Fluke 7341 User manual

7341
Calibration Bath
User’s Guide
Rev. 681504
Hart Scientific

Limited Warranty & Limitation of Liability
Each product from Fluke's Hart Scientific Division ("Hart") is warranted to be free from defects in mate-
rial and workmanship under normal use and service. The warranty period is one year for the Calibration
Bath. The warranty period begins on the date of the shipment. Parts, product repairs, and services are
warranted for 90 days. The warranty extends only to the original buyer or end-user customer of a Hart
authorized reseller, and does not apply to fuses, disposable batteries or to any other product which, in
Hart's opinion, has been misused, altered, neglected, or damaged by accident or abnormal conditions of
operation or handling. Hart warrants that software will operate substantially in accordance with its func-
tional specifications for 90 days and that it has been properly recorded on non-defective media. Hart does
not warrant that software will be error free or operate without interruption. Hart does not warrant calibra-
tions on the Calibration Bath.
Hart authorized resellers shall extend this warranty on new and unused products to end-user customers
only but have no authority to extend a greater or different warranty on behalf of Hart. Warranty support is
available if product is purchased through a Hart authorized sales outlet or Buyer has paid the applicable
international price. Hart reserves the right to invoice Buyer for importation costs of repairs/replacement
parts when product purchased in one country is submitted for repair in another country.
Hart's warranty obligation is limited, at Hart's option, to refund of the purchase price, free of charge re-
pair, or replacement of a defective product which is returned to a Hart authorized service center within
the warranty period.
To obtain warranty service, contact your nearest Hart authorized service center or send the product, with
a description of the difficulty, postage, and insurance prepaid (FOB Destination), to the nearest Hart au-
thorized service center. Hart assumes no risk for damage in transit. Following warranty repair, the prod-
uct will be returned to Buyer, transportation prepaid (FOB Destination). If Hart determines that the
failure was caused by misuse, alteration, accident or abnormal condition or operation or handling, Hart
will provide an estimate or repair costs and obtain authorization before commencing the work. Following
repair, the product will be returned to the Buyer transportation prepaid and the Buyer will be billed for
the repair and return transportation charges (FOB Shipping Point).
THIS WARRANTY IS BUYER'S SOLE AND EXCLUSIVE REMEDY AND IS IN LIEU OF ALL
OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IM-
PLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
HART SHALL NOT BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL. OR CONSE-
QUENTIAL DAMAGES OR LOSSES, INCLUDING LOSS OF DATA, WHETHER ARISING FROM
BREACH OF WARRANTY OR BASED ON CONTRACT, TORT, RELIANCE OR ANY OTHER
THEORY.
Since some countries or states do not allow limitation of the term of an implied warranty, or exclusion or
limitation of incidental or consequential damages, the limitations and exclusions of this warranty may not
apply to every buyer. If any provision of this Warranty is held invalid or unenforceable by a court of com-
petent jurisdiction, such holding will not affect the validity or enforceability of any other provision.
Rev. 681504
Fluke Corporation, Hart Scientific Division
799 E. Utah Valley Drive • American Fork, UT 84003-9775 • USA
Phone: [phone] • Telefax: +1.801.763.1010
E-mail: [email protected]
www.hartscientific.com
Subject to change without notice. • Copyright © 2005 • Printed in USA

Table of Contents
1 Before You Start . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Symbols Used . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.1 WARNINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.2 CAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3 Authorized Service Centers. . . . . . . . . . . . . . . . . . . . . . 5
2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3 Specifications and Environmental Conditions . . . . . . . . . 11
3.1 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2 Environmental Conditions. . . . . . . . . . . . . . . . . . . . . . 12
4 Quick Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.1 Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.2 Set Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.3 Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.4 Setting the Temperature . . . . . . . . . . . . . . . . . . . . . . . 15
5 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.1 Moving or Uncrating the Bath . . . . . . . . . . . . . . . . . . . 17
5.2 Bath Environment . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.3 Tipping Prevention Bracket Installation. . . . . . . . . . . . . . . 17
5.3.1 Installation On A Wood Floor . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.3.2 Installation On a Concrete Floor . . . . . . . . . . . . . . . . . . . . . . . . 18
5.3.3 Installation Of The Bath . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
5.4 “Dry-out” Period . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5.5 Bath Preparation and Filling . . . . . . . . . . . . . . . . . . . . 19
5.6 Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
6 Bath Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
6.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
6.2 Comparison Calibration . . . . . . . . . . . . . . . . . . . . . . . 21
6.3 Calibration of Multiple Probes . . . . . . . . . . . . . . . . . . . 22
7 Parts and Controls . . . . . . . . . . . . . . . . . . . . . . . . 23
i

7.1 Front Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . 23
7.2 Refrigeration Condenser Access Door . . . . . . . . . . . . . . . 24
7.3 Bath Tank and Lid . . . . . . . . . . . . . . . . . . . . . . . . . . 24
7.4 Back Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
7.4.1 Fluid Expansion Reservoir . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
8 General Operation . . . . . . . . . . . . . . . . . . . . . . . . 27
8.1 Heat Transfer Fluid . . . . . . . . . . . . . . . . . . . . . . . . . 27
8.1.1 Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
8.1.2 Viscosity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
8.1.3 Specific Heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
8.1.4 Thermal Conductivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
8.1.5 Thermal Expansion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
8.1.6 Electrical Resistivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
8.1.7 Fluid Lifetime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
8.1.8 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
8.1.9 Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
8.1.10 Commonly Used Fluids. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
8.1.10.1 Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
8.1.10.2 Ethylene Glycol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
8.1.10.3 Mineral Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
8.1.10.4 Silicone Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
8.1.11 Fluid Characteristics Charts. . . . . . . . . . . . . . . . . . . . . . . . . . . 31
8.1.11.1 Limitations and Disclaimer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
8.1.11.2 About the Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
8.2 Stirring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
8.3 Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
8.4 Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
8.5 Temperature Controller . . . . . . . . . . . . . . . . . . . . . . . 35
8.6 Refrigeration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
9 Controller Operation . . . . . . . . . . . . . . . . . . . . . . . 37
9.1 Bath Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . 37
9.2 Reset Cutout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
9.3 Temperature Set-point . . . . . . . . . . . . . . . . . . . . . . . . 39
9.3.1 Programmable Set-points . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
9.3.2 Set-point Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
9.3.3 Set-point Vernier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
9.4 Scan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
9.4.1 Scan Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
9.4.2 Scan Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
9.5 Temperature Scale Units . . . . . . . . . . . . . . . . . . . . . . 42
9.6 Ramp and Soak Program . . . . . . . . . . . . . . . . . . . . . . 42
9.6.1 Number of Program Set-points . . . . . . . . . . . . . . . . . . . . . . . . . 42
9.6.2 Set-points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
ii

9.6.3 Program Soak Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
9.6.4 Program Function Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
9.6.5 Program Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
9.7 Secondary Menu. . . . . . . . . . . . . . . . . . . . . . . . . . . 45
9.8 Heater Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
9.9 Proportional Band . . . . . . . . . . . . . . . . . . . . . . . . . . 45
9.10 Cutout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
9.11 Controller Configuration . . . . . . . . . . . . . . . . . . . . . . 49
9.12 Probe Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . 49
9.12.1 R0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
9.12.2 ALPHA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
9.13 Operating Parameters . . . . . . . . . . . . . . . . . . . . . . . . 50
9.13.1 Cutout Reset Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
9.13.2 Cooling Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
9.13.3 Hot Gas Bypass Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
9.14 Serial Interface Parameters . . . . . . . . . . . . . . . . . . . . . 52
9.14.1 Baud Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
9.14.2 Sample Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
9.14.3 Duplex Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
9.14.4 Linefeed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
9.15 IEEE-488 Parameters . . . . . . . . . . . . . . . . . . . . . . . . 54
9.15.1 IEEE-488 Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
9.15.2 Transmission Termination . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
9.16 Calibration Parameters . . . . . . . . . . . . . . . . . . . . . . . 55
9.16.1 CTO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
9.16.2 CO and CG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
9.16.3 H and L . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
9.16.4 HGbt. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
10 Digital Communication Interface . . . . . . . . . . . . . . . . 57
10.1 Serial Communications . . . . . . . . . . . . . . . . . . . . . . . 57
10.1.1 Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
10.1.2 Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
10.1.2.1 Baud Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
10.1.2.2 Sample Period. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
10.1.2.3 Duplex Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
10.1.2.4 Linefeed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
10.1.3 Serial Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
10.2 IEEE-488 Communication (optional) . . . . . . . . . . . . . . . . 59
10.2.1 Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
10.2.1.1 IEEE-488 Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
10.2.1.2 Transmission Termination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
10.2.2 IEEE-488 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
10.3 Interface Commands . . . . . . . . . . . . . . . . . . . . . . . . 60
10.4 Cooling Control . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
iii

11 Calibration Procedure . . . . . . . . . . . . . . . . . . . . . . 65
11.1 Calibration Points . . . . . . . . . . . . . . . . . . . . . . . . . . 65
11.2 Measuring the Set-point Error. . . . . . . . . . . . . . . . . . . . 65
11.3 Computing R0 and ALPHA . . . . . . . . . . . . . . . . . . . . . 65
11.4 Calibration Example. . . . . . . . . . . . . . . . . . . . . . . . . 66
12 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
13 Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . 71
13.1 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
13.2 Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
13.2.1 EMC Directive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
13.2.1.1 Immunity Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
13.2.1.2 Emission Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
13.2.2 Low Voltage Directive (Safety) . . . . . . . . . . . . . . . . . . . . . . . . . 75
iv

v
Figures
Figure 1 Stir Baffle Fill Levels . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 2 Tipping Prevention Bracket Installation . . . . . . . . . . . . . . . . . 18
Figure 3 Front Control Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 4 Chart of Various Bath Fluids and Their Properties . . . . . . . . . . . 33
Figure 5 Controller Operation Flowchart . . . . . . . . . . . . . . . . . . . . . 38
Figure 6 Bath Temperature Fluctuation At Various Proportional Band Settings . 46
Figure 7 Serial Communications Cable Wiring . . . . . . . . . . . . . . . . . . 58
Figure 8 Calibration Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

vi
Tables
Table 1 International Electrical Symbols . . . . . . . . . . . . . . . . . . . . . 1
Table 2 Table of Various Bath Fluids and Their Properties. . . . . . . . . . . . 32
Table 3 Program Mode Setting Actions . . . . . . . . . . . . . . . . . . . . . 44
Table 4 Typical Proportional Band Settings for Various Fluids . . . . . . . . . 47
Table 5 Interface Command Summary . . . . . . . . . . . . . . . . . . . . . . 62
Table 5 Interface Command Summary Continued . . . . . . . . . . . . . . . . 63
Table 5 Interface Command Summary Continued . . . . . . . . . . . . . . . . 64

1 Before You Start
1.1 Symbols Used
Table 1 lists the International Electrical Symbols. Some or all of these symbols
may be used on the instrument or in this manual.
Symbol Description
AC (Alternating Current)
AC-DC
Battery
Complies with European Union directives
DC
Double Insulated
Electric Shock
Fuse
PE Ground
Hot Surface (Burn Hazard)
Read the User’s Manual (Important Information)
Off
On
Canadian Standards Association
OVERVOLTAGE (Installation) CATEGORY II, Pollution Degree 2 per IEC1010-1 re-
fers to the level of Impulse Withstand Voltage protection provided. Equipment of
OVERVOLTAGE CATEGORY II is energy-consuming equipment to be supplied from
the fixed installation. Examples include household, office, and laboratory appliances.
1
1 Before You Start
Symbols Used
Table 1 International Electrical Symbols

Symbol Description
C-TIC Australian EMC mark
The European Waste Electrical and Electronic Equipment (WEEE) Directive
(2002/96/EC) mark.
1.2 Safety Information
Use this instrument only as specified in this manual. Otherwise, the protection
provided by the instrument may be impaired. Refer to the safety information in
Warnings and Cautions sections.
The following definitions apply to the terms “Warning” and “Caution”.
•“WARNING” identifies conditions and actions that may pose hazards to
the user.
•“CAUTION” identifies conditions and actions that may damage the in-
strument being used.
1.2.1 WARNINGS
To avoid possible electrical shock or personal injury, follow these guidelines.
GENERAL
•DO NOT use the instrument for any application other than calibration
work. The instrument was designed for temperature calibration. Any other
use of the instrument may cause unknown hazards to the user.
•DO NOT use the instrument in environments other than those listed in
the user’s guide.
•DO NOT overfill the bath. Overflowing extremely cold or hot fluid may
be harmful to the operator. See Section 5.3, Bath Preparation and Filling,
for specific instructions.
•Follow all safety guidelines listed in the user’s manual.
•Calibration Equipment should only be used by Trained Personnel.
•If this equipment is used in a manner not specified by the manufacturer,
the protection provided by the equipment may be impaired.
•Before initial use, or after transport, or after storage in humid or semi-hu-
mid environments, or anytime the instrument has not been energized for
more than 10 days, the instrument needs to be energized for a "dry-out"
period of 2 hours before it can be assumed to meet all of the safety re-
quirements of the IEC 1010-1. If the product is wet or has been in a wet
environment, take necessary measures to remove moisture prior to apply-
ing power such as storage in a low humidity temperature chamber operat-
ing at 50°C for 4 hours or more.
7341 Calibration Bath
User’s Guide
2

•DO NOT operate high temperature baths (500°C) near flammable materi-
als. Extreme temperatures could ignite the flammable material.
•Overhead clearance is required. Do not place the instrument under a cabi-
net or other structure. Always leave enough clearance to allow for safe
and easy insertion and removal of probes.
•The instrument is intended for indoor use only.
•The bath is a precision instrument. Although it has been designed for op-
timum durability and trouble free operation, it must be handled with care.
Position the bath before the tank is filled with fluid by rolling it into
place. DO NOT attempt to lift the bath. Due to the weight of the com-
pressor, it may require two people to safely move the bath. The area con-
taining the compressor will be heavier than the rest of the bath. DO NOT
move a bath filled with fluid (see Section 5.1, Moving or Uncrating the
Bath).
BURN HAZARD
•Extremely cold temperatures may be present in this equipment. Freezer
burns and frostbite may result if personnel fail to observe safety precau-
tions.
•High temperatures may be present in this equipment. Fires and severe
burns may result if personnel fail to observe safety precautions.
•The drain tube and dust cover of the Fluid Expansion Reservoir may be
hot. Handle them carefully and always be sure the drain tube is fully in-
serted into the elbow of the dust cover.
•The drain tube of the Fluid Expansion Reservoir is not designed to handle
large flow rates encountered by overfilling the tank. It is intended for ex-
panding fluid rates from heating only. Fill tank only until the level reaches
the top of the baffle (see Figure 1 on page 14).
ELECTRICAL HAZARD
•These guidelines must be followed to ensure that the safety mechanisms
in this instrument will operate properly. This instrument must be plugged
into a 115 VAC, 60Hz (230 VAC, 50Hz optional), AC only electric outlet.
The power cord of the instrument is equipped with a three-pronged
grounding plug for your protection against electrical shock hazards. It
must be plugged directly into a properly grounded three-prong receptacle.
The receptacle must be installed in accordance with local codes and ordi-
nances. Consult a qualified electrician. DO NOT use an extension cord or
adapter plug.
•DO use a ground fault interrupt device. This instrument contains a fluid.
A ground fault device is advised in case fluid is present in the electrical
system and could cause an electrical shock.
•Always replace the power cord with an approved cord of the correct rat-
ing and type. If you have questions, contact an Authorized Service Center
(see Section 1.3).
3
1 Before You Start
Safety Information

•High voltage is used in the operation of this equipment. Severe injury or
death may result if personnel fail to observe the safety precautions. Before
working inside the equipment, turn off the power and disconnect the
power cord.
BATH FLUIDS
•Fluids used in this bath may produce noxious or toxic fumes under certain
circumstances. Consult the fluid manufacturer’s MSDS (Material Safety
Data Sheet). Proper ventilation and safety precautions must be observed.
•The instrument is equipped with a soft cutout (user settable firmware) and
a hard cutout (set at the factory). Check the flash point, boiling point, or
other fluid characteristic applicable to the circumstances of the bath oper-
ation. Ensure that the soft cutout is adjusted to the fluid characteristics of
the application. As a guideline, the soft cutout should be set 10°C to 15°C
below the flash point of the bath fluid. See Section 8.1, Heat Transfer
Fluid, for specific information on bath fluids and Section 9.10, Cutout.
1.2.2 CAUTIONS
•Always operate this instrument at room temperature between 41°F and
122°F (5°C to 50°C). Allow sufficient air circulation by leaving at least 6
inches (15 cm) of clearance around the instrument.
•When filling the tank, ensure the immersion coils are completely covered.
DO NOT fill above the stir baffle (see Figure 1 on page 14).
•DO NOT overfill the bath. Overflowing fluid may damage the electrical
system. See Section 5.3, Bath Preparation and Filling, for specific instruc-
tions.
•Read Section 6, Bath Use, before placing the bath into service.
•DO NOT turn the bath on without fluid in the tank and the heating coils
fully immersed. See Section 7.4.1, Fluid Expansion Reservoir, for more
information on Fluid Expansion Reservoir use.
•DO NOT change the values of the bath calibration constants from the fac-
tory set values. The correct setting of these parameters is important to the
safety and proper operation of the bath.
•The refrigeration may be damaged or the lifetime shortened if the
set-point temperature is set above 60°C for more than one hour with the
refrigeration manually on. Ensure that the refrigeration is off when the
bath is used above 60°C.
•The Factory Reset Sequence should be performed only by authorized
personnel if no other action is successful in correcting a malfunction. You
must have a copy of the most recent Report of Test to restore the test pa-
rameters.
•DO NOT operate this instrument in an excessively wet, oily, dusty, or
dirty environment. Silicone oils require additional ventilation to prevent
an oily, dirty environment.
7341 Calibration Bath
User’s Guide
4

•Most probes have handle temperature limits. Be sure that the probe handle
temperature limit is not exceeded in the air above the instrument.
•The instrument and any thermometer probes used with it are sensitive in-
struments that can be easily damaged. Always handle these devices with
care. Do not allow them to be dropped, struck, stressed, or overheated.
COLD BATHS
•Refrigerated baths require that the condensing coil be cleaned periodi-
cally. Accumulation of dust and dirt on the condenser will result in pre-
mature failure of the compressor.
•This bath has been equipped with a brownout and over voltage protection
device as a safety feature to protect the system components.
•Mode of Operation: This bath needs to be plugged into the line voltage
for at least 2 minutes before operation. This is only necessary for the first
time the bath is energized or when it is moved from one location to an-
other. Turning the bath ON or OFF does not trigger the delay.
•If a High/Low voltage condition exists for longer than 5 seconds, the bath
de-energizes. An amber indicator on the back panel lights when this con-
dition exists.
•Re-energization is automatic upon correction of the fault condition and af-
ter a delay cycle of about 2 minutes. If a fault condition exists upon appli-
cation of power, the bath will not energize.
•Under and Over Voltage Protection at 115 VAC
♦Voltage Cutout: ±12.5% (101 - 129 VAC)
♦Voltage Cut In: ±7.5% (106 - 124 VAC)
•Under and Over Voltage Protection at 230 VAC
♦Voltage Cutout: ±12.5% (203 - 257 VAC)
♦Voltage Cut In: ±7.5% (213 - 247 VAC)
1.3 Authorized Service Centers
Please contact one of the following authorized Service Centers to coordinate
service on your Hart product:
Fluke Corporation, Hart Scientific Division
799 E. Utah Valley Drive
American Fork, UT 84003-9775
USA
Phone: [phone]
Telefax: +1.801.763.1010
5
1 Before You Start
Authorized Service Centers

E-mail: [email protected]
Fluke Nederland B.V.
Customer Support Services
Science Park Eindhoven 5108
5692 EC Son
NETHERLANDS
Phone: [phone]
Telefax: [phone]
E-mail: [email protected]
Fluke Int'l Corporation
Service Center - Instrimpex
Room 2301 Sciteck Tower
22 Jianguomenwai Dajie
Chao Yang District
Beijing 100004, PRC
CHINA
Phone: [phone]
Telefax: [phone]
E-mail: [email protected]
Fluke South East Asia Pte Ltd.
Fluke ASEAN Regional Office
Service Center
60 Alexandra Terrace #03-16
The Comtech (Lobby D)
118502
SINGAPORE
Phone: [phone]
Telefax: [phone]
E-mail: [email protected]
When contacting these Service Centers for support, please have the following
information available:
•Model Number
7341 Calibration Bath
User’s Guide
6

•Serial Number
•Voltage
•Complete description of the problem
7
1 Before You Start
Authorized Service Centers

2 Introduction
The Fluke’s Hart Scientific’s 7341 is a compact constant temperature bath use-
ful in temperature calibration and other applications requiring stable tempera-
tures. An innovative state of the art solid-state temperature controller has been
incorporated which maintains the bath temperature with extreme stability. The
temperature controller uses a micro-controller to execute the many operating
functions.
User interface is provided by the 8-digit LED display and four key-switches.
Digital remote communications is standard with an RS-232 and optional with
an IEEE-488 interface.
The 7341 bath was designed to be compact and low cost without compromising
performance. The 7341 bath operates over a wide temperature range from
–40°C to 150°C. The refrigeration permits sub-ambient temperature control.
The 7341 features:
•Rapid heating and cooling
•RS-232 (standard) and IEEE-488 (optional)
•Temperature scan rate control
•Ramp and soak functions
•Compact size
•Eight set-point memory
•Adjustable readout in °C or °F
•Automatic refrigeration control
9
2 Introduction

3 Specifications and Environmental
Conditions
3.1 Specifications
Range –45°C to 150°C
Stability (2 sigma) ±0.005°C at –40°C (ethanol)
±0.005°C at 25°C (water)
±0.007°C at 150°C (5012 oil)
Uniformity ±0.007°C at –40°C (ethanol)
±0.007°C at 25°C (water)
±0.010°C at 150°C (5012 oil)
Heating Time
†
120 minutes, from 25°C to 150°C (5012 oil @ 115V)
Cooling Time 120 minutes, from 25°C to –40°C (ethanol)
Stabilization Time 15-20 minutes
Temperature Setting Digital display with push-button entry
Set-point Resolution 0.01°; 0.00018° in high resolution
Display Temperature Resolution 0.01°
Digital Setting Accuracy ±1°C
Digital Setting Repeatability ±0.01°C
Heater 700 Watts @ 115V (230V) Nominal
Access Opening 6.8" x 4.7" (172 x 119 mm)
Immersion Depth 18" (457 mm) without liquid-in-glass thermometer cal kit
19" (482 mm) with liquid-in-glass thermometer cal kit
Wetted Parts 304 Stainless Steel
Power
†
115 VAC (±10%), 60 Hz, 16 A, 1660 VA
[230 VAC (±10%), 50 Hz, 8 A, 1450 VA, optional]
Note: If the voltage is outside ±10%, the compressor may be dam-
aged. Check the back panel label for the correct voltage and frequency
prior to energizing the instrument.
System Fuse 115V: 20A 250V slow blow
230V: 10A 250V slow blow
Volume 4.2 gal. (15.9 liters)
Weight 150 lb. (68 kg)
Size(wxf–bxh) 14" W x 31" D x 42" H (356 x 788 x 1067mm); 37" (940 mm) from floor
to tank access opening
Safety OVERVOLTAGE (Installation) CATEGORY II, Pollution Degree 2 per
IEC 1010-1
Refrigeration R-507 single stage
Interface Package RS-232 included, IEEE-488 optional
†
Rated at listed 115 V (or optional 230 V).
11
3 Specifications and Environmental Conditions
Specifications

3.2 Environmental Conditions
Although the instrument has been designed for optimum durability and trou-
ble-free operation, it must be handled with care. The instrument should not be
operated in an excessively dusty or dirty environment. Maintenance and clean-
ing recommendations can be found in the Maintenance Section of this manual.
The instrument operates safely under the following conditions:
•temperature range: 5–40°C (41–104°F)
•ambient relative humidity: maximum 80% for temperatures < 31°C de-
creasing linearly to 50% at 40°C
•pressure: 75kPa - 106kPa
•mains voltage within ±10% of nominal
•vibrations in the calibration environment should be minimized
•altitudes less than 2000 meters
•indoor use only
7341 Calibration Bath
User’s Guide
12

4 Quick Start
CAUTION: Read Section 6 entitled BATH USE before placing the bath in
service.
This chapter gives a brief summary of the steps required to set up and operate
the bath. This should be used as a general overview and reference and not as a
substitute for the remainder of the manual. Please read Section 5, Installation,
through Section 8, General Operation, carefully before operating the bath.
4.1 Unpacking
Unpack the bath carefully and inspect it for any damage that may have oc-
curred during shipment. If there is shipping damage, notify the carrier immedi-
ately. Verify that all components are present:
•7341 Bath
•Access Hole Cover
•Fluid Expansion Reservoir with Cover
•User's Guide
•RS-232 Cable
•Report of Test
•Drain Valve
•9930 Interface-it Software and User's Guide
•Tipping Prevention Bracket, including mounting hardware for wood or
concrete floor
•2019-DCB Kit, Liquid-in-Glass (LIG) Adapter and Carousel (optional)
•2069 Scope, Liquid-in-Glass (LIG) with mounts (optional)
If you are missing any item, please call an Authorized Service Center. To locate
an Authorized Service Center near you see Section 1.3 on page 5.
4.2 Set Up
WARNING: The instrument is equipped with a soft cutout (user settable
firmware) and a hard cutout (set at the factory). Check the flash point,
boiling point, or other fluid characteristic applicable to the circumstances
of the instrument operation. Ensure that the soft cutout is adjusted to the
fluid characteristics of the application. As a guideline, the soft cutout
should be set 10°C to 15°C below the flash point of the bath fluid. See
Section 8.1, Heat Transfer Fluid, for specific information on bath fluids
and Section 9.10, Cutout.
13
4 Quick Start
Unpacking

Set up of the bath requires careful unpacking and placement of the bath, filling
the bath with fluid, and connecting power. Consult Section 5, Installation, for
detailed instructions for proper installation of the bath. Be sure to place the
bath in a safe, clean and level location. Refer to Section 5.3, Tipping Prevention
Bracket, for Tipping Prevention Bracket installation instructions.
Fill the bath tank with an appropriate liquid. Be sure to select the correct fluid
for the temperature range of the calibration. Bath fluids should be selected to
operate safely with adequate thermal properties to meet the application require-
ments. For operation at moderate bath temperatures, clean distilled water works
well. Carefully pour the fluid into the bath tank through the large rectangular
access hole above the tank avoiding spilling any fluid.
CAUTION: When filling the tank, ensure the immersion coils are com-
pletely covered. DO NOT FILL ABOVE THE STIR BAFFLE. See Figure 1.
7341 Calibration Bath
User’s Guide
14
MIN FILL
Maximum Fill Level
Top of Baffle
Minimum Fill
Level Line
Figure 1 Stir Baffle Fill Levels