Micromod Micro-DCI: 53MC5000 Multi-Loop Process Controller CUSTOMIZATION GUIDE - Manual (Page 18)

Data Type Positions Required
L and B 1
C 3
H 5
A 10
F 5
F-TRAN statements must be written in Reverse Polish Notation (RPN). This is a form of post fix no-
tation (commonly used in many engineering calculators) that conforms to the following rules:
1. Expressions in RPN are always evaluated from left to right; no parenthesis - no operator prece-
dence.
2. The operator directly follows its operands. For comparison purposes, some examples of alge-
braic equations restated in RPN are given below.
Algebraic Equation RPN
A + B AB +
A (B + C) BC + A *
A - B AB -
A
B
+ C AB / C +
A
+B
C
AB + C /
2.4.4.2 Stack Memory Operation
The following example statement includes a combination of operands and operators from the F-
TRAN instruction set as used for a mathematical computation.
C33 = C01 C13 * C12 +
The equal sign directs that we execute the right hand side of the statement and then replace the
previous value of C33 with the solution value. Following the equal sign, reading from left to right,
the computation would be executed as follows:
“C01” 1) Place the value of C01 in the stack memory (level 1).
“C13” 2) Place the value of C13 in the stack memory (level 1),
pushing the value of C01 down to (level 2).
“*” 3) Remove and multiply the top two values in the stack
and place the resulting value back in the stack (level 1),
leaving (level 2) clear.
“C12” 4) Place the value of C12 in the stack (level 1), pushing
the product value “C01 C13 *” down to (level 2).
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