Presentation of Real Time Monitoring & Alert

Systems used in Singapore

By : Dr G H Tan (SysEng)

Agenda

1. Introduction

2. Automatic Real Time Monitoring & Alert System used in

Deep Excavations

3. Challenges of Operating the Real Time Systems

4. Workings of Vibrating Wire Gages and Manufacturer

Specifications

5. Measurement Flow from Vibrating Wire Signals until the

Engineering Units of kN force

6. Data Quality affected by Electromagnetic Noise Sources

and On site troubleshooting

7. Planning for Data Quality starts with proper site planning

8. Live Demonstration of the Types of Noise which can

increase or decrease the Strain Gage Forces measured

9. Q & A

Straits Times March 24th 2007

`

• SysEng is a System

Engineering Company with

Multi-disciplinary Engineering

Capabilities

• Started in 1994 by Engineers

• To deliver the Right Data , at

the Right Time, at the Right

Place with the Right Price

and the Right Quality to

make the Right Decision

• Vertical Integration of M2M

applications with a One-

Stop Shop Engineering

Solution Service to ease the

deployment and support of

complex technologies to

help in the growth of the

client’s business

An Automatic Real Time Monitoring & Alert System to help

Professional Engineers, Consultants and Authorities

monitor Geotechnical and Structural movements 24 x7

without any human effort.

The Benefits are :-

• Equipments & System are leased to clients without Fixed

Overheads, Engineering Team and Investments.

• Pays for Timely, Quality and Reliable data.

• No Hidden Repair and Support costs.

• One time setup fee and monthly monitoring fee to help your

cash flow.

• Leverage on SysEng Engineering Expertise in Sensors,

Electronics, Communication, Software, EMI Noise Prevention &

troubleshooting to support the clients.

• Technical Service Support with 24 Hours Alarm Monitoring

Everybody knows what is expected about a

Real Time Monitoring & Alert System

Doctor tells the Nurse “Please monitor the Patient and call me immediately (Real Time) if there is any change in

his condition”. This means Nurse has to check the patient regularly and inform the Doctor when the

Patient gets worse.

Similarities between

Hospital = Construction

Patient (Surgery) = Excavation Site (Soil Cut &Open)

Doctor = Professional Engineer

Nurse = Monitoring Specialist

Immediately = Real Time of 10 minutes

A Proven Real Time Monitoring

& Alert System (eMonitoring

System) which addresses the

Real Time challenges which

were uncovered in the Nicoll

Highway Inquiry

Nicoll Highway Court of Inquiry has taught us a valuable lesson that

having data in the instrument and then getting information only after

24 hours is NOT Real time. The system can fail with 999 readings

and NOBODY is even aware of such systematic failures !

Three Points highlighted in by the

inquiry

1. The Real Time System used is an

in-correct Real Time System

2. If sensor is not working with “999”

readings and nobody is alert about this

error

3. Alerts are send via email only once a

day

How could it occur at your site if you use

real time monitoring ? It is better to use a

professional service to protect lives and

your reputation

SysEng’s Proven Automated Real Time

Monitoring & Alert System (eMonitoring

System) which addresses theses challenges

•This System has been presented in many

International Civil Engineering Conferences

•It’s Development was funded by Singapore

InfoComm Development Authority

•It is used many Singapore Land Transport

Authority Monitoring Projects after the

Nicoll Highway incident

Timing Chart from sensor readings to end user SMS alert

using GPRS 32,000 bps on-line

Total of 7 mins per Measurement and Alert cycle

with the guaranteeing of 10 mins cycle time

GPRS

4 mins

100 sensors Tx Data

1 min

Analyze

1 min

SMS Alert

1 min

Process Time for one Measurement cycle

A Wire-less Dial up GSM system cannot

have 64 data loggers simultaneously

connected to the server

Real Time Data Logger System• The Campbell Scientific

CR10X is Data Logger Unit

• Real Time Data transmitted out by GPRS @ every 10 minutes to Central Server

• Powered by Solar Panel

• Local Power Stabilizer and Battery backup

• Signal Conditioner

• Measure Maximum up to 96 VWSG with 96 Temperature channels (Max 112)

• Weather Proof Enclosure IP65 rating

• Manufactured with Local on site Service supported by SysEng in Singapore

Advantages of Always On-line

connected GPRS over Dial up GSM

Depend on connection

time

Occupied full bandwidth

even without data

transfer

By demand through dial-

up

9,600 bps

GSM

Depend on amount of data

send

Wire-less

Charges

Occupied bandwidth only

during data transfer

Wire-less

Bandwidth

Always onConnection

Mode

32,000 bpsData Speed

GPRS (General Packet

Radio Service)

WAN System

IDA featured

SysEng in

their

Website as a

Recognition

of our

contribution

towards

M2M

In the International Workshop of

ITU, this paper showcased the

Advance Wire-less application

deployments in Singapore.

SysEng M2M Real Time

Monitoring System was

described in this prestigious

workshop

SysEng M2M application in

Construction site Temporary

Strut Force Real Time

Monitoring & Alert System

Mar 2004 - “Real Time Monitoring Systems in Tunnel & Deep Excavation Projects” at

Geotechnical Conference, Malaysia

Aug 2004 - “Real Time Monitoring and Alert Systems for Civil Engineering applications

using Machine-to-Machine Technologies” at International Conference on Structural

and Foundation Failures, Singapore

Jan 2005 - “Evolution of Remote Structural Health Monitoring Systems with M2M

Technologies” at Society of Experimental Mechanics, IMAC XXII Florida, USA.

Oct 2005 - “Ubiquitous Real Time Monitoring and Alert applied to Excavation Works” at

4th International Symposium on New Technologies for Urban Safety of Mega

Cities in Asia, Nanyang Technological University, Singapore

Nov 2005 - “Real Time Monitoring and Alert in Excavation Works using Machine to

Machine (M2M) Technologies” at 2nd International Conference on Structural

Health Monitoring of Intelligent Infrastructure, Shenzhen, China

Mar 2006 - Improving Instrument Data Quality from Excavation sites to the Right

person to make the Right Decision at the Right Time, International Conference and

Exhibition on Tunneling and Trench less Technology, Malaysia

Apr 2006 - Conference Paper Automatic Real Time Monitoring using M2M Technology”

in Seminar on Instrumentation Monitoring for Underground and Tunneling

Construction Safety in Chengdu Railway Co. Ltd and Southwest Research Institute

of China Railway Engineering, Chengdu China

Real Time & Alert System presented in

numerous Civil Engineering Conferences

In the New Nicoll Highway Real Time & Alert Monitoring

System as required by LTA has raised the System Quality

Specifications to address previous shortcomings.

•Real Time is 10 minutes

•On-Line Central Server

system

•Web Page System

•Automatically sending

out of data

SysEng System Specifications implemented :-

•Measuring and Sending sensor data every 7 minutes to the

Central Monitoring System with sufficient redundant readings

per sensor point.

•SMS Alerts sends out only after the second cycle Alert

verification (20 minutes delay from the first Alert trigger).

•Smart SMS Alert re-triggering techniques to prevent too

many SMS Alerts.

•Every 60 seconds Server system health checks.

System Specifications guaranteed to the Clients :-

•Measuring and Sending sensor data every 10 minutes to the

clients.

•SMS Alerts sends out only after the second cycle Alert

verification (20 minutes delay from the first Alert trigger).

•Respond to client within 2 hours to bring the system back

during office hours and 12 hours during weekends & holidays.

The eMonitoring Real Time Monitoring & Alert System has

many Smart Technologies to detect various fault conditions to

ensure that the entire system has Higher Service Uptime.

The Smart Technologies detect when:-

•Individual sensor cable faults of open or short circuits

•Data Logger Backup Battery Health status

•Data Logger cannot send sensor data to the Central

Monitoring System (CMS) for processing as well as its sub-

systems

•Wire-less GPRS and Internet Data Communication not

available

It automatically monitors the entire system every 60 seconds

and alerts SysEng support staff to correct the situation in a

proactive way. This makes it more reliable than human-

supervised monitoring system.

The System automatically sends SMS Alerts when sensor cables are cut,

VWSG Cables cut

SMS Alert

automatically

pushed to all

users

The System automatically sends them SMS Alerts when :-

On-site RTU/Data Logger

has not send Sensor

data to the on-line

Central Server System

On-site RTU/Data Logger

Backup Battery Voltage

falls below 11.0V

SMS Alert

VWSG Sensor reading

has exceeded its Alarm

Limit

With Real Time

Monitoring & Alert

System, the Demand

for Higher Sensor

Quality Data becomes

a Major Challenge

Real Time Service Level our clients by Monitoring the

Performance of every sensor & data logger

a) Number of sensor data received by client / Number of

sensor data installed per day : > 99.9 %

Example:-

Measures 224 sensor points (112 VWSG + 112 ToC) per Data

Logger at every 10 minutes.

It generates (224 x 24 x 6 =) 32,256 data points per Data

Logger. Hence a 0.1% error means 32 data points per day

are allowed to have missing readings.

b) Number of times (Gateway/Incoming/Processing PC) down

per month : < 2 per month

Now SMS False Alerts becomes a major challenge when

Electromagnetic Interference (EMI) can corrupt the Data

Logger Readings

Factors affecting the Quality

of data of sensors

VW gage

Pluck Coil

Vibrating Wire Strain Gage (VWSG)

Functionality

External Electrical &

Magnetic Interferences

Not properly shielded

or grounded Sensor

Cables ??

Speaker

Analyzer

The VWSG Specifications are taken from the

Manufacturers Website

Read the Fine print from the various Vibrating Wire

Strain Gage Manufacturers

•All VWSG can transmit out over long distances

without affecting output Quality ?

•How long is long 10 m or 10 km ?

•Immunity to noise, how high is the Noise level ?

•How large is the Signal to Noise ?

RST

SINCO

GEOKON

EMI Noise affecting the sensor readings

Under Ideal condition, the Data Quality is

maintained even if 1000 m cables are used

Site conditions generate EMI Noise due to Arc Welding,

Power Generators and High Current AC current wires

inducing noise into sensor wires due to cross coupling.

Cables with improper shielding configuration, ungrounded

shielded cable ends, exposed cable joints can corrupt

sensor readings

But the Reality is that a site condition is very different

Non Noise site ~ 500m while Noisy site ~ 200m

Portable

EMI Meter

to pin-

point the

source

What is Actually EMI ?

Generate EMI

No affected by EMI source

Electro Magnetic Interference Field

obeys the Rule of Inverse Square Law

EMI

Source

0

2

4

6

8

10

12

3 4 5 6 7 8

DISTANCE (CM)

ST

RE

NG

TH

(dB

)

Strength

proportional to 1.000

Distance2

Moving EMI source from 1 m

to 5 m away reduces 100% to

4 % in EMI signal strength !

How does the external EMI signal

which affects the frequency in

turn corrupt the strain readings ?

Strain is proportional to Frequency

x Frequency.

A 5% error in Frequency Reading

is a 25 % Strain calculation

µЄ = Frequency 2 x 5.0000 (Gage Factor)

1000

Frequencyo = 802 Hz

µЄo = 3216 (Datum)

If Frequency = 644 Hz , then

µЄ = 2073 – 3216 = - 1143 (Compressive)

If Frequency = 1171 Hz

µЄ = 6856 - 3216 = + 3640 (Tensile)

A 1 Hz increase to Frequency of 803 Hz

µЄ = 3224 - 3216 = + 8 (Tensile)

Vibrating Wire

Signal @ 900 Hz

Vibrating Wire

Signal @ 900 Hz

10KHz High Frequency

Noise Interference

50Hz Low Frequency

Noise Interference

Electromagnetic Interference EMI• From Electric Field (Welding) causes High Frequency Noise

• From Magnetic Field (High Current Induction) causes Low

Frequency Noise

Actual Force Sensor Readings

dropped (Tensile) caused by

Electrical Noise (High Frequency)

VWSG Sensor Noise Checks

for EMI at site location using

EMI Analyzers

EMI

Spectrum

Various Portable EMI Analyzers

For analyzing

noise signals in

VWSG cables

For tracing noise

source on sites

Power Transformer 50Hz and its

Harmonics Magnetic Field site survey

at Labrador Sub-Station done on

18/03/2005.

The EMI checks were carried out at

the VW Strain gage outputs without

VW Excitation Signals. This formed

the base noise level which would be

mixed together with the VWSG

signals into the Data Logger

EMI Analyzer Results

Location 13d2. 50 Hz @ -75.17dB Lowest Interference !

Clean output

EMI Spectrum Plot

EMI Analyzer Results

Location 13d. 50Hz @ -50.19 dB

Sum Noise of 50 up to 500 Hz

EMI Spectrum Plot

1200 to 1330

830 to 1200

1330 to 1830

1830 to 2000

Site

Activity

Report

20 Nov 21 Nov 22 Nov 23 Nov

Data Logger

cannot Read

VWSG Frequency

Decrease in RED

VWSG

Frequency

Increase

in Yellow

20 Nov

Vibrating Wire

Signal @ 900 Hz

50Hz Low

Frequency Noise

Interference

EMI due to Magnetic Field (High Current Induction)

causing Low Frequency Noise

Alert Trigger Level

Is the strut highly compressed or

is it a noise spike ?

Same Data Logger but monitoring different sensors via

Multiplexers showing EMI noise affecting readings over days

EMI Noise

Time scale in days

Time scale in days

Real Time scale in minutes

Time

% of

Design

Limit 1

2

3Sensor

Alert

Limit

Bands

Normal

Operational

Zone

Smart SMS Alert Trigger Algorithm to

prevent user information overload

• Rate of Change of every sensor

• Multiple Triggering Level Thresholds

• Each type of Alert will have 3 Trigger Levels per sensor

• Programmable Re-Trigger Alert period

Site Layout Design Consideration

Consideration factors

• Maximum signal cable length– Reduce noise pickup possibility

• Cable installation– Avoid noise source

– Avoid wielding cable and power generator cable crossing

• Max numbers of channels per logger

• Cluster design– Easy to view sensors info at Real Time monitoring & Alert

System

160.86m

24m

24m

Depth =27m

A B

C

D

Max distance

A - ~ 60meter

B - ~ 60meter

C - ~ 45meter

D - ~ 40meter

Cluster design

-Easy to install and Maintain

-Keep out from noise source

-Keep out from working place

-Avoid cable crossing power cables

Site sensor position total sensor

sensor per

logger spare channels Mux

Nicoll Highway Station

logger 1 NA 31 SG and Temp+ 3LC and Temp 40 VW +Temp 8 VW +Temp 3

logger 2 NA 31 SG and Temp+ 3LC and Temp 40 VW +Temp 8 VW +Temp 3

Total 62 SG and Temp+ 6LC and Temp 80 VW +Temp

site sensor position total sensor

sensor per

logger spare channels Mux

Nicoll Highway Station

logger 1 (station-1) HS-2,HS-5,HS-9,DS-3,DS-4 30 SG and Temp+ 9LC and Temp 57 VW +Temp 7 VW +Temp 4

logger 2 (station-2)

HS-14,HS-18,HS-23,DS-10,DS-

11 30 SG and Temp+ 9LC and Temp 57 VW +Temp 7 VW +Temp 4

logger 3 (Entrance 1&

Vent 2)

HS-41,HS-44,DS-50,DS-58,HS-

83,HS-88,HS-94 52 SG and Temp+ 5LC and Temp 67 VW +Temp 13 VW +Temp 5

logger 4 (Entrance 2) HS-123,HS-125,HS-127,DS124 42 SG and Temp 42 VW +Temp 6 VW +Temp 3

Total 154 SG and Temp+ 23LC and Temp 223 VW +Temp

• Number of channels required increase by 278%

• Loggers required = 2.3 loggers 3 loggers

• We proposed 4 loggers to avoid crossing zones

Quality Plan for VWSG

Sensor Installation Checks

And

EMI Noise Spectrum Checks

Instrumentation Planning Guidelines1. Shorten the cable lengths (~ 500 m) from the VWSG to the multiplexer

even though the VWSG can function up to 1,000 m. Under ideal condition,

data logger will get idea readings.

2. Lay VWSG cables 5 m away from Power cables as high currents with

pulsing currents, such as welding or motor currents, will cause cross

induced magnetic cross coupling interference.

3. Ground the cables from VWSG sensors, data loggers, chassis to a

signal ground. Differentiate Earth Lightning Protection CP33 ground

(GREEN wire to protect human lives) from signal ground.

4. Design a grounding discharge wiring topography and not a wiring

diagram as the CP33 is for electronic equipment protection code NOT for

noise grounding.

5. Perform signal site survey with EMI Spectrum Analyzer with EMI

readings as datum levels

6. Provide voltage surge protection at mains inlet, DC power supply inlet,

sensor and multiplexer inputs with discharge ground wires.

Installation Quality Control by

measuring VWSG readings at

various installation process1. VWSG reading from manufacturer for un-

strain values with serial number ID

2. VWSG reading after welding onto struts to

ensure that the welding do not stress the gage

3. Adjust the VWSG by pre-loading

4. VWSG after cabling to the data logger box

~ 100m to measure VWSG. Record EMI

Spectrum Analyzer Levels as datum values

5. Connect VWSG to Data Logger. Verify that

the VWSG reading is same as that before

connection to Data Logger

6. During the monitoring period, if the VWSG

readings are erratic due to EMI noise,

measurements of step 4 & 5 must be repeated

and then compare to the datum at step 4.

+ Strut

+ Strut + Cable

+

Strut Cable+ +

Data

Logger

+EMI

Spectrum

Analyzer

Process Steps of Manual and

Semi-Auto Monitoring Systems

Measure

Record

Download/Transfer

Process

Analyze

Inform

Respond

The Challenge to

maintain

Data Quality

Data Reliability

&

Data Timeliness

Real Time Monitoring

Using

Machine to Machine (M2M)

Technology

Applied to

Manual Data Collection

Manual Instruments such as

Water Stand Pipe, Piezometer,

Tilt, Pressure, etc

Collect Instrument Data on site

Download to Notebook•Collect field data

•Stores field data

•Reduces time to report generation

Pocket PC stored Data on

site can be also be

downloaded via Wire-less

GPRS

Cable / Wire-less

GPRS communications

Real Time Monitoring

Using

Machine to Machine (M2M)

Technology

Applied to

Semi-Automatic Data Collection

+ GPRS Public

Network

Office PC system

Simple steps for Data retrieval from sites

Process Steps

1. Take Inclinometer readings

2. Switch ON GPRS modem

3. Select file to transfer

4. Press Transfer BUTTON

5. Wait for 2 minutes

6. Get SMS acknowledgment that file is received at office

7. PC automatically generates Reports

30 mins

Bore

Hole#1

Timing chart for one walk round site with 10 bore holes

Walk for

20 mins

Inclinometer Timing Chart from taking remote site readings

to the end user in the main office for analysis

Bore

Hole#2

Bore

Hole#3

Walk for

20 mins

Walk for

20 mins

Bore

Hole#n

30 mins 30 mins 30 mins

GPRS back to Main

Office and

automatically analyze

Case#C: Total Throughput time for Bore Hole#1 data to reach send user is

30+1+1 mins = 32 mins

Maximum utilization of investments as the Inclinometer and Readout unit is always on

site , rather than idle for travelling back to office and data download. Instead of

carrying the data back to office, the system enjoys the Advanced Wire-less technology

to send it back like a Mobile phone advantage

With immediate analysis, if the data seems to be noisy, the measurement is usually re-

do almost immediately giving Geotechnical engineer instant data for analysis

1 min1 min

Automated Real Time

Tunnel Monitoring System

In Business Times

23th March 2003,

SysEng was

featured at the

center page by

IDA as a State of

the Art Wire-less

Technology

System Developer

for Automatic

Tunnel Monitoring

System. This is the

innovative method

of deploying Wire-

less and

Inforcomm

Technologies for

Tunnel Monitoring

Instrument setup

inside the MRT tunnel

• Fully Automatic system

• Glass prism as reflectors

• Range 20 to 100m

• Accuracy +/- 1.0mm + 1ppm

• Proven system

• High reliable for continuous

use in Tunnels

Automated Surveying Instrument

The Solution for

Real Time Monitoring &

Alert System

Transmission Time Consistency with Data

Communication Error Recovery Algorithm

Tunnel movements and SMS Alert

Smarter structural geometric

cross checking algorithms will be

introduced to avoid overloading

and False SMS alerts. The

proposed algorithm will deploy

more 3D numerical checks for the

following: -

Within the same segment

Movements in the 4 prisms shifting

in space

Vertical Movements in the Crown

and Track for vertical loading

Horizontal Movements in the Left

and Right for horizontal loading

Cross-segments

Movements in the prisms along the

same axes in the tunnel

Adjacent Prisms

also move

Crown Prisms

Crown Prisms

Thank You