MKS 651C - How To Activate the Learn Function

Chapter Five: Local Operation How To Activate the Learn Function
53
How To Activate the Learn Function
The learn function, activated by pressing the [L
EARN
] key, enables the 651 unit to identify
important system characteristics for Self-Tuning control. Use the learn function whenever the
651 controller is used in a new vacuum system or when processing conditions are changed (such
as changed flow rate, new or refurbished pump, or piping modifications). The learning process
may take several minutes to complete.
Note
The s
y
stem
p
ressure will var
y
durin
g
the learn c
y
cle to as low and hi
g
h as
is possible for the current flow rate.
1. Initiate the proper gas flow into the system.
The Gas flow rate should be close to that used for the actual process (use the maximum
flow rate if several flow rates are used in the process).
Do not vary the gas flow rate during learning.
2. Press the [L
EARN
] key for about three seconds.
The system responds by illuminating a light in the [L
EARN
] key, and initiating the
learning process. The front panel window displays the changing values of pressure and
position as the instrument learns the system. The light stays on until the learn function is
complete.
How To Stop the Learn Function
It is recommended that the learn function go through to completion. However, if your process is
slow to reach its highest pressures
and
your process will not be operating at those pressures, it is
possible to stop the learn function early.
Caution
Do not stop the learn function until it is well above the highest
pressure at which the process will be operating.
Press the [L
EARN
] key and the [S
TOP
] key simultaneously for about three seconds. The
system responds by stopping the learn function and returning to its prior operation. For example,
if the valve was closed before the [L
EARN
] key was pressed, the valve will now close.