2. Using coordinate special item 1 for the prealigner (station c), it is possible to shift the radial value for
Get/Put of 4-inch wafers. Normally, the robot will Get/Put 6-inch wafers on center, and will Get/Put 4-
inch wafers slightly off center. In order to Get/Put both 6-inch and 4-inch wafers on center, use the
command SCSI c,1,-400 and then save the coordinates as shown in the discussion of Optional Timing
Changes. No change has been programmed for 8-inch wafers.
3. The new program called stations can be used to save robot station coordinates AND scanning
coordinates.
Grind Seal Protection
An optional hardware modification allows installation of sensors to determine whether the left and right grind
seals are truly inflated or deflated. Without this option, software behaves as it has always done, remembering
whether its most recent request was inflate or deflate. That has worked well until a vacuum or air pressure
failure has misled software into thinking the seal was deflated when it was not.
If the sensors are installed, software can be told to read them by setting Machine Variable 47, Grind Seal
Sensors 0=No, to a non-zero value. Setting this variable without the sensors installed will result in a “Left
Grind Seal” or “Right Grind Seal” fault. Those faults and the “Left Grind Seal Vacuum” and “Right Grind
Seal Vacuum” faults signal a problem with the seals and will stop bridge movement and prevent grinding.
If Machine Variable 47 is turned on or off during 7AF operation, it may be necessary to cycle the
inflate/deflate of each seal one time to bring software and hardware into sync. It is only necessary to cycle
these if a fault message appears. To cycle the grind seals, select Machine Maintenance, then Inputs/Outputs.
Press the icon for the Left Work Chuck and then press the Grind Seal box once to inflate and then again to
deflate. If you look at the Input Status on the other side of the screen, you will see Inputs 29 and 30 change
from black (off) to green (on). Inflate just changes one time, but deflate changes twice. Input 30 will turn
green then black then green again. This shows that the vacuum is working properly to fully deflate the seal.
If Input 30 were to turn green and stay green on deflate, this would mean that the vacuum is not working
properly. After cycling the Left Grind Seal, select Close and then repeat this process with the Right Work
Chuck icon and its grind seal.
Password Change
A modification is introduced to the 7AF password security system. Up to this time, Machine Variable 53,
Password Needed 0=No, had two meanings. If zero, no password was needed. Otherwise there are levels
of password security and different levels allow access to various screens of the 7AF. This is described in the
paper “7AF Password Security” dated 12/6/96. These two possibilities are still available, but are now
activated by setting Machine Variable 53 to zero and one respectively.
If Machine Variable 53 is set to two, passwords are required. All password levels have access to all screens
of the 7AF, but the lowest level, Operator, is unable to make use of the Reset Meter button on the Grind
Data screen. The two higher levels do have access to that button. This change was made to alleviate
situations where passwords were wanted but were an inconvenience.
Changing Machine Variable Values Made Easier
In the past, changing any machine variable required homing and referencing the 7AF. This has now been
relaxed. If a variable related to homing and referencing is changed, home and reference will still be needed.
But if the only variables changed are unrelated to homing and referencing, it will not be necessary to home
and reference before continuing work.
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