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COMMAND
Description Command
Function
Pressure setpoint
Sxvalue
Set target pressure; where
value
is the pressure, x is
the recipe number and value is the target pressure
in % FS of the high range sensor.
Slow Pump rate
SRvalue
Set slow pump rate, where value is the slow pump
rate (Torr/sec). Value must be positive. The value
of zero is not allowed.
Slow Pump
Enable
SEvalue
Set slow pump enable, where value is either a 0
(disabled), 1 (enabled both increasing and
decreasing), 2 (decreasing only) or 3 (increasing
only). When slow pump is disabled the target
setpoint will be approached at full speed by the
controller, limited only by controller tuning. When
slow pump is enabled the target setpoint will be
approached at the rate defined by slow pump rate.
REQUEST
Request Message
Information Requested
Response
RSR
Slow pump rate
SR +
value
Where value is slow pump rate
(Torr/s)
RSE
Slow pump enable
SE +
value
Where value is slow pump enable
status (0=disabled, 1 =enabled,
2=decreasing only, 3=increasing
only)
Slow Pump Behavior
When slow pump is changed to enabled (and for each time a new setpoint is entered while slow
pump is enabled), the controller will read the current pressure and compare it with the desired
pressure to determine if the pressure should be increased or decreased to get to the desired setpoint.
Subsequently, the current setpoint will be modified (decremented or incremented per above) every
control cycle until the current setpoint is equal to the desired setpoint. In this way the chamber may
be adjusted in pressure in a gradual manner.
