Transcript Alternative Energy Automation Control System

Alternative Energy Class Room
Automation Control System
Lighting and Temperature Control
By: Al Woodward EET-2011
Description Of Operation
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The Alternative energy room has four packaged console heat pumps. Two units are for first stage
and two are for second stage. A set of units will consist of unit 1 and unit 3. Another set of units will
consist of unit 2 and unit 4.
Operation will consist as follows:
First stage will consist of one set of units.
Second stage will consist of the other set of units.
The sets of units will alternate as first or second stage through a flip-flop in the plc program.
Upon power up there will be a one-shot in plc program that will activate a two-minute on-delay
timer for two-minutes to prevent compressor operation for two minutes.
The staging of units will be based on input from the room temperature sensor.
When compressor operation is initiated there is an off-delay for two minutes to insure operation
for two minutes.
Upon completion of compressor operation there will be a two-minute on-delay timer to prevent
compressor short cycling.
Occupied and unoccupied time periods will be controlled through a time schedule in the plc
program.
The lighting momentary toggle switches are inputs to the PLC.
The two room motion sensors are input to the PLC for night time operation of lighting system.
A Heat Pump Loop System
Terms
• Ambient temperature is the temperature of the
medium surrounding a body, for example, the room air
temperature.
• Sensible heat is the heat which results in a
temperature change only when a transfer takes place.
It is sensible heat that is produced by a heating system,
is lost through a building wall, or is removed by a
refrigeration system.
• Latent heat is absorbed or released when a material
changes phase without a change in temperature. The
three phases are solid, liquid, and gas.
Terms
• Thermal capacity is the amount of heat required to raise the temperature
of a unit of mass of a material one degree.
• Quantity of heat:
• Btu or British thermal unit is the unit of measure of quantity of heat in
the IP system and is the heat required to raise the temperature of one
pound of water one degree Fahrenheit. This is approximately the amount
of heat given off by burning one kitchen (wood) match. The term therm is
often used as a measure of heating fuel. A therm is equal to 100,000
• Ton of refrigeration is used to size air condition or refrigeration units. The
term was developed when ice was used to provide refrigeration. It is equal
to the cooling effect (heat removal) that would be developed by melting a
ton of ice over a 24 hour period. Since the latent heat of fusion for ice is
144 Btu/lb, we have: 2000 lb x 144 Btu/lb/24 he = 12000 Btu/h
• Mechanical equivalent of heat
• 1 hp = 2545 Btu/h
• 1 kW = 3413 Btu/h
Automation Direct PLC
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DL06 PLC Units
The DL06 micro PLC line has nine base units to choose from, each has 20 built-in inputs and 16
built-in outputs. The DL06 is a great fit for high voltage, 220-240 VAC applications or remote 12
VDC applications, and everything in between. The DL06 line of modular micro PLCs offers an
inexpensive solution for small to medium size I/O applications with features such as:
20 built-in inputs and 16 built-in outputs, expandable to 100 I/O total
Nine combinations of AC or DC powered PLC units with AC, DC and relay I/O
14.8 KB of total memory
229 instructions, including 8 PID loops
Built-in real-time clock/calendar
Two communication ports, including RS232/ 422/ 485 capability
Supports networking for MODBUS RTU, Ethernet, DeviceNET, Profibus, and ASCII in/out
Integrated high-speed inputs and pulse output
12 discrete I/O option modules
7 analog I/O option modules
7 communications and specialty option modules
Thermocouple and RTD temperature inputs
Removable terminal blocks
ZIPLink compatibility with 16-point discrete I/O option cards
Optional LCD display for operator interface or maintenance troubleshooting
Block Diagram For PLC Temperature
Control System
PLC
RTD
Heat Pumps
Transfer Function
A Typical Console Heat Pump
One of the four heat pumps.
Automation Direct PLC
F0-04RTD 4-Channel Resistive
Temperature Input Module
An RTD is a temperature device made
from platinum, copper, or nickel.
RTD = Resistive Temperature Device
PLC is controlling room within 0.1
degrees Fahrenheit 72.3 vs. 72.4.
Inside the control cabinet the plc and
electronics are housed.
Control cabinet and associated
conduit.
An electrical safety switch was
installed for lockout / tagout.
Fluorescent Lighting System Is
Controlled Through The PLC.
Momentary Wall Toggle Switches Are
Used For Input To The PLC To Operate
Lighting
Standard toggle switches were removed
and momentary toggle switches were
installed for input to the plc
Lighting Control In The Evening Is
Operated Through A Motion Detector.
Opt isolator Is Used For An Interface
between 277V and 110V PLC Input.
J1
R1
R3
J4
277V Input
15kΩ
5%
2 Watt
12kΩ
5%
2 Watt
120V Output
2
D1
LED1
U1
4
1
3
MDA2501
MOC 3010
J2
J5
Neutral
Neutral
2
D2
LED2
U2
4
1
3
J3
R2
R4
277V Input
15kΩ
5%
2 Watt
12kΩ
5%
2 Watt
MDA2501
MOC 3010
J6
120V Out
Title:
277VIsolator2
PLC Input Level Converter
Designed by:
DEM
Document N:
0001
Checked by:
DEM
Date:
2011-05-09
Approved by:
DEM
Sheet
1
of
Revision:
1
Size:
A
1.0
In the future classroom PLC’s can be
networked with RS-485