User`s manual

2-2 • E2 User’s Manual Supplement: Flexible Combiner 026-1620 Rev 0 09-15-05
Digital Input Values and Analog Conversion
A digital input value is converted to a numerical value
when read into Flexible Combiner equations. A digital
input that is ON is treated as a unitless analog value of 1.0.
An OFF is treated as an analog value of 0.0. Logical oper-
ators such as AND, OR, XOR, and other functions typi-
cally used to combine digital inputs are all designed to
treat non-zero values as ONs for purposes of logic, and
zero values as OFFs.
2.2 Constants
In addition to inputs, Flexible Combiner equations will
typically require use of constants. These can be either
numeric constants (entered as numbers and used as num-
bers), named consents (named strings that are parsed as
numbers), or time constants (times of day used in com-
parisons). Table 2-4 and Table 2-5 show the different
types of numeric and named constants.
2.2.1 Constants and Engineering
Units
Numerical and named constants are assumed to be
Electrical
Current
amperes (A)
milliamperes (MA)
amperes (A)
Power Rate watts (W)
kilowatts (KW)
watts (W)
Power Con-
sumption
watt-hours (WH)
kilowatt-hours(KWH)
watt-hours
(WH)
Lumination foot-candles (FTC)
lux (LUX)
lux (LUX)
EXAMPLE EQUATIONS: INPUTS
Equation Description
AI4 The real-time value of AI4
AI1+AI2+AI3 Total sum of inputs AI1,
AI2, and AI3
Table 2-3 - Equation Examples: Inputs
Input Type Choices SI Unit
Table 2-2
- SI Units for Analog Inputs
Numeric
Constant
Types
Examples Description
Integers 7, -30 Whole numbers. A minus
sign in front will make it
negative.
Non-integers 1.0, -0.3,
3.14
Also called decimal or float-
ing-point values. A minus
sign in front will make it
negative.
Exponential
Numbers
1.1E04
-4.5E-12
Large numbers can be
entered in exponential for-
mat. Format should be a
number with one significant
digit to the left of the deci-
mal, followed by an E, then
followed by an integer that
corresponds to the power of
ten the number will be mul-
tiplied by. Example: 1.1E06
is 1.1 times 10 to the sixth
power, or 1,100,000.
A minus sign to the left of
the number makes the num-
ber negative. A minus sign
in between the E and the
exponent specifies a nega-
tive exponent.
Table 2-4 - Numeric Constants
Named
Constant
Description
PI The value of pi (3.1415926535897)
TRUE 1.0 (to signify a logical TRUE)
FALSE 0.0 (to signify a logical FALSE)
ON 1.0 (to signify a logical ON)
OFF 0.0 (to signify a logical OFF)
Table 2-5 - Named Constants