SYST-001

Check teach pendant HOLD button

Inspect the yellow HOLD button on the teach pendant. Verify it is not stuck in the depressed position. The button should spring back when released. If stuck, the button mechanism may need replacement.

Do not disable hold functionality by bypassing buttons. HOLD is a critical safety feature for operator intervention.

Check operator panel HOLD button

Locate the HOLD button on the main operator panel (typically yellow or orange). Ensure it is in the released position and not mechanically jammed. Press and release to verify proper spring action.

Older panels may have accumulated dirt or adhesive residue causing buttons to stick. Clean around button housing with isopropyl alcohol.

Verify hold circuit continuity

Navigate to MENU > I/O > Signal > HOLD to view real-time hold circuit status. All hold inputs should show '0' (not active) when buttons are released. If showing '1' with no button pressed, suspect wiring or switch contact failure.

The hold circuit is series-connected. A fault anywhere in the chain will trigger this alarm.

Clear alarm and resume

After releasing the HOLD button, press the RESET button to clear the alarm. Press and hold CYCLE START to resume program execution. The alarm will immediately return if hold condition persists.

Check digital input status

Navigate to MENU > I/O > Digital > IN. Scroll to find *HOLD or HOLD input signal (commonly DI[18-24] depending on configuration). Status shows [ON] when active. Note which input number is causing the hold condition.

Press F1 [TYPE] and select 'Comment' to see descriptive labels for I/O points configured by the integrator.

Verify PLC output status

Check the corresponding PLC output that controls the HOLD input signal. Verify PLC logic conditions are satisfied for releasing hold (e.g., safety gates closed, upstream equipment ready). Use PLC HMI or programming software to monitor output coil status.

Do not jumper or force HOLD inputs. These signals are typically part of safety interlocks and must be properly satisfied.

Inspect I/O configuration

Navigate to MENU > I/O > Config. Verify the HOLD input is correctly assigned. Check MENU > SYSTEM > Config > DI Assignment for standard input mapping. Verify proper signal type (sink/source) and voltage levels match field wiring.

Check parameter 'I/O' parameters via MENU > SYSTEM > Variables > $DIN for runtime signal state vs configuration.

Test signal isolation

Temporarily disconnect the external HOLD input wire at the robot's I/O terminal block while in a safe test mode. If alarm clears, the issue is external. If alarm persists, check internal wiring or configuration. Reconnect and resolve external cause.

Only perform this test when safe to do so and with proper lockout/tagout procedures. Document which wire was disconnected.

Check UOP signal status

Navigate to MENU > I/O > UOP Signal. Verify UI[02] HOLD status. When active (value=1), the external controller is asserting hold. UI signals are typically mapped starting at UI[01]. Check UOP panel display for status indicators.

UOP signals operate through the controller's panel interface port, not standard I/O. Verify panel cable CN5 connection on the controller is secure.

Verify UOP configuration parameters

Check MENU > SYSTEM > Config > Panel Config. Verify UOP is enabled and configured correctly. Review parameter settings for UOP_TYPE and UOP_PANEL. Incorrect settings can cause spurious hold signals.

Common UOP types: 0=iPendant only, 1=UOP enabled. If recently changed, power cycle controller to reinitialize panel communication.

Diagnose external controller logic

Review the integrated HMI or PLC program that controls UOP signals. Check for hold interlock conditions such as safety circuit faults, mode selection conflicts, or communication timeouts. Verify HOLD release conditions are met in external logic.

Many integrators use UOP HOLD during mode changes or when the external HMI is in setup mode. Check mode selector status on UOP.

Test UOP communication

Disconnect the UOP panel cable at the controller (CN5 connector on main CPU board). If alarm clears, the UOP device is actively sending HOLD. If alarm persists, internal configuration issue exists. Reconnect and troubleshoot UOP device program.

Disconnecting UOP during production may trigger additional alarms. Coordinate with operations before testing.

Identify program position

Note the current program name and line number displayed on the teach pendant when alarm occurs. Press SELECT to view the current program. Look for HOLD instruction at or near the current line number.

HOLD instructions are often placed after critical operations requiring verification, such as 'Wait for inspection' or 'Manual load part'.