Sequence Troubleshooting

The following operations are performed in each module.
Z axis and θ axis: Stops according to the acceleration and deceleration coefficient set in the sequence.
Air drive: Maintains the same status as when stopped.
Sensor: Cancels the target value judge setting.
Status: When the sequence is stopped by a stop input, a sequence stop signal is output. At this time, no timeout signal is output.

Emergency stop is performed by turning off the 24 V power supplied to the controller.

Operation of Each Axis:
Z axis: Servo turns off immediately and the Z axis brakes.
If the operation is being performed at high speed in the downward direction, there is a possibility that inertia may cause it to drop slightly.
Θ axis: Servo turns off immediately. Θ axis has no brake, so it rotates through inertia, loses momentum, and then stops.
Air drive: Both the vacuum valve and the release valve turn off.
During workpiece suction, negative pressure gradually decreases through the gaps in the vacuum structure.
Please contact us for further information regarding the emergency stop.

Homing is required.
Because an incremental encoder is used, the home position is forgotten when the power is turned off.
Also note that homing is generally required when an alarm occurs.
(Alarms for which the home status in the event list in section 8-1-1 of the instruction manual is reset require homing after alarm occurrence.)

Confirm the waveform on the monitor and event history screens.
When the timeout occurred, which module was the last module in operation? If that step operates and a timeout occurs, it is very like that it is stopping at the following step.

If you send us the waveform data, we will be able to assist you in your investigation.

As for the PPR's sequence, it is possible, for example, to determine whether suction has occurred with a pressure sensor.
The various sensor values are transmitted to the host PC/PLC via cyclic communications so that the PC/PLC can also utilize these sensors values.
The timing determined by the pressure sensor can be communicated as a step completion signal.

Here are some example ideas of how to shorten the operation of the picking template.
(1) Speed up the Z axis positioning operation.
(2) Adjust the starting position of the contact stop and shorten the stroke of the contact stop.
Or, increase the speed of the contact stop (make sure that the impact force on the workpiece is in an acceptable range at this time).
(3) Lower the judgment threshold value setting for the pressure sensor.

We can check your actual operations and provide you with improvement proposals if you provide us with the waveform data and information on the current program.

For example, for the following judgments:
- Picking operation failure is determined by whether suction is completed within a certain period of time after the solenoid valve is turned on.
- Placing operation failure is determined by whether pressure is restored after vacuum breakage.

Both can use the timeout judgment in the pressure module.
When the pressure module is operated after the operation of the air drive, it judges whether the pressure reaches the set value.

At this time, if the set time for timeout elapses, the judgment will be a failure. When the timeout operation setting is set to stop, sequence stop will be output to the PLC, so when this signal is output, it can be assumed that suction or release has failed.

We propose two methods.
Method 1: Perform height judgment at contact stop in the PPR's sequence program
Method 2: Set everything until contact stop as a single sequence, and judge height with the PLC when stopped.
You can also consult with us on how to program other operations that you wish to achieve.

Upon confirmation of the monitor waveform, no change was observed in the pressure sensor.
However, the solenoid valve is working.

Possible causes in this situation are as follows:
・The vacuum pump is not working normally.
・It is not properly piped for suction air.
・The solenoid valve is malfunctioning.

We can confirm and analyze the actual operation if you provide us with waveform data and information on the program at the time of occurrence.

Upon confirmation of the monitor waveform, the STEP2 contact stop on the Z axis was the last operation. There is also no change in the value of the force sensor when the machine stops, and the Z axis has reached the contact failure position.

The reason for this may be that the Z axis contact stop operation did not contact the workpiece and instead failed to make contact. The following situations are possibilities, so please confirm the status.
・There is no workpiece.
・The target position of the sequence was just short of reaching the workpiece.
・Because the home position was changed in the user home settings, the workpiece was not reached due to a change in the arrival position.

We can confirm and analyze the actual operation if you provide us with waveform data and information on the program at the time of occurrence.