Atmospheric Single-Arm Robot Manual
4000-0016 Rev A
57
Scanner Mapping
The mapping operation consists of several steps. You run the MAP macro
(MAP <station name>) by issuing the command from Terminal mode on
the Teach Pendant, EQT, or from your host system. The MAP macro can
vary from system to system, but the normal sequence of robot actions is as
follows:
1. Moves to the taught position where the sensor is at the prescribed
distance from center on the T axis (T-axis Offset), the correct focal
distance (R-axis Offset) away, and below the first slot of the cassette
(Z-axis Offset).
2. Turns on the laser scanner.
3. Makes the first scan pass.
4. Turns off the laser scanner.
5. Offsets an equal and opposite distance from center on the T axis and
moves Z distance down.
6. Turns on the laser scanner.
7. Makes the second scan pass.
8. Turns off the laser and retracts.
During each scan pass, the laser sensor passes in front of each wafer in the
cassette. When the laser meets the edge of a wafer, the reflected signal is
sensed and a change of state occurs. Another change of state occurs when
the sensor no longer “sees” the wafer. The Z-axis coordinates for the
changes of state are stored, compared, and processed by the controller.
Using the various scanning parameters, the controller determines the status
of each slot and stores the value in a register.
At this point, you can query the controller for the scan results of a
specified slot or all slots by using the RSR macro, which calls the RSS
command. The slot status is given by one digit, as follows:
0 = No wafer in slot
1 = Wafer in slot.
2 = Wafer cross-slotted between two slots.
3 = Scanner failed to detect the wafer.
For example, if all slots are queried, a string of digits is returned:
100011111221111100011221
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