restore machine power. Verify all axes can be moved in JOG mode.

If alarm returns immediately after reset, the E-stop circuit is still open

Check Machine Enclosure Doors

Verify all machine doors and access panels are fully closed and latched. Check door limit switches for proper engagement and alignment.

Door switches should make audible contact when doors are closed - listen for the 'click'

Inspect External Safety Devices

Check any customer-installed safety devices like light curtains, safety mats, or additional E-stop stations. Verify beam paths are clear and devices are powered.

Never bypass safety devices - identify and correct the safety condition

Verify Safety Chain Continuity

Access DIAGNOSTICS > I/O and check E-stop related inputs. All safety devices in series must show closed/active status before alarm can be cleared.

Document which safety device caused the trip for future reference

Check E-Stop Wiring Connections

Inspect wiring at main E-stop button, pendant connector (if equipped), and any junction boxes in the E-stop chain for loose or corroded connections.

Power down machine and follow LOTO procedures before checking electrical connections

Test E-Stop Circuit Continuity

Using a multimeter, verify continuity through the complete E-stop chain from the NGC control E-stop input terminals through all series-connected safety devices.

E-stop circuit should read near 0 ohms when all devices are in normal operating position

Repair Wiring Faults

Repair any broken wires, tighten loose connections, or replace damaged connectors. Ensure all connections are secure and properly insulated.

Use proper gauge wire and maintain the series safety chain - never parallel safety devices

Verify External Circuit Integrity

Confirm E-stop circuit continuity with multimeter while alarm is present. If external circuit tests good but alarm persists, suspect control input failure.

Measure voltage at NGC E-stop input terminals - should see 24VDC when circuit is closed

Check NGC Diagnostics

Access DIAGNOSTICS > PARAMETERS and check E-stop related parameters. Review DIAGNOSTICS > I/O for E-stop input status display.

Do not modify safety-related parameters without proper authorization and documentation

Contact Haas Service

If external E-stop circuit tests good but NGC control continues to show Alarm 190, contact Haas technical support for control module diagnosis and potential replacement.

Document all test results and parameter values before calling for faster diagnosis

Disconnect Pendant Cable

Unplug the pendant cable from the machine and check if Alarm 190 clears. If alarm persists, fault is not in pendant circuit.

Pendant E-stop is wired in series with main E-stop chain through the pendant connector

Test Pendant E-Stop Function

With pendant connected, manually activate pendant E-stop button and verify it creates firm contact. Check for loose button or damaged internal switch.

Replace entire pendant if E-stop button is damaged - do not attempt internal repairs

Inspect Pendant Cable

Check pendant cable for damage, especially at connection points and where cable flexes during use. Test continuity through E-stop circuit wires in cable.

Pendant cables fail most often at the machine connection end due to repeated flexing