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Programming Function Blocks and Features
Video Recorder – User Manual 114
Math
Performs math on up to 8 inputs using a single operator. Output is CVn OV. Division by 0 is indicated
by CVn OV’s displayed value flashing 0.
Table 4-22 describes the Math prompts. See Table 4-2 for additional prompts.
Table 4-22 Math Prompts
Prompt Range/Selections Definition
INPUT A - INPUT H OFF, analog parameter,
number.
Enter up to 8 input sources.
If connecting to an upstream loop, that loop output (LP# OV)
MUST be INPUT A (see Feedback).
OUTPUT LOW LIMIT
OUTPUT HIGH LIMIT
Enter limits Displayed output value will be clamped and will flash when
these limits are exceeded.
OPERATOR ADD, SUBT, MULT, DIV,
ABSVAL, SQRT and
STDDEV.
1. Input A OPERATOR Input B OPERATOR...Input H
where OPERATOR is one of these:
add, subtract, multiply, or standard deviation
(Standard Deviation uses all inputs.)
Example: Input A minus Input B minus ...Input H.
2. OPERATOR Input A
where OPERATOR is absolute value or square
root.
3. Input A OPERATOR Input B
where OPERATOR is divide.
Note: Inputs 3-8 are not used in division.
FEEDBACK OFF, analog parameter,
number
Select LP# BC or AO# BC to propagate the back calculation
(BC) value from a downstream loop or AO. Also, program
the upstream loop's feedback with this Math CV's back
calculation value (CV# BC). You MUST program this CV's
feedback to NONE if this CV is not used as part of a control
loop output configuration (Figure 4-4). If it is part of a loop
configuration, the math operator cannot be ABSVAL, SQRT,
or STDDEV.
BC
PID
AO
PID
FB
INP 1
MATH
CV
BCFB
OR
Figure 4-4 Math CV Feedback Programming