MKS 651C - How To View and Adjust Set Points

How To View and Adjust Set Points Cha
p
ter Five: Local O
p
eration
50
How To View and Adjust Set Points
The 651 instrument provides five user-definable set points (set point A through set point E).
Each set point can be configured as a
pressure
set point or a valve
position
set point. Pressure
set points are displayed in units of Torr, mTorr, mbar, µbar, Pascal, or kPa. Position set points
are displayed in % open of F.S., where 0 = closed, and 100 = open.
Only one set point can be designated as the active set point. The active set point (or valve
position) is indicated by a light in the appropriate set point key.
1. Hold down both arrow keys, [
] and [ ] for approximately three seconds to enter
the Setup menu.
2. Scroll until the Control mode screen appears and verify that PID is selected.
3. If Self-Tuning is selected, turn the Adjust knob clockwise to select PID control.
4. Scroll to the set point A screen.
A sample display of set point A (SP A) is shown below. In this example, set point A is
defined as 100 mTorr, and the system
pressure
at this time is also 100 mTorr.
SP A 100 mTorr
PRES 100 mTorr
5. Adjust the displayed set point with the Adjust knob on the front panel.
The system responds by immediately storing the set point value. The system pressure
does not change however, unless the displayed set point is the active set point.
The display shown below provides another example of a set point display. In this case, set point
D (SP D) is configured as a valve
position
set point. The valve position is indicated in % open of
F.S., where 0 = closed, and 100 = open. In this example, set point D is configured for a valve
position of 60.0% open of F.S., and the system pressure is shown as 2.000 Torr.
SP D 60.0 %
PRES 2.000 Torr