P stc-2002, Deposition controller y – INFICON STC-2002 Thin Film Deposition Controller Operating Manual User Manual
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p STC-2002
DEPOSITION CONTROLLER
y
SECTION 2.XX
e page 43 of 276 ^
I/O programs are constructed using the LCD/touch panel menus. Programs are written in Reverse Polish
Notation (RPN) by constructing one (or more) line entities that are called rungs. If a single I/O
programming task of the total work to be accomplished takes more than one line, an intermediate variable
called a softnode can be used to carry the partial result of the task from one line into another line that
completes the work.
Example illustrating softnodes:
(where
x and y are used like softnodes in the following 3 generalizations)
2 + 3 + 5 = x
← assignment of the x softnode, one program line (or rung)
in Algebraic Notation
2 + 5 = y
←
assignment of the y softnode, another program line (or rung)
in Algebraic Notation
x + y – 3
← combining the softnodes, another program line (or rung)
in Algebraic Notation
Example illustrating notations:
Algebraic Notation (2 + 3 x 5) vs RPN (2 3 5 x +) answer (in either notation): 17
Algebraic Notation ((2 + 3) x 5) vs RPN (5 3 2 + x) answer (in either notation): 25
[RPN is used to eliminate abiguous and error prone precedence rules determining the order of evaluation and
because of the stack oriented nature of RPN that is conducive to the I/O programming structures.]
The line length limitation is purely a result of LCD screen size limitations. Each program line (or rung)
has an input statement, an output and a consecutive line number (for line identification). A softnode can be
used as the output of the line (or rung).
Aside from states and events, there are arithmetic, relational, selectional and logical (Boolean)
operators used for I/O programming. The logical operators are AND, OR, XOR and NOT. A Boolean
value can have only 2 states. There are many alternate names for these 2 states (respectively): true/false,
on/off, 1/0, high/low, closed switch/open switch, system voltage/zero voltage, positive voltage/negative
voltage, even negative voltage/positive voltage, etc. Logic levels conform to the following table:
Where logic level 0 = zero volts, logic level 1 = system high volts, Boolean value T = true and Boolean value F = false.
Logic Levels In
Boolean Value In
AND [&] result OR [¦] result
XOR [^] result
NOT [!] result
0 F
(2 or more inputs only)
(2 or more inputs only)
(2 or more inputs only)
T
1 T
(2 or more inputs only)
(2 or more inputs only)
(2 or more inputs only)
F
00 FF F
F
F
(uses 1 input only)
01 FT F
T
T
(uses 1 input only)
10 TF F
T
T
(uses 1 input only)
11 TT T
T
F
(uses 1 input only)
(with 3 inputs )
(using 2 AND operators )
(using 2 OR operators )
(using 2 XOR operators )
(uses 1 input only)
000 FFF F
F
F
(uses 1 input only)
001 FFT F
T
T
(uses 1 input only)
010 FTF F
T
T
(uses 1 input only)
011 FTT F
T
F
(uses 1 input only)
100 TFF F
T
T
(uses 1 input only)
101 TFT F
T
F
(uses 1 input only)
110 TTF F
T
F
(uses 1 input only)
111 TTT T
T
T
(uses 1 input only)
Although the above table ends with three inputs, this does not imply an I/O programming input limitation
as many elements can be OR'ed, XOR'ed or AND'ed together but there is a syntactical limit of 2 elements
only per each OR, XOR or AND operator. These can be cascaded to the limit of the line length and,
beyond that, using softnodes, to the limit of the program maximum length.
The constituent parts of a program line (or rung) consist of logical operators and elements that are logically
combined or altered by them. These elements involve what was previously described as a token.
Token
constituent elements can also include a single Boolean operator.