Fluke 7341 User manual

August 2012
© 2012 Fluke Corporation. All rights reserved. Specifications are subject to change without notice.
All product names are trademarks of their respective companies.
7341
Calibration Bath
Users Guide
Via Acquanera, 29 22100 Como
tel. 031.526.566 (r.a.) fax 031.507.984
[e-mail] www.calpower.it

LIMITED WARRANTY AND LIMITATION OF LIABILITY
Each Fluke product is warranted to be free from defects in material and workmanship under normal use and
service. The warranty period is one year and begins on the date of shipment. Parts, product repairs, and
services are warranted for 90 days. This warranty extends only to the original buyer or end-user customer of
a Fluke authorized reseller, and does not apply to fuses, disposable batteries, or to any product which, in
Fluke's opinion, has been misused, altered, neglected, contaminated, or damaged by accident or abnormal
conditions of operation or handling. Fluke warrants that software will operate substantially in accordance
with its functional specifications for 90 days and that it has been properly recorded on non-defective media.
Fluke does not warrant that software will be error free or operate without interruption.
Fluke 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 Fluke. Warranty support is
available only if product is purchased through a Fluke authorized sales outlet or Buyer has paid the
applicable international price. Fluke reserves the right to invoice Buyer for importation costs of
repair/replacement parts when product purchased in one country is submitted for repair in another country.
Fluke's warranty obligation is limited, at Fluke's option, to refund of the purchase price, free of charge repair,
or replacement of a defective product which is returned to a Fluke authorized service center within the
warranty period.
To obtain warranty service, contact your nearest Fluke authorized service center to obtain return
authorization information, then send the product to that service center, with a description of the difficulty,
postage and insurance prepaid (FOB Destination). Fluke assumes no risk for damage in transit. Following
warranty repair, the product will be returned to Buyer, transportation prepaid (FOB Destination). If Fluke
determines that failure was caused by neglect, misuse, contamination, alteration, accident, or abnormal
condition of operation or handling, including overvoltage failures caused by use outside the product’s
specified rating, or normal wear and tear of mechanical components, Fluke will provide an estimate of 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 IMPLIED WARRANTY
OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. FLUKE SHALL NOT BE LIABLE
FOR ANY SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES OR LOSSES,
INCLUDING LOSS OF DATA, ARISING FROM ANY CAUSE OR 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 or other
decision-maker of competent jurisdiction, such holding will not affect the validity or enforceability of any other
provision.
Fluke Corporation
P.O. Box 9090
Everett, WA 98206-9090
U.S.A.
Fluke Europe B.V.
P.O. Box 1186
5602 BD Eindhoven
The Netherlands
11/99
To register your product online, visit register.fluke.com

i
Table of Contents
Chapter Title Page
1 Before You Start .................................................................................. 1-1
Symbols Used .................................................................................................... 1-3
Safety Information ............................................................................................. 1-4
Authorized Service Centers ............................................................................... 1-7
2 Introduction ......................................................................................... 2-1
3 Specifications and Environmental Conditions ................................. 3-1
Specifications..................................................................................................... 3-3
Environmental Conditions ................................................................................. 3-4
4 Quick Start ........................................................................................... 4-1
Unpacking.......................................................................................................... 4-3
Set Up ................................................................................................................ 4-3
Power ................................................................................................................. 4-5
Setting the Temperature..................................................................................... 4-5
5 Installation ........................................................................................... 5-1
Moving or Uncrating the Bath ........................................................................... 5-3
Bath Environment .............................................................................................. 5-3
Tipping Prevention Bracket Installation ............................................................ 5-3
Installation On A Wood Floor....................................................................... 5-3
Installation On a Concrete Floor ................................................................... 5-4
Installation Of The Bath ................................................................................ 5-4
“Dry-out” Period................................................................................................ 5-4
Bath Preparation and Filling .............................................................................. 5-5
Power ................................................................................................................. 5-5
6 Bath Use............................................................................................... 6-1
General............................................................................................................... 6-3
Comparison Calibration..................................................................................... 6-3
Calibration of Multiple Probes........................................................................... 6-4

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Users Guide
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7 Parts and Controls .............................................................................. 7-1
Front Control Panel............................................................................................ 7-3
Back Panel ......................................................................................................... 7-3
Fluid Expansion Reservoir................................................................................. 7-3
8 General Operation ............................................................................... 8-1
Heat Transfer Fluid............................................................................................ 8-3
Temperature Range ....................................................................................... 8-3
Viscosity........................................................................................................ 8-3
Specific Heat ................................................................................................. 8-3
Thermal Conductivity.................................................................................... 8-3
Thermal Expansion........................................................................................ 8-3
Electrical Resistivity...................................................................................... 8-4
Fluid Lifetime................................................................................................ 8-4
Safety............................................................................................................. 8-4
Cost................................................................................................................ 8-5
Commonly Used Fluids................................................................................. 8-5
Water......................................................................................................... 8-5
Ethylene Glycol......................................................................................... 8-5
Mineral Oil................................................................................................ 8-5
Silicone Oil ............................................................................................... 8-6
Fluid Characteristics Charts........................................................................... 8-6
Limitations and Disclaimer ....................................................................... 8-6
About the Chart ......................................................................................... 8-8
Stirring ............................................................................................................... 8-10
Power ................................................................................................................. 8-10
Heater................................................................................................................. 8-10
Temperature Controller...................................................................................... 8-10
Refrigeration ...................................................................................................... 8-11
9 Controller Operation ........................................................................... 9-1
Bath Temperature .............................................................................................. 9-3
Reset Cutout....................................................................................................... 9-3
Temperature Set-point ....................................................................................... 9-5
Programmable Set-points .............................................................................. 9-5
Set-point Value.............................................................................................. 9-5
Set-point Vernier ........................................................................................... 9-6
Scan.................................................................................................................... 9-6
Scan Control .................................................................................................. 9-6
lScan Rate...................................................................................................... 9-6
Temperature Scale Units.................................................................................... 9-7
Ramp and Soak Program ................................................................................... 9-7
Number of Program Set-points...................................................................... 9-7
Set-points....................................................................................................... 9-8
Program Soak Time....................................................................................... 9-8
Program Function Mode................................................................................ 9-8
Program Control ............................................................................................ 9-9
Secondary Menu ................................................................................................ 9-9
Heater Power...................................................................................................... 9-9
Proportional Band .............................................................................................. 9-10
Cutout ................................................................................................................ 9-12
Controller Configuration.................................................................................... 9-13
Probe Parameters ............................................................................................... 9-13
R0 ..................................................................................................................
9-13

Contents (continued)
iii
ALPHA.......................................................................................................... 9-13
Operating Parameters......................................................................................... 9-13
Cutout Reset Mode ........................................................................................ 9-13
Cooling Mode................................................................................................ 9-14
Hot Gas Bypass Mode ................................................................................... 9-14
Serial Interface Parameters ................................................................................ 9-15
Baud Rate ...................................................................................................... 9-15
Sample Period................................................................................................ 9-15
Duplex Mode................................................................................................. 9-15
Linefeed......................................................................................................... 9-16
IEEE-488 Parameters......................................................................................... 9-16
IEEE-488 Address ......................................................................................... 9-16
Transmission Termination............................................................................. 9-17
Calibration Parameters....................................................................................... 9-17
CTO ............................................................................................................... 9-17
CO and CG .................................................................................................... 9-17
H and L.......................................................................................................... 9-17
HGbt .............................................................................................................. 9-17
10 Digital Communication Interface ....................................................... 10-1
Serial Communications...................................................................................... 10-3
Wiring............................................................................................................ 10-3
Setup.............................................................................................................. 10-3
Baud Rate.................................................................................................. 10-4
Sample Period ........................................................................................... 10-4
Duplex Mode............................................................................................. 10-4
Linefeed .................................................................................................... 10-4
Serial Operation............................................................................................. 10-4
IEEE-488 Communication (optional) ................................................................ 10-4
Setup.............................................................................................................. 10-5
IEEE-488 Address..................................................................................... 10-5
Transmission Termination ........................................................................ 10-5
IEEE-488 Operation ...................................................................................... 10-5
Interface Commands .......................................................................................... 10-5
Cooling Control ................................................................................................. 10-5
11 Calibration Procedure......................................................................... 11-1
Calibration Points .............................................................................................. 11-3
Measuring the Set-point Error ........................................................................... 11-3
Computing R0 and ALPHA............................................................................... 11-3
Calibration Example .......................................................................................... 11-4
12 Maintenance......................................................................................... 12-1
13 Troubleshooting .................................................................................. 13-1
Troubleshooting ................................................................................................. 13-3
Comments .......................................................................................................... 13-6
EMC Directive............................................................................................... 13-6
Immunity Testing ...................................................................................... 13-6
Emission Testing....................................................................................... 13-6
Low Voltage Directive (Safety) .................................................................... 13-6

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Users Guide
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v
List of Tables
Table Title Page
1-1. International Electrical Symbols ............................................................................ 1-3
3-1. Specifications ......................................................................................................... 3-3
8-1. Various Bath Fluids and Their Properties .............................................................. 8-7
9-1. Program Mode Setting Actions.............................................................................. 9-9
9-2. Typical Proportional Band Settings for Various Fluids ......................................... 9-11
10-1. Interface Command Summary ............................................................................... 10-6

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Users Guide
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vii
List of Figures
Figure Title Page
4-1. Stir Baffle Fill Levels............................................................................................. 4-4
5-1. Tipping Prevention Bracket Installation ................................................................ 5-4
7-1. Front Control Panel ................................................................................................ 7-3
8-1. Chart of Various Bath Fluids and Their Properties................................................ 8-9
9-1. Controller Operation Flowchart ............................................................................. 9-4
9-2. Bath Temperature Fluctuation At Various Proportional Band Settings ................. 9-10
10-1. Serial Communications Cable Wiring.................................................................... 10-3
11-1. Calibration Example............................................................................................... 11-4

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Users Guide
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1-1
Chapter 1
Before You Start
Title Page
Symbols Used ...................................................................................................... 1-3
Safety Information ............................................................................................... 1-4
Authorized Service Centers ................................................................................. 1-7

7341
Users Guide
1-2

Before You Start
Symbols Used 1
1-3
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.
Table 1-1. International Electrical Symbols
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)
OOff
IOn
Canadian Standards Association
CAT II
OVERVOLTAGE (Installation) CATEGORY II, Pollution Degree 2 per IEC1010-1 refers 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.
C-TIC Australian EMC mark
The European Waste Electrical and Electronic Equipment (WEEE) Directive (2002/96/EC)
mark.

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Users Guide
1-4
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 instrument being
used.
Warning
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 Bath Preparation
and Filling in Chapter 5 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-humid 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 requirements 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 applying power such
as storage in a low humidity temperature chamber
operating at 50°C for 4 hours or more.
•DO NOT operate high temperature baths (500°C) near
flammable materials. Extreme temperatures could ignite the
flammable material.
•Overhead clearance is required. Do not place the
instrument under a cabinet or other structure. Always leave
enough clearance to allow for safe and easy insertion and
removal of probes.

Before You Start
Safety Information 1
1-5
•The instrument is intended for indoor use only.
•The bath is a precision instrument. Although it has been
designed for optimum 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 compressor,
it may require two people to safely move the bath. The area
containing the compressor will be heavier than the rest of
the bath. DO NOT move a bath filled with fluid (see Moving
or Uncrating the Bath in Chapter 5).
BURN HAZARD:
•Extremely cold temperatures may be present in this
equipment. Freezer burns and frostbite may result if
personnel fail to observe safety precautions.
•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 inserted 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 expanding fluid rates
from heating only. Fill tank only until the level reaches the
top of the baffle (see Figure 4-1).
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 ordinances. 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
rating and type. If you have questions, contact an Authorized
Service Center (see Authorized Service Centers in Chapter 1).
•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.

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Users Guide
1-6
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 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 Transfer Fluid (Chapter 8), for specific
information on bath fluids and Cutout (Chapter 9).
Caution
•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 4-1).
•DO NOT overfill the bath. Overflowing fluid may damage
the electrical system. See Bath Preparation and Filling
(Chapter 5) for specific instructions.
•Read Chapter 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 Fluid Expansion
Reservoir (Chapter 7) for more information on Fluid
Expansion Reservoir use.
•No matter what fluid is used, DO NOT exceed the
recommended fluid viscosity.
•DO NOT change the values of the bath calibration
constants from the factory 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 parameters.
•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.

Before You Start
Authorized Service Centers 1
1-7
•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 instruments 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 periodically. Accumulation of dust and dirt on the
condenser will result in premature failure of the
compressor.
•Bath or compressor lifetime may be affected by:
oCycling the heat source through extreme temperature ranges (the
full temperature limit of the heat source). Cycling the instrument
can cause excessive stress on the compressors. Compressor
manufacturers recommend, for longest lifetime, that the
instrument be set at one temperature and left on at that
temperature.
oTurning the instrument on and off frequently adds wear and tear
to the compressor.
Authorized Service Centers
Please contact one of the following authorized Service Centers to coordinate service on
your Fluke product:
Fluke Corporation
799 E. Utah Valley Drive
American Fork, UT 84003-9775
USA
Phone: [phone]
Telefax: +1.801.763.1010
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]

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Users Guide
1-8
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
•Serial Number
•Voltage
•Complete description of the problem

2-1
Chapter 2
Introduction
The Fluke’s 7341 is a compact constant temperature bath useful in temperature
calibration and other applications requiring stable temperatures. 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

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Users Guide
2-2