102777-YIM-E-0206
98
Unitary Products Group
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Unit model number
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Unit serial number
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Unit Name
DIGITAL LINGO
This training manual is intended to help you with the commis-
sioning process by illustrating the use of tools like the con-
trol’s digital input and software engineered specifically for
starting up and servicing a Millennium rooftop unit.
You should become familiar with some common terminology
and lingo used in the digital controls industry. [If you are famil-
iar with the Synthesys controller, the logic of the Simplicity will
be familiar territory.]
If this is your first exposure to the world of digital controls you
may experience a lot of new terms, acronyms and technical
lingo commonly used in the controls industry. For example,
the Simplicity input and output hardware points are described
as
analog
, relating to a continuous scale of value readings
such as a temperature sensor ranging from -40
0
F to 160
0
F
range, or
binary
, meaning 2-states, either on or off, open or
closed, true or false, one or zero. The term “digital” also
means two states and its use is often interchanged with
“binary”. These points may be either factory- or field-set.
THE PI ALGORITHM
Another common “digital controls” term is the PI algorithm or
Proportional-Integral control loop. The PI algorithm is a con-
tinuously updated math calculation that the controller uses to
modulate an analog output point. For example, a variable
speed drive uses a PI loop to maintain a desired setpoint (in
this case, a duct static pressure value). The algorithm takes
into account several parameters to calculate the output. The
PI loop needs parameters such as the proportional operating
bandwidth, integral time constant, deadband, desired set-
point value, sensed input value(s), start up ramp time, initial
start value, maximum output control value, a status point to
initiate the control action (i.e. a fan ON status), Direct or
Reverse Controlling Action, and several other parameters to
calculate a simple 0 to 100% analog output control. The PI
algorithm is also called a PI loop because it “loops” the output
back to the input (feedback) and determines a new output
value based on the “error” or difference between the setpoint
value and the sensed input value, and how that difference
relates proportionally to the 0 to 100% output value. Time is
the ”integral” constant that is factored in to increase or
decrease the controlling output action depending on how long
the sensed value remains away from its desired setpoint.
Fortunately, you do not have to determine all of these param-
eters since they are pre-programmed at the factory. You need
only to set a desired setpoint and ensure that the inputs and
outputs are properly wired and working. This is referred to as
commissioning a system.
ANALOG TO DIGITAL CONVERTER
Computers can only understand a simple binary language.
Remember, “binary” means two states - ON or OFF. Analog
(continuous) values of voltages, currents, and resistances are
supplied by sensors and transducers to the control. These
values must be converted in to a binary code so that the com-
puter can understand them. This conversion process is per-
formed through a combination of hardware and software. For
example, the 0-5VDC analog value from a static pressure
transducer is divided into thousands of steps with a binary
coded number, often called “counts”, assigned to each step.
SOFTWARE TERMINOLOGY
A digital controller handles its control functions through soft-
ware programming rather than with interlocking hardware and
wiring. The software then becomes key to how controlled
functions are handled. Software is a set of statements
(referred to as the “program”) that define the function of the
controller’s internal microprocessor computer.
Software procedurally tells the computer the sequence and
order of tasks that need to be performed using a language
that the computer can understand.
Software is stored in a computer’s memory. There are several
types of memory in a computer. Each type has a specific
function to perform.
EPROM
- This is “nonvolatile” memory, meaning it will not be
erased on a power loss. This memory is usually programmed
prior to assembly of the controller. Since this memory is not
changed during normal operation of the Simplicity control,
only basic operation instructions are stored in this type of
memory.
FIGURE 33 -ANALOG TO DIGITAL CONVERTER
BINARY NUMBER EQUIVALENT
0 1 2 3 4 5 6 7------------- n
Summary of Contents for MILLENNIUM Y22
Page 47: ...102777 YIM E 0206 Unitary Products Group 47 FIGURE 20 ALTITUDE TEMPERATURE CONVERSION FACTOR ...
Page 50: ...102777 YIM E 0206 50 Unitary Products Group FIGURE 21 FAN PERFORMANCE 25 TON ...
Page 53: ...102777 YIM E 0206 Unitary Products Group 53 FIGURE 22 FAN PERFORMANCE 30 TON ...
Page 56: ...102777 YIM E 0206 56 Unitary Products Group FIGURE 23 FAN PERFORMANCE 40 TON ...
Page 126: ...102777 YIM E 0206 126 Unitary Products Group FIGURE 52 TYPICAL CONTROL WIRING ...
Page 127: ...102777 YIM E 0206 Unitary Products Group 127 FIGURE 53 LEGEND ...
Page 128: ...102777 YIM E 0206 128 Unitary Products Group FIGURE 54 TYPICAL 25 TON POWER WIRING ...
Page 129: ...102777 YIM E 0206 Unitary Products Group 129 FIGURE 55 TYPICAL 30 40 TON POWER WIRING ...
Page 130: ...102777 YIM E 0206 130 Unitary Products Group FIGURE 56 TYPICAL GAS HEAT WIRING ...
Page 134: ...102777 YIM E 0206 134 Unitary Products Group FIGURE 58 25 TON CHARGING CURVE ...
Page 139: ...102777 YIM E 0206 Unitary Products Group 139 ...