Writing Expressions - YOKOGAWA GX20 User Manual

1.8.3 Writing Expressions
Common Items
IM 04L51B01-01EN
Follow the rules below when writing expressions.
• Use up to 120 characters to write expressions.
• The precedence of computing terms can be specified using parentheses.
• Specify channels in expressions using channel numbers.
Example: 0001, 0012, A001, C001, W1, Z1
• The "0" in the top digit of I/O channel numbers (0101), math channel numbers (A001),
communication channel numbers (C010), constants (K), internal switch numbers (S),
flags (F), and recording status (REC), variable constants (W), integer data (Z) can be
omitted.
Examples: 101, A1, C10, K1, S1, F1, REC1
• The data of the previous scan is used in the computation for its own channel number and
channel numbers greater than its own channel number in the expression.
• Write special computations (HOLD, RESET, and CARRY) and conditional expressions at
the beginning of expressions.
Order of Precedence in Computations
The order of precedence of computation in expressions is as follows:
Type Computing Element
Function ABS(), SQR(), LOG(), LN(), EXP(), TLOG.MAX(), TLOG.MIN(), TLOG.
AVE(), TLOG.SUM(), TLOG.P-P(), TLOG.PSUM(), CLOG.MAX(), CLOG.
MIN(), CLOG.AVE(), CLOG.SUM(), CLOG.P-P(), BIT, INT, SIN, COS,
CLOG.PAVE, CP.O2, CP.CO2
Special computation and PRE, HOLD, RESET, CARRY, [a?b:c]
conditional expression
Power **
Logical negation NOT
Multiplication and division *, /, MOD
Addition and subtraction +, –
Greater than and less than .GT. (or >), .LT. (or <), .GE. (or >=), .LE. (or <=)
Equal and not equal .EQ. (or =), .NE. (or <>)
Logical product AND
Logical sum and exclusive OR, XOR
logical sum
1.8 Configuring Math Channels (/MT option)
1
2
3
4
5
App
Index
1-91