Automation for an HVAC System Final Report SC 206522329

Automation for HVAC system 2010

SCHOOL OF ELECTRICAL, ELECTRONIC AND COMPUTER ENGINEERING

Electrical Design 5 Final Report for

Automation For HVAC system

Author: Ndovela Sibonelo

Author’s Student Number: 206522329

Project supervisor: Prof. E Boje

External Examiner: T. Dzwig

Report Due date: 05 May 2010

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AbstractThis report presents the design of a SCADA Adroit User Interface for an HVAC System. The report presents the system specifications and their breakdown into a design problem. Which is then developed into component blocks and the tasks to be performed in each block to meet the specifications.

The design involves the use of Adroit7 software and Omniflex software. Since the Interface in created in Adroit’s Classic User Interface the report presents how the Adroit components used work and interact with each other. Problems associated with dealing with Adroit and the OPC server are present together with their solutions.

Components that can be further investigated and developed as addition to this project are also presented.

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Table of ContentsAbstract....................................................................................................................................................2

Acronyms.................................................................................................................................................4

1. Introduction......................................................................................................................................5

1.1. SCADA System.......................................................................................................................5

1.2. HVAC System.........................................................................................................................5

2. Design Outline.................................................................................................................................6

2.1. Project Specification................................................................................................................6

2.2. Overall System Overview and Design Proposal......................................................................6

2.2.1. Air Handling Unit(s)........................................................................................................7

2.2.2. PLC..................................................................................................................................7

2.2.3. Supervisory Computer.....................................................................................................7

2.2.4. Air-conditioner and heater (and Lights)..........................................................................7

2.2.5. Remote Computer access.................................................................................................8

3. Design Process.................................................................................................................................9

3.1. Design Breakdown...................................................................................................................9

3.2. Design Components...............................................................................................................10

3.2.1. OPC Server....................................................................................................................10

3.2.2. ACUI..............................................................................................................................10

3.2.2.1. Pictures.......................................................................................................................10

3.2.2.1.1. Testing interface........................................................................................................11

3.2.2.1.2. Designed interface.....................................................................................................12

3.2.3. Database...............................................................................................................................18

3.2.3. Internet...........................................................................................................................22

4. Management...................................................................................................................................23

4.1. Time schedule........................................................................................................................23

4.2. Problems Experienced...........................................................................................................25

5. Conclusion.....................................................................................................................................28

References..............................................................................................................................................28

Appendix A............................................................................................................................................29

Appendix B............................................................................................................................................30

Appendix C............................................................................................................................................32

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Acronyms

SCADA Supervisory Control and DATA acquisitionHVAC Heating, Ventilation and Air ConditioningRTU Remote Terminal UnitsPLC Programmable Logic ControllersAHU Air Handling UnitOPC Object Linking and Embedding for Process

controlSASRI South Africa Sugar Research InstituteACUI Adroit Classic User InterfaceAAS Adroit Agent ServerRH Relative HumidityTA Ambient Temperature LL Light Level

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1. Introduction

1.1. SCADA System

A SCADA system supervises and controls a process while it simultaneously gathers data from it and sends it to a central computer. The system also sends commands to the process. SCADA systems can be thought of as industrial control systems. The basic structure of a SCADA system consists of a supervisory computer, an HMI, RTUs or PLCs and communication tools. [1]

1.2. HVAC SystemHeat, Ventilation and Air Conditioning systems are important in the design of medium to large industrial buildings, office buildings and environments where the safety and health condition of the building are controlled with humidity, fresh air from outdoors and temperature. [2]Such an Environment exist at SASRI manufacturing company in Durban. They need have an Automation system that controls the humidity and temperature of (4×9) rooms, where they groom sterile insects (male). This is so as to put them in the sugar cane farm to mate with female and while reproduction does not result. The temperature and humidity is controlled so as to stimulate faster breeding of the insect. The current system installed for the control works very well, but the monitoring ,by the company, of what is happening inside the rooms (environmental conditions) is a problem as they don’t have a properly working interface to the automation system. In this project such an interface will be developed using Adroit software (HMI).

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2. Design Outline

2.1. Project Specification

The project description as can be found in [3] is :

“Design and develop an ADROIT Scada interface for a PLC based HVAC system. The design will include understanding programming of the PLC, sensors (which already exist), OPC server and the Scada packages.”

From the project description and supervisor’s explanation it was clear that the student had to design an interface (HMI) to PLC system using Adroit SCADA. The Scada system is for an HVAC system, thus the author would have to familiarise himself with all the components of such a system. Thus the part in the description about understanding the programming of PLC and sensors.

2.2. Overall System Overview and Design Proposal

From the given description the author’s overall idea of the complete system should look like (with the author’s design included).

Figure 1Author's overall project overview

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2.2.1. Air Handling Unit(s)In the actual system there are 9 AHUs. Each air handling unit has up to four sensors connected to it. This is because the handling units are each used to monitor up to 4 rooms simultaneously. The sensors sense temperature, humidity and light intensity in the rooms they are installed in. This data is the taken to the PLC using RS485 (Physical Layer) and Modbus (Protocol Layer). The sensors have been designed, built and tested before. The sensors were not built and connected to the PLC as the was not enough time left to get the components ordered and assembled, to test the user interface. The Device “NET1” was simulated to test the User Interface.

2.2.2. PLCThe PLC collects data from the sensors, does the necessary manipulation (calculations) , carries out the necessary control(Turning the Heater and Air conditioning units on/off) and make values available on its OPC server. These values can then be accessed by Scada Adroit for display and writing into a database.

2.2.3. Supervisory ComputerThe PLC will be linked to the author’s Laptop (which will serve as the supervisory computer) over the LAN. On this supervisory computer will be the OPC server, SCADA Adroit interface and Database.

2.2.3.1. OPC serverThis comes embedded in the Omniflex installation package. The OPC server will be configured to go into the PLC registers, read values and make them available to the ADROIT Scada interface.

2.2.3.2. Scada Adroit InterfaceThe Adroit software installation installs the Adroit OPC client, the Adroit Classic User Interface and the Adroit Agent Server amongst its other applications. The Adroit OPC client will see the OPC server and use it to access the tags (values) stored on the server from the PLC. The AAS stores real time and historical data, it allows agents (intelligent objects) to exchange data with other agents or pictures on the ACUI. These data can then be displayed on the ACUI on graphs (with a time base) and on textboxes. It can also be written to a database. There are different types of agents and each types performs its particular type of task. Agents not only contain data but can operate and act on their own data, drive their values and read and write to other objects .[4]

2.2.3.3. DatabaseThe database is used to store the data from the PLC and Adroit. This data is available for use as historical data.

2.2.4. Air-conditioner and heater (and Lights)If time permits the user will test Scada Adroit interface in a plant where it is intended to operate. The air conditioning unit and heater are contained in their setting. Four rooms share an Air conditioner and a heater.

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2.2.5. Remote Computer access The author should also try to access the Scada outputs (Adroit Interface) from another PC on the same network and over the internet. This will be done if time permits.

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3. Design Process

3.1. Design BreakdownFrom the project description and overall system overview given above, the author’s task was clearly identified as designing an Adroit Scada interface. The design revolved around the proper understanding and use of the Adroit software in order to achieve this. From figure 1(Page6) it is seen that the design is actually concentrated on the components in the Laptop block (Supervisory Computer). Then from the proper functioning of the inner blocks(components) within this block, which will be designed, the other block (components), which make up the complete system, can be integrated as described above. The design can be broken down as follows:

Figure 2Scada Adroit interface design break down

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OPC ServerTagsTag Addresses

ACUIPicturesTrends

DatabaseAHU Values TableRooms' Values Table

Agents

Agents


3.2. Design ComponentsFrom the breakdown given above ( 3.1.) this section will look at the work that was done on each of the sub-components to complete the project.

3.2.1. OPC ServerA configuration file was provided to configure the OPC server for the PLC. The configuration file had the PLC’s IP address, register addresses and the variable names given to them. Then the configuration file can be run on the Modbus TCP OPC configurator, in simulation mode and in real life mode. These modes are respectively used in the absence and in the presence of a target device (PLC). In either case the configuration file must be made active; so as to be the device being configured can be visible on the OPC server. The OPC server is then able to read off values from the PLC using IP (Ethernet cable). For this to occur, the author’s laptop had its IP address set and connected to the PLC using an Ethernet cable. An OSU file on Omniflex was used to connect the computer to the PLC, thus enable the OPC server to see it. The connection mode is Conet/e on Network card.

This task took some time as the PLC initially was connected using a serial to USB. Trying to achieve the connection was initially a failure. Then after going to Omniflex the problem was discovered to have been the serial to USB drivers and the Vista. New drivers were installed and then Omniflex CServer registered on the windows system32 registry. It was then found that for the values on the PLC to appear on the OPC Server further configuration would have to be done. To overcome this, the Ethernet connection as described above was used. The OPC server is currently fully functional.

3.2.2. ACUIThe ACUI has a lot of different components that can be added together to form an Adroit Scada interface. These components include pictures, trends, web, etc. The picture (mimic) is where a combination of textboxes, buttons and jpegs can be placed to form a user interface, as in Visual Basic. The trends can be added to graphically represent values as they change with time. The complete user interface has been designed and developed using the ACUI. The basics of how to get things done were extracted from an example in [5]. This example was then extended to see how some required functionalities can be achieved in the actual user interface.

3.2.2.1. PicturesThe mimic is formed by a combination of buttons and textboxes. These can be associated with certain behaviours, which in turn is associated with an agent. The behaviour determines what the mimic component will do when triggered (when button is clicked on for example) . The agents are configured in the ACUI configurator. There they are given a name and the type (Database, Analogue, Boolean, etc) of agent they are.

3.2.2.1.1. Testing interfaceThe testing interface, which was extracted and expanded from example in [5] is given below.

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Figure 3 Testing User Interface

Figure 4 The test interface mimic

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The testing interface comprises of the mimic and a trend. The trend shares an analogue agent, Speed, with the green textbox. This agent was configured (Appendix A) to scan the PLC alive-counter tag on the OPC server. To get to the scan configurator; Select an agent (Appendix A) and then click on scan button in the Agent configurator. The write enable check box (Appendix A) was checked so that if the value is manually changed on the interface it changes on the server and thus the PLC registers. The value of the red textbox was changed manually. It was associated with the agent called Temperature. Both the text boxes were associated with the display value and operator action behaviour. The first behaviour says which tag to display. The second one tells which action (Data entry) the textbox take when should it is clicked on. The update button was used to trigger the addition the values in the textboxes into the Database. The database set up and configuration will be discussed in section 3.2.2.2. This button was associated with a Boolean agent, “Trigger”, and the behaviour “operator action”. The operator action was a control action called “digital toggle. The same agent was used on the max Trend button, which was used to maximise the trend window. This button’s behaviour was selected to be the “Execute Command”. Since the same agent was used in both buttons, the effects of the agent on one button were present on the other. On the actual system one agent is used per tag. After a lot of experimentation and read-up when working with the test interface the author had an idea of how his user interface will look and will be configured. The trend was graphing the values on the alive-counter.

3.2.2.1.2. Designed interface

AHU8 Set points MimicBelow is the designed interface. Figure5 shows the 24 hour set points pop up that was going to pop up when, the “Change RH SP” button, on the AHU8 block is clicked (Figure7).A new interface was developed with the TA set points included in the mimic (Figure6). To pop this interface one button. This allows the 24 hour set points to be viewed and set in 1 window.

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Figure 5 AHU 24 Set point pop up (RH)

The final 24 hour final set point mimic is shown in Figure7 below.

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Figure 6 AHU8 RH and TA24 hour set points mimic

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Final Main User InterfaceThe main user interface is given below (Figure8). The textboxes and buttons were associated with similar behaviours and agents as in the testing user interface, respectively. Since it has shown that they can achieve the required tasks. For illustration and demonstration, AHU8 and the 4 rooms (rooms32,33,34 and 35) it monitors were fully configured. This is because if these work perfectly, the same configuration can be applied to the rest of the interface components.

Figure 7 Main User Interface design

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AlarmsThe alarms were configured using the high and low values of the tag. The dead band is given to tell the alarm how far above the low value, after the alarm was triggerred by the value going low, should the alarm turn off. The sirmilar case exists for a high alarm. The “Edit Analog Agent” window for “ROOM32_RH” is give in Appendix C showing these values. The Alarm for Room32 RH is associated with the its textbox’s blinking (text colour) behaviour,using the agent “ROOM32_RH” “high” slot. The sirmilar setting is done for the Room 32 TA,but with backround colour instead of text cololour.The triggerered alarms are shown in red on the the interface below (Figure8).

Figure 8 ACUI mimic showing the alarming of tags

The trends for each variable in each room include the AHU8 SP and MV values. Below is a trend for RH in Room 32.

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Figure 9 Room 32 Relative Humidity (Showing the behaviour at 22:30 and Past 30 minutes )

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Figure 10 Room 32 Temperature (Showing the behaviour at 22:38 and Past 30 minutes )

The navigation panel (circled in green on Figure10) is used to view different times in the trend. For data that was logged in the past and the logging had been stopped, or the database had data logged to it and was written to disk, an agent can be used to log values to this database. How to do this is explained in the following section. Then the data can be retrieved for a specified period. This data can then displayed on a trend for a user specified time interval.

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3.2.3. DatabaseThe Database structure initially selected was the one that was presented to the author by the supervisor, which is currently in use at SASRI. The supervisor advised that should the student be capable of reproducing the similar structure of the database as one presented (Figure11 and Figure12) to him he should do so. The required variables can also be observed from the figures below.

Figure 11 Database Structure showing tables and require room variables [6]

Figure 12 Database Structure showing tables and require AHU variables [6]

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Currently the student has developed the database given below as based on the test interface. To create a data base to write values to from Adroit, the following steps were taken [5]:

1. Open a blank access database.2. Create a table and Insert the required fields3. Save and close database4. Configure agents for the tags to be stored in the database5. Configure a database agent

Figure 13 Author's test interface database

Following the steps above, the same database format as the one given in Figures 11 & 12 can be created. To write values into the database automatically the transaction scheduling and triggering is edited. The time for each transaction can then be specified and a trigger that will force a write if required. This was done with the values being “scanned” into the database. The author found that for trends the historical data had to have been logged. That is the scanned data could not be retrieved for use in Adroit. The tags thus had to be logged. This lead to the initial structure of the database not being able to be kept. The first proposal was to have each tag stored in it own Database, thus the data could not get too big in time as compared to when all the tags are in one database. This idea would require a lot of different databases to be opened when data was to be evaluated or viewed. Thus it was aborted. The possible structures of logged data are shown below.

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In Figure14 below the tables for different tags and logging methods are shown on the left. The database values shown are the “RH” values for Room32. The agent was just configured to log the tag to the database. This method automatically creates a table, but gives the value and its timestamp and does not the date of the sample. This would work fine for retrieving the data to display on a trend in Adroit, but if a user wanted to view the data from the database, the data would not be useful.

Figure 14Room32_RH logged tags

The second way was to create a table and log values into that table. The table “Room32” (Figure15) was created and the agents, ‘Room32_RH” and “Room32_LL” , were configured to log values to this table.

Figure 15 Room32 database table

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The values were logged to the table. The logging changed the table’s format and had the values in one column alternating (Figure16). This was going to be a problem when just trying to look at the behaviour of one variable in a room.

Figure 16 Room 32 table showing the LL and RH values in one Database Table

The solution was to have a data base that has each tag in its own table. The tables are created then in the configuration, each agent is give a table to write values to. See Appendix B for the configuration steps.

Figure 17 The final database structure Showing the tag tables on the left

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3.2.3. InternetThe author had to investigate how he could connect to the interface and thus the its information using the internet, if time permits. Then furthermore implement this method of internet connection. Time could have allowed this but there was a problem with the ACUI connecting to the server.(This is explained in section 4.2.). But some investigation was done and attempts made to get the internet connection. Firstly it was found that ADROIT7 cannot host a web site[3] and this was confirmed with the ADROIT technical support [7]. Two possible solutions were considered.

Microsoft Silverlight (C#) What Adroit can do is create images of mimics and trends at given time intervals to a chosen folder. Another student was working with putting up images from a camera on the web. His project had two parts. A main page which could be accessed over the web which shows the images. The images on this page were small. This was supposed to link to another page that has a slide show of the pictures taken that were saved in a folder. The author found out about more information about this and how he could use a template like this one to view picture of the ACUI. In the investigation the author found that the was a problem with connecting to the slide show. This was because the slide shows’ page was created using Silverlight (and programmed in C#) which was a folder system. This application can thus only work on a computer that has the application running on. Thus not helpful in solving the problem at hand. Now if an internet hosting application could be written to pull this images from the folder to a web page which can be access over the internet then the problem could be solved.[9]

VIZNET VIZNET comes embedded in the ADROIT installation package. This component, just like Adroit 7,can be used to create user interfaces. It has the capabilities to host a website. The author investigated the VIZNET features and capabilities. At the point of documenting this report the author had not gotten around connecting to the VIP server on his PC. The author will continue to work on VIZNET and if any progress is made by the oral presentation day, it will be presented there.

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4. Management

4.1. Time scheduleThe original time schedule is given below together with the new time schedule. The Author and His supervisor had weekly meetings on Tuesdays at 12h00 (Not shown on Schedule).

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The new time schedule shows the modifications that were made to the original time plan. In the schedule the tasks whose time has elapsed are complete. The tasks which were performed before the actual time scheduled have been moved to the weeks in weeks in which they were performed. Some of the reasons why changes occurred is due to the problems faced. For example in waiting for the licensing other tasks the author investigated which adroit component he would have to use to achieve the required design.

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4.2. Problems ExperiencedThe main problem experienced towards the completion of the project was the Omniflex trial software expiring. This led to the OPC Server not being able to connected to by the ACUI. In the beginning the Agents in Adroit could not be configured to scan the tags on the server, but the values of the tags that were already scanned could appear on the ACUI. The Omniflex software was registered but the problem persisted. Then an e-mail was sent to Adroit to try to and identify the possible cause of the problem. The possible causes were thought of to be Adroit being out of date or the “opc_cl.dll” being deleted or outdated. The link for the updates was not accessible. The author later found that the cause to this was that the File Transfer Protocol (ftp) link needed a password. The “opc_cl.dll” file was copied to the Adroit folder and registered on the system. When the agent server was started it failed to initialise “NET1”. The old “opc_cl.dll” file was copied back and registered.

Then the values of the tags already scanned started having problems with showing the changes that were configured to the(With device in simulation mode in the Modbus TCP OPC Configurator). This is shown in Figure18 below, where the value of the alive counter is circled in red on the Adroit ACUI mimic, Adroit browser and the Modbus TCP OPC configurator.

Figure 18 Alive Counter values shown on Adroit ACUI interface, Adroit OPC browser and Modbus TCP OPC Configurator

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The Adroit Configuration Setup was showing that the device (NET1) is unhealthy. The changes in the Alive Counter could also be viewed in the Matlab OPC Tool.

Figure 19 Matlab OPC Tool showing the value of the "Alive Counter"

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From this the author’s could conclude that the problem is rooted in the connection between the ACUI mimic and the OPC Server. Since this connection is performed by “Adroit agents”. It was required to look at what can possibly be the problem with the agents. The author noted that the “.WGP”, “.LGD”, “.LGI” and “.BAK” files, accumulate data pertaining to the ADROIT ACUI. What could have caused the problem could still be have been stored in these files. The author decided to cut all these files and put them elsewhere. Then the agent server was started and then an Analogue agent created. This analogue agent was configured to scan “NET1” and thus creating a device agent for “NET1”. “NET1” then appeared healthy on the Adroit Configuration Setup.

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5. ConclusionThe project has been described and planned for. As indicated in the timeline the project can be finished within the required time. The project was thus finished in time and the Adroit interface working properly on both the central computer (Laptop). It has been shown that Adroit 7 has the capabilities to achieve the required tasks. The author gathered enough knowledge on these capabilities to finish the project on time. This knowledge and tools were used to achieve a final design that will have meets the requirements. Since Adroit cannot host a website[4],[7] this feature could not be done. Instead other possibilities were investigated together their abilities and functionalities they could implement. Since a lot time was lost in solving the problem that was happening with the OPC Server, not enough time was spent on VIZNET to get an interface that can be accessed using internet. Such a delay had not been anticipated [8] as the problem was not expected. Further work can be done on VIZNET to get an interface that can be accessed over the internet. It was thus found that all major projects components should be finished well in advance and additional features left for the end. This is so as to give the designer time to go back to the main project should a problem be encountered.

References

1. www.wikipedia.com/Scada, accessed 15 February 2010

2. www.wikipedia.com/HVAC, accessed 15 February 2010

3. Prof. E Boje, Electrical Design titles for 1st semester 2010

4. Adroit 7.0 Help

5.Adroit Technologies, Step by step guide Adroit database connectivity

6. SASRI (Prof Boje) , May 27 2008 (Access Database)

7.Stephen,Adroit Technical Support, [email protected]

8.S.C. Ndovela, Electrical Design 5 Interim Report

9. Sithembiso Gama, (Computer Engineering Student), Electronic Design 3, MMS Camera

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mailto:[email protected]


Appendix A

Figure A 1 Adroit Agent Configurator showing 2 Analog agents

Figure A 2 Agent (Speed) Scan configuration

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Appendix B

How to set up the agent log into a specified table in a database. Open the Agent Configuration window, then click on the log button. The “Edit DataLog” window appears (Figure B1). Clicking on SQL will open up the “Data Link Properties” window (Figure B1). Select the Microsoft Jet4 OLE DB Provider,then click next. The select the database to store the values in from its directory. Then test the connection. Clicking on “OK” takes one back to the “Edit DataLog” window. To connect the agent to a specifific table type a “$” at the beginning of the Datasource string and type “$TableName” at the end (Figure B1)

Figure B 1 Edit DataLog Agent window for ROOM32_RH, Left: the $ at the beginning of the Datasource string. Right: “$TableName” at the end of the Datasource string.

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Figure B 2 Data Link Properties window

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Appendix C

The “Edit Analog Agent” window for “ROOM32_RH” showing the alarm triggering limits and deadbands.

Figure C 1 Edit Analogue Agent for ROOM32_RH

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Documents

Automation for an HVAC System Final Report SC 206522329