portable data collection system (pdcs) operating manual

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Portable Data Collection System

(PDCS)Operating Manual

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PDCS Operating Instruction Manual – (C)t/¢9 2010

The Portable Data Collection System (PDCS) unit components

Main Instrument Case

Probe to instrument cable

Battery charger and lead

Laptop AC supply cables

Figure 1: Main Instrument Case

Figure 2: Computer and Probe cables


Description

The corrosion monitoring portable data collection system when used with the ‘Type CL’corrosion monitoring probe is an advanced embeddable corrosion rate monitoring system.Using the probes unique design – four independent LPR electrodes at varying levels ofconcrete cover and automated testing software allow the determination of a variety ofparameters relating to the condition of the structure. The monitoring system collects thedata so it can be analysed to provide an indication of the rate of ingress of corrosivesubstances into the concrete and hence estimates can be made regarding the potential lifeof the structure.

Functions

Corrosion Rate measurements at each of the four electrodes plus main steelreinforcement

Corrosion Potential measurements at each of the four electrodes plus main steelreinforcement

Electrical Resistance (between three pairs of electrodes) Temperature of probe Estimation of rate of ingress of corrosive substances

Specification

Size: 53cm W x 43cm D x 18cm HWeight: 9kg

Operating Instructions

Step 1: Prior to using the meter, ensure that the instrument battery is fully charged. Connectthe charger to the instrument using the DC IN socket. Plug the charger into a 240V ACsupply and switch on, ensure the selector switch is set to “CHARGE”.

The unit cannot run from an external power source. When using the meter remove theDC IN connection to the battery charger.

Step 2: Ensure that the Notebook is fully charged and switch on and if necessary connect tothe internet either by wireless or network connection and ensure that Windows is up to date

Step 3: once you have arrived at a probe location, open the lid and switch on the computer.

Step 4: Attach the Probe to the main instrument using the cable provided. The connectersmust be aligned correctly, and the locking swivel turned to secure the cable.

Step 5: Switch the instrument selector switch to ON. The POWER ON LED will illuminate.


Step 6: Run the CMSCL (Corrosion Monitoring System – CL) program by double clicking theicon on the desktop or by finding the program on the start menu.

Figure 3: The CMSCL program running

Step 7: The unit is delivered with the USB configured to “Com Port 4”. The USB connector

should always be inserted in the same slot as delivered.

Figure 4: The CMSCL program running


Step 8: The software can check whether all the connections have been made correctly by

using the “Test” button. This will open the monitor screen to the left of the CMS interface

screen. If there are any errors, then the monitor will stay blank. If all the connections are

correct and the battery is sufficiently charged, then the instrument will perform a quick self

diagnostic and display the remaining battery charge in the CMS interface screen.

Figure 5: The self diagnostic screen after the "Test" button has been pushed

Step 9: Before the program can be run, a save file must be created/selected. To do this, usethe “Set File” button which opens the windows saving screen. The default file is “CMSdata”

Figure 6: The save screen showing the default save


Step 10: Once the save file has been created, the “Run” button becomes available (as long

as the save file is not being viewed in a spreadsheet (see step 11) and once clicked, the

instrument will begin its operation. The progress can be viewed using the “Show Monitor”

button and can be interrupted at any point by using the “Stop” button. Once the operation

has been completed, the “Stop” button will become non selectable again.

Figure 7: The monitor, showing the progress of the operation

Figure 8: The monitor once the operation has finished, note the "Stop" button hasbecome non selectable


Step 11: When the operation has been completed, all the cables can be removed and stored

in preparation for their next use. The data from the probes can be reviewed by opening the

saved file selected/created earlier in the spreadsheet.

Figure 9: Spreadsheet showing the data recorded by the PDCS unit


Interpretation

Corrosion rates are best monitored over long periods analysing ‘trending’ to determine ifconditions change and if corrosion rates increase with time.

Graphical presentation of the measured corrosion rate data, plotted against time,demonstrates trends and enables assessment of the corrosion condition of the structure.Plots showing corrosion rates and corrosion potentials at each carbon steel element depthalong with those of the main rebar are useful. Results should however be reviewed by acorrosion engineer with particular experience in interpreting corrosion rate data in reinforcedconcrete.

A broad set of criteria for corrosion has been developed from field and laboratoryinvestigations and is reproduced in Figures 4.12 and 4.14 in the book “Corrosion of Steel inConcrete” authored by John P Broomfield (1).

Based on the actual surface areas of the four Type CL probe carbon steel elements theinformation given in tables by Broomfield can be adapted as a basis for interpretation for theelements. These readings provide a measure of the corrosion rates at the time of testing.

Table 1 – Readings taken by PDCS of Type CL probe elements (µm/yr)

< 0.3 Passive conditions0.3 – 3.0 Low to Moderate Corrosion3.0 – 30.0 Moderate to High Corrosion

> 30.0 High Corrosion

For the main rebar a calibration divisor should be derived by equating the measuredcorrosion rate of the fourth carbon steel element to that of the main rebar. The main rebarshould be at the same depth in the concrete and therefore in similar conditions.

For example, if the PDCS reading of corrosion rate for the fourth element is 3.5 µm/yr andthe main rebar is 15.5 µm/yr, then use a divisor of 3.5/15.5 = 0.223. Multiply all further mainrebar readings by 0.223. The actual divisor should be derived from the first few readings sayat 3 monthly intervals.

This is because the actual surface area of the main rebar measured during themeasurement process is unknown and the measurement meter uses a standard 100cm²surface area to derive corrosion rates. The fourth carbon steel element (surface area of30cm²) is used as a means of calibrating the surface area of the main rebar perturbatedduring the measurement process.

Care must be used in interpretation. Passivation of steel in new concrete can be quite slow.

Initial measured corrosion rates may decrease over the first few years as available oxygen is

used in the initial corrosion process, then stabilise, thereafter increasing when the onset of

contamination (chloride or carbonation) induced corrosion takes place.

It is likely that the corrosion rates for the outermost element (element No1 closest to the

concrete surface) will be higher than that for element No 2 etc. This provides an indication of

ingressing depassivating ions (usually chlorides). The rebar should be in similar condition to

the fourth carbon steel element.

(1)Broomfield, J P, “Corrosion of Steel in Concrete 2

ndEdition”, Taylor & Francis – ISBN 978-0-415-33404-4,

2007


Fault Finding

Fault Possible cause Solution

POWER ON LED does not

light

Switch is in the CHARGE

positionTurn unit to ON position

Battery is flat Charge battery with the

supplied chargerFuse is blown Replace fuse

No communication with

probe

Switch is in the CHARGE

positionTurn unit to ON position

Check probe cable is

connected

Check connections are

correct and ensure the

swivels are in the locked

positionCommunication channel

incorrect

Select the correct

communication port in the

software on the computer

Battery Level LowCharge battery with the

supplied charger

Damaged cable Replace cable

Damaged Connectors Replace cable

Computer fails to switch on Battery is flatCharge battery with the

supplied charger

Battery fails to charge

Switch position not set to

CHARGE

Turn unit to CHARGE

position

Fuse is blown Replace fuse

Contact Detail

Technical support & spares are available from:

portable data collection system (pdcs) operating manual

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