Why Open Protocols…
Why Alerton…
DDC Basics
Introduction
ƒ Ken Nekvasil – Sales Manager
1
Agenda
ƒ Control Basics
ƒ Communication Fundamentals
ƒ Protocols
ƒ Integration
ƒ The future of BAS
ƒ Questions | Discussion
Control Basics
ƒ What is BAS?
2
Control Basics
ƒ ACS, DDC, BAS, BMS, EMS, FMS, …..
ƒ Building Automation System:
ƒ A network of integrated computer components that
automatically control a wide range of building
operations such as HVAC and lighting.
History
ƒ History of Building Controls
ƒ 1950’s - Basic Pneumatics
ƒ 1960’s - Advanced Pneumatics (Receiver/Controller)
ƒ 1970’s - Basic Central Control (DDC)
ƒ 1980’s - Distributed Logic Controllers (DDC)
ƒ 1990’s - Open Protocols (BACnet, Lon)
ƒ 2000’s - Web Based Controls, Wireless
3
Controllers
ƒ Controllers
ƒ Freely Programmable
ƒ Application Specific
ƒ Functions
ƒ Input Data (Inputs)
ƒ Process Input (Controller)
ƒ Generate Output (Outputs)
ƒ Communicate to other Controllers
Inputs
ƒ Analog Inputs (AI)
ƒ Bring an analog signal into the controller
ƒ Temperature (Thermistor, RTD)
ƒ Humidity | Pressure – (0-10 VDC, 4-20 ma )
ƒ Binary or Digital Inputs (BI or DI)
ƒ Read a Binary signal
ƒ Contacts | Current Switch | Pressure Switch
4
Outputs
ƒ Analog Outputs (AO)
ƒ Generate a modulating signal out of the controller
ƒ Valves | Actuators | Speed Control (VFD)
ƒ 0-10 VDC | 4-20 ma
ƒ Binary or Digital Output (BO or DO)
ƒ Enable/Disable a device or piece of equipment
ƒ Relays | Two position Actuators
PID Loops
ƒ PID Loops
ƒ Proportional
ƒ The proportional term produces an output value
that is proportional to the current error value…
ƒ Integral
ƒ The contribution from the integral term is
proportional to both the magnitude of the error and
the duration of the error...
ƒ Derivative
ƒ The derivative of the process error is calculated by
determining the slope of the error over time…
5
PID Loops
ƒ PID Loops
ƒ Proportional
ƒ 10 deg P means 1 deg error = 10% movement
ƒ Integral
ƒ Continuously adjusts for error
ƒ Derivative
ƒ For don’t use
ƒ Adjust for how fast you are moving towards or away
from set point
Control Basics
ƒ Control Languages
ƒ Graphical Based
ƒ Function Blocks
ƒ Similar to pneumatic devices
ƒ Text Based
ƒ “If then do this……”
ƒ Similar to Basic programming
6
Gateways
ƒ Gateways
ƒ Convert one protocol to another
ƒ Pro’s
ƒ Lower cost
ƒ Con’s
ƒ Single point of failure
ƒ Functionality
ƒ Less information
Communication
ƒ Communication of BAS Systems
ƒ Ethernet - Hard Wired
ƒ Ethernet - Wireless
ƒ RS-485 (2 wire serial comm )
ƒ Wireless - Zigbee Mesh
7
Protocols
ƒ Protocols
ƒ Language for a controller
ƒ Proprietary
ƒ Open
ƒ BACnet (ASHRAE)
ƒ Lon (Echelon)
ƒ Modbus (Modicon)
ƒ XML
Protocols
ƒ Why BACnet?
ƒ Kind of like pneumatics
ƒ Has what an owner wants in a BAS
ƒ Alarming
ƒ Trending
ƒ Scheduling
ƒ Ethernet Routing
ƒ Self Discovery
ƒ Not a panacea
ƒ Different programming types
ƒ Not everyone does it the same…
8
BACnet Vendors
Open System Architecture
9
Integration
ƒ What is it…
ƒ Integration (from the Latin integer, meaning whole or
entire) generally means combining parts so that they
work together or form a whole…
ƒ Two or more different manufacturers devices talk to
each other…
Integration
ƒ Pro’s
ƒ Can lower cost…competition
ƒ Potentially options available
ƒ New devices/systems being added daily
ƒ Con’s
ƒ You get what you get – application specific
ƒ Additional field coordination
ƒ Not everybody does BACnet the same
10
The future of BAS
ƒ Energy Awareness
ƒ Energy Analytics
ƒ Metering (Sub-metering)
ƒ Dashboards
ƒ Continuous Commissioning/Fault Detection
ƒ 24/7 intelligence watching equipment
ƒ Finding the energy wasters $$$
ƒ Connectivity to everything
Questions?
Thank you for your time!
11
