Configuring NXC100 Motion Hold for Funnel Interlocks

After the fix, the robot can lower the pump only while the funnel-open permissive remains valid; loss of that permissive pauses the path, and a validated return permits continuation toward the programmed target. Implement this as a maintained motion permissive using the Job Interrupt option, not as a one-time input check before the move.

Interlock approach comparison

The critical distinction is whether the controller evaluates the funnel signal once or monitors it throughout the hazardous portion of the path. A wait instruction before the move proves only that the funnel was open at one instant. It does not react if the input drops after motion begins.

Recommended control architecture

Use the funnel-open indication as a maintained permissive for the final lowering move. Configure loss of that permissive to invoke an interrupt job containing Pause. Generate the resume request only after the funnel-open state has returned and remained acceptable through the input-conditioning logic.

Separate three meanings in the interface even if they originate from one physical sensor:

Do not derive Pause and Start as simultaneous inverses of a noisy input. Apply signal discrimination so the restart condition cannot become true during the same transition that generated the pause. Determine any delay from measured sensor stability and controller response rather than assigning an arbitrary time.

Prerequisite validation

1. Confirm the physical state. Before anything else, verify that the sensor proves the funnel is mechanically open, not merely that the pneumatic valve has been commanded open. Cycle the gripper slowly and compare the input transition with the actual jaw position.
2. Confirm input polarity. Record which monitored input state means open and which means closed, disconnected, or unpowered. Do not move on until removing sensor power or disconnecting the signal produces the motion-inhibiting state.
3. Confirm stopping clearance. Measure whether the robot can stop from the highest commanded speed before the pump or tooling reaches a closed funnel. A software pause is ineffective if total detection and stopping distance exceeds the remaining clearance.
4. Confirm controller capability. Check that the Job Interrupt option is enabled on the NXC100 controller and that the running job can be interrupted at the required point.
5. Confirm restart authority. Decide whether restoration of the sensor may restart automatically or whether the machine sequence must provide a separate restart authorization. Use a manual or supervisory restart when automatic movement after a field-device recovery would create an unacceptable hazard.

This equipment-protection interlock does not establish a personnel-safety function. Where personnel exposure is possible, perform the stop and restart control through the machine's risk-assessed safety system and approved robot safety functions.

Interrupt and restart procedure

1. Create the interrupt job. Place Pause in the job invoked when the funnel-open permissive is lost. Keep this job limited to the actions needed to stop and establish a known paused state.
2. Map the interrupt condition. Associate loss of the validated funnel-open input with the interrupt job. Test the mapping from the controller input monitor before enabling automatic motion.
3. Gate the final lowering move. Require the funnel-open permissive before starting the motion that lowers the remainder of the pump onto the bottle neck. This initial gate prevents a move from starting while the funnel is already closed.
4. Maintain monitoring during travel. Leave the interrupt condition active for the full segment in which a closed funnel could be struck. Do not clear or mask it immediately after the move begins.
5. Condition the restart signal. Generate Start only after the open input has returned to a stable state and the pause request has cleared. If one sensor drives both decisions, use state logic so the controller completes the pause transition before accepting restart.
6. Preserve the target. Resume the interrupted job rather than issuing a new move from an assumed position. Confirm in reduced-speed testing that the controller continues the original programmed path instead of restarting the whole placement sequence.
7. Handle persistent faults. If the permissive does not return, keep the robot paused and report the missing funnel-open condition to the machine sequence. Do not bypass the input to finish the cycle.

Stop-and-resume mechanism

A robot move is planned and executed over multiple controller cycles. Testing an input immediately before the move controls entry into that operation, but the path continues unless another controller function changes the running state. The interrupt supplies that asynchronous path: loss of the permissive diverts execution to the interrupt job, where Pause requests the stop.

When the permissive returns, Start releases the paused execution. The controller should then continue toward the programmed target. Verify this behavior on the installed controller because interrupt scope, job resumption, and restart handling depend on the configured option and job structure.

Recurring faults in this design come from sensor chatter, using a valve command instead of position feedback, masking the interrupt too early, and allowing a restored input to restart motion without sequence authorization. A second appropriately mounted sensor can validate the mechanism when one device cannot reliably prove the full-open position. Combine the two signals into one validated permissive and make any disagreement inhibit motion.

Commissioning verification

1. Run the sequence at reduced speed with the funnel opening normally. Confirm the final lowering move starts only after the open permissive becomes valid.
2. Remove the permissive shortly after the final move starts. Confirm the interrupt job executes Pause and the robot stops with physical clearance from the funnel.
3. Restore the input while restart authorization remains blocked. Confirm the robot stays paused.
4. Apply the authorized Start condition. Confirm the robot continues toward the original programmed target without repeating an earlier placement step.
5. Toggle the sensor near its switching point. Confirm input conditioning prevents alternating pause and start commands.
6. Test a disconnected or unpowered sensor. Confirm the resulting state inhibits the move and cannot generate an automatic restart.

Frequently asked questions