TVM802A:      Unboxing   ·   Setup   ·   First PCB   ·   Mods   ·   «Hacks»   ·   Eagle ULP


Overview

Connections:

  • Power
  • USB Camera 1 (cameras are directly connected to host PC and not recognized by machine, camera lighting may run via USB or separate channel)
  • USB Camera 2
  • Ethernet with fixed IP (TCP/IP connection)

Actors:

  • X Stepper Motor
  • Y Stepper Motor
  • Suction Pump
  • Suction Relays 1 and 2
  • Pressure Relays 1 and 2
  • Vaccum Tip lift 1 and 2
  • Tip Rotation
  • Transport Plunger
  • Reel Waste Transport
  • Camera LEDs
  • Status LEDs

Sensors:

  • X Endpoints (left, right)
  • Y Endpoints (left, right)
  • Vacuum tip top (1 and 2)
  • ?? Vaccum tip 0 angle (1 and 2)
  • Suction (1 and 2)
  • Plunger top
  • Push buttons (7)
  • Cameras (facing up, facing down)


Camera Protocol

The camera report as XBOX Vision Cameras to the system. Both Win8 and OS X 10 recognize the cameras without installing a driver. Great!


Ethernet Protocol

The Ethernet connection is TCP/IP. All numbers are in LSB/Intel format (not in network order!).

A status request is sent from the host every 20ms (word 0). The machine replies with a status report, probably for every sensor in the machine. So far, I found the X and Y endstop bits and the bits for the pushbuttons.

Every 200ms, the machine sends a register request (command 1 and the address of some register) which is answered by tha machine with the status of the give register.

When the software establishes a first connection, some 400 registers are pulled form the machine. The use of those registers is so far unknown. I am sure it will contain all the calibrartion data found in the software settings.


Conclusion

The controller in the machine seems to be quite limited. Is has no card reader or any other intelligence. I assume that it is limited to interpreting commands and sending status reports. The commands will include simple on/off requests for motors, relays, and lights, as well as positioning commands for the stepper motors (X, Y, Tip1/2, Tip rotation, Waste).

Creating a clone of the software that comes with the machine should be quite easy. The resulting software could be improved in usabilty and import functionality. And it could work on Apple OS X.


How the Feeder transport works

Most SMT components come in rolls. The rolls have a plastic strip with little indentations for the part. A thin film covers the strip to keep the parts from falling out.

The TVM802A holds a stack of 24(?) rolls. The strip passes trough a metal clamp and spring. The picker nozzle uses a vacuum to pick the part from the dip in the strip. If picking fails (the vaccum switch is not triggeres), the part the head moves to a waste bin, then returns to the feeder to try to pick the next part.

To advance to the next part, a plunger (a little steel rod) is mounted to coil (the yellow cylinder in the photo) on the p'n'p head. The head moves to the index hole in strip, then the magnet pulls the plunger down into the index hole. Next, the head moves a few milimeters to the right, advancing the strip. Then, the magnet lets go of the plunger and a spring pulls the plunger upwards and out of the way. Finally, a smaller plastic wheel turns and peels back the thin film on the strip, giving access to the next SMD in the strip. This all happens in a fraction of a second.

The plunge has a sensor that i triggered if the plunger does not return to its top position. This happens if there is too much tension on the strip, and moving the gead would create a huge mess. If it happens, the machine will beep continuously and a dialog box will appear on the host computer.