Emerson E2 User manual

026-1620 Rev 3 06-JAN-2011
E2 User’s Manual Supplement: Flexible Combiner
Programming

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E2 User’s Manual Supplement: Flexible Combiner Table of Contents • v
Table of Contents
1 FLEXIBLE COMBINER.......................................................................................................................................... 1-1
1.1 OVERVIEW ................................................................................................................................................................. 1-1
1.2 HOW ITWORKS......................................................................................................................................................... 1-1
1.2.1 Example.............................................................................................................................................................. 1-1
1.3 INPUT AND OUTPUT ASSIGNMENT............................................................................................................................. 1-2
1.3.1 Programming the Inputs and Outputs................................................................................................................ 1-2
1.3.1.1 Adding a Flexible Combiner Application................................................................................................................ 1-2
1.3.1.2 Flexible Combiner General Setup............................................................................................................................ 1-2
1.3.1.3 Inputs........................................................................................................................................................................ 1-3
1.3.1.4 Outputs..................................................................................................................................................................... 1-3
1.4 EQUATIONS................................................................................................................................................................ 1-4
1.4.1 Types of Equations and Where Equations are Entered ..................................................................................... 1-4
1.4.2 Output Equations ............................................................................................................................................... 1-4
1.4.3 Delay Equations................................................................................................................................................. 1-5
1.4.4 Pulse Width Equations....................................................................................................................................... 1-5
1.5 ENGINEERING UNITS.................................................................................................................................................. 1-6
1.6 DESCRIPTION PROPERTIES ......................................................................................................................................... 1-7
1.7 ALARMS..................................................................................................................................................................... 1-7
2 BUILDING EQUATIONS ........................................................................................................................................ 2-1
2.1 INPUT AND OUTPUT VARIABLES ............................................................................................................................... 2-1
2.2 CONSTANTS ............................................................................................................................................................... 2-2
2.2.1 Constants and Engineering Units...................................................................................................................... 2-2
2.2.2 Specifying a Constant’s Engineering Unit with Type Suffixes........................................................................... 2-3
2.2.3 Time Constants................................................................................................................................................... 2-3
2.3 OPERATORS ............................................................................................................................................................... 2-5
2.3.1 Multiple Operators and Parenthesis.................................................................................................................. 2-5
2.4 FUNCTIONS ................................................................................................................................................................ 2-6
2.4.1 Extended Math Functions .................................................................................................................................. 2-7
2.4.2 Extended Logical Functions............................................................................................................................... 2-9
2.4.3 Logarithm Functions........................................................................................................................................ 2-10
2.4.4 Trigonometry Functions................................................................................................................................... 2-10
2.4.5 Analog Change Detection................................................................................................................................ 2-11
2.4.6 Unit Conversion and Temperature Functions ................................................................................................. 2-11
2.4.7 Extended Digital Functions ............................................................................................................................. 2-12
2.4.8 Time and Date Functions................................................................................................................................. 2-12
2.4.9 IF Functions..................................................................................................................................................... 2-14
3 TESTING AND TROUBLESHOOTING EQUATIONS....................................................................................... 3-1
3.1 CHECKING FOR ERRORS ............................................................................................................................................ 3-1
3.1.1 Equation Troubleshooting Tips.......................................................................................................................... 3-2
APPENDIX...................................................................................................................................................................... A-1

Overview Overview • 1-1
1 Flexible Combiner
1.1 Overview
The Flexible Combiner application, a new feature of
E2 versions 2.20 and above, is a highly advanced and ver-
satile I/O control program used to combine multiple ana-
log and digital input values using programmed equations
similar to those used in spreadsheets.
A Flexible Combiner application may have up to eight
analog outputs and four digital outputs, each of whose val-
ues are determined by user-programmed equations that
mathematically combine up to eight analog inputs and
eight digital inputs. Four of the analog outputs have the
ability to remember their output state over an E2 power
cycle. Additionally, up to four alarms can be set up whose
trigger and alarm delays are equations. Alarm type, prior-
ity, and the message for each alarm are user-configurable.
Equations used to calculate output values and time
delays may use mathematical combinations of any of the
Flexible Combiner’s analog and digital inputs, as well as
numeric and named constants, operators, functions, and
even rudimentary if-then logic functions.
For control of digital outputs the Flexible Combiner
also supports separate equations that determine ON and
OFF delays. The Flexible Combiner may also be pro-
grammed to operate a digital output as a PWM (pulse-
width modulation) output. In this instance, the equation
written for a PWM output determines its period and pulse
width.
1.2 How It Works
A typical Flexible Combiner application consists of
three types of components: inputs, equations, and out-
puts.
Inputs
Inputs for a Flexible Combiner applications may be
sensor values from input points on a MultiFlex input board
or outputs from other software applications in the E2.
Inputs are the building blocks you will use to create the
control function you need.
A Flexible Combiner output may be configured with
up to eight analog inputs and eight digital inputs.
Equations
Equations are used to combine or otherwise mathemat-
ically alter one or more inputs from the Flexible Combiner
to create an output that performs a desired function. Each
output has its own equation (a string of characters up to 80
characters in length) that the E2 “parses,” or decodes, to
determine the output’s value.
Equations must be entered by the user and require
some basic knowledge of the E2’s scripting language,
which is further explained in this section of the manual.
Outputs
The outputs of the Flexible Combiner are the real-time
results of the application’s equations. Each output’s value
is determined by the equation assigned to it in the Flexible
Combiner application.
Outputs of the Flexible Combiner application may be
tied to relay or analog output points on a Retail Solutions
output board, or they may be passed along to the inputs of
other E2 applications.
1.2.1 Example
Figure 1-1 shows a symbolic diagram of an example
Flexible Combiner application. In this diagram, there are
two equations shown: one for analog output AO1 and
another for digital output DO2.
The equation in AO1 is set up to make analog output
AO1 equal to the average value of the two analog inputs
AI1 and AI7. The equation adds these two values together
and then divides the result by two.
The equation in DO2 performs a logical AND function
on digital inputs DI1 through DI3. When all of these out-
puts are ON, the value of DO2 will be ON; otherwise, if
one or more of the inputs are OFF, DO2 will be off.
Figure 1-1 - Flexible Combiner Control Diagram

1-2 • E2 User’s Manual Supplement: Flexible Combiner 026-1620 Rev 3 06-JAN-2011
1.3 Input and Output
Assignment
The first step in setting up a Flexible Combiner is con-
figuring the application’s inputs.
The first question that must be answered before input
assignment can begin is “What do I want the Flexible
Combiner to do?” Will it choose the highest value from a
series of temperature sensors? Will it calculate enthalpy
from temperature and humidity sensors? Will it read a set
of proofs and turn an output ON if more than half of them
fail?
When you have determined this, make a note of the
following:
• How many inputs of each type you will need (ana-
log and digital)
• How many outputs of each type you will need (ana-
log and digital)
• The types of analog inputs that will be used (tem-
perature, pressure, etc.)
• For analog outputs, the range of values you want
each output to vary between (0-5V, 0-10V, 1-5V,
etc.)
• For digital outputs, whether you want each output
to be a simple ON/OFF digital output or a one-shot
output.
The next step is to assign all the inputs and outputs to
the numbered input and output slots in the Flexible Com-
biner application.
1.3.1 Programming the Inputs
and Outputs
1.3.1.1 Adding a Flexible Combiner
Application
If you haven’t added a Flexible Combiner application
yet, you will need to create it in the E2’s Add Application
screen.
1. Press  to access the Add Application
screen.
2. With the cursor highlighting the Type field, press
and choose “Flexible Combiner” from the
Look-Up Table. Note: If Flexible Combiner does
not appear in this list, it may be because your E2
is not version 2.20 or higher.
3. Enter the number of Flexible Combiners you
wish to add in the “How many?” field.
4. Press to add the new applications.
5. When the E2 asks “Do you wish to edit the new
applications now?” press . The E2 will take you
to the first setup screen of the application you
added (or, if you added multiple applications, it
will take you to the first application you added).
1.3.1.2 Flexible Combiner General Setup
The first screen of the Flexible Combiner is where you
will set up the general parameters required to further
define the application’s functions.
Name
Enter a short description of the Flexible Combiner’s
function in the Name field.
Num of AI
Enter the number of analog inputs the Flexible Com-
biner will use in this field.
Num of AO
Enter the number of analog outputs the Flexible Com-
biner will use in this field.
Num of DI
Enter the number of digital inputs the Flexible Com-
biner will use in this field.
Num of DO
Enter the number of digital outputs the Flexible Com-
biner will use in this field.
Show Eq Line 2
Each output in the Flexible Combiner has two lines of
40 characters each that may be used to enter its equation.
Since an equation rarely exceeds 40 characters, it is usu-
ally safe to hide the second line from display to make the
screen easier to read. This will be explained in further
detail in Section 1.4.1; for now, leave this field set to NO.
DO1-DO8 Type
The eight DO1-DO8 Type fields are used to specify
Figure 1-2 - Flexible Combiner General Setup

Input and Output Assignment Input and Output Assignment • 1-3
whether each digital output will be a simple ON/OFF digi-
tal output or a one-shot pulse output. Choose the desired
output type here.
DO1-DO8 Trigger
If any of the DO1-DO8 Type fields were set up as one-
shot outputs, choose the method the Flexible Combiner
will use to generate pulses. The choices are:
•Edge - Pulse is generated when the application tran-
sitions the output from OFF to ON.
•Inv Edge - Pulse is generated when the application
transitions the output from ON to OFF.
•Both Edge - Pulse is generated every time a state
transition occurs, whether it is OFF to ON or ON to
OFF.
Press to proceed to the Inputs screen.
1.3.1.3 Inputs
The Inputs screen will show the input definitions for
the number of analog and digital inputs you specified in
Screen 1: General.
The default input format is “Controller:Applica-
tion:Output.” If you wish to use the output from another
E2 application as an input for the Flexible Combiner appli-
cation, use the Look-Up Table () to select the con-
troller, application name, and output name for each field in
the definition.
If you want an input to be a board and point address
from a MultiFlex input board, press  to change
the I/O format, and select from the menu to change the
format to Board and Point. Then, enter the board and point
address of the input point in each field.
NOTE: If a point you enter in this manner has not been
configured yet from the Input Summary screen, you will
need to do so before entering its board and point address
here. Refer to the E2 User’s Manual (P/N 026-1610) for
more details.
Once all inputs are defined, make a note of the names
of each input you defined (AI1-AI8 and DI1-DI8). These
names are the ones that are used when building equations.
When finished, press to proceed to the Outputs
screen.
1.3.1.4 Outputs
The Outputs screen will show the output definitions for
the number of analog and digital outputs you specified in
Screen 1: General.
The default output format is “Controller: Application:
Input.” If you wish to use the input of another E2 applica-
tion as the destination for a Flexible Combiner’s output
value, use the Look-Up Table () to select the con-
troller, application name, and input name for each field in
the definition.
If you want an output to be a board and point address
from a MultiFlex output board, press  to change
the I/O format, and select from the menu to change the
format to Board and Point. Then, enter the board and point
address of the relay or analog point in each field.
ON DELAY and OFF DELAY
Each digital output will have two corresponding out-
puts, one for its on delay and one for its off delay. It is not
necessary to configure these outputs. They are only there
so the value of the on and off delays may be logged, used
in generic alarm control, and presented in status screens.
Once all inputs and outputs are configured, you will be
ready to complete the Flexible Combiner programming by
building equations.
Figure 1-3 - Flexible Combiner Inputs
Figure 1-4 - Flexible Combiner Outputs

1-4 • E2 User’s Manual Supplement: Flexible Combiner 026-1620 Rev 3 06-JAN-2011
1.4 Equations
The value of each output in a Flexible Combiner appli-
cation is determined by its own equation, which usually
takes the values of one or more inputs and performs a
mathematical operation or function on them to yield a sin-
gle numerical value or digital state.
When entering an equation, you must follow a strict
format so that the E2 can properly understand and use the
equation. This section will explain how to build equations
in detail.
1.4.1 Types of Equations and
Where Equations are Entered
There are three different screens in the Flexible Com-
biner setup for output equations.
• Screen 4, the Output Eq screen, is where equations
that determine the output’s value are entered.
• Screen 5, the Delay Eq screen, is only visible if dig-
ital outputs are present. Equations that determine
the ON and OFF delays for digital outputs are
entered in this screen.
• Screen 6, the PW Eq screen, is only visible if one or
more digital outputs have been set up as “one-shot”
outputs. Equations that determine the pulse width
and period are entered in this screen.
Each of these screens lists the application outputs that
apply to it along with a 40-character field where the equa-
tion must be entered.
Section 2, Building Equations, provides a detailed
explanation of equation syntax in the Flexible Combiner
application.
Using the Second Line
If the “Show Eq Line 2” field is set to “Yes” in Screen
1, a “Line 2” field will be directly underneath each equa-
tion to expand the total equation size to 80 characters. If an
equation takes more than 40 characters to write, simply
write the first 40 characters in the first line and write the
remaining ones in the second line as if it were an extension
of the first line.
You can split variable names, constants, etc. between
the two lines with no problem. For example, if while writ-
ing an equation you have only two spaces left at the end of
line 1 and you must write the variable name “AO3,” sim-
ply write “AO” in the last two spaces and the “3” as the
first character of line two. When E2 parses the equation, it
will push line 1 and line 2 together into one long string,
and it will recognize the variable name as AO3.
1.4.2 Output Equations
Screen 4 of the Flexible Combiner setup screens is
where equations that determine the output’s value are
entered. An output equation typically involves using math-
ematical operators or functions to combine or compare one
or more analog or digital outputs to yield a new output
result. Table 1-1 gives some useful examples of sensor
control applications used in refrigeration/HVAC applica-
tions and the equations used to achieve them. See Section
2, Building Equations, for a more detailed explanation of
equation components and functions.
Figure 1-5 - Flexible Combiner Output Equations
Desired
Function Equation
Averaging
three tempera-
ture sensors
AI1 through
AI3, and pass-
ing the result
to AO4.
AO4:
AVG(AI1,AI2,AI3)
The output of
analog mem-
ory equation
is stored so
the value is
consistent
across
reboots. This
is useful for
implementing
long term
counters or
timers.
AM1:
If (DI1 = ON, AM1 + 1, AM1)
Using AM1 as a counter that increments
when DI1 is ON.
The current value of AM1 will be preserved
even if the E2 is rebooted.
Table 1-1 - Commonly Used Equation Examples

Equations Equations • 1-5
1.4.3 Delay Equations
The digital outputs of a Flex Combiner application
have optional equations that can be used to program ON
and OFF delays. If the outputs are directly controlling
devices, ON and OFF delays can help minimize switching
by turning the output ON or OFF only when the equation
result that caused the transition remains in that state for
longer than the delay.
In other words, if an OFF delay is 30 seconds, and the
result of the input equation transitions from ON to OFF,
the result must remain OFF for thirty seconds before its
corresponding output actually changes state.
Delay equations do not actually have to be equations.
Most commonly, they will be constants. However, a delay
equation can be any mathematical expression (including
inputs, constants, operators, or functions) that results in an
analog value representing number of seconds.
If you have digital outputs and would like to use ON
and OFF delays, enter constants or equations in these
fields. See Section 2, Building Equations, for a more
detailed explanation of equation components and func-
tions.
1.4.4 Pulse Width Equations
If one or more digital inputs have been configured to
be “One Shot” type outputs, the width of the ON pulse is
Turn on an
exhaust fan at
DO2 when a
temperature
AI1 rises
above 120°F,
and turn it off
again when
the tempera-
ture falls
below 100°F.
DO2:
CUTINOUT(AI1,120DF,100DF,DO2)
AND combi-
nation of digi-
tal inputs DI1
through DI8
DO1:
AND(DI1:DI8)
Figure 1-6 - Flexible Combiner Delay Equations
Desired
Function Equation
Table 1-1 - Commonly Used Equation Examples
Desired
Function Equation
Output DO1
has a 60 sec-
ond ON delay
and a 60 sec-
ond OFF
delay
DO1 OFF Delay:
60
DO2 OFF Delay:
60
Output DO2
has a 90-min-
ute ON delay
and a 90-min-
ute OFF
delay.
DO2 OFF Delay
01:30
DO2: OFF Delay
01:30
Output DO3
uses a 5 min-
ute delay
between the
hours of 9
p.m. and mid-
night, and a 3
minute delay
otherwise.
DO3:
IF(TIME()>9:00p,00:05:00,00:03:00)
Table 1-2 - Commonly Used Equation Examples
Figure 1-7 - Flexible Combiner Pulse Width Equations

1-6 • E2 User’s Manual Supplement: Flexible Combiner 026-1620 Rev 3 06-JAN-2011
determined by the value of the Pulse Width equations.
When a one-shot output is called to be ON, the Flex Com-
biner will run this equation and use the resulting value as
the number of seconds the output will pulse ON.
Like delay equations, pulse width equations most com-
monly will only be constant values, since there is usually
little need for variance in one-shot pulse width. However,
a delay equation can be any mathematical expression
(including inputs, constants, operators, or functions) that
results in an analog value representing number of sec-
onds.
1.5 Engineering Units
The engineering units used for each analog input and
output must be defined in Screen 7 of the Flexible Com-
biner setup screens: the Eng Units screen.
The units chosen for inputs are particularly important
in determining how the value will be scaled and used in
equations (see Section 2.2.1, Constants and Engineering
Units).
For outputs, setting an engineering unit determines
how it is displayed in the Flex Combiner status screen. If a
unit is chosen for an output that is different from the
default engineering unit of the same type used by the E2 in
General Controller Info, the chosen type is substituted for
the default type on this screen only.
In other words, if AO1 is set to display in DF in the
Flexible Combiner cell but the default temperature unit for
the E2 is in DC, the output value will only be displayed in
DF on the Flex Combiner status screen — everywhere else
(including the Flex Combiner Summary Screen) it will
display in DC.
Desired
Function Equation
5 second
pulse on DO1 DO1 PulseWidth: 5
2 minute
pulse on DO2 DO2 PulseWidth 00:02
15 second
pulse width
on DO3
unless the cur-
rent time is
before 8 a.m.,
in which case
the pulse
width is 10
seconds
DO3 PulseWidth
IF((TIME()<08:00a)=TRUE,15,10)
Table 1-3 - Commonly Used Equation Examples
Figure 1-8 - Engineering Units

Description Properties Description Properties • 1-7
1.6 Description Properties
The Description Properties screen will show the
descriptions of the associated inputs and outputs entered
by the user. Pertinent descriptions can be entered that
explain inputs and outputs to aid in understanding the
intent of the programming performed in the flexible com-
biner. (Descriptions for analog memory outputs appear
only in expanded status.)
If text is not entered for a description for an input and a
connection is made to the output of another application,
the description is automatically filled in with the applica-
ton name and property of that output. If text is entered for
an input and a new connection is made, the text is not
automatically changed. This applies to inputs only; out-
puts are not affected.
1.7 Alarms
The alarm output and delay equations control the trig-
ger of the alarm and how long to delay before setting an
advisory in the advisory log. These equations are executed
exactly like analog and digital outputs. The alarm output
equations combined with the delay equations control the
outputs AL1 - AL4. The results of the delay equation are
sent to outputs AL1 - AL4 DELAY. The alarm type can be
set to either Notice or Alarm. The alarm priority sets the
priority of the advisory generated. For a complete list of
advisory text, see the Appendix section.
Figure 1-9 - Flexible Combiner Description Properties Figure 1-10 - Flexible Combiner Alarm Setup

Input and Output Variables Input and Output Variables • 2-1
2 Building Equations
Equations are made up of different combinations of
four major elements: inputs, defined in the Flexible Com-
biner application, constants such as numerical values used
in mathematical computations, operators such as plus
signs (+) or greater than signs (>) used to perform basic
math functions, and functions such as if-then statements
or boolean logic (AND/OR).
2.1 Input and Output Vari-
ables
The most commonly used variables in an equation will
be the Flexible Combiner’s input values. These are repre-
sented in equations by their variable names, AI1-AI8 and
DI1-DI8.
To use input values in an equation, just enter their
names (AI for analog input or DI for digital input, and a
number from 1 through 8 corresponding to the input num-
ber). The E2 will look for input variable names and create
a link to the input’s value when parsing the equation.
Analog Input Values and SI Units
The value of an AI input will always be equal to the
current input value in the E2’s internal standard (SI)
units. This is important to remember because any mathe-
matical operations that involve this value will use its SI
units, which may cause the equation to be wrong if you are
assuming the wrong units.
Example: AI1 is reading a value of 212°F. If you
wanted to write an equation that added 10°F to the value
of AI1, the equation “AI1+10” would be incorrect because
this would add 10 to the value of AI in Celsius, since E2’s
SI unit for temperature is Celsius.
The way to correct this would be convert the number
10 to an equivalent number of degrees C (“AI1+5.6”), or
else use a type suffix so the E2 knows you want to add 10
degrees (“AI1+10DDF”). Type suffixes are explained in
further detail in Section 2.2.2, Specifying a Constant’s
Engineering Unit with Type Suffixes.
Table 2-2 lists the SI units used by E2:
Variable Name Description
AIx (x=input
number) The analog value of input AIx, in SI units
DIx (x=input
number) The digital state of input DIx, converted to analog:
1.0 if input is ON
0.0 if input is OFF
AOx (x=output
number) The analog value of output AOx, in SI units
DOx (x=output
number) The digital state of output DOx, con- verted to analog:
1.0 if input is ON
0.0 if input is OFF
Table 2-1 - Input and Output Variable Names
Input Type Choices SI Unit
Temperature degrees Fahrenheit (DF)
degrees Celsius (DC) degrees C (DC)
Change in
Temperature delta degrees Fahrenheit (DDF)
delta degrees Celsius
(DDC)
delta degrees C
(DDC)
Pressure inches of water (INW)
centimeters of water
(CMW)
pounds per sq. inch (PSI)
bars (BAR)
kilopascals (KPA)
pascals (PA)
pascals (PA)
Change in
Pressure delta inches of water (DINW)
delta centimeters of water
(DCMW)
delta pounds per sq. inch
(DPSI)
delta bars (DBAR)
delta kilopascals (DKPA)
delta pascals (DPA)
delta pascals
(DPA)
Air Velocity feet per minute (FPM)
meters per minute (MPM)
meters per second (MPS)
meters per sec-
onds (MPS)
Liquid
Velocity gallons per minute (GPM)
liters per second (LPS)
liters per sec-
ond (LPS)
Volume
Flow cubic feet per minute (CFM)
cubic meters per second
(CMS)
cubic meters
per second
Table 2-2 - SI Units for Analog Inputs

2-2 • E2 User’s Manual Supplement: Flexible Combiner 026-1620 Rev 3 06-JAN-2011
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

Constants Constants • 2-3
unitless numbers. In other words, a “3.0” in an equation by
itself is not assumed to be 3.0 degrees or kilowatts. How-
ever, when used with a function or operator that involves
inputs of a specific type, the result of the operation or
function will use the inputs’ engineering unit designation.
For example, if analog input AI6 is a 0-100% humidity
sensor that is currently reading a humidity of 50%, the
result of the equation “AI6 / 5” will result in an output
value of 10%, even though the number 5 has no unit.
2.2.2 Specifying a Constant’s
Engineering Unit with Type Suffixes
Occasionally you may want to be specific about a con-
stant’s engineering units. The equation parser supports the
use of a type suffix at the end of a constant to specify a
particular engineering unit. Table 2-6 lists all type suffixes
recognized by the Flexible Combiner’s equation parser.
Type suffixes must be placed directly after the constant
with no spaces in between the constant and the suffix (i.e.
75DF, not 75 DF). It is important to note that when type suffixes are used
that are different from the E2’s internal SI values, they are
“converted” to the SI units behind the scenes. For exam-
ple, the equation “AI1+0.2BAR” actually adds 20,000 to
the raw value of AI1 (0.2 bars converted to pascals, or
20,000PA).
Type Suffixes for Temperature Offsets (DDF and DDC)
If you are using a constant in an equation that is being
used to offset the value of a temperature sensor, you must
use the delta degrees suffixes (DDF and DDC), not the
standard temperature suffixes (DF and DC). A constant
with a DF or DC suffix is interpreted as a literal tempera-
ture and converted before the math operation is performed,
so an equation like AI1+10DF is interpreted as “AI1 plus
the value of 10DF converted to Celsius (12.2).” The cor-
rect way to write this would be AI1+10DDF, which would
add 10°F to the value of AI1 before converting the entire
equation to SI units.
Use the DDF and DDC suffixes in every equation that
uses basic math in conjunction with temperature offsets.
2.2.3 Time Constants
Used in delay equations and pulse width (PW) equa-
tions, constants representing times of day or delay time
durations can be entered into equations in a variety of
ways:
•As a duration in HH:MM (hours/minutes).
Example: “01:45” sets the time delay to 1 hour, 45
minutes (6300 seconds).
•As a duration in HH:MM:SS (hours/minutes/
seconds). Example: “01:00:00” sets the time delay
to 1 hour (3600 seconds). Use this format for min-
Suffix Unit Suffix Unit
DF degrees F % percent
DC degrees C W watts
DDF delta degrees F
(use this suffix
for offsets)
KW kilowatts
DDC delta degrees C
(use this suffix
for offsets)
WH watt-hours
DFH °F per hour KWH kilowatt-hours
DFC °C per hour FTC foot-candles
DFM °F per minute LUX lux
DCM °C per minute PPM parts per million
INW inches of water OHM ohms
CMW cm of water RPM revolutions per
minute
PSI pounds per
square inch RPMM RPM per minute
BAR bars DINW differential
inches of water
KPA kilopascals DCMW differentialcmof
water
PA pascals DPSI differential pres-
sure in PSI
RH relative humidity DBAR differential in
bars
FPM feet per minute DKPA differential in
kilopascals
Table 2-6 - Type Suffixes for Flexible Combiner Constants
MPM meters per min-
ute DPA differential in pascals
MPS meters per sec-
ond GAL gallons
GPM gallons per min-
ute Lliters
LPS liters per second CF cubic feet
CFM cubic feet per
minute CM cubic meter
CMS cubic meters
per second CCF cubic centi-feet
V volts CCFH cubic centi-feet
per hour
A amps FT feet
MA milliamps M meters
PCT percent
Suffix Unit Suffix Unit
Table 2-6 - Type Suffixes for Flexible Combiner Constants

2-4 • E2 User’s Manual Supplement: Flexible Combiner 026-1620 Rev 3 06-JAN-2011
ute/seconds by entering “00” for the hour (example:
“00:30:00” for 30 minutes).
•As a time of day in HH:MMx, where xis “a” if the
time is a.m. or “p” if the time is p.m. This is con-
verted to a number of seconds after midnight.
Example: 04:00a is converted to 14400 seconds.
In all cases, time constants are all converted to a num-
ber of seconds when used by the Flex Combiner, so that
mathematical operations like “00:01:00*2” results in 120
(60 seconds multiplied by 2).
In the case of a time constant in HH:MMx format, this
can be used along with the TIME() function to do compar-
isons between the current time and the setpoint. For exam-
ple, IF((TIME()>06:00p)=TRUE,60,50) compares the
current TIME, which returns the time in a number of sec-
onds since midnight, to 06:00p, which is converted to
21600 seconds.
EXAMPLE EQUATIONS: INPUTS AND
CONSTANTS
Equation Description
AI4+60 The value of AI4 plus 60.
(PI*(10M^2))*AI2 Assuming AI2 is a linear
sensor whose output reflects
a water level position in
meters, this equation calcu-
lates the volume of a cylin-
drical tank whose radius is
10 meters. The constant PI is
multiplied by the radius
squared (10M^2) to yield the
circular area of the tank, and
this value is multiplied with
AI2 to yield volume.
AI1+(3DDF*DI2) Assuming AI1 is a tempera-
ture sensor, this equation
adds three degrees Fahren-
heit to the value of AI1 when
DI2 is ON. Because ON is
equal to 1.0, then 3DDF *1.0
= 3DDF. When DI2 is OFF
(0.0), the expression 3DDF *
0.0 = 0DDF
Table 2-7 - Equation Examples: Inputs Using Constants

Operators Operators • 2-5
2.3 Operators
Operators are symbols in equations that perform cer-
tain mathematical or logical operations. The most recog-
nizable (and perhaps most common) example of operators
are plus (+) and minus (-) signs. An operator is typically
placed between two inputs and/or constants in an equation
and yield a single value. Table 2-8 lists the operators avail-
able in Flexible Combiner.
2.3.1 Multiple Operators and
Parenthesis
Often an equation will contain more than one operator.
The order in which these operators are used can be signifi-
cant and may cause error if not arranged correctly.
When parsing an equation, the E2 follows a specific
order when multiple operators are present:
1. All exponent (^) operators, from left to right.
2. All multiplication and division (* and /) opera-
tors, from left to right.
3. All addition and subtraction (+ and -) operators,
from left to right.
4. All greater than/less than operators (<,>,<=, and
>=), from left to right.
5. All equality and inequality operators (=,<>) from
Operator Description Examples
+Adds two values 4+2 result: 6
4+3+2 result: 9
-Subtracts two values 4-2 result: 2
4-3-2 result: -1
*Multiplies two values 4*2 result: 8
4*3*2 result: 24
/Divides two values 4/2 result: 2
4/3/2 result: 0.67
^Exponential. The value on the left is raised to the power of the value on the right. 4^2 result: 16
4^3^2 result: 4096
=Equality comparison of two values. Result is 1.0 if the two values are equal, 0.0 if the values
are not equal. 4=2 result: 0.0 4=3+1 result: 1.0
<> Inequality comparison of two values. Result is 1.0 if the two values are not equal, 0.0 if the
values are equal. 4<>2 result: 1.0 4<>3+1 result: 0.0
>Greater than comparison of two values. Result is 1.0 if the value to the left of the sign is
greater than the value to the right of the sign. If they are equal, or if the value to the right is
greater, the result is 0.0
4>2 result: 1.0
4>3+1 result: 0.0
<Less than comparison of two values. Result is 1.0 if the value to the right of the sign is
greater than the value to the left of the sign. If they are equal, or if the value to the left is
greater, the result is 0.0
4<2 result: 0.0
4<3+1 result: 0.0
3<5 result: 1.0
>= Same as greater than (>) except the result will also be 1.0 if the two values are equal. 4>=2 result: 1.0
4>=3+1 result: 1.0
<= Same as less than (<) except the result will also be 1.0 if the two values are equal. 4<=2 result: 0.0
4<=3+1 result: 1.0
!Digital inversion of the value to the right of this sign. If the value is non-zero, the result is
0.0. If the value is zero, the result is 1.0. !0 result: 1.0 !7 result: 0.0
NOT Same as !, only using a different format. The value to be inverted must be put in parenthesis
next to the NOT operator (see example). NOT(0) result: 1.0 NOT(7) result: 0.0
&& Logical AND. If the values to the right and left of these symbols are both non-zero numbers,
the result will be 1.0. Otherwise, if one or both values are 0, the result will be 0.0. 4&&2 result: 1.0 4&&0 result: 0.0
0&&0 result: 0.0
|| Logical OR. If either of the values to the left or right of these symbols are non-zero num-
bers, the result is 1.0. If both are zero, the result is 0.0 4||2 result: 1.0 4||0 result: 1.0
0||0 result: 0.0
Table 2-8 - Operators

2-6 • E2 User’s Manual Supplement: Flexible Combiner 026-1620 Rev 3 06-JAN-2011
left to right.
6. All logical operators (!, NOT, &&, ||) from left to
right.
If you cannot arrange an equation’s operators in a way
that parses them in the order you need (or if you simply
want to remove all doubt), you may use parenthesis to
specify a different order of operator execution. Expres-
sions that are in parenthesis are executed first before any
operators outside of parenthesis are used. For example,
“5+2*3” without parenthesis results in 11 because the
multiplication is executed first before the addition. How-
ever, in the equation “(5+2)*3” the addition is executed
first because it is in parenthesis, resulting in 21.
Equations and operators in parenthesis can themselves
contain other operators and equations in parenthesis. For
example “((5+2)*3)^2” executes the addition first, fol-
lowed by the multiplication, and finally the exponent,
resulting in 441.
2.4 Functions
Equations for most applications can be built using
nothing but inputs, constants, and operators. However, in
some cases it is not always practical or easy to use nothing
but these components (and in some cases, the equation
you’d have to build would exceed the 80-character limit).
Furthermore, you may sometimes need equations to do
more complicated things (such as converting a floating-
point number to an integer or converting a temperature to
dewpoint) that cannot be handled with operators alone.
For these reasons, the Flexible Combiner offers a large
number of functions that can be used in output equations.
A function is essentially a small mathematical formula that
accepts one or more variables as inputs and returns a
numeric result.
In an equation, a function typically takes the form of
the name of the function followed by a set of parenthesis
that contain the value or values the function will use as
inputs. The values inside the parenthesis of a function may
be constants or inputs.
Functions are always evaluated first in an equation
(from left to right, unless parenthesis are used) before
operators are executed.
EXAMPLE EQUATIONS:INPUTS, CONSTANTS,
AND OPERATORS
Equation Description
AI4+60 The value of AI4 plus 60.
!DI1=DI2 The expression DI1=DI2
returns a 1.0 when both
inputs are ON and a 0.0 if
only one or the other is ON.
The “!” at the beginning of
this equation then inverts the
result of that expression. The
final result is a logical XOR
of DI1 and DI2. (Note: this
can be done more elegantly
with the XOR function,
which is explained later in
this section).
(DI1&&DI2)*AI1 Because DI1&&DI2 is in
parenthesis, the logical AND
of DI1 and DI2 is performed
first. The result of this is
multiplied with AI1. This
means the output will be
equal to AI1 (1.0*AI1) when
DI1 and DI2 are both ON,
and zero (0.0*AI1) when one
or both are OFF.
Table 2-9 - Equation Examples: Inputs Using Constants