TA AR-G2 User manual

Revision R Issued January 2011
Getting Started Guide
AR-G2/AR 2000ex/AR 1500ex
Rheometers

Page 2 AR-G2/AR 2000ex/AR 1500ex Getting Started Guide
Notice
The material contained in this manual, and in the online help for the software used to support this instru-
ment, is believed adequate for the intended use of the instrument. If the instrument or procedures are used
for purposes other than those specified herein, confirmation of their suitability must be obtained from TA
Instruments. Otherwise, TA Instruments does not guarantee any results and assumes no obligation or liabil-
ity. TA Instruments also reserves the right to revise this document and to make changes without notice.
TA Instruments may have patents, patent applications, trademarks, copyrights, or other intellectual prop-
erty covering subject matter in this document. Except as expressly provided in written license agreement
from TA Instruments, the furnishing of this document does not give you any license to these patents, trade-
marks, copyrights, or other intellectual property.
TA Instruments Operating Software, as well as Module, Data Analysis, and Utility Software and their asso-
ciated manuals and online help, are proprietary and copyrighted by TA Instruments. Purchasers are granted
a license to use these software programs on the module and controller with which they were purchased.
These programs may not be duplicated by the purchaser without the prior written consent of TA Instru-
ments. Each licensed program shall remain the exclusive property of TA Instruments, and no rights or
licenses are granted to the purchaser other than as specified above.
©2011 by
TA Instruments — Waters LLC
159 Lukens Drive
New Castle, DE 19720

AR-G2/AR 2000ex/AR 1500ex Getting Started Guide Page 3
Introduction
Important: TA Instruments Manual Supplement
Please click the TA Manual Supplement link to access the following important information
supplemental to this Getting Started Guide:
• TA Instruments Trademarks
• TA Instruments Patents
• Other Trademarks
• TA Instruments End-User License Agreement
• TA Instruments Offices

Page 4 AR-G2/AR 2000ex/AR 1500ex Getting Started Guide
Notes, Cautions, and Warnings

This manual uses NOTES, CAUTIONS, and WARNINGS to emphasize important and critical
instructions. In the body of the manual these may be found in the shaded box on the outside of the page.
NOTE: A NOTE highlights important information about equipment or procedures.
CAUTION: A CAUTION emphasizes a procedure that may damage equipment or cause loss of data if not
followed correctly.
Regulatory Compliance
Safety Standards
For Canada
CAN/CSA-C22.2 No. 61010-1 Safety requirements for electrical equipment for measurement, control, and
laboratory use, Part 1: General Requirements.
CAN/CSA-C22.2 No. 61010-2-010 Particular requirements for laboratory equipment for the heating of
materials.
For European Economic Area
(In accordance with Council Directive 2006/95/EC of 12 December 2006 on the harmonization of the laws
of Member States relating to electrical equipment designed for use within certain voltage limits.)
EN 61010-1:2001 Safety requirements for electrical equipment for measurement, control, and laboratory
use, Part 1: General Requirements + Amendments.
EN 61010-2-010:2003 Particular requirements for laboratory equipment for the heating of materials +
Amendments.
For United States
UL61010-1:2004 Electrical Equipment for Laboratory Use; Part 1: General Requirements.
UL61010A-2-010:2002 Particular requirements for laboratory equipment for the heating of materials +
Amendments.
A WARNING indicates a procedure that may be hazardous to the operator or
to the environment if not followed correctly.

AR-G2/AR 2000ex/AR 1500ex Getting Started Guide Page 5
Electromagnetic Compatibility Standards
For Australia and New Zealand
AS/NZS CISPR11:2004 Limits and methods of measurement of electronic disturbance characteristics of
industrial, scientific and medical (ISM) radio frequency equipment.
For Canada
ICES-001 Issue 4 June 2006 Interference-Causing Equipment Standard: Industrial, Scientific, and Medical
Radio Frequency Generators.
For the European Economic Area
(In accordance with Council Directive 2004/108/EC of 15 December 2004 on the approximation of the
laws of the Member States relating to electromagnetic compatibility.)
EN61326-1:2006 Electrical equipment for measurement, control, and laboratory use-EMC requirements-
Part 1: General Requirements. Emissions: Meets Class A requirements per CISPR 11. Immunity: Per
Table 1 - Basic immunity test requirements.
For the United States
CFR Title 47 Telecommunication Chapter I Federal Communications Commission, Part 15 Radio
frequency devices (FCC regulation pertaining to radio frequency emissions).

Page 6 AR-G2/AR 2000ex/AR 1500ex Getting Started Guide
Safety
Do not attempt to service this instrument, as it contains no user-serviceable components.
Required Equipment
While operating this instrument, you must wear eye protection that either meets or exceeds ANSI Z87.1
standards. Additionally, wear protective clothing that has been approved for protection against the
materials under test and the test temperatures.
Instrument Symbols
The following label is displayed on the instrument for your protection:
Please heed the warning labels and take the necessary precautions when dealing with these areas. This
Getting Started Guide contains cautions and warnings that must be followed for your own safety.
Symbol Explanation
This symbol on the AR-G2 indicates that you should read this Getting Started
Guide for important safety information. This guide contains important warnings
and cautions related to the installation, operation, and safety of the instrument.
This symbol indicates that a hot surface may be present. Take care not to touch
this area or allow any material that may melt or burn come in contact with this
hot surface.
This symbol indicates that you are advised to consult this manual for
instructions.

AR-G2/AR 2000ex/AR 1500ex Getting Started Guide Page 7
Warnings
WARNING: This equipment must not be mounted on a flammable surface if low
flashpoint material is being analyzed.
WARNING: An extraction system may be required if the heating of materials
could lead to liberation of hazardous gasses.
WARNING: It is recommended that this instrument be serviced by trained and
skilled TA Instruments personnel at least once a year.
WARNING: The material used on the top surface of the Peltier Plate is hard,
chrome-plated copper and the material used for the 'skirt' of the Peltier is stain-
less steel. Therefore, use an appropriate cleaning material when cleaning the
Peltier Plate.
WARNING: The internal components of the ETC are all constructed from chemi-
cally resistant materials, and can therefore be cleaned with standard laboratory
solvents. The only exception is the cladding for the thermocouples, which
should not be immersed in a solvent for long periods. Use a small amount of
solvent on a soft cloth and wipe the soiled area gently. This procedure should
never be conducted at any temperature other than ambient.
WARNING: During the installation or reinstallation of the instrument, ensure that
the external connecting cables (i.e., data, RS232 etc.) are placed separate from
the mains power cables. Also, ensure that the external connecting cables and
the mains power cables are placed away from any hot external parts of the
instrument. Note: Ensure that the mains power cable is selected such that it is
suitable for the instrument that is being installed or reinstalled, paying particular
attention to the current rating of both the cable and the instrument.
WARNING: During operation, extreme hot or cold surfaces may be exposed.
Take adequate precautions. Wear safety gloves before removing hot or cold
geometries.

Page 8 AR-G2/AR 2000ex/AR 1500ex Getting Started Guide
WARNING: Liquid nitrogen can cause rapid suffocation without warning. Store
and use in an area with adequate ventilation. Do not vent liquid nitrogen in con-
fined spaces. Do not enter confined spaces where nitrogen gas may be present
unless the area is well ventilated. The warning above applies to the use of liquid
nitrogen. Oxygen depletion sensors are sometimes utilized where liquid nitro-
gen is in use.
WARNING: The various surfaces and pipes of the ETC and the supply Dewar can
get cold during use. These cold surfaces cause condensation and, in some
cases, frost to build up. This condensation may drip to the floor. Provisions to
keep the floor dry should be made. If any moisture does drip to the floor, be sure
to clean it up promptly to prevent a slipping hazard.
WARNING: Always unplug the instrument before performing any maintenance.
WARNING: No user serviceable parts are contained in the rheometer. Mainte-
nance and repair must be performed by TA Instruments or other qualified ser-
vice personnel only.
WARNING: This instrument must be connected to an earthed (grounded) power
supply. If this instrument is used with an extension lead, the earth (ground) con-
tinuity must be maintained.
WARNING: Take adequate precautions prior to heating of materials if it can lead
to explosion, implosion or the release of toxic or flammable gases.
WARNING: The impeller is constructed from a rigid polymer composite material
of density about 1.6 g cm-3. It he usual operating angular speed is 160 revolu-
tions per minute, rpm, (16.76 radians per second). Under these conditions the
unit is unlikely to provide a significant hazard to the user, and only the normal
precautions observed when operating the rheometer need be taken.
The instrument software does permit operation of the rheometer at its maximum
angular speed, without immersion of the impeller. Take reasonable precautions
to avoid contact with the impeller when it is rotating at high angular speed.
Ensure that clothing, jewelry, etc. does not become entangled in the impeller.

AR-G2/AR 2000ex/AR 1500ex Getting Started Guide Page 9
Electrical Safety
Always unplug the instrument before performing any maintenance.
Supply voltage: 110 to 230 VAC
Fuse type: 2 x T15A H250 V
Mains frequency: 50 to 60 Hz
Power: 1.4 kW
Liquid Nitrogen Safety
DANGER: Because of the high voltages in this instrument, maintenance and
repair of internal parts must be performed by TA Instruments or other qualified
service personnel only.
Potential Asphyxiant
WARNING: Liquid nitrogen can cause rapid suffocation without warning.
Store and use in an area with adequate ventilation. Do not vent liquid nitrogen
in confined spaces. Do not enter confined spaces where nitrogen gas may be
present unless the area is well ventilated. The warning above applies to the
use of liquid nitrogen. Oxygen depletion sensors are sometimes utilized
where liquid nitrogen is in use.
Extremes of temperature
During operation, extreme hot or cold surfaces may be exposed. Take
adequate precautions.
Wear safety gloves before removing hot or cold geometries.

Page 10 AR-G2/AR 2000ex/AR 1500ex Getting Started Guide
Handling Liquid Nitrogen
The ETC uses the cryogenic (low-temperature) agent, liquid nitrogen, for cooling. Because of its low tem-
perature [–195°C (–319°F)], liquid nitrogen will burn the skin. When you work with liquid nitrogen, use
the following precautions:
• Liquid nitrogen evaporates rapidly at room temperature. Be certain that areas where liquid nitrogen is
used are well ventilated to prevent displacement of oxygen in the air.
• Wear goggles or a face shield, gloves large enough to be removed easily, and a rubber apron. For extra
protection, wear high-topped, sturdy shoes, and leave your trouser legs outside the tops.
• Transfer the liquid slowly to prevent thermal shock to the equipment. Use containers that have
satisfactory low-temperature properties. Ensure that closed containers have vents to relieve pressure.
• The purity of liquid nitrogen decreases as the nitrogen evaporates. If much of the liquid in a container
has evaporated, analyze the remaining liquid before using it for any purpose where high oxygen con-
tent could be dangerous.
• The oven inner doors have a trough around the bottom of the element assembly for collection of excess
liquid nitrogen. Any excess fluid collected will drain out from the oven at the lower outer edge.
If a person is burned by liquid nitrogen:
1IMMEDIATELY flood the area (skin or eyes) with large quantities of cool water, then apply cold
compresses.
2If the skin is blistered or if there is a chance of eye infection, take the person to a doctor IMMEDIATELY.
Chemical Safety
• Do not use hydrogen or any other explosive gas with the ETC.
• Use of chlorine gas will damage the instrument.
• If you are using samples that may emit harmful gases, vent the gases by placing the instrument
near an exhaust.
Usage Instructions
Before connecting the rheometer to auxiliary equipment, you must ensure that you have read the relevant
installation information. Safety of the rheometer may be impaired if the instrument:
• Shows visible damage
• Fails to perform the intended measurements
• Has been badly stored
• Has been flooded with water
• Has been subjected to severe transport stresses.

AR-G2/AR 2000ex/AR 1500ex Getting Started Guide Page 11
Maintenance and Repair
CAUTION: Adjustment, replacement of parts, maintenance and repair should be carried out by trained
and skilled TA personnel only. The instrument should be disconnected from the mains before removal of
the cover.
WARNING: The cover should only be removed by authorized personnel. Once the
cover has been removed, live parts are accessible. Both live and neutral supplies
are fused and therefore a failure of a single fuse could still leave some parts live.
The instrument contains capacitors that may remain charged even after being dis-
connected from the supply.

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This page is intentionally blank.

AR-G2/AR 2000ex/AR 1500ex Getting Started Guide Page 13
Table of Contents
Introduction ......................................................................................................................................... 3
Important: TA Instruments Manual Supplement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Notes, Cautions, and Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
Regulatory Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Safety Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Electromagnetic Compatibility Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Required Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Instrument Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Electrical Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Liquid Nitrogen Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Chemical Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Usage Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Maintenance and Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Chapter 1:
About the AR Series Rheometers ................................................................................ 17
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
A Brief History of Rheology and the Development of CMT Rheometers . . . . . . . . . . . . . . .17
The AR-G2, AR 2000ex, and AR 1500ex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Key Rheometer Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Casting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Ball Slide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Magnetically-Levitated Bearing (AR-G2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Air Bearing (AR 2000ex/AR 1500ex) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Radial Air Bearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Rotational Mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Optical Encoder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Normal Force Transducer (AR-G2 and AR 2000ex Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Smart Swap™ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Auto GapSet Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Environmental Control Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Peltier Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Peltier Concentric Cylinders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
Upper Heated Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
The Electrically Heated Plate (EHP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
The Pressure Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
The Starch Pasting Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Asphalt Submersion Cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
The Environmental Test Chamber (ETC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Page 14 AR-G2/AR 2000ex/AR 1500ex Getting Started Guide
Bicone Interfacial Accessory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36
The Interfacial Double Wall Ring (DWR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37
The ETC Viewer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
The UV Curing Accessory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Small Angle Light-Scattering (SALS) Accessory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
AR Rheometer Geometries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Smart Swap™ Geometries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Instrument Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Chapter 2:
Installing the Instrument .............................................................................................. 43
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Removing the Packaging and Preparing for Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
Installation Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
In . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
On . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
Near . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
Away from . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Connecting the System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Connecting the Rheometer to the Electronics Control Box . . . . . . . . . . . . . . . . . . . . . . . . . .45
Connecting the Computer to the Electronics Control Box Using
Ethernet Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Connecting Air and Water to the Rheometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46
Leveling the Rheometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Installing a Geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48
Chapter 3:
Use, Maintenance, and Diagnostics ............................................................................. 49
Start-Up and Shut-Down Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Starting Up the Rheometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49
Shutting Down the Rheometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Maintenance and Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Moving the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Error & LCD Display Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52
Power On Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Initialising ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Bearing overspeed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Bearing pressure too low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Encoder index not found . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Nf gauge fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Nf temp sensor fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
Operator stop event . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
Power cable fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
Signal cable fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53

AR-G2/AR 2000ex/AR 1500ex Getting Started Guide Page 15
Temp sys element fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Temp system environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
Temp system sensor fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
Other Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
Index ................................................................................................................................................... 55

Page 16 AR-G2/AR 2000ex/AR 1500ex Getting Started Guide
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AR-G2/AR 2000ex/AR 1500ex Getting Started Guide Page 17
Chapter 1:
About the AR Series Rheometers
Overview
This chapter reviews the history of rheology, and traces the development of combined motor and trans-
ducer (CMT) rheometers. The AR-G2, AR 2000ex, and AR 1500ex are introduced, and brief descriptions
of their main components and accessories are given. Please read this chapter carefully to familiarize
yourself with the terminology used throughout this manual.
A Brief History of Rheology and the Development of CMT Rheometers
In 1929, Professor Eugene Bingham, a physical chemist working at Lafayette College in Pennsylvania,
decided that the study of the deformation and flow of matter was important enough to merit its own title.
On the advice of a Professor of Classics, he coined the term “rheology”, from the Greek rew (rheo) mean-
ing flow. But the discipline of rheology is much older than the word. The first formal scientific description
of a rheological phenomenon appeared in Isaac Newton's Principia Mathematica, published in 1687, where
he suggested that “the resistance which arises from the lack of slipperiness of the parts of [a] liquid, other
things being equal, is proportional to the velocity with which the parts of the liquid are separated from one
another.” Today we would say that the shear stress is proportional to the shear rate, and we would call the
constant of proportionality the viscosity of the liquid. As we now know, Newton's postulate applies only to
a limited class of low molecular weight liquids, over finite ranges of shear rate or stress. Rheology is usu-
ally more concerned with materials whose behavior is non-Newtonian, in that their viscosity is a function
of shear rate or stress. Such materials include polymers, paints, inks, creams, gels, shampoos, drilling flu-
ids, adhesives, and many foodstuffs.
It seems that Newton conducted no experimental work on the viscosity of liquids, and it was not until the
middle of the nineteenth century that work in that area was led by Poiseuille. The operating principle of
most of the early viscometers, including Poiseuille's, was that the fluid was driven by pressure or gravity
through a capillary or other constriction, and the rate of flow measured. Devices of this design are still in
use today, but, although they may have the advantage of simplicity of construction and operation, they
have the drawback that the sample can only be subjected to a finite strain.
However, a great step forward was made in the 1880's when the rotational viscometer was introduced by
Couette and others. In this type of device, the sample is situated either in the annular gap between two con-
centric cylinders, as in Couette's original design, or in the gap between two concentric, horizontally
mounted, parallel platens. One of the cylinders or platens (the stator) is fixed, the other (the rotor) is
rotated, and provided that the rotation can be permanently maintained, there is no limit to the strain that the
sample can be subjected to. In Couette's design, the outer cylinder was fixed, the inner was driven by a
weight connected to it through a series of pulleys. The angular velocity of the rotating cylinder was calcu-
lated from the time taken for the weight to fall. This design is interesting for two reasons, one being that it
was the stress that was controlled (through the weight) rather than the strain or strain rate, the other being
that actuator and detector were mounted on the same axis. It happens that the first of these gave rise to the
term used to describe the successors to this type of viscometer: “controlled stress”. They might alterna-
tively have been described by the second as “combined motor and transducer” (CMT). This term is now
preferred, since modern rheometers can operate in both controlled stress and controlled rate modes.

Page 18 AR-G2/AR 2000ex/AR 1500ex Getting Started Guide
It was many years before an electrically driven version of Couette's CMT apparatus was developed. The
next major advance in rheological instrumentation was introduced by Weissenberg in the 1940's. Weissen-
berg's intention was to investigate the viscoelasticity of polymer melts and solutions, but the viscometers
that existed at the time were not suitable for this study. This led to the next advance in instrumentation.
The study of elasticity parallels closely the study of viscosity. The first scientific reference to elasticity was
made by Robert Hooke, a correspondent and rival of Newton's, who published his famous anagram “CEI-
INOSSITTUU” in 1676, revealed as “ut tensio sic uis" (as the extension, so the force) in 1679. Hooke's
Law, as it came to be called, was supported by experimental observation, but it was not until the work of
Young in the early nineteenth century that it was realized that the law could be applied to material proper-
ties, rather than simply to extensive sample properties. In modern terminology, we would summarize
Young's findings by saying that the strain is proportional to the stress, and we would refer to the “constant
of proportionality” as the “modulus of the material.” Later in the nineteenth century, the work of Maxwell,
Voigt, Kelvin, Boltzmann and others showed that the distinction between viscous liquids and elastic solids
was not as clear as had previously been thought. Most of the materials listed above as non-Newtonian, are
also viscoelastic, in that they exhibit aspects of both types of behavior. (The names of the scientists who
contributed to the development of rheology reveal its importance: Einstein was also involved, and rheolo-
gists like to say that in their discipline Newton, Maxwell and Einstein did the easy bits.)
To conduct his investigation into polymer viscoelasticity, Weissenberg developed the first modern, electri-
cally driven, rheometer during the early 1940s, the basis of which was a lathe turned on its end. As such it
differed in two very significant ways from the Couette viscometers, firstly in that it was what later became
called a controlled rate rheometer, and secondly in that the actuator and detector were mounted on separate
axes. To adopt the principle of naming used above, this can be called the “separate motor and transducer”
(SMT) design. The principle of operation was that one of the platens of the measuring system was rotated
at a set angular speed, the torque transmitted by the sample being measured at the other platen. Weissen-
berg called his instrument a “Rheogoniometer”, since both the torque and the axial force could be mea-
sured, the latter being used to calculate the normal stress which results from the elasticity of the sample. In
the late 1940s the rheogoniometer was commercialized, but its price was beyond the range of most materi-
als testing laboratories. In 1970 Chris Macosko and Joe Starita formed the Rheometrics company (later
renamed Rheometric Scientific) to produce a lower cost alternative, and launched the first of a long line of
high quality SMT rheometers that led eventually to the modern ARES. Rheometric Scientific was acquired
by TA Instruments in January 2003, and its products continue to be manufactured and developed.
In the meantime, interest revived in CMT instruments, partly because of a desire to perform creep tests,
and partly because of the need to investigate the phenomenon of the yield stress in more detail, for which
the available SMT rheometers lacked the sensitivity. To these ends, Jack Deer, who was employed as a
technician at the London School of Pharmacy, designed a rotational rheometer based on the Couette vis-
cometer, but with the weight replaced, originally by an air-turbine drive, and later by a drag cup motor
(both shown in Figure 1). To reduce the friction in the instrument, an air bearing was introduced. Deer's
first published description of the instrument appeared in 1968 [Davis, Deer and Warburton, J. Sci. Instr. 2,
933-936, 1968]. He began to commercialize it shortly afterwards. In the early 1980's the design was taken
up by the Carri-Med company, at Deer's instigation, and that company launched its first rheometer, the
CSR, in 1984 (show n in Figure 2).

AR-G2/AR 2000ex/AR 1500ex Getting Started Guide Page 19
Figure 1 Jack Deer’s Air Turbine Rheometer (left); Deer Rheometer (right).
Figure 2 CSR.

Page 20 AR-G2/AR 2000ex/AR 1500ex Getting Started Guide
Carri-Med acquired the rights to the Weissenberg rheogoniometer in 1990, but the mainstay of its business
remained the CMT successors to the Deer, which included the CSL and CSL2 (shown in , until the com-
pany was purchased by TA Instruments in 1994. From that time on, progress in CMT technology has been
remarkable, with the AR 1000 launched in 1996 and the AR 2000 in the year 2000 by TA Instruments.
Both these instruments used air bearings, but the limits of that technology appear to have been reached, and
for the AR-G2, launched in 2005, a magnetically levitated bearing was used. This and other developments
by TA Instruments have advanced the instrumentation further. Developments, for example, in the drag cup
motor and the electronics, have led to substantial improvements in the low torque, controlled rate, and tran-
sient performances of the instrument. TA Instruments' AR-G2 is now the world's most advanced CMT rhe-
ometer. Some of the improvements made in the electronics and other components of the rheometer have
also been incorporated into the AR 2000 to form the AR 2000ex and AR 1500ex.
Figure 3 CSL2.