PCE Instruments VL7-100B-d15, VL7-100B-d20, VL7-100B-d21 Users guide

Viscolite VL7

Guarantee

Hydramotion Ltd will repair a Viscolite portable viscometer free of charge within
24 months of the date of purchase if satised that the fault is the result of defective
materials and/or workmanship and if the instrument is returned to Hydramotion
Ltd carriage prepaid and undamaged in transit.

This Guarantee shall not
proper care by the owner or user, (ii)
in this User Manual, or (iii ) normal wear and tear on the instrument .

Hydramotion Ltd shall in no case be liable for any loss of output, revenue or any
other losses or costs, consequential or otherwise, howsoever incurred.

apply to any fault resulting from (i) negligence or lack of

a failure to follow the recommendations set out

© 2013 Hydramotion Ltd

The Vis colite and all it s associated t echnologie s are protected b y UK and Interna tional Patent Ap plications .

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Viscolite VL7

Viscolite VL7

portable viscometer

Contents

Introduction 5

1 Getting started

1.1 Packaging 7

1.2 Specification 7

1.3 Fitting the batteries 9

2 Using the Viscolite

2.1 Turning on 10

2.2 Operation check 10

2.3 Measuring viscosity 11

2.4 Measuring temperature 12

2.5 Temperature-corrected viscosity 12

2.6 General maintenance 13

2.7 Guidelines for optimum performance 13

3 Temperature correction

3.1 Introduction 14

3.2 E-format numbers 14

3.3 How to enter an E-format parameter 15

3.4 Setting the reference temperature 16

3.5 Saving changes 17

3.6 Determination of correction factors 18

4 Operational adjustment

4.1 Introduction 20

4.2 How to modify a numerical value 20

4.3 Accessing calibration and adjustment menus 21

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Viscolite VL7

4.4 Minor null adjustment 22

4.5 Stabilise reading (averaging filter) 22

4.6 Scale reading by any desired factor 23

4.7 Take account of f luid density 24

4.8 How to display viscosity in centistokes 24

4.9 Matching to reference instrument 25

5 Calibration and Maintenance

5.1 Introduction 26

5.2 Calibration check 26

5.3 Full recalibration 27

5.4 Instrument Verification Service 27

5.5 Service and repair 28

Appendix 1: Operating principles 29

Appendix 2: Menu overview 31

Troubleshooting/Alarms 33

Index 34

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Viscolite VL7

Introduction

The Viscolite® VL7 is an easy-to-use portable

instrument for the instant measurement of viscosity

anywhere at any time using a simple dip-in probe. No

prior setting-up or adjustment is required.

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The sensor is a solid probe with no moving parts, seals

or bearings. It is connected by a coiled f lexible cable

to a display unit powered by four AA batteries. The

probe also incorporates an integral platinum resistance

thermometer (PRT). The whole system is supplied in a

compact carrying case for ease of transport.

The Viscolite can be used with any volume of fluid,

from a cupful to a tank. Readings are made instantly,

enabling rapid assessment of samples or batches in situ.

The solid sensor can be wiped clean in moments.

This combination of toughness, flexibility and

portability make the Viscolite the ideal instrument for

the spot measurement of viscosity at a remote site, in

the laboratory or in a busy factory.

5

Viscolite VL7

How it works

The Viscolite is a “resonant” or “vibrational” viscometer. The sensor consists of a steel

shaft with an end mass (“bob”) which is made to vibrate at its natural frequency. The

actual vibrational movement is very small, but it is enough. As the vibrating sensor

shears through a fluid, it loses energy as a result of the viscous drag exerted by the f luid.

The viscosity of the fluid can therefore be determined by measuring the amount of

energy loss. This technique, combined with high-performance transducer architecture,

leads to extremely high repeatability.

Since a Hydramotion viscometer produces no compression or sound waves it can be used

in any vessel, regardless of size. The smooth, monolithic design of the sensor eliminates

any chance of solid or bubble entrapment. And as the shear rate is high, the effect of

external factors such as vibration or changes in fluid velocity will be negligible.

For more details of how the energy loss is converted into a measurement of viscosity, see

Appendix 1 (p. 29).

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Viscolite VL7

1.1 Packaging1.1 Packaging

• First, inspect the contents of the carrying • First, inspect the contents of the carrying

• Please do not discard the • Please do not discard the

• Keep the Viscolite in its carrying case • Keep the Viscolite in its carrying case

• The metal probe can move slightly relative • The metal probe can move slightly relative

1 Getting started

1.1 Packaging

• First, inspect the contents of the carrying

case. Immediately report any apparent

shipping damage to Hydramotion Ltd or its

representatives as well as to the carrier.

• Please do not discard the packaging. Use

it if you need to forward the instrument to

another recipient or return it to the factory.

• Keep the Viscolite in its carrying case

whenever it is not in use.

• The metal probe can move slightly relative

to the black acetal enclosure: this is quite

normal.

• For correct operation it is essential that the sensor shaft is perfectly straight. Do not

leave the transducer resting on the sensor shaft.

1.2 Specification

Viscosity range

model type VL7-100B-d15 0 – 5,000 centipoise (cP)
model type VL7-100B-d20 0 – 1,000 cP
model type VL7-100B-d21 0 – 10,000 cP

Temperature range –20 to +120 °C

Materials

sensor 316L stainless steel (unless otherwise specified)
enclosure acetal polymer

Power source 4 × 1.5V alkaline batteries size AA

Options

POL high polished sensor surface 0.4 micron AA

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7

Viscolite VL7

Immersion depths:
B viscosity or temperature
A viscosity only

All dimensions to nea rest mm

flexible coil lead

display unit

Hydramotion

show units

CAL

inc

dec

viscosity

ON

OFF

iscolite 700

portable viscometer

VL7-100 B- d15

Figure 1

Viscolite VL7

Dimensions (mm):

display unit L 180 W 95 H 40
probe (overall) L 215 (d15 model),
L 305 (d20/d21 models)

sensor probe

B

∅ 15

62

35

A

∅ 15

VL7-100B-d20 & -d21

30

115

sensor probe

B

∅ 22

A

20 (type d20)

∅

21 (ty pe d21)

• The full designation of an instrument includes the model type and any applicable

Option. Thus “VL7-100B-d15-POL” indicates the d15 model with a high-polish finish.

• A Certificate of Calibration and Conformity is included with each Viscolite. It should

be carefully checked against the shipping documents and the serial number stamped on

the instrument, then stored in a safe place.

Record the details of your instrument

Model type:
Serial number:
Certificate of Calibration and Conformity number:

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Viscolite VL7

1.3 Fitting the batteries

• The Viscolite uses four 1.5V batteries, ty pe AA or

equivalent (LR6, AM 3, MN 1500).

TAG

SER.

MALTON • YORK • ENGLAND

TYPE

MODEL

Figure 2

Underside of display unit

• Locate the battery compartment on the underside

of the display unit (see Figure 3).

• Remove the lid by pressing the part marked

' and

sliding sharply backwards.

• Place the batteries in the battery cradle, taking care

that they are inserted the right way round.

• Clip the cradle firmly to the connector.

• Place the battery cradle in the compartment and

replace the lid.

Note:

• Alkaline batteries (“Duracell” or equivalent) should

give up to 50 hours’ use under normal operating

conditions.

• Rechargeable batteries are not suitable.

Figure 3

Fitting the batteries

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9

Viscolite VL7

2 Measuring viscosity

Figure 4

Display unit

2.2 Operation check

2.1 Turning on

• Press the * key on the display unit and

hold it down for a second or two.

• The display shows a succession of digits

while the microprocessor goes through a

start-up routine. It will then show “VL”

briefly before settling on the “ live viscosity”

reading. This is the dynamic viscosity

in centipoise (cP) of whatever fluid is

surrounding the sensor.

• The reading is updated every 1.5 seconds

approximately.

• Pressing the

other measurements, “

“

VC” (temperature-corrected viscosity). For

more details, see pages 12 and 13.

• A beeper sounds each time a key is pressed.

• To switch off, press the

) or ( keys will bring up two

t” (temperature) and

* key again.

• The display unit should read 0.0 (zero) so long as the sensor is

(i) perfectly clean, dry and

(ii) wholly in air and not touching any thing.

• The display should show

For details of the checking procedure, see Section 5.2.

• If the air reading is not exactly zero:

(1) check that the sensor is perfectly clean, dry and not in contact with anything.

(2) if necessary, perform a “minor null adjustment” as described in Section 4.4 (p. 22).

10

1.0 (exactly one) if the sensor is immersed in water at 20 °C.

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Viscolite VL7

Minimum immersion depths:
B viscosity or temperature
A viscosity only

Do not clamp
below here

B
A

VL7-100B-d20 and VL7-100B-d21 VL7-100 B- d15

Measuring viscosity

Do not clamp
below here

B

A

Figure 5

2.3 Measuring viscosity

• Switch on the Viscolite.

• Immerse the sensor into the f luid to be measured to the depth shown in Figure 5.

• If the fluid is likely to be at a different temperature to that of the sensor, be sure to allow

suff icient time for complete temperature equalisation before taking a reading.

• The display unit shows the dynamic viscosity of the fluid in centipoise (cP), equivalent

to millipascal-second (mPa·s).

• Instability in the reading may be caused by

(1) temperature differences between the fluid and the sensor,

(2) the presence of suspended solids in the f luid, or

(3) a notable yield stress in a fluid exhibiting plastic behaviour ( Bingham effect).

If the instability is caused by (2) or (3) (suspended solids or plastic behaviour), use the

probe to stir the fluid gently.

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11

Viscolite VL7

• The viscosity reading may be noticeably higher or lower than expected if:

(1) the temperature of the f luid is significantly different from that at which the

reference measurement was made, or

(2) the sensor is not immersed to the depths shown in Figures 1 and 5, or

(3) the fluid is non-New tonian and the reference measurement was made using a

significantly different shear rate*, or

(4) the fluid density is significantly higher or lower than the nominal factory setting of

1.0 g/cm

3

. In this case, enter the correct density value using the procedure described in

Section 4.8 (p. 24).

2.4 Measuring temperature

• Switch on the Viscolite.

• Ensure that the sensor is immersed to the depth shown in Figure 5.

• Press the

) key. The display will show “t” (temperature) brief ly, then the temperature

of the fluid surrounding the sensor.

• Allow time for the sensor to reach the fluid temperature before noting the reading.

• To return to viscosity measurement, press the

( key. The display will show “VL” briefly

before showing the current live viscosity again.

2.5 Temperature-corrected viscosity

• If the display unit is showing live viscosity, press the ) key twice or the ( key once.

The display will show “

• For details of how to set the reference temperature, see Section 3.4 (p. 16).

• The displayed reading is calculated using the measured viscosity and temperature and

applying two correction factors specific to the fluid under test. See section 3 (p. 14) for

details of how to enter these correction factors.

*The Viscolite operates at a very high shear rate, which helps to give it high repeatability. Many laboratory
viscometers operate at low shear rates. If the f luid is shear-t hinning (pseudoplastic or t hixotropic), t he Viscolite
readi ng will be lower than t hat obtained with a low shear-rate viscometer. If the f luid is shear-thickening
(dilatant or rheopect ic), the Viscol ite wi ll give a higher reading. See also Section 4.9 (p. 25).

12

VC” briefly and then temperature-corrected viscosity.

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Viscolite VL7

• To return to viscosity measurement, press the ( key twice or the ) key once. The

display will show “

VL” brief ly before showing the current live viscosity again.

2.6 General maintenance

• Check periodically that the instrument gives a zero reading in air.

• Clean the sensor after each measurement. It is not usually necessary to switch the

Viscolite off while cleaning. The sensor can withstand vigorous cleaning so long as the

shaft is not bent or distorted in any way.

• It may be necessary to carry out a calibration check if:

(1) signs of appreciable wear or abrasion are observed, or

(2) the instrument is dropped or knocked sharply.

• Carry out a calibration check immediately if the shaft does not look perfectly straight.

• Further calibration checks are not necessary if the instrument is still giving a zero

reading in air and a reading of 1 in water at 20 °C.

• If required, certain minor adjustments are possible, as outlined in Section 4 below

(p. 20). For any other calibration problem, please contact Hydramotion Ltd or its

representative for details of the Instrument Verification Service.

2.7 Guidelines for optimum performance

• Do not operate the instrument outside its specification. In particular, do not subject the

sensor to extremes of heat or cold.

• Remove the batteries if the Viscolite is to remain out of use for a prolonged period.

• Whenever possible, keep the transducer in its carrying case.

• Never leave the transducer resting on the sensor shaft.

• Never use the sensor as a lever or for any other non-measurement purpose.

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Viscolite VL7

3 Temperature-corrected viscosity

3.1 Introduction

• The Viscolite uses an internal algorithm to calculate temperature-corrected viscosity

from the measured live viscosity and the measured temperature. (For more details see

Appendix 1, p. 29.)

• To enable temperature-corrected viscosity readings to be calculated, it is necessary for

the user to enter

(1) the desired reference temperature, and

(2) correction factors specific to the f luid under test.

• To determine the correction factors, see Section 3.6 (p. 18).

• The correction factors (and some other parameters) are entered, stored and displayed

in “ E-format”. Details of how to enter these parameters are given in Section 3.3 (p. 15).

3.2 E-format numbers

• The structure of an E-format number is:

- E -

•

- E - is the exponent (always displayed as two digits).

•

Int is the integer component of the number (always four digits).

•

FrAC is the fraction component (decimal part) of the number (also four digits).

Int

FrAC

• To get the complete number, the sum of the integer and fraction components is

multiplied by 10 raised to the power given by the exponent. I.e.,

number = (

Int + 0.FrAC) × 10

• For example:

0.61280473 = 6128.0473 × 10

E

- E -Int FrAC

–4

Thus the exponent - E - indicates how many places the decimal point should move to

the left (if negative) or right (if positive) of the number when expressed as “

14

Int.FrAC”.

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Viscolite VL7

• Other examples :

Number

0.6059132781

–58.8009340804

43629.5787797

- E - Int

– 04 6059 13 28

– 02 – 5880 0934

01 4362 9579

*Note rounding of last digit.

FrAC

*

3.3 How to enter an E-format parameter

• Check that the Viscolite is switched on and displaying live viscosity (VL), temperature

(

t), or temperature-corrected viscosity (VC).

• Press and hold down the

display will show “

• Navigate through the menus to the desired parameter using the

indicated in Figure 7 (p. 16) or (for calibration and adjustment) Figure 11 (p. 21).

• With the desired parameter displayed (e.g.

• The display will show “

• To go to the integer component

component

• To change a displayed value:

(1) press

(2) Use the

(3) When the desired value has been reached, press

VISC”. The instrument is now in “ Setup Mode”.

FrAC from the exponent, press ). To return to the parameter, press *.

+. The value will flash.

) or ( keys to increase or decrease the value.

+ and ( keys simultaneously for a second or two. The

( or + keys as

P91), press + for 3 seconds (Figure 6 below).

- E -” briefly followed by the value of the exponent.

Int from the exponent, press (. To go to the fraction

+ again.

Figure 6 Entering numerical data in E-format: overview

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15

Viscolite VL7

3.4 Setting the reference temperature

• Put the instrument into Setup Mode as described in Section 3.3 (p. 15), so that “VISC” is

showing on the display.

Figure 7

Overview of the temperature-correction menu. Use the < or > keys to navigate
through the sub-menus (e.g. to go from P90 to P91, etc).

Details of the Calibration and adjustment menus are given in Section 4 (p. 20).

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Viscolite VL7

Figure 8 General functions of keys

accesses a sub-menu,



CAL

enables a numerical value to be changed, or



fixes or burns a numerical value.





move up or down through a menu or a sub-menu, or



increase or decrease a numerica l value.



exits a sub-menu.

ON

• Press

( twice. The display will show “VC” (see temperature-correction menu, p. 16).

• Press

+. The display will show “P90” briefly, then its value.

• Press

( twice. The display will show “ t rEF” (reference temperature) briefly, then its

value in °C. The factory default setting is 15.0.

• Press

+. The display will begin to f lash.

• Use the

• Press

• Press

• Return to normal operating mode (“

• If required, save the change as described in Section 3.5 below before switching off the

( or ) keys to change the value as required.

+. The value will cease flashing.

*. The display will revert to “VC”.

VL”) using the ) and * keys as indicated on the

menu on p. 16.

Viscolite.

3.5 Saving changes

• Any newly-entered value will be lost on power-down unless it is “burned” into

permanent (non-volatile) memory. To do this:

(1) Navigate through the relevant menu(s) to

(2) Press

• The “burn” can be done at any time before powering-down the Viscolite. It is not

necessary to save the data after each entry.

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+ for 3 seconds. The display will show “b uSY” briefly as the data is saved.

burn .

17

Viscolite VL7

VISCOSITY

3.6 Determination of temperature correction factors

• The correction factors are called P90 and P91 (see p. 30). The f irst of these (P90) is

simply an offset and can be left at zero. The factory default setting for

P91 is also zero.

• There are two ways of determining

(i) Calculation of

P91

P91: (i) calculation and (ii) trial-and-error.

• To calculate P91, it is necessary to know the viscosity of the f luid at two temperatures.

Figure 9

Calculation of P91

V

1

V

2

The calculation is:

where

• If possible, use values of t

reference temperature.

typical viscosity/temperature
characteristic

t

1

P91 =

V

V

t

2

TEMPERATURE (°C)

logeV1 – logeV

2

[1/(t1 + 273)] – [1/(t2 + 273)]

= viscosity at temperature t1 °C

1

= viscosity at temperature t2 °C

2

and t2 that are close to the f luid temperature and the

1

• Enter the calculated value of

P91 as described in Section 3.3 (p. 15).

• If required, save the value as described in Section 3.5 (p. 17) before switching off the

Viscolite.

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Viscolite VL7

(ii) Trial-and-error determination of P91

• This method can only be used if

(a) variation in f luid temperature is causing the live viscosity reading (

VL) to fluctuate,

and

(b) it is known that the temperature-corrected viscosity would be stable, i.e. truly

constant, despite the fluctuations in

• Using the

( or + keys as indicated in Figure 7 (p. 16), navigate through the

temperature-correction menu to

• Enter a value of 5000 (

• Navigate to

• Go back to

• Go back to

VC. Note the degree of f luctuation in the reading.

P91 and enter a higher value, say 5250 (- E - = 00, Int = 5250, FrAC = 0000).

VC and see if there is more or less fluctuation in the reading.

- E - = 00, Int = 5000, FrAC = 0000) as described in Section 3.3.

• If the reading is fluctuating less, go back to

amount of f luctuation in the

• If the reading is fluctuating more, go back to

amount of f luctuation in the

VL.

P91.

P91 and increase the value again. Check the

VC reading. Continue in this way until VC stabilises.

P91 and reduce the value. Check the

VC reading. Continue in this way until VC stabilises.

• If required, save the value as described in Section 3.5 (p. 17) before switching off the

Viscolite.

Figure 10

VISCOSITY / TEMP

VL / VC

TEMP

VISCOSITY / TEMP

VL

VC

TEMP

Trial-and-error

determination

of P91

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TIME

P90 = P91 = 0 P91 CHANGED

VL

VC

TEMP

VISCOSITY / TEMP

TIME

TIME

P91 FINE TUNED

VL

VC

TEMP

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Viscolite VL7

4 Operational adjustment

4.1 Introduction

• Minor operational adjustments are carried out using the Calibration and adjustment

menus shown in Figure 11 (p. 21).

• The following adjustments can be made:

Reference Page

correct small non-zero reading of viscosity in air Section 4.4 22

stabilise reading (especially in high-noise conditions) Section 4.5 22

scale reading by any desired factor Section 4.6 23

take account of fluid density Section 4.7 24

express reading in centistokes (cSt) Section 4.8 24

match Viscolite to reference viscometer Section 4.9 25

4.2 How to modify a numerical value

• Parameters stored in “E-format” must be changed as described in Section 3.3 (p. 15).

• Other items are changed as follows:

(1) Navigate through the appropriate menu(s) until the desired item is reached.

(2) The name of the item will appear brief ly, followed by its value.

(3) Press

(4) Use the

(5) Press

(6) To go to the next item in the same submenu, press

(7) To go to the previous item in the same submenu, press

(8) To exit the submenu, press

20

+. The value will flash.

( or ) keys to decrease or increase the value as desired.

+again. The value will cease f lashing.

(.

).

*.

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Viscolite VL7

4.3 Accessing calibration and adjustment menus

• To access these menus from normal operating mode (“VL”, e tc):

(1) Bring the instrument into Setup Mode by pressing

display will show “

(2) Press

• Use the keypad to navigate through the menus as indicated below:

+. The display will show “ dAC”.

VISC”.

+ and ( simultaneously. The

Figure 11

Calibration and adjustment
menus.
Use the < or > keys to
navigate through the sub­menus

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21

Viscolite VL7

4.4 Minor null adjustment (offset)

• If the VL reading is not zero when the sensor is perfectly clean and dry and completely

surrounded by air:

(1) Navigate to

(2) Press

(3) Press

(4) Modify the value of

Example : If the

FCAL. (To do so from dAC, simply press (.)

+. The display will show “SPA n” brief ly, followed by its value.

(. The display will show “OSEt” (offset) briefly, then its value.

OSEt using the procedure described in Section 4.2 (p. 20).

VL reading in air is 0.3 and the value of OSEt is 0.1, reduce the value of

OSEt to –0.2.

(5) Navigate down the submenu to

necessary to navigate back to the main operating mode to reach

(6) If desired, compare the adjusted value (

submenu.

(7) Save the change as described in Section 3.5 (p. 17) before switching off the Viscolite.

• Once back in normal operating mode, the main

reading.

VL and check that its adjusted value is zero. (It is not

VL — see Figure 11.)

VL) with the unadjusted value (V) in the same

VL display will show the adjusted

4.5 Stabilise reading (averaging filter)

• The Viscolite has a very high natural rejection of exterior noise and vibration. Under

normal circumstances the reading should be stable.

• If there is noticeable instability in the reading, or if very high sensivity readings are

required over a long period of time, an averaging filter can be used.

• The filter is set by changing

readings included in the averaging calculation.

• In fact, the displayed

recalculated each time the Viscolite display is updated (every 1.5 seconds, approx.).

• If

nV is set to 1, there is no averaging.

22

nV in the FCAL submenu. The value of nV is the number of

VL reading is the average of nU measurements. The average is

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Viscolite VL7

• To set the averaging filter:

(1) Navigate to

(2) Adjust the value as desired.

(3) Navigate down the submenu to “

(4) The filtered reading can be compared with the unfiltered reading (

submenu.

(5) If necessary, go back and increase

(6) If desired, the change can be saved as described in Section 3.5 (p. 17).

• Once back in normal operating mode, the main

reading.

nV in the FCAL submenu (see Figure 11, p. 21).

VLAV” (filtered live viscosity).

VLAV by a further amount.

VL display will show the averaged

no filtering light

filtering

heavier
filtering

V) in the same

Figure 12

Application of

averaging filter

4.6 Scale reading by any desired factor

• The factory default setting is for the display to show dynamic (absolute) viscosity in

centipoise (cP), equivalent to millipascal-seconds (mPa ·s).

• To scale the reading by any desired factor:

(1) Navigate to

setting is 1.000.

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SCAL in the LCAL submenu (see Figure 11, p. 21). The default factory

23

Viscolite VL7

(2) Enter the appropriate conversion factor (see below).

(3) If desired, save the change as described in Section 3.5 (p. 17) before switching off.

Scaling from centipoise (cP)

unit symbol cP equivalent conversion factor

poise P 100 0.01

2

poiseuille Pl (≡ Pa·s, N·s/m

) 1000 0.001

• A Viscolite display can show only one decimal place. The

SCAL parameter may therefore

be used to bring more significant figures into the display. For example:

SCAL = 1 SCAL = 10 SCAL = 100

Reading on display

1.2 12 .3 12 3.4

Viscosity in cP 1.2 1.23 1.234

4.7 Take account of fluid density

• The factory default setting for f luid density is 1.000 g/cm3. To change this:

(1) Navigate to

(2) Enter the appropriate value for the fluid density in g/cm

d_n (nominal density) in the LCAL submenu (see Figure 11, p. 21).

3

.

(3) If desired, save the change as described in Section 3.5 (p. 17) before switching off.

4.8 How to display viscosity in centistokes (cSt) ( kinematic viscosity)

(1) If the f luid density is d, calculate the value of d2, i.e. the square of the density.

(1) Navigate to

(2) Enter the calculated value of

display will show viscosity in centistokes (i.e. kinematic viscosity).

d_n in the LCAL submenu (see Figure 11, p. 21).

2

d

. Once back in normal operating mode, the main VL

(3) If desired, save the change as described in Section 3.5 (p. 17) before switching off.

• Note that this procedure is fluid-specific.

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Viscolite VL7

4.9 Matching to reference instrument

• The Viscolite is rigorously calibrated at the factory to traceable standards using certified

test f luids.

• The instrument has very high repeatability. A Viscolite reading should therefore

compare very well with that obtained using any other viscometer that has been properly

calibrated and well maintained.

• If the Viscolite is being used correctly, its reading may not match that obtained with a

reference viscometer because:

(1) measurements are not being made at the same temperature;

(2) the fluid is non-Newtonian and the reference viscometer is operating at a

significantly different shear rate;

(3) the reference viscometer has not been calibrated or maintained properly;

(4) the operating parameters of the Viscolite do not match those of the reference

viscometer (for example, readings in centipoise are inadvertently being compared with

readings in other units); or

(5) the Viscolite transducer is worn, bent or damaged.

• If none of the above apply and the discrepancy remains unacceptable:

(1) note the reading obtained with the Viscolite. Call this reading

(2) Note the reading obtained with the reference viscometer under the same

measurement conditions. Call this reading

(3) Calculate the ratio

(4) Navigate to

(5) The adjusted reading (

same submenu.

U01-04-013 R1 08/13

VR/VL.

SPAn in the FCAL submenu and enter the calculated ratio.

VL) can be compared with the unadjusted reading (V) in the

VR.

VL.

25

Viscolite VL7

5 Calibration and Maintenance

5.1 Introduction

• All instruments are factory-calibrated using a range of certified silicone oils.

• Alternative calibration fluids can be used by special request.

• Minor adjustments can be made as described above (Section 4).

• Factory calibration can easily be checked by taking readings in air and water (see

Sections 2.2 above and 5.2 below).

5.2 Calibration check

• To check calibration:

(i) Check that the sensor is clean

and dry.

(ii) Set up the instrument as shown

in Figure 13.

Figure 13

Calibration check

(iii) Ensure the transducer is stably

supported. Apply clamps to the

black plastic enclosure, not t he

metal shaft.

(iv) Switch the Viscolite on and

note the reading with the sensor

in air (i.e. not in contact with any

fluid or surface). Switch off.

(v) Immerse the sensor in clean

water at least to the minimum

immersion depth as shown in

Figures 1 and 5.

(vi) Switch on the Viscolite.

26

temperature
probe

Do not clamp below here

clean water

temperature­controlled
water bath

stirrer

U01-04-013 R1 08/13

Viscolite VL7

(vii) Stir the water to ensure that it is all at a uniform temperature.

(viii) Allow plenty of time for the sensor and water to reach the same temperature.

This may take some minutes.

(ix) Note the viscosity and temperature readings (see Section 2.2).

Note: Do not hurry this test. Errors can result if sufficient time is not allowed for

temperature equalisation.

• Please contact Hydramotion Ltd or its representative if the readings are unacceptable

and the problem cannot be resolved using the procedures described in Section 4.

5.3 Instrument Verification Service

• Please contact Hydramotion Ltd or its representative if you wish to arrange a calibration

check or require a full recalibration.

• A Viscolite may be fully recalibrated:

(1) to comply with quality assurance requirements, or

(2) (by request) to adapt the instrument for use with a specific non-Newtonian fluid.

• Otherwise, full recalibration should only be necessary:

(1) after a damaged transducer has been repaired,

(2) if the sensor has become corroded or eroded, or

(3) if the Viscolite has been operated outside specification (e.g. subjected to extreme

heat).

5.4 Service and repair

• Please do not hesitate to contact Hydramotion at any time for advice or assistance.

• There are no user-serviceable parts in the Viscolite. If a fault is suspected, please

contact Hydramotion or its representative. Do not attempt to repair the unit.

• If reporting an apparent fault, please provide the following information:

(a) Serial number of the unit
(b) How long the Viscolite has been in service
(c) The type/composition of the fluid(s) being measured

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27

Viscolite VL7

(d) Measurement conditions (especially temperature)
(e) Observed and expected viscosity values
( f) Stability of the measurement(s)

( g) When the fault was  rst noticed

(h) Whether the fault is continuous or intermittent.

• Prior to shipping:

(1) Clarif y any s uch m atter s a s cos ts, liab i lity, insuranc e, i mpor t/ e x por t

documentation, customs declarations etc.

(2) Fax or mail a Returned Goods COSHH Declaration, duly completed, to:

Hydramotion Ltd
1 York Road B
Seven Street
Malton
York YO17 6YA
England

• When shipping:

(1) Use the original packaging.

(2) Ensure the Viscolite is securely packed.

(3) Include documentation clearly stating the serial number and the reason(s) for

return.

usiness Park

28

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Viscolite VL7

Appendix 1: Operating principles

How the Viscolite determines viscosity

The signal generated by the transducer is called the “ loss factor” L. It is converted to the

“raw” calculated viscosity

V = (1/d)(P30 + P31L + P32L

Here

d is the density of the fluid and P30, P31, P32, etc. are “ calibration constants”

which are unique to each instrument and must be empirically determined. The number

of terms used varies between transducer models. All the Calibration Constants are set

out on the Certificate of Calibration and Conformity and can be accessed from the

submenu.

In fact, the response of a resonant viscometer like the Viscolite is not purely with

viscosity but with the product of viscosity and de nsit y, i.e. viscosity × density. In

practice, however, repeatability is generally far more important than absolute accuracy.

Since viscosity changes on a far greater scale than density, changes in density can in most

cases safely be ignored.

V using the following polynomial equation:

2

+ P33L3 + P34L4 + ... )

LCAL

For maximum accuracy, the density

d of the fluid can be entered in the d_n parameter.

See Section 4.8 above.

Scaling

If the scaling factor SCAL (Section 4.6) is applied, the equation becomes:

SCAL



VL =



(



P30 + P31L + P32L



d

2

+ P33L3 + P34L4 + ... )

The “live” viscosity reading displayed in normal operational mode (

product of the “raw” viscosity

V and SCAL, i.e.

VL = V × SCAL

U01-04-013 R1 08/13

VL) is therefore the

29

Viscolite VL7

Viscometer matching

When matching the Viscolite response to that of a reference instrument, the SPAn factor

is applied (Section 4.9). The viscosity reading displayed in normal operational mode (

is then the product of the calculated viscosity

VL and SPAn , i.e.

VL)

VL = VL × SPAn

Null adjustment

To correct a small non-zero reading in air, an offset OSEt is added (Section 4.4). The

viscosity reading displayed in normal operational mode (

product of the calculated viscosity

VL and SPAn , i.e.

VL) then becomes OSEt plus the

VL = (VL × SPAn) + OSEt

Temperature correction (Section 3)

To correct the measured viscosity to viscosity at a given reference temperature, the

Viscolite uses an algorithm based on the commonly-accepted Arrhenius relationship

viscosity = Ae

where T is the absolute temperature and A and B are constants depending on the

particular fluid. The following equation is used to calculate the temperature-corrected

viscosity

VC from a viscosity reading VL:

VC = {VL . e

P91[1/(trEF + 273) – 1/(tL + 273)]

B/T

} – P90

where

trEF = reference temperature (°C) (Section 3.4)

These parameters can all be accessed from

VC = viscosity corrected to reference temperature
VL = calculated viscosity

tL = measured temperature (°C)
P90 = correction factor (offset)
P91 = correction factor

(Section 3.6)

VC in the temperature-correction menus.

30

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Viscolite VL7

Appendix 2: Menu overview

Item index

(sub)menu item description section(s) page(s)

burn save settings in non-volatile memory 3.5 17
LCAL d-n fl uid density 4.8 24
t - FCAL dEGC measured temperature
P30 (etc) - E - exponent of E-format number 3.3 14
P30 (etc) FrAC fraction of E-format number 3.3 14
P30 (etc) Int integer component of E-format number 3.3 14
tESt L measured loss
FCAL nV averaging sample number 4.5 22
t - FCAL OFSt temperature null offset
FCAL OSEt viscosity null offset 4.4 22
LCAL P30 – 38 calibration constants Appx 1 29
t - VC P90, P91 temperature correction factors 3.6 18
t - FCAL rES PRT resistance
LCAL SCAL scaling factor 4.6, 4.7 23, 24
FCAL SPAn gain factor 4.9 25
t live temperature 2.4 12
VISC t temperature menu 3.4 16
tESt tL live temperature
t - VC tL live temperature Appx 1 29
t - VC trEF reference temperature 3.4 16
FCAL V unadjusted viscosity 4.4 22
tESt V unadjusted viscosity
VC temperature-corrected viscosity 2.5 12
tESt VC temperature-corrected viscosity
t - VC VC temperature-corrected viscosity
FCAL VCAV fi ltered temperature-corrected live viscosity
tESt VCAV fi ltered temperature-corrected live viscosity
VISC viscosity main menu 3.3 15
VL live viscosity 2.1 10
tESt VL live viscosity
t-VC VL live viscosity
FCAL VLAV fi ltered live viscosity 4.5 22
tESt VLAV fi ltered live viscosity

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31

Viscolite VL7

Figure 14

Menu

overview

32

U01-04-013 R1 08/13

Viscolite VL7

Troubleshooting

Problem Possible cause Remedy Section

No display Not switched on Switch on 2.1

Batteries f lat Replace batteries 1.3

Reading high Shear-thickening f luid — 2.3, 4.9

Fluid temperature low Use temperature correction 2.3

Fluid density high Enter density value 4.8

Reading low Shear-thinning fluid — 2.3, 4.9

Fluid temperature high Use temperature correction 2.3

Fluid density very low Enter density value 4.8

Insufficient immersion Increase immersion depth 2.3

Unstable/jittery
reading

Reading not
precise enough

Sensor warmer or colder
than fluid

Suspended solids in
fluid

Plastic fluid (Bingham
effect)

High-frequency external
noise

Fluid has very low
viscosity

Allow equalisation 2.3

Stir gently; filter fluid if
possible

Stir gently 2.3

Set averaging filter 4.5

Change scaling factor 4.6

Alarm displays

batteries low — save any changes without delay to avoid loss of entered data

bAtt

d EAd batteries exhausted — temporary memory no longer operational

S IG no signal from transducer*

*Please contact Hydramotion Ltd or its representative if you see this display.

U01-04-013 R1 08/13

2.3

33

Viscolite VL7

General index

adjustments 20
air reading 10
alarm displays 33
averaging fi lter 22

bAtt 33

batteries 9, 13
battery cradle 9
beeper 10
Bingham 11
calibration and adjustment menus 21
calibration check 10, 13
calibration constants 29
centipoise 10, 23
centistokes 24
Certifi cate of Calibration and Conformity 8, 29
clamping 11, 26
cleaning 13
correction factors 12, 14

determination of 18

damage 7

dEAd 33

density 12, 24, 29
display unit 10
E-format 14, 15

fraction component 14

integer component 14
exponent 14
fi lter 22
instability (in reading) 11, 22
kinematic viscosity 24
live viscosity 10
loss factor 29
maintenance 13
matching 25, 30
materials 7
menu

calibration and adjustment 21

temperature correction 16
minor null adjustment 22, 30
model type 7, 8
non-Newtonian fl uids 12, 25
numerical value, modifi cation of 20
options 7

P30 etc 29

P90, P91 18, 19

packaging 7
plastic behaviour 11
platinum resistance thermometer 5
polished 7
power source 7
POL 7
PRT 5
range 7
recalibration 27
reference instrument, matching 25, 30
reference temperature 16
repeatability 6, 25
Returned Instrument Health & Safety Certifi cate 28
return to factory 28
scaling 23, 29
serial number 8
setting

fi lter 22

reference temperature 16
Setup Mode 15
shaft 7
shear rate 12, 25

SIG 33

specifi cation 7
stabilise reading 22
start-up 10
suspended solids 11
switching off 10
switching on 10
temperature

correction factors 13

equalisation 11

measurement 12
temperature-corrected viscosity 12, 14, 30
turning off 10
turning on 10
viscosity

dynamic 11

kinematic 24

measurement 10

measurement principles 29

34

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