This FAQ is contains information relating to the operation of the autohandler, specifically the Z axis, faults and remedies.
This does not cover all potential faults, but wil lbe expanded as and when they are found to aid in future debugging scenarios.
Explanation of Pick Process
The 4X autohandler uses the Galil Motion Controller to send step and direction signals to X and Y to get them to the X/Y encoder position for the pickup location.
When the encoders report the correct taught position, Galil turns on the vacuum and reads the Vacuum Transducer.
Z step and direction signals are sent to the Z driver to drive the Z down to the taught Z position plus the Pickup Overdrive, all the time monitoring the vacuum transducer looking for a vacuum change greater than N (typically 1.5 VDC for non VSP devices) and within a time-out period (default is 300 ms.).
Assuming a vacuum change is detected, Galil sends Z step and direction signals to drive the Z back to the home position plus the Alignment Offset.
The Cyberoptics camera will flash on for a quick check, looking for the presence of a device on the nozzle. If no device is found, there is a certain error message, "Vacuum change detected, but no device on the nozzle.").
Assuming a device is detected, Galil then sends step and direction signals to X and Y to go to the X/Y encoder position for the placement, while at the same time, the Cyber subsystem performs the laser alignment on the fly. Any X or Y offset from the alignment if fed back to Galil to be applied to the placement for accuracy.
Knowing this process, we can interoperate any errors that are displayed which relate to vacuum, pickup, alignment and axis control.
Fault
Cyber view does not detect the presence of a device or nozzle
Tests
Cyberoptics is a laser line which is used to detect the nozzle width and device as it passes through it, imagines a cross-section of the item in its view.
This is a critical component for the pick and place and measurement aspect of the system.
In this case, standard Cyber troubleshooting techniques apply, clean the camera lenses using lint-free cloths (no chemicals) and then get a screenshot of Cyberview.
Cyberview is a utility inside BPWin software, which will enable you to see a waveform representing anything in the Cyberoptics field of view.
When the Z-axis is homed (up), this waveform will be horizontal, nothing detected.
When the Z-axis is brought down into the Cyberoptics field of view than a falling and rising edge, similar to a square wave, will be seen. It is this waveform that is used to determine the width.
We need to understand if this is functioning correctly with nozzle up and down.
More information on Cyberview can be found in BPWin help file, simply press F1 when BPWin is running and search for Cyberview.
Fault
During initialization, the 4x handler attempts to Home the Z-axis first, if this fails then no other axis will be tested.
The Z axis is taken up until the Cyberoptics sees that the underside of the Z rod nozzle is clear however the upper limit sensor is reached and the motor continues to move, thumping up against the mechanical limit.
Remedy
Replacing the upper limit sensor resolved this issue.
Check the LED status on the rear side of the Head Board. Z Upper Limit Sensor LED on DN1 should come ON, when the Z axis is in the upper position.
Check that the black Z Upper Flag passes into the Z Upper Limit Sensor which is fixed to the Spline assembly
Replacing the Head Board resolved this issue.
Fault
BPwin and BlackBox files detect an issue with homing the Z axis or the Z axis does not move correctly.
Remedy
Shut down the system and then disconnect the 4 Way connector from the Z-axis motor, which connects to the front of the Head Board.
Power is not required for this test.
Check resistance between pins on the Z-axis motor, refer to the attached drawing 622848891_Measuring Z Motor (1).bmp and ensure that you obtain correct results.
If they do not match or measure open circuit, then replace the motor.
NOTE, this could be a secondary fault, with the primary fault being with the Z-Axis Motor Driver board. Fault process depends on the type of Motor Driver installed in the system.
Fault
Z-axis appears to be hot, subjective, can indicate a faulty motor or overdrive from motor driver board.
Replacing the Z motor driver board.
This is located at the back of the system. You will see a panel at the lower left-hand side, which needs to be removed via a set of Phillips screws.
Once inside, on the left you will see two PCBs Z and T, there are some ID marks on the chassis. Some systems may have uprated X and Y motor driver packs, these are the two black boxes on the right side and can be ignored at this stage.
The Z axis board is the one that needs to be swapped out, but first confirm what the switch settings are. If you have a known working motor driver board, then I would swap them over to see if the fault moves. For example, if you swap Z and T the fault should move the T axis, confirming a defective board.
You could take Z from a working machine as that is 100% functional, but that has production implications, alternatively, Z and T can be swapped but you will need to change the DIP switches. Care must be taken when swapping motor drivers board, they look the same but are configured and calibrated differently depending on the axis they are used on and if they are used in a DOS or Windows system.
DOS boards MUST be converted to Windows versions before being used.
if in doubt, please ask.
Voltage values need to be set on the driver board. Measure at the test pins above and below the DIP Switches, with Positive on bottom. Measurements should be made with the system powered on, with all associated cables connected and in an idle state. Voltages are DC.
Driver board fully connected.
Z 1.0
T 1.0
Notes:
1. The voltages have a tolerance of about 10%.
2. In either condition, a good motor being connected will have no effect on the voltage. I don't know what effect, if any, a bad motor has on the voltage. The best way I know to check a motor is to measure the resistance on both windings. (Pins 1 and 2, compared to pins 3 and 4)
X or Y motor - 0.8 ohms typical
Z motor - 1.7 ohms typical
T motor - 1.2 ohms typical
A resistance of 37 ohms is typical of a bad motor winding.
3. The DIP switch sets the resolution of the motor. (mils per pulse)
How can a Z rod crash occur?
If there is a fault with the Z motor driver relating to step pulses and the device selected is similar in length as the attached nozzle, then there is a slim chance this could occur.
Essentially, the Z rod goes down to pick up a device and a vacuum change is detected indicating it found the device. On some faults the nozzle may not go up completely when it is commanded. The cyber optics camera will flash on and see the Z rod, assumed it is a device, and then drive X and Y bending the Z bellows and scattering parts.
We can confirm that the Cyberoptics is functioning correctly using the process mentioned above.