This document discusses using wireless networks for industrial control applications. It outlines three levels of networks in control systems, focusing on the challenges of using wireless at the sensor network level. It presents different wireless network topologies and describes a demonstration project using Microchip Development Tools to establish a wireless infrastructure. The project aims to allow future substitution of control algorithms or protocols. An example application uses MATLAB and wireless nodes to simulate controlling a pendulum over the wireless network under two different protocols. Comparing the protocols revealed features like synchronization, unicast addressing, and network joining procedures.

1. The Use of Wireless networks
for Control Applications
Project By:
Alon Tzeiri
Nativ Levi
Advisor:
Dr. Gera Weiss
April 2011

2. The Hardware

3. Introduction
• There has been tremendous interest in the research and development of wireless
technology
• There is a set of well-known and agreed upon challenges that we have to
overcome to apply wireless to industry control; such as, security, robustness, delay,
and power
The Structure of Control Systems (Figure 1)
There are three levels of networks in a typical process control system:

4. • Level 1 :
 The control networks that physically manage the plant process.
 The controllers are connected to the devices via the cards (i.e control networks)
 The controller reads data from the sensors and writes data to the actuators
 The controllers are actually the coordinators in a starmeshcluster-tree networks
 The wireless network at this level is usually called sensor network
• Level 2 :
 It connects controllers that control devices in the field and workstations that
interface with the user
• Level 3 :
 The corporation’s network
We shall issue and focus on the challenges that are entailed with the
sensor network on level 1.

5. Network Topologies
1. Star Toplogy
2. Mesh Network
no must of the FFD
to follow the
tree route to the
coordinator.
1. Cluster Tree Network

6. Main Goal:
Establish an infrastructure for the Research of the use of wireless
networks as a control application.
Objectives:
1. To study and document the way of using Microchip Development Tools
(Writing tutorials for a futuristic use)
2. Develop a demonstration of how to use it as control applications.
3. Allow a futuristic substitution of components in the network such as the
control Algorithm( ‫הבקרה‬ ‫)אלגוריתם‬ or the join-the-network protocol.
4. Prepare the ground for the build of a network protocol
5. Make MATLAB and the network communicate (sendreceive data,
knowing the format of sending it etc)
The final use will be for the testing and verification of algorithms and
technologies.

7. Issues and difficulties
1. Using of MPLAB IDE & the in-circuit debugger
2. Learning the Library’s API (functions), structures (Incoming messages etc)
3. Learning the hardware and application files (headers)
4. Learning the Hardware’s features (P2P,Miwi application) & mechanisms
(Watchdog timers, synchronizations)
5. Interleaving MATLAB and the network

8. Example – The pendulum
Consider a rod standing on top of a rolling cart , and a matlab’s
model that is designed to keep the rod standing vertically.
We would like to use MATLAB model as the controller which
involves the wireless network as a part of the simulation.

10. • First Option – using the protocol of p2p .
• Description :
-N2 reads vectors from com1 as <first_float , second_float> on each
sample
-Calculates the scalar to be sent back to the simulation
-Sends them to N1
-N1 sends it to Com2 as <ans>
-the scope shows the number that com2 received and the lower one
shows the number that was supposed to be received
• Features and new discoveries:
-Using “To Instrument” & “Query Instrument” Blocks on MATLAB
-Sending a vector from MATLAB
-Knowing how to handle a float as a received message(unsigned char)
-Prioritization of blocks on MATLAB (synchronization wise)

11. • Features and new discoveries(cont’d):
- Real-Time Interaction between the cards and MATLAB.
- Hand Shake mechanism
- Unicasting via Address (i.e MiApp_UnicastAddress() )

12. • Second Option – using the protocol of miwi™.
• Description :
Does the same thing with MATLAB , but with different interintra cards
interactions
• Features and new discoveries:
- All the interactions with MATLAB features remain the same
- First use in MiWi™ Protocol Stack
- The join of N2 to the network
- Use of N1 as the network coordinator
- Use of N2 as the network role node
- Uses the node’s Connection table
- Use in MiApp_UnicastConnection
- Establishing a connection with a specific node in the network 
- Channels Scanning By N1
- MiApp_SearchConnection() – N2 searching for N1 and joins the network after
scanning all possible channels
- Characterizing each node by the field “ADDITIONAL_NODE_ID(1)”

13. • Second Option – using the protocol of miwi™.
example:
i = MiApp_SearchConnection(10, 0xFFFFFFFF);//searching the network for neighbors
if( i > 0 ){
for(j = 0; j < i; j++){
if(ActiveScanResults[j].PeerInfo[0]== 0x01 //N1’s info is 0x01
peerIndInASR=(int)j;
}
}
Else{
Printf("number of found peers was smaller than onern");
}
while( (i = MiApp_EstablishConnection(peerIndInASR, CONN_MODE_DIRECT)) == 0xFF );
~~~~filling the buffer~~~~
MiApp_UnicastConnection(i,FALSE);

14. • Second Option – using the protocol of miwi™ (cont’d)

16. Results comparison

17. References
[1] ZigBee alliances, http://www.zigbee.org/.
[2] David Flowers and Yifeng Yang , Microchip MiWi™ Wireless Networking Protocol
Stack , Microchip Technology Inc. (AN1066/AN1204).
[3] Jianping Song ,Aloysius K, Mok Deji Chen and Mark Nixon, Challenges of Wireless
Control in Process Industry.
[4] J Bester, I Robertson and B Groenewal, Wireless Control Network For Building
Automation Using IEEE 802.15.4
[5] Mathworks – MATLAB and Simulink for Technicalk Computing ,
http://www.mathworks.com/ .

18. Thank You!!!!!
Questions??