Elcometer protovale P330 User manual

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Elcometer P330
Covermaster® CM9
Concrete Covermeter
Operating Instructions

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As supplied, this product has two language options. The instrument will al-
ways start up in one of these languages. This is known as the first language
and should have been selected at the time of order. The second language
may be selected at any time by following the description on page 24.
Software version
(and Language Code)
First Language
(Factory Set)
Second Language
(User Settable)
1.5Q English French
1.5E English Spanish
1.5G German English
1.5Q French English
1.5R Italian English
Supplied
1.5E Spanish English
1.4G English German
This product meets the emc directive 89/336/EEC, amended
92/31/EEC and 93/38/EEC.
This product has been tested in accordance with EU regulations governing
Electromagnetic Compliance and it meets the required directives.
Note - performance may be affected if the unit is operated within a radio
frequency electromagnetic field strength greater than 3V/m.
and are registered trademarks of Elcometer
Instruments Ltd.
© Elcometer Instruments Ltd. England 1996-2005
All rights reserved. No part of this document may be reproduced, transmitted,
transcribed, stored (in a retrieval system or otherwise) or translated into any
other language in any form or by means (electronic, mechanical, magnetic,
optical, manual or otherwise) without the prior written permission of Elcometer
Instruments Ltd.
Doc. No:TMA-0275 Iss. 01
Part No: 18481 Issue 01

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Contents
Guided Tour of Front Panel ............................................................................3
Starting up and the Menu................................................................................4
Title Screen .......................................................................................................4
Main Menu ........................................................................................................4
Help on options .................................................................................................4
Selecting a mode...............................................................................................5
To switch the back-light on ................................................................................5
Audio output ......................................................................................................6
Bar location indicating LED................................................................................6
To switch the instrument off...............................................................................6
To switch the back-light off ................................................................................6
Battery charging ................................................................................................6
LOCATE mode.................................................................................................7
Bar location techniques .....................................................................................8
Systematic location of rebars.............................................................................9
Welded mesh and joined bars .........................................................................10
DEPTH mode..................................................................................................12
Audible guide to cover .....................................................................................13
Symbols used in the display of cover...............................................................14
Accuracy of cover............................................................................................15
AutoSizing accuracy ........................................................................................15
Lapped bars ....................................................................................................15
SIZE mode......................................................................................................16
Orthogonal sizing precautions .........................................................................17
Orthogonal sizing error estimation ...................................................................19
Optional LARGE HEAD .................................................................................20
UNDERCOVER mode.....................................................................................20
MAXPIP mode................................................................................................22
Pre-Configuration..........................................................................................23
Version number ...............................................................................................23
UnderCover .....................................................................................................23
MaxPip ............................................................................................................23
Language ........................................................................................................23
Pre-release and experimental versions........................................................24
Version Release Note......................................................................................25

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Guided Tour of Front Panel
At the left-hand end are the two on-off buttons:
the green button turns the CM9 ON; and
the red button turns the instrument OFF.
(A second press of the ON button switches on a back-light for the display;
to conserve the battery, the back-light goes out after about a quarter of an
hour).
Along the bottom of the panel are the four main control buttons; all the
many facilities of the CM9 are accessed using just these four buttons
(which are also duplicated on the standard head).
The green button is the general INFO button,
and is also used to return to the MAIN MENU .
The blue button usually means “decrease” or “back”.
The red button similarly means “increase” or “forward”.
The black button is the SET button;
it is used to select an operating mode from the MENU,
and also as the AUTO-ZERO button.
Above the buttons is the LCD screen; this displays the readings, and also
the INFO messages and any prompts.
At top-left is the AUDIO control knob; the AUDIO LOCATE signal operates
continuously and independently of the digital measuring mode.
The knob can be swung through the spotted positions to adjust the
background sound to suit; is the MUTE position.
At top-right is the head connector, marked .
If headphones are used, they plug into the 3.5mm Stereo Jack socket
marked on the housing just below the loudspeaker grille.
Remember that whenever the instructions ask you to press any one of the
, , or buttons, you may press either the appropriate one on the
front panel or the corresponding one on the search head.
On the rear panel you will find the connector for the battery charger.
This completes the description of the unit and its controls;
it couldn‘t be much simpler !

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Starting up and the Menu
First connect the Search Head to the Electronic Unit, using the lead
supplied.
Note that the end with the black plastic plug connects to the head and has
a bayonet locking action; the end with the metal plug connects to the front
panel and has a screw locking action.
To simplify things at this stage, turn the AUDIO knob back until it clicks
into the MUTE position.
Now for what you‘ve been itching to do all along:
to switch on, press the green ON button.
The LCD screen will show its TITLE SCREEN for a couple of seconds:
after which it will go straight to the MAIN MENU :
The four options offered are:
for information,
for the re-bar LOCATE mode,
for the DEPTH of cover mode, and
for the determination of bar SIZE.
The flashing blob (shown as above), initially superimposed on the
option, is the CURSOR.
The symbol at the beginning of the second line is there deliberately to
tempt you into pressing the INFO button, so feel free to do so; the
display will show:
The text only remains for a couple of seconds, and then disappears to be
replaced by the MAIN MENU; if you want more time to read it, press and
hold the INFO button.

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You can now use the and buttons to move the CURSOR back and
forward (respectively) along the options; if you move the cursor off the end
of the line, it reappears at the opposite end.
If you press the button while the cursor is on one of the modes (for
example), you will get information on that particular mode of operation, viz:
which is typical of the meaning of the buttons in a measurement mode (as
opposed to their use within the menu).
Help on options:
If you press the SET button while the cursor is on the option, you
will be told of two additional features
which will be described later.
Selecting a mode:
If you press the SET button while the cursor is on one of the three
measurement options , or , the CM9 will select and “enter”
that option.
As explained in the INFO you have already read, the button is used to
return to the MENU, but please note that the first message from the option
may be
in which case it will only respond to the button, which you will therefore
have to press first.
To switch the back-light on:
A second press of the ON button switches on a back-light for the display;
to conserve the battery, the back-light goes out after about a quarter of an
hour
.

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AUDIO output
To turn the audio signal on, rotate the AUDIO knob away from the
position clockwise towards the position to set the sound to a steady
ticking when the head is away from metal. As the head is brought towards
metal, the sound increases in frequency, and the indicator on the head
glows brighter.
When investigating congested areas, the AUDIO knob can and should be
turned back somewhat to improve bar resolution.
Note that the sound system operates quite independently of the digital
system:-
the AUDIO knob does not affect the display; and sound is available in any
MODE, even no mode at all, e.g. at the MAIN MENU!
Bar Location Indicating LED
The LED built in to the search head to visually indicate the location of a
bar duplicates the sound signal and is controlled by the audio system;
therefore the AUDIO knob must be turned on (away from the position)
in order for the LED to operate.
When the AUDIO knob is set to optimum (as described above), the LED
will be seen to either glow faintly or pulse slowly; when the head is moved
over a bar, the LED will glow more brightly.
To switch the instrument OFF
press the red button.
To switch the back-light only off (without turning the whole instrument
off):
hold down the button; press and release the button; release the
button.
Battery Charging
Ensure the instrument is OFF before charging (press the button).
Connect the coaxial plug from the charger into the socket marked
on the rear panel, and plug the charger module in to the mains.
The red LED on the charger glows to indicate that charging is taking
place. Allow 14 to 16 hours (e.g. overnight) for a full charge.

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LOCATE mode
This mode is intended for situations where the prime requirement is to
locate all bars, or when both location and cover are required, but the audio
signal cannot be used (the DEPTH mode described later will probably be
preferred for general-purpose cover-measuring use — but please read this
section anyway).
From the Menu, select and enter the “Loc.” mode; if you have just
switched on,
the sequence will be
If this is the first measuring mode you have entered since switching on, the
display shows:
Hold the search head well away from any metal, and press ; the display
will show
with a row of dots running along the bottom, taking about one second.
The LOCATE screen will now be displayed, initially looking (typically) like
The shows the current manually-set bar diameter which can be
decreased or increased by pressing or respectively.
(For location only, the diameter setting is not critical; but if cover is to be
measured, the bar size must be considered).
The following indicates that the instrument is correctly
zeroed.
If you bring the head up to a 16mm bar spaced 30mm away, the display
will typically show:
where the is the cover calculated on the assumption that the
bar diameter is indeed 16mm as set; the is the AutoSizing estimate
of the bar diameter, and the is its estimate of cover, disregarding
the manual diameter:– which are in agreement.

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If you now bring the head up to a 25mm bar at 30mm distance, the display
might show
The signal-strength stripe at the bottom has grown (the bigger bar
produces more signal), and the indicated cover (based on a ø16 bar) has
therefore been under-estimated; but the cover estimated by AutoSizing (of
an unknown bar size) is correct, and the estimated bar size is
also approximately correct.
To return to the main Menu, press .
Bar location techniques
The search head is directional, that is, it has maximum sensitivity to bars
running parallel to the long axis of the head, and least sensitivity to those
at right angles.
Therefore, the head should be orientated parallel to the bars being sought,
and then scanned sideways across them.
When the reinforcement consists of two layers, the second layer running
transverse to the first, the scanning is done twice, once for each layer.
If the two layers are made up of bars of similar size, it is usually easier to
look for the nearer layer first (as it gives a stronger signal, and is least
influenced by the other bars); and then look for the second layer, this time
scanning the head in lanes between the now-known positions of the first
layer of bars. But if the nearer layer is made up of relatively thin tie-wires
or stirrups, and the deeper layer comprises much larger main structural
bars, it will often be easier to look for the second layer first.
Although the LOCATE mode shows a signal-strength stripe running across
the bottom of the display as a visual aid in finding the maximum signal, it
will be found that the built-in audio signal is much more informative (and
does not require you to look at the display); to switch this on, rotate the
AUDIO knob clockwise away from the (mute) position towards the
position.
The sound is at its most sensitive when the AUDIO knob is adjusted to
produce a slow tick-over when the head is held away from all metal.
However, especially when locating shallow or closely-spaced bars, the
resolution will be improved by turning the AUDIO knob back somewhat
from the optimum-sensitivity position; (but if you turn it back too far, you
may miss some deeper-than-average bars).

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Systematic Location of Rebars
(1) With head aligned horizontally,
scan up and down to locate
(predominantly) horizontal
bars.
(2) With head aligned vertically,
scan from side to side between
horizontals to locate vertical
bars.
(3) (optionally) with head aligned
horizontally, scan up and down
between verticals to confirm all
horizontal bars.
(In some situations, it will be more
appropriate to scan first for the
verticals and then the horizontals)

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Because the CM9 CoverMaster is unaffected by the nature of the material
covering the reinforcing bars, the easiest way to practice location
technique is to use uncovered bars which you can see. A block of wood or
plastic of 20 to 45mm thickness can be held between the search head and
the bars to simulate the depth of concrete cover.
Start from the simplest situation, a single straight bar, and progress
through parallel bars, lapped bars, and crossing bars. As you develop skill
and confidence with uncovered bars, move on to locating bars in more
realistic situations.
Welded mesh and joined bars
With isolated reinforcing bars, the eddy currents are induced within the
individual bars. Welded mesh reinforcing creates current loops which
produce additional strong indications.
Very strong signals are obtained when the search head is across the
centre bar of a double or ‘figure-of-eight’ loop but these locations must not
be used for cover measurements. Minimum signals are obtained as
before when the search head is over the centre of a single loop, and
ordinary-strength indications when the head is accurately aligned with the
middle of a side. Only the last kind of indication is suitable for measuring
depth of cover.
In any situation where signals are very strong, the audible indication may
be driven towards its highest pitch and the LED on the head to its
maximum brightness, and no longer increase in proportion to the signal.
To avoid this, back off the AUDIO control counterclockwise until the sound
and LED are again responding readily to changes.
CAUTION – Backing off the AUDIO control does not reduce the overall
sensitivity of the instrument, but will silence the audible and LED
indications when the search head is removed from the region of high
signal strength. This may cause deeply covered bars to be missed.

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Effect of welded mesh
Please note that all the location techniques described in the last few
pages are equally important and applicable when making
measurements of concrete cover or bar diameter.
Please also note that the Orthogonal Sizing method must not be attempted
on welded mesh fabric.

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DEPTH mode
This is the usual mode for surveying for depth of cover to reinforcement and
can be used for bars of known or unknown diameter; it will usually be used
with the audio signal turned on to assist in bar location.
From the Menu, select the “Dep.” mode; if you have just switched on,
the sequence will be .
If this is the first time you have entered this mode since switching on, the
display shows:
Hold the search head well away from metal, and press ; the display will
show
with a row of dots running along the bottom, taking about one second.
The DEPTH screen will now be displayed, initially looking (typically) like
The shows the current manually-set bar diameter. This should be
set to the known or most likely diameter for the bar to be measured, using
and to decrease or increase the value respectively (to make large
changes in value, you can press and hold the appropriate button as an
alternative to repeated pressings).
The jumbo-sized signs indicate that the instrument is correctly zeroed.
If you bring the head up to a 16mm bar spaced 30mm away, the display
might typically show:
where the is the cover calculated on the assumption that the bar
diameter is indeed 16mm as set; the is the AutoSizing estimate of the
bar diameter, and the is its estimate of cover, disregarding the
manual diameter:- which are in agreement.

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If you now bring the head up to a 25mm bar at 30mm distance, the display
might show
The larger bar has caused the indicated cover (based on a ø16 bar) to be
under-estimated; but the AutoSizing estimate of the cover to a bar of
unknown size is correct, and the estimated bar size is also
approximately correct.
To return to the main Menu, press .
Please note that the previous three sections “Bar location techniques”,
“Systematic location of bars” and “Welded mesh and joined bars” are also
relevant, and should be read in conjunction with this section.
Audible guide to cover
As explained on the previous page, the sound signal should normally be
turned on during cover measurement in order to assist bar location (both
audibly, and by the indicator lamp on the search head).
The section “Bar Location Techniques” explains that, for optimum
sensitivity, the audio knob should be set to a tickover in the absence of
metal, but that the knob can be turned back to improve the (audible)
resolution of closely-spaced bars.
If the audio knob is set to optimum sensitivity, the loudness and pitch of
the sound will consistently give a good guide to the extent of cover, with
shallower-than-average bars producing a clearly noticeable more intense
sound, which can be used to draw the operator’s attention to such bars.
However, if the audio knob had been turned to an arbitrary position, the
necessary degree of consistency may not be achieved.
It is also possible to deliberately back off the audio knob so that bars of
adequate cover are not indicated, but bars of shallower cover are. The
user may find this trick to be a simpler and quicker method (albeit
somewhat less precise) than the “UnderCover” mode described later; but
please note that both methods share the same disadvantage that they only
indicate bars with shallow cover, but do not confirm the presence of bars
with adequate or deeper cover.

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Symbols used in the display of cover
You will already have come across the use of the pair of equals ==
symbols used to indicate that the instrument has been zeroed and there
are some other symbols which may be shown. These are listed below
under the circumstances in which they may appear.
When the head is held well away from metal:
indicates that the instrument is correctly zeroed and will therefore
work to full accuracy;
indicates that the instrument is only approximately zeroed: cover
measurements to bars of known diameter will still be reliable for all except
the deepest bars, but the instrument should be zeroed correctly before
attempting to measure bars of unknown size or deeper-than-usual cover;
indicates that the instrument is not correctly zeroed. This may
appear after the first few minutes of warm-up time; but is more likely to be
a result of having previously zeroed the instrument while the head was
near some metal.
When the head is on the concrete surface (after being correctly
zeroed):
indicates that no metal is being detected;
may indicate that the concrete contains some ferrous aggregate;
but is more likely to mean that the presence of some metal has been
detected, but it is too far away for a meaningful cover measurement;
or indicate that (in these examples) the cover is 8mm or less
or 10mm or less respectively;
means that the instrument has calculated a cover of zero or less;
this only occurs under exceptional circumstances, such as telling the CM9
that the bars are 5mm diameter and then placing the head directly on a
50mm bar!

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Accuracy of cover
The displayed cover will only be correct if:
(a) the head is exactly over the centre-line of the bar;
(b) the head is exactly parallel to the bar;
(c) the instrument has been correctly zeroed (with AutoZero, this is no
problem);
(d) the head is not over, or near, any other bars, parallel or transverse;
(e) the correct bar size has been set (for the main display; not necessary for
AutoSizing).
Note to (d): if neighbouring bars are too close, they will cause the main display
to read too low a cover (and cause the AutoSizing to over-estimate bar
diameter); the main display of cover can only read too high if the actual bar
size is smaller than the diameter you have set.
AutoSizing accuracy
Since the instrument has to extract more information from the raw signal data
than in the simpler case of computing the cover to a bar of known size, it
stands to reason that the original data must be appropriately more reliable.
Hence the conditions (a) to (d) above must again be carefully met (but not (e)
of course), and furthermore the bar must not be too deep (otherwise the signal
may be too weak to be reliable); but in the majority of cases, the first layer of
bars will be well within range.
If the head is moved away from a bar, the “ordinary” cover reading will indicate
a higher value, correctly indicating that the bar is further away; but when the
head is not over a bar, the AutoSizing results are meaningless and should be
ignored. At deeper covers, the AutoSizing will lose accuracy, and this will be
apparent as a fluctuating value of estimated diameter; but the deduced cover
will usually be stable and correct. At very deep covers, AutoSizing is not even
attempted, and blanks are shown between the parentheses in the display.
In congested situations, the AutoSizing will tend to over-estimate bar diameter
— correctly reflecting the fact that there is a greater mass of metal present than
a single bar — but will nevertheless continue to give an essentially correct
value for the cover. In the case of lapped bars, AutoSizing will typically show
double the true diameter of a single bar, but the correct cover — which is
generally the desired result.
It should be stressed that the AutoSizing facility is intended to determine the
cover to a bar of unknown size; the value of diameter it gives is an estimation
only, which is however available immediately with no user-intervention
required; when you require more accurate determination of diameter, you
should use SIZE mode.

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SIZE mode
This mode is intended to be used to determine the diameter of a (single)
bar. Whilst the associated cover will also be displayed, this mode is not
intended for scanning areas, and indeed the LOCATE or DEPTH modes
should have already been used to establish bar locations; also the AUDIO
signal should be turned on to further assist precise positioning.
(If the determination of the cover to the unknown bar is more important
than the size of the bar itself, the DEPTH mode may be adequate, and will
also give an estimation of bar size).
From the Menu, select and enter the “Size” mode; if you have just
switched on, the shortest sequence is .
Since this procedure depends critically on accurate zeroing, the display
always shows:
Hold the search head well away from any metal, and press ; the display
will show
with a row of dots running along the bottom, taking about one second.
The SIZING screen will now be displayed:
Place the head exactly over and parallel to the bar, such that you are
getting the maximum audio signal and press ;
place the head over the bar but orthogonal (at right angles), this time
getting a minimum audio signal and press .
The two measurements may be taken in either order providing the
correct button is pressed (memory-jogger: LINE it up and press the LINE
button; put it ACROSS and press the CROSS).
The first measurement taken will replace with
;
if the signal strength was too weak or too strong, the warning
appears briefly.

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After an acceptable pair of readings has been taken, the result is shown,
for example:
unless there were detectable errors in the calculation, in which case it
shows
To make another measurement, move the head away from all metal, and
repeat the zeroing and then the display will ask for the next pair of Orth/
Para readings.
When finished, press to return to the Menu.
Please note that this orthogonal sizing method is not suitable for welded
mesh fabric, as the orthogonal reading will be invalid. However, the
AutoSizing method available in both the Depth and Locate modes may be
used.
Orthogonal sizing precautions
How it works.
When you are using the CM9 as a locator, and making good use of the
directionality of the search head to distinguish between vertical and
horizontal bars, as you rotate the head away from being parallel to a bar,
you will have noticed that: if it is a large bar, the signal merely decreases
somewhat, whereas for a small bar, the signal decreases drastically to
practically nothing by the time the head is at right-angles.
The orthogonal sizing technique utilises this phenomenon and quantifies it
to yield a direct determination of bar size.
Since the orthogonal/parallel comparison is essentially independent of
cover, this method is in principle capable of accurate results on a single
bar in isolation.
However, like all bar-sizing methods, it is sensitive to errors in head-
positioning and also to the presence of neighbouring bars.

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Head-positioning:
When taking the Parallel reading, the head should be getting the maximum
possible signal from the bar: any mis-alignment of the head can only reduce
this signal; when taking the Orthogonal reading, the head should be getting
the minimum possible signal from the bar: any mis-alignment of the head–
in either angle or position– can only increase this signal.
Therefore, either form of positioning error will always result in the diameter
being over-estimated (and so too will be the cover).
Neighbouring bars:
Any other metal within range of the search head will increase both the
(orthogonal and parallel) readings by an unknown amount — but not
necessarily the same for both readings. In practice, since the orthogonal
signal is the weaker of the two, it is more susceptible to “interference”, and
so the deduced diameter will probably again be too high.
Although, in normal use, transverse bars have comparatively little effect on
the cover obtained, these same transverse bars will have a serious effect
on this bar-sizing method: when the head is rotated to take the orthogonal
reading, the signal from the bar under investigation decreases, but the
signal from any nearby transverse bars increases.
Again, the result is a (possibly serious) over-estimation of bar diameter.
In particular, orthogonal sizing should never be attempted over the
crossing-point of transverse bars.
Neighbouring parallel bars, whilst not causing such drastic effects as
transverse ones, should nevertheless be taken into consideration; when the
head is rotated to the orthogonal position, such bars will become nearer to
the ends of the head than they were to its sides.
Welded mesh:
As explained in the earlier section on joined bars, the orthogonal reading
will receive an additional signal from the rectangular loop of bars. This will
result in a gross over-estimate of bar-size (or even the “does not compute”
message).
The net result is that all error-generating influences always result in the
deduced
bar-size (and cover) being too high.
Hence the displayed result should be taken as an upper limit, never as a
lower limit.