7037/7038/7040/7041
Calibration Bath
May 2016
© 2016 Fluke Corporation. All rights reserved. Specifications are subject to change without notice.
All product names are trademarks of their respective companies.
User's Guide
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
Table of Contents
Title Page
Before You Start .................................................................................... 1
Symbols Used ................................................................................... 1
Safety Information .............................................................................. 2
Cautions ............................................................................................ 5
How to Contact Fluke Calibration .......................................................... 6
Product Introduction .............................................................................. 7
Specifications ........................................................................................ 8
Environmental Conditions .................................................................. 9
Quick Start ............................................................................................. 9
Unpacking .......................................................................................... 9
Set Up ................................................................................................ 10
Power ................................................................................................ 10
Set the Temperature .......................................................................... 10
Installation ............................................................................................. 12
Bath Environment .............................................................................. 12
“Dry-out” Period ................................................................................. 12
Bath Preparation and Filling .............................................................. 12
Probe ................................................................................................. 13
Power ................................................................................................ 13
Bath Use ................................................................................................ 13
General .............................................................................................. 14
Comparison Calibration ..................................................................... 14
Calibration of Multiple Probes ............................................................ 15
Parts and Controls ................................................................................. 16
Front Control Panel ........................................................................... 16
Side Panel ......................................................................................... 17
Back Panel ........................................................................................ 19
Bath Tank and Lid ............................................................................. 20
General Operation ................................................................................. 22
Bath Fluid .......................................................................................... 22
Temperature Range ...................................................................... 22
Viscosity ........................................................................................ 22
Specific Heat ................................................................................. 22
Thermal Conductivity ..................................................................... 23
Thermal Expansion ........................................................................ 23
Electrical Resistivity ....................................................................... 23
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7037/7038/7040/7041
User's Guide
Fluid Lifetime ................................................................................. 23
Safety ............................................................................................ 23
Cost ............................................................................................... 24
Commonly Used Fluids ................................................................. 24
Fluid Characteristics Charts .......................................................... 25
About the Graph ............................................................................ 25
Stirring ............................................................................................... 29
Power ................................................................................................ 29
Heater ................................................................................................ 29
Cooling .............................................................................................. 30
Temperature Controller ..................................................................... 30
Controller Operation .............................................................................. 31
Bath Temperature .............................................................................. 31
Reset Cutout ...................................................................................... 31
Temperature Set-point ....................................................................... 33
Programmable Set-points .............................................................. 33
Set-point Value .............................................................................. 34
Set-point Vernier ............................................................................ 34
Temperature Scale Units ................................................................... 35
Secondary Menu ............................................................................... 35
Heater Power ..................................................................................... 36
Proportional Band .............................................................................. 36
Cutout ................................................................................................ 38
Controller Configuration ..................................................................... 39
Probe Parameters .............................................................................. 39
R0 .................................................................................................. 40
ALPHA ........................................................................................... 40
Operating Parameters ....................................................................... 40
Cutout Reset Mode ........................................................................ 40
Serial Interface Parameters ............................................................... 40
Baud Rate ...................................................................................... 41
Sample Period ............................................................................... 41
Duplex Mode ................................................................................. 42
Linefeed ......................................................................................... 42
IEEE-488 Parameters ........................................................................ 42
IEEE-488 Address ......................................................................... 43
Calibration Parameters ...................................................................... 43
CTO ............................................................................................... 43
BO and BG .................................................................................... 43
H and L .......................................................................................... 43
Digital Communication Interface ............................................................ 44
Serial Communications ...................................................................... 44
Wiring ............................................................................................ 44
Setup ............................................................................................. 45
Serial Operation ............................................................................. 46
IEEE-488 Communication (optional) ................................................. 46
Setup ............................................................................................. 46
IEEE-488 Operation ...................................................................... 46
Interface Commands ......................................................................... 46
Power Control Functions ................................................................... 49
Heater Control ............................................................................... 49
Cooling Control .............................................................................. 50
Full Remote Operation .................................................................. 50
Calibration Procedure ............................................................................ 51
Calibration Points .............................................................................. 51
ii
Contents (continued)
Measuring the Set-point Error ........................................................... 51
Computing R
and ALPHA ................................................................ 52
0
Calibration Example .......................................................................... 52
Maintenance .......................................................................................... 53
Troubleshooting ..................................................................................... 55
Troubleshooting Table ....................................................................... 55
Comments ......................................................................................... 58
EMC Directive ................................................................................ 58
Low Voltage Directive (Safety) ...................................................... 59
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7037/7038/7040/7041
User's Guide
iv
List of Tables
Table Title Page
1. Symbols ..................................................................................................... 1
2. Table of Various Bath Fluids and their Properties ..................................... 26
3. Proportional Band- Fluid Table .................................................................. 37
4. Interface Command Summary .................................................................. 47
5. Serial Power Control Functions ................................................................. 50
6. Remote Operation Ranges and Settings ................................................... 51
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7037/7038/7040/7041
User's Guide
vi
List of Figures
Figure Title Page
1. Bath Assembly .......................................................................................... 7
2. Front Panel ................................................................................................ 16
3. Refrigeration Side Panel Controls ............................................................. 17
4. Back Panel ................................................................................................ 19
5. Drain Location and Lid Options ................................................................. 21
6. Chart of Various Bath Fluids and their Properties ..................................... 28
7. Controller Operation Flow Chart ................................................................ 32
8. Bath Temperature Fluctuation at Various Proportional Band Settings ...... 37
9. Serial Cable Wiring .................................................................................... 44
10. Calibration Example .................................................................................. 53
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7037/7038/7040/7041
User's Guide
viii
Before You Start
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. Symbols
Symbol Description
X WARNING. HAZARDOUS VOLTAGE. Risk of electric shock.
W WARNING - RISK OF DANGER. Consult user documentation.
T
.
O
I
AC (Alternating Current)
AC-DC
DC
Double Insulated
PE Ground
Battery
Hot suface
Off
On
) Certified by CSA Group to North American safety standards.
Measurement Category II is applicable to test and measuring circuits connected directly
to utilization points (socket outlets and similar points) of the low-voltage MAINS
installation.
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7037/7038/7040/7041
User's Guide
P Conforms to European Union directives.
Conforms to relevant Australian EMC standards.
Fuse
à Conforms to relevant South Korean EMC Standards.
~
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
Table 2.
The following definitions apply to the terms “Warning” and “Caution”.
This product complies with the WEEE Directive marking requirements. The affixed label
indicates that you must not discard this electrical/electronic product in domestic
household waste. Product Category: With reference to the equipment types in the WEEE
Directive Annex I, this product is classed as category 9 "Monitoring and Control
Instrumentation" product. Do not dispose of this product as unsorted municipal waste.
“WARNING” identifies conditions and actions that may pose hazards to the user.
“CAUTION” identifies conditions and actions that may damage the instrument
being used.
XWWARNING
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 the Bath
Preparation and Filling section for specific instructions.
• Follow all safety guidelines listed in the user’s manual.
• Calibration Equipment should only be used by Trained
Personnel.
2
• If this equipment is used in a manner not specified by the
manufacturer, the protection provided by the equipment
may be impaired.
Calibration Bath
Before You Start
• 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 61010-1. 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.
• 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. This bath is not designed to be
portable. Therefore, moving the bath once it has been
installed should be kept to a minimum. Position the bath
before the tank is filled with fluid. DO NOT attempt to lift the
bath. Due to the weight of the compressor, it may require
four 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. This action could be
extremely dangerous and could result in personal injury to
the person moving the bath. The fluid can splash causing
injury or if the bath and cart tip, the fluid could cause
damage to the surrounding area and personal injury to
personnel.
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.
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7037/7038/7040/7041
User's Guide
ELECTRICAL HAZARD
• These guidelines must be followed to ensure that the safety
mechanisms in this instrument will operate properly. This
mains supply for the instrument must be capable of the
power requirements for the instrument as listed in the
Specifications section. 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 the How to Contact Fluke
Calibration section.
• 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 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 the Bath Fluid section, for specific
information on bath fluids and the Cutout section.
4
Calibration Bath
Before You Start
Cautions
WCAUTION
• Always operate the instrument in room temperatures listed in
the Environmental Conditions section. Allow sufficient air
circulation by leaving at least 15 cm (6 inches) of clearance
around the instrument.
• DO NOT overfill the bath. Overflowing fluid may damage the
electrical system. See the Bath Preparation and Filling section,
for specific instructions.
• Read the Bath Use section, before placing the bath into
service.
• DO NOT turn the bath on without fluid in the tank.
• 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.
• 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.
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7037/7038/7040/7041
User's Guide
COLD BATHS
• Refrigerated baths require that the condensing coil be cleaned
• This bath has been equipped with a brownout and over voltage
• Mode of Operation: This bath needs to be plugged into the line
• If a High/Low voltage condition exists for longer than
• Re-energization is automatic upon correction of the fault
periodically. Accumulation of dust and dirt on the condenser
will result in premature failure of the compressor.
protection device as a safety feature to protect the system
components.
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 another. Turning the bath ON or
OFF does not trigger the delay.
5 seconds, the bath de-energizes. An amber indicator on the
back panel lights when this condition exists.
condition and after a delay cycle of about 2 minutes. If a fault
condition exists upon application of power, the bath will not
energize.
o Under and Over Voltage Protection at 115 VAC
o Voltage Cutout: ±12.5% (101 - 129 VAC)
o Voltage Cut In: ±7.5% (106 - 124 VAC)
o Under and Over Voltage Protection at 230 VAC
o Voltage Cutout: ±12.5% (203 - 257 VAC)
o Voltage Cut In: ±7.5% (213 - 247 VAC)
How to Contact Fluke Calibration
To contact Fluke Calibration, call one of the following telephone numbers:
• Technical Support USA: 1-877-355-3225
• Calibration/Repair USA: 1-877-355-3225
• Canada: 1-800-36-FLUKE (1-800-363-5853)
• Europe: +31-40-2675-200
• Japan: +81-3-6714-3114
• Singapore: +65-6799-5566
• China: +86-400-810-3435
• Brazil: +55-11-3759-7600
6
• Anywhere in the world: +1-425-446-6110
Calibration Bath
Product Introduction
To see product information and download the latest manual supplements, visit Fluke
Calibration’s website at www.flukecal.com.
To register your product, visit http://flukecal.com/register-product.
When contacting Fluke Calibration, please have the following information:
• Model Number
• Serial Number
• Voltage
• Complete description of the problem
Product Introduction
The Fluke Calibration Model 7037/7038/7040/7041 are very precise constant
temperature baths. An innovative state of the art solid-state temperature
controller has been incorporated which maintains the bath temperature with
extreme stability. The controller uses a microcontroller to execute the many
operating functions.
User interface is provided by the 8-digit LED display and four key-switches.
Digital remote communications is optionally available with a RS-232 or IEEE-488
interface.
There are two lids available for the 7037 and 7040 baths; the standard lid with a
rectangular access hole and an optional lid with a recirculation pump (see
Figure 5).
Figure 1. Bath Assembly
figure 1.eps
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7037/7038/7040/7041
User's Guide
Specifications
Specifications 7037 7038 7040 7041
Operating Range –40°C to
110°C
Stability ±0.002°C at -40°C (ethanol)
±0.0015°C at 25°C (water)
±0.003°C at 100°C (oil 5012)
Uniformity ±0.004°C at -40°C (ethanol)
±0.002°C at 25°C (water)
±0.004°C at 100°C (oil 5012)
Temperature Digital display with push-button data entry
Set-Point 0.01°C; high-resolution mode, 0.00007°C
Display 0.01°C
Digital Setting
Accuracy
Digital Setting
Repeatability
Heater Power 500 and 1000 Watts
Power 115 VAC (±10%), 60 Hz, 2000 W
±1.0°C
±0.01°C
230 VAC (±10%), 60 Hz, 2000 W
230 VAC (±10%), 50 Hz, 2000 W
Note: If voltage is outside ±10% VAC, the compressor may be damaged. Check the
back panel label for the correct voltage and frequency prior to energizing the
instrument.
–10°C to
110°C
–40°C to 110°C
8
System Fuse 115 VAC: 20 A 250 V slow blow
230 VAC: 10 A 250 V slow blow
Heater Fuse 115 VAC: 10 A 250 V fast blow
230 VAC: 6 A 250 V fast blow
Work Area
(HxWxD)
Tank Capacity 41.6 liters 56.6 liters 26.5 liters (7 gal) 39.3 liters (10.4 gal)
Wetted Parts 304 stainless steel
Exterior
Dimensions
(HxWxD)
Weight 68 kg (150 lbs) 63.5 kg (140 lbs)
Safety OVERVOLTAGE (Installation) CATEGORY II, Pollution Degree 2 per IEC61010-1
45.7 x 29.2 x
16.2 cm
(18 x 11.5 x
6.375
77.5 x 76.8 x 48.3 cm
(30.5 x 30.25 x 19 inches)
45.7 x 25.4 x
12.7 cm
(18 x 10 x 5
inches)
30.5 x 25.4 x 12.7 cm
(12 x 10 x 5 inches)
62.2 x 76.8 x 48.3 cm
(24.5 x 30.25 x 19 inches)
33 x 32.4 x 18.4 cm
(13 x 12.75 x 7.25
inches)
Calibration Bath
Quick Start
Environmental Conditions
Although the instrument has been designed for optimum durability and troublefree operation, it must be handled with care. The instrument should not be
operated in an excessively dusty or dirty environment. Maintenance and cleaning
recommendations can be found in the Maintenance Section of this manual.
The instrument operates safely under the following conditions:
• ambient temperature range: 5 – 50 °C (41 – 122 °F)
• ambient relative humidity: maximum 80% for temperature <31°C, decreasing
linearly to 50 % at 40 °C
• pressure: 75 kPa – 106 kPa
• mains voltage within ± 10 % of nominal
• vibrations in the calibration environment should be minimized
• altitude less than 2,000 meters
• indoor use only
Quick Start
READ the Bath Use section before placing the bath in service.
Incorrect handling can damage the bath and void the warranty.
This section 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 Installation through
General Operation carefully before operating the bath.
Unpacking
Unpack the bath carefully and inspect it for any damage that may have occurred
during shipment. If there is shipping damage, notify the carrier immediately.
Verify that all components are present:
• 7037/7038/7040/7041 Bath
• Controller Probe
• Access Hole Cover
• User’s Guide
• Report of Test
• Drain Elbow
If you are missing any item, please contact Fluke Calibration.
WCaution
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7037/7038/7040/7041
User's Guide
Set Up
Set up of the bath requires careful unpacking and placement of the bath, filling
the bath with fluid, installing the probe and connecting power. Consult the
Installation section for detailed instructions for proper installation of the bath. Be
sure to place the bath in a safe, clean and level location.
Fill the bath tank with an appropriate liquid. 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. The fluid must not exceed a height of 1/2 inch below the bath
lid.
The control probe must be inserted through the lid into the bath and plugged into
the socket at the back of the bath.
Power
Plug the bath power cord into a mains outlet of the proper voltage, frequency,
and current capability (see the Specifications section). Refer to and read the
Caution at the front of the manual concerning brownout and over voltage
protection.
WCaution
Check the back panel label for the correct voltage and
frequency prior to energizing the unit.
Set the “HEATER” switch on the front panel to position “LOW” and turn the bath
on using the front panel “POWER” switch. The bath will turn on and begin to heat
or cool to reach the previously programmed temperature set-point. The front
panel LED display will indicate the actual bath temperature.
Set the Temperature
In the following discussion a solid box around the word SET, UP, EXIT or DOWN
indicates the panel button while the dotted box indicates the display reading.
Explanation of the button or display reading are to the right of each button or
display value.
To view or set the bath temperature set-point proceed as follows. The front panel
LED display normally shows the actual bath temperature.
24.68 C
When “SET” is pressed the display shows the set-point memory that is currently
being used and its value. Eight set-point memories are available.
Access set-point selection
1.
25.0
Bath temperature display
Set-point 1, 25.0 °C currently used
10
Calibration Bath
Quick Start
Press “SET” to select this memory and access the set-point value.
Access set-point value
C
C
25.00
30.00
Press “UP” or “DOWN” to change the set-point value.
Increment display
Press “SET” to accept the new value and display the vernier value. The bath
begins heating or cooling to the new set-point.
Current value of set-point 1, 25.00 °C
Store new set-point, access vernier
0.00000
Press “EXIT” and the bath temperature will be displayed again.
Return to the temperature display
The bath heats or cools until it reaches the new set-point temperature. Set the
heater switch to position “HIGH” to allow the bath to more quickly reach a higher
temperature. The “HIGH” setting may be necessary to reach higher temperatures
and control at high temperatures.
When setting the set-point temperature be careful not to exceed the temperature
limit of the bath fluid. The over-temperature cut-out should be correctly set to
prevent this from happening. See the Cutout section.
If operating the bath below 45 °C set the COOLING power switch to ON. The
cooling temperature may require adjustment to provide the proper amount of
cooling. See the Cooling section.
To obtain optimum control stability adjust the proportional band as discussed in
the Proportional Band section.
24.73 C
Current vernier value
Bath temperature display
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7037/7038/7040/7041
User's Guide
Installation
This bath is not designed to be portable. Therefore, moving the bath once it has
been installed should be kept to a minimum.
If the bath is going to be placed in an area where it will need to be moved
frequently, a special cart can be designed to accommodate the bath making the
bath much more portable. Fluke Calibration sells carts designed for these baths.
However, even with a cart the bath should not be moved full of fluid. The fluid
can splash causing injury or if the bath and cart tip, the fluid could cause damage
to the surrounding area and personal injury to personnel.
WCaution
Read the Bath Use section before placing the bath in service.
Incorrect handling can damage the bath and void the warranty.
WWarning
Never move a bath that is full of fluid. This action could be
extremely dangerous and could result in personal injury to the
person moving the bath.
If the bath must be moved, be sure to drain the fluid to prevent any injury. The
side of the bath with the compressor is heavier than the tank side. To safely
move the bath, two people are required.
Bath Environment
The bath is a precision instrument which should be located in an appropriate
environment. The location should be free of drafts, extreme temperatures and
temperature changes, dirt, etc. The surface where the bath is placed must be
level.
If used at higher temperatures where fluid vaporization is significant, a fume hood
should be used.
“Dry-out” Period
Before initial use, after transport, and any time the instrument has not been
energized for more than 10 days, the bath will need to be energized for a “dryout” period of 1-2 hours before it can be assumed to meet all of the safety
requirements of the IEC 1010-1.
Bath Preparation and Filling
The bath is not provided with a fluid. Various fluids are available from Fluke
Calibration and other sources. Depending on the desired temperature range, any
of the following fluids, as well as others, may be used in the bath:
• Water
• Ethylene Glycol/Water
12
• Methanol
• Mineral oil
• Silicone oil
Fluids are discussed in detail in the Bath Fluid section.
Calibration Bath
Bath Use
Remove any access hole cover from the bath and check the tank for foreign
matter (dirt, remnant packing material, etc.). Use clean unpolluted fluid. Carefully
fill the bath through the large square access hole to a level that will allow for
stirring and thermal expansion. The fluid should never exceed a height of
12.7 mm (1/2 inch) below the top of the tank. Carefully monitor the bath fluid level
as the bath temperature rises to prevent overflow or splashing. Remove excess
fluid if necessary and with caution if the fluid is hot.
Be careful to prevent bath fluid from spilling on the stirring motor while filling.
WCaution
Underfilling may reduce bath performance and may possibly
damage the bath heater.
Probe
Inspect the bath controller probe. This probe should not be bent or damaged in
any way. Reasonable caution should be used in handling this probe as it
contains a precision platinum sensor and is mechanically shock sensitive.
Dropping, striking, or other physical shock may cause a shift in resistance in the
probe resulting in diminished bath accuracy. If damaged, the probe can be
replaced by contacting an Authorized Service Center for assistance.
Insert the probe into the 6.35 mm (1/4 inch) probe hole at the top left side of the
bath lid. The tip of the probe must be well immersed in the fluid. The probe
connector is plugged into the rear of the bath into the socket labeled “PROBE”.
Power
With the bath power switch off, plug the bath into an AC mains outlet of the
appropriate voltage, frequency, and current capacity (see the Specifications
section). Refer to and read the Caution at the front of the manual concerning
brownout and over voltage protection.
Check the back panel label for the correct voltage and
frequency prior to energizing the unit.
Be sure the stirring motor power cord is plugged into the “STIRRER” socket at
the back of the bath.
Bath Use
READ BEFORE PLACING THE BATH IN SERVICE.
The information in this section is for general information only. It is not designed to
be the basis for calibration laboratory procedures. Each laboratory will need to
write their own specific procedures.
WCaution
13
7037/7038/7040/7041
User's Guide
General
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 requirements. Also, be aware that some fluids
expand and could overflow the bath if not watched. Refer to the General
Operation section for information specific to fluid selection and to the MSDS
sheet specific to the fluid selected. Generally, baths are set to one temperature
and used to calibrate probes only at that single temperature. This means that
the type of bath fluid does not have to change. Additionally, the bath can be left
energized reducing the stress on the system.
The bath generates extreme temperatures. Precautions must be taken to
prevent personal injury or damage to objects. Probes may be extremely hot or
cold when removed from the bath. Cautiously handle probes to prevent
personal injury. Carefully place probes on a heat/cold resistant surface or rack
until they are at room temperature. It is advisable to wipe the probe with a
clean soft cloth or paper towel before inserting it into another bath. This
prevents the mixing of fluids from one bath to another. If the probe has been
calibrated in liquid salt, carefully wash the probe in warm water and dry
completely before transferring it to another fluid. Always be sure that the
probe is completely dry before inserting it into a hot fluid. Some of the high
temperature fluids react violently to water or other liquid mediums. Be aware
that cleaning the probe can be dangerous if the probe has not cooled to room
temperature. Additionally, high temperature fluids may ignite the paper towels
if the probe has not been cooled.
For optimum accuracy and stability, allow the bath adequate stabilization time
after reaching the set-point temperature.
Comparison Calibration
Comparison calibration involves testing a probe (unit under test, UUT) against a
reference probe. After inserting the probes to be calibrated into the bath, allow
sufficient time for the probes to settle and the temperature of the bath to stabilize.
One of the significant dividends of using a bath rather than a dry-well to calibrate
multiple probes is that the probes do not need to be identical in construction. The
fluid in the bath allows different types of probes to be calibrated at the same time.
However, stem effect from different types of probes is not totally eliminated. Even
though all baths have horizontal and vertical gradients, these gradients are
minimized inside the bath work area. Nevertheless, probes should be inserted to
the same depth in the bath liquid. Be sure that all probes are inserted deep
enough to prevent stem effect. From research at Fluke Calibration, we suggest a
general rule-of-thumb for immersion depth to reduce the stem effect to a
minimum: 15 x the diameter of the UUT + the sensor length.
14
Calibration Bath
Bath Use
WCaution
Do not submerge the probe handles. If the probe handles get
too warm during calibration at high temperatures, a heat shield
could be used just below the probe handle. This heat shield
could be as simple as aluminum foil slid over the probe before
inserting it in the bath or as complicated as a specially
designed reflective metal apparatus.
When calibrating over a wide temperature range, better results can generally be
achieved by starting at the highest temperature and progressing down to the
lowest temperature.
Probes can be held in place in the bath by using probe clamps or drilling holes in
the access cover. Other fixtures to hold the probes can be designed. The object
is to keep the reference probe and the probe(s) to be calibrated as closely
grouped as possible in the working area of the bath. Bath stability is maximized
when the bath working area is kept covered.
In preparing to use the bath for calibration start by:
• Placing the reference probe in the bath working area.
• Placing the probe to be calibrated, the UUT, in the bath working area as close
as feasibly possible to the reference probe.
Calibration of Multiple Probes
Fully loading the bath with probes increases the time required for the
temperature to stabilize after inserting the probes. Using the reference probe as
the guide, be sure that the temperature has stabilized before starting the
calibration.
15
7037/7038/7040/7041
User's Guide
Parts and Controls
Front Control Panel
The following controls and indicators are present on the controller front panel
(see Figure 2 below):
the digital LED display
the control buttons
the bath on/off power switch
the control indicator light’
the heater power switch
the cooling power switch.
Figure 2. Front Panel
figure 2.eps
The digital display is an important part of the temperature controller because it
not only displays set and actual temperatures but also displays various bath
functions, settings, and constants. The display shows temperatures in values
according to the selected scale units °C or °F.
The control buttons (SET, DOWN, UP, and EXIT) are used to set the bath
temperature set-point, access and set other operating parameters, and access
and set bath calibration parameters.
A brief description of the functions of the buttons follows:
SET – Used to display the next parameter in a menu and to set parameters to
the displayed value.
DOWN – Used to decrement the displayed value of setable parameters.
UP – Used to increment the displayed value.
EXIT – Used to exit from a menu. When EXIT is pressed any changes made to
the displayed value will be ignored.
16
Calibration Bath
Parts and Controls
The on/off switch controls power to the entire bath assembly. It powers the
stirring motor and the bath controller/heater circuit.
The control indicator is a two color light emitting diode. This indicator lets the
user visually see the ratio of heating to cooling. When the indicator is red the
heater is on. When the indicator is green the heater is off and the bath is cooling.
The heater power switch is used to select the appropriate heater power levels for
heating and controlling the bath at various temperatures.
The cooling power switch controls power to the cooling compressor and cooling
fan.
Side Panel
The side panel has three features (see Figure 3):
the back pressure valve
the cooling temperature regulating valve
the cooling temp gauge.
With the interface option an extra cooling valve (HIGH) is provided.
Figure 3. Refrigeration Side Panel Controls
figure 3.eps
17
7037/7038/7040/7041
–
–
User's Guide
1. The back pressure valve adjustment is used to control the amount of
cooling supplied to the system. This valve reduces the cooling capacity by
restricting the flow of refrigerant to the bath, allowing the adjustment of
the heating to cooling percentage. Under normal operation the valve
should be fully open (counter clockwise).
2. The cooling temperature regulating valve is used to adjust the
temperature at which the refrigerant evaporates, which determines
cooling efficiency. Refer to the label below the gauge for approximate psi
and evaporative temperature settings. The following table is reproduced
from the label.
For this bath: Control Temperature Set the Cooling Temp. Valve to this
pressure
°C °F Nominal Cooling PSIG
40
–35 –31 3
–30 –22 5
25 –13 9
–20 –4 15
–15 5 22
–10 14 29
–5 23 38
0 32 48
5 41 60
10 50 72
15 59 87
20 68 90
25 77 90
30 86 90
35 95 90
DO NOT set the Cooling Pressure above 90 PSIG
40 0 to 3
3. The cooling temp gauge is used to indicate the pressure at which the
evaporating temperature is adequate. the cooling temp regulating valve is
used to adjust and then control this temperature. Interpolate for
temperatures in between those shown.
18
Calibration Bath
Parts and Controls
Back Panel
The back panel has six standard features and two optional features (see
Figure 4):
the probe connector
the stirrer power outlet
the power cord
the drain valve
the serial number
the RS-232 interface connector (optional)
the IEEE-488 interface connector (optional)
the mains out of range indicator. The system fuses are 20 amps for 115 V
operation and 10 amps for 230 V operation. These fuses are internal.
Figure 4. Back Panel
figure 4.eps
19
7037/7038/7040/7041
User's Guide
1. The probe connector in the back panel is used for the temperature
controller probe.
2. The stirrer power is provided for the stirring motor.
3. The power cord
4. A drain valve is provided for ease of removing the fluid media from the
bath. Always use a container of adequate size to hold the FULL LOAD of
fluid. Some oils are more easily drained at higher temperatures. (See
caution note in next section.)
5. The serial number is located on the upper right corner of the back panel.
The series is also stamped on this panel. When consulting with an
Authorized Service Center, use the model number and the serial number.
6. If the bath is supplied with a serial RS-232 interface, the interface cable is
attached to the back of the bath at the connector labeled “Serial Port”.
7. If the bath is supplied with a GPIB IEEE-488 interface, the interface cable
is attached to the back of the bath at the connector labeled “IEEE”.
8. The mains out of range indicator is on (red) when the line voltage is low.
See the Warnings in the Safety Information section for details.
Bath Tank and Lid
There are two different types of lids. They both have the same overall
dimensions but the optional lid (see Figure 5) has a recirculation pump and the
standard lid has a stirring motor with rectangular access hole. Their features are
described with reference to figure numbers as follows:
1. The top half of the latch attaches the lid to the bath. There are two latches
one on the front and one on the back.
2. The thermometer/liquid level is a hole in the lid for filling and removing of
liquid, checking liquid level and for mounting a thermometer. A hole may be
drilled in the rubber stopper supplied for inserting a thermometer into the
bath.
3. The rectangular access hole (standard lid) may be used to insert the users
device to be thermostatted. To obtain specified control levels this hole must
be covered to prevent thermal disturbance to the bath. Covers may be
purchased separately from Fluke Calibration.
4. The circulation inlet outlet (pump lid) is the access area or the inlet and outlet
for the circulation pump.
5. The stirrer/pump motor drives the stirring propeller to provide mixing of the
bath fluid. Proper mixing of the fluid is important for good constant
temperature stability. The stir motor power cord plugs into the back of the
bath at the power socket labeled “STIRRER”.
20
6. The probe hole is for the temperature controller probe. The probe must be in
this hole for the bath to operate.
7. A drain valve is provided for ease of removing the fluid media from the bath.
Always use a container of adequate size to hold the full load of fluid. Some
oils are more easily drained at higher temperatures. (See caution note
below.)
Calibration Bath
Parts and Controls
Figure 5. Drain Location and Lid Options
WWarning
Extreme caution must be maintained to prevent harm to the
user or the surrounding environment. Do not exceed a 120 °C
fluid temperature for draining. The valve could be damaged if
120 °C is exceeded.
Insulate the container from the floor or other objects that may
be damaged by high temperatures as required.
figure 5.eps
21
7037/7038/7040/7041
User's Guide
General Operation
Bath Fluid
Many fluids will work with your bath. Choosing a fluid requires consideration of
many important characteristics of the fluid. Among these are temperature range,
viscosity, specific heat, thermal conductivity, thermal expansion, electrical
resistivity, fluid lifetime, safety, and cost.
Temperature Range
One of the most important characteristics to consider is the temperature range of
the fluid. Few fluids work well throughout the complete temperature range of the
bath. The temperature at which the bath is operated must always be within the
safe and useful temperature range of the fluid. The lower temperature range of
the fluid is determined by the freeze point of the fluid or the temperature at which
the viscosity becomes too great. The upper temperature is usually limited by
vaporization, flammability, or chemical breakdown of the fluid. Vaporization of the
fluid at higher temperatures may affect temperature stability because of cool
condensed fluid dripping into the bath from the lid.
The bath temperature should be limited by setting the safety cut-out so that the
bath temperature cannot exceed the safe operating temperature limit of the fluid.
Viscosity
Viscosity is a measure of the thickness of a fluid, how easily it can be poured
and mixed. Viscosity affects the temperature stability of the bath. With low
viscosity, fluid mixing is better which creates a more uniform temperature
throughout the bath. This improves the bath response time which allows it to
maintain a more constant temperature. For good control the viscosity should
be less than 10 centistokes. 50 centistokes is about the upper limit of allowable
viscosity. Viscosities greater than this cause very poor control stability and
may also overheat or damage the stirring motor. With oils viscosity may vary
greatly with temperature.
When using fluids with higher viscosities the controller proportional band may
need to be increased to compensate for the reduced response time.
Otherwise the temperature may begin to oscillate.
Specific Heat
Specific heat is the measure of the heat storage ability of the fluid. Specific heat,
though to a lesser degree, also affects the control stability and the heating and
cooling rates. Generally, a lower specific heat causes slightly better control
stability and quicker heating and cooling. With fluids with higher specific heat the
controller may require a decreased proportional band to compensate for the
decrease in sensitivity of the bath temperature to heat input
22
Calibration Bath
General Operation
Thermal Conductivity
Thermal conductivity measures how easily heat flows through the fluid. Thermal
conductivity of the fluid affects the control stability, temperature uniformity, and
probe temperature settling time. Fluids with higher conductivity distribute heat
more quickly and evenly improving bath performance.
Thermal Expansion
Thermal expansion describes how the volume of the fluid changes with
temperature. Thermal expansion of the fluid used must be considered since the
increase in fluid volume as the bath temperature changes may cause overflow.
Excessive thermal expansion may also be undesirable in applications where
constant liquid level is important. Oils typically have significant thermal
expansion.
Electrical Resistivity
Electrical resistivity describes how well the fluid insulates against the flow of
electric current. In some applications, such as measuring the resistance of bare
temperature sensors, it may be important that little or no electrical leakage occur
through the fluid. In this case consider a fluid with very high resistivity.
Fluid Lifetime
Many fluids degrade over time because of evaporation, water absorption, gelling,
or chemical breakdown. Often the degradation becomes significant near the
upper temperature limit of the fluid.
Safety
When choosing a fluid always consider the safety issues associated. Obviously,
where there are extreme temperatures there can be danger to personnel and
equipment. Fluids may also be hazardous for other reasons. Some fluids may be
considered toxic. Contact with eyes, skin, or inhalation of vapors may cause
injury. A proper fume hood must be used if hazardous or bothersome vapors are
produced.
WWarning
Fluids at high temperatures may pose danger from BURNS,
FIRE, and TOXIC fumes. Use appropriate caution and safety
equipment.
Fluids may be flammable and require special fire safety equipment and
procedures. An important characteristic of the fluid to consider is the flash point.
The flash point is the temperature at which there is sufficient vapor given off so
that when there is sufficient oxygen present and an ignition source is applied the
vapor will ignite. This does not necessarily mean that fire will be sustained at the
flash point. The flash point may be either of the open cup or closed cup type.
Either condition may occur in a bath situation. The closed cup temperature is
always the lower of the two. The closed cup represents the contained vapors
inside the tank and the open cup represents the vapors escaping the tank.
Oxygen and an ignition source will be less available inside the tank.
Environmentally hazardous fluids require special disposal according to applicable
federal or local laws after use.
23
7037/7038/7040/7041
User's Guide
Cost
Cost of bath fluids may vary greatly, from cents per gallon for water to hundreds
of dollars per gallon for synthetic oils. Cost may be an important consideration
when choosing a fluid.
Commonly Used Fluids
Below is a description of some of the more commonly used fluids and their
characteristics.
Water
Water is often used because of its very low cost, availability, and excellent
temperature control characteristics. Water has very low viscosity and good
thermal conductivity and heat capacity which makes it among the best fluids for
control stability at low temperatures. Temperature stability is much poorer at
higher temperatures because water condenses on the lid, cools and drips into
the bath. Water is safe and relatively inert. The electrical conductivity of water
may prevent its use in some applications. Water has a limited temperature range,
from a few degrees above 0 °C to a few degrees below 100 °C. At higher
temperatures evaporation becomes significant. Water used in the bath should be
distilled or softened to prevent mineral deposits. Consider using an algaecide
chemical in the water to prevent contamination.
Ethylene Glycol
The temperature range of water may be extended by using a solution of 1 part
water and 1 part ethylene glycol (antifreeze). The characteristics of the ethylene
glycol-water solution are similar to water. Use caution with ethylene glycol since
the fluid is very toxic. Ethylene glycol must be disposed of properly.
Methanol
Methanol or methyl alcohol is often used at low temperatures below 0 °C.
Methanol is relatively inexpensive, has good control characteristics, and has a
low freeze point. Methanol is very toxic so care must be taken when using and
disposing of this fluid.
Mineral Oil
Mineral oil or paraffin oil is often used at moderate temperatures above the range
of water. Mineral oil is relatively inexpensive. At lower temperatures mineral oil is
quite viscous and control may be poor. At higher temperatures vapor emission
becomes significant. The vapors may be dangerous and a fume hood should be
used. As with most oils mineral oil expands as temperature increases so be
careful not to fill the bath too full that it overflows when heated. The viscosity and
thermal characteristics of mineral oil is poorer than water so temperature stability
will not be as good. Mineral oil has very low electrical conductivity. Use caution
with mineral oil since it is flammable and may also cause serious injury if inhaled
or ingested.
24
Calibration Bath
General Operation
Silicone Oil
Silicone oils are available which offer a much wider operating temperature range
than mineral oil. Like most oils, silicone oils have temperature control
characteristics which are somewhat poorer than water. The viscosity changes
significantly with temperature and thermal expansion also occurs. These oils
have very high electrical resistivity. Silicon oils are fairly safe. These oils are
relatively expensive.
Fluid Characteristics Charts
Table 2 and Figure 6 have been created to provide help in selecting a heat
exchange fluid media for your constant temperature bath. The charts provide
both a visual and numerical representation of most of the physical qualities
important in making a selection. The list is not all inclusive, many usable fluids
may not have been shown in this listing.
Limitations and Disclaimer
Every effort has gone into making these charts accurate, however, the data here
does not imply any guarantee of fitness of use for a particular application.
Working near the limits of a property such as the flash point or viscosity limit can
compromise safety or serviceability. Sources of information sometimes vary for
particular properties. Your company’s safety policies as well as personal
judgment regarding flash points, toxicity, etc. must also be considered. You are
responsible for reading the Material Safety Data Sheets and making a judgment
here. Cost may require some compromises as well. Fluke Calibration cannot be
liable for the suitability of application or for any personal injury, damage to
equipment, product or facilities in using these fluids.
The charts include information on a variety of fluids which are often used as heat
transfer fluid in baths. Because of the temperature range some fluids may not be
useful with your bath.
About the Graph
The fluid graph visually illustrates some of the important qualities of the fluids
shown.
Temperature Range: The temperature scale is shown in degrees Celsius. A
sense of the fluid’s general range of application is indicated. Qualities including
pour point, freeze point, important viscosity points, flash point, boiling point and
others may be shown.
25
7037/7038/7040/7041
User's Guide
Table 2. Table of Various Bath Fluids and their Properties
Fluid
(# = Fluke Cal Part
No.)
Halocarbon 0.8 –90°C (v)**
#5019
Methanol
Water
Ethylene
Glycol—50%
#5020
Mineral Oil
Dow Corning
200.5
Silicone Oil
Dow Corning
200.10
#5012
Dow Corning
200.20
#5013
Dow Corning
200.50
Silicone Oil
Dow Corning 55 0 70°C (v)
#5016
Lower
Temperature
Limit*
–96°C (fr)
0°C (fr)
–35°C (fr)
40°C (v)
–40°C (v)**
Upper
Temperature
Limit*
70°C (e)
60°C (b)
95°C (b)
110°C (b)
190°C (fl)
133°C (fl, cc)
Flash
Point
NONE 5.7 @ –50°C
54°C
NONE 1 @ 25°C
NONE 7 @ 0°C
190°C
133°C
Viscosity
(centistokes)
0.8 @ 40°C
0.5 @ 70°C
1.3 @ –35°C
0.66 @ 0°C
0.45 @ 20°C
0.4 @ 75°C
2 @ 50°C
0.7 @ 100°C
15 @ 75°C
5 @ 125°C
5 @ 25°C
Specific
Gravity
1.71 @ 40°C 0.2
0.810 @ 0°C 0.6
0.792 @ 20°C
1.00
1.05
0.87 @ 25°C 0.48 @ 25°C 0.00025 @ 25°C 0.0007 @ 50°C 5 @ 25°C
0.84 @ 75°C 0.53 @ 75°C
0.81 @ 125°C 0.57 @ 125°C
0.92 @ 25°C 0.4
–35°C (v)**
165°C (fl, cc)
165°C
10 @ 25°C
3 @ 135°C
0.934 @ 25°C 0.43 @ 40°C 0.00032 @ 25°C 0.00108
7°C (v)
230°C (fl, cc)
230°C
20 @ 25°C
0.949 @ 25°C 0.370 @ 40°C 0.00034 @ 25°C 0.00107
25°C (v)
280°C (fl, cc)
280°C
20 @ 25°C
0.96 @ 25°C 0.4
232°C (fl, cc)
300°C (fl, oc)
232°C
50 @ 70°C
10 @ 104°C
1.07 @ 25°C 0.358 @ 40°C 0.00035 @ 25°C 0.00075
Dow Corning 71 0 80°C (v)
#5017
Dow Corning
210-H
Silicone Oil
Heat Transfer 145°C (fr)
Salt
#5001
302°C (fl, oc)
302°C
50 @ 80°C
7 @ 204°C
1.11 @ 25°C 0.363 @ 40°C 0.00035 @ 25°C 0.00077
66°C (v)
315°C (fl, oc)
315°C
50 @ 66°C
14 @ 204°C
0.96 @ 25°C
530°C
NONE 34 @ 150°C
6.5 @ 300°C
2.4 @ 500°C
2.0 @ 150°C 0.33
1.9 @ 300°C
1.7 @ 500°C
Specific Heat
(cal/g/°C)
1.00
0.8 @ 0°C
0.45 @ 100°C
0.482 @ 200°C
0.393 @ 100°C
0.420 @ 200°C
0.386 @ 100°C
0.433 @ 200°C
0.454 @ 100°C
0.505 @ 200°C
0.34 @ 100°C 0.0003
Thermal
Conductivity
(cal/s/cm/°C)
0.0004
0.0005 @ 20°C 0.0014 @ 25°C
0.0014
0.001
0.00028 @ 25°C 0.00105
0.00037 @ 25°C 0.00104
0.0014
Thermal
Expansion
(cm/cm/°C)
0.0011
0.0002 @ 25°C
Resistivity
(1012Ω
0.00095
0.00041
1000 @ 25°C
10 @ 150°C
1000 @ 25°C
50 @ 150°C
1000 @ 25°C
50 @ 150°C
1000 @ 25°C
50 @ 150°C
100 @ 25°C
1 @ 150°C
100 @ 25°C
1 @ 150°C
100 @ 25°C
1 @ 150°C
1.7 Ω
-cm )
/cm
3
*Limiting Factors — b - boiling point e - high evaporation fl - flash point fr - freeze point v - viscosity — Flash point test oc = open cup cc = closed cup
**Very low water solubility, ice will form as a slush from condensation below freezing.
26
Calibration Bath
General Operation
Freezing Point: The freezing point of a fluid is an obvious limitation to stirring.
As the freezing point is approached high viscosity may also limit good stirring.
Pour Point: This represents a handling limit for the fluid.
Viscosity: Points shown are at 50 and 10 centistokes. Greater than 50
centistokes stirring is very poor and unsatisfactory for bath applications. At 10
centistokes and below optimum stirring can occur. These are rules of thumb
which have been useful for most applications.
Fume Point: The point at which a fume hood should be used. This point is very
subjective in nature and is impacted by individual tolerance to different fumes
and smells, how well the bath is covered, the surface area of the fluid in the bath,
the size and ventilation of the facility where the bath is located and others. We
assume the bath is well covered at this point. This is also subject to company
policy.
Flash Point: The point at which ignition may occur. See flash point discussion
in the Safety section. The point shown may be either the open or closed cup
flash point.
Boiling Point: At the boiling point of the fluid the temperature stability is
difficult to maintain. Fuming is excessive. Excessive amounts of heater power
may be required because of the heat of vaporization.
Decomposition: All high temperature fluids may be reach a temperature point
at which decomposition of some form will begin. While it always begins slowly
at some lower temperature, the rate can increase to the point of danger or
impracticality at a higher temperature.
27
7037/7038/7040/7041
–100°C 0°C 100°C 200°C 300°C 400°C 500°C 600°C
BP - Boiling Point
CS - Centistokes
EP - Evaporation Point
(fluid loss
due to evaporation)
FL - Flash Point
FR - Freeze Point
PP - Pour Point
User's Guide
Silicone Oil
5017
Silicone Oil
5014
Silicone Oil
5013
Silicone Oil
5012
Silicone Oil
5010
HFE 7500
5023
Halocarbon
5019
Mineral Oil
5011
Water
Methanol
Ethanol
Ethylene Glycol
(50/50 with H O)
Dynalene HF/LO
2
5020
5022
Bath Salt
5001
PP
PP
PP
PP
10 CS
FR (Pure)
10 CS
10 CS
FR
10 CS
10 CS
10 CS
10 CS
EP
10 CS
FR
FL 12°C
BP
FL 16°C
10 CS
FL 60°C
10 CS
10 CS
FL 232°C
FL 211°C
FL 133°C
EP 100°C
FL 177°C
BP
BP
FR
Legend
Shaded area represents usable range of fluid starting at
50 centistokes. Lighter shading represents decreasing
viscosity, while vaporization and decomposition increase.
Black area represents liquid range with excessive
viscosity.
Range over which a fume hood is recommended.
FL 302°CPP
FL 280°C
Decomposition Starts
Figure 6. Chart of Various Bath Fluids and their Properties
figure 6.eps
28
Calibration Bath
General Operation
Stirring
Stirring of the bath fluid is very important for stable temperature control. The fluid
must be mixed well for good temperature uniformity and fast controller response.
The stirrer is precisely adjusted for optimum performance.
Power
Power to the bath is provided by an AC mains supply. See the Specifications
section for power details. Refer to and read the CAUTION in front of this manual
concerning brownout and over voltage protection.
WCaution
Check the back panel label for the correct voltage and
frequency prior to energizing the unit. Power to the bath passes
through a filter to prevent switching spikes from being
transmitted to other equipment.
To turn on the bath switch the control panel power switch to the ON position. The
stir motor will turn on, the LED display will begin to show the bath temperature,
and the heater will turn on or off until the bath temperature reaches the
programmed set-point.
When powered on the control panel display briefly shows a four digit number.
This number indicates the number of times power has been applied to the bath.
Also briefly displayed is data which indicates the controller hardware
configuration. This data is used in some circumstances for diagnostic purposes.
Heater
The power to the bath heater is precisely controlled by the temperature controller
to maintain a constant bath temperature. Power is controlled by periodically
switching the heater on for a certain amount of time using a solid-state relay.
The front panel red/green control indicator shows the state of the heater. The
control indicator glows red when the heater is on and glows green when the
heater is off. The indicator will pulse constantly when the bath is maintaining a
stable temperature.
The heater has two power level settings. The “HIGH” heater power setting is
used to quickly heat up the bath fluid to the desired operating temperature. The
“HIGH” heater power setting may also be required for control at high
temperatures. The “LOW” setting is used for control at lower temperatures and
for scanning at slower rates. When controlling at the “HIGH” heater power setting
instead of “LOW” the proportional band may need to be increased (typically by a
factor of four) to compensate for the increase in power gain. Otherwise the
temperature may oscillate.
29
7037/7038/7040/7041
User's Guide
Cooling
The back pressure control valve limits the cooling capacity of the unit. It will
normally be open all the way (full CCW) for temperature slewing and operation. If
during operation the front panel meter indicates excessive cooling, this valve is
closed partially (turn CW) until the percentage of heating to cooling is brought
into line. Wait a few minutes after each adjustment until the system settles.
The cooling temperature should NOT be set above 90 psig. About 45 °C the
refrigeration is not required as there is sufficient cooling to the room. Wait a few
minutes after each adjustment until the system establishes itself. Readjust if
required after settling for a while.
For maximum cooling for slewing to lower temperatures, the back pressure valve
should be fully open and the cooling temperature set to 0 °C. Readjust higher or
lower as required after set temperature is reached.
Temperature Controller
The bath temperature is controlled by Fluke Calibration’s unique hybrid
digital/analog temperature controller. The controller offers the tight control
stability of an analog temperature controller as well as the flexibility and
programmability of a digital controller.
The bath temperature is monitored with a platinum resistance sensor in the
control probe. The signal is electronically compared with the programmable
reference signal, amplified, and then fed to a pulse-width modulator circuit which
controls the amount of power applied to the bath heater.
The bath is operable within the temperature range given in the specifications. For
protection against solid-state relay failure or other circuit failure, the
microcontroller automatically turns off the heater with a second mechanical relay
anytime the bath temperature is more than a certain amount above the set-point
temperature. As a second protection device, the controller is also equipped with
a separate thermocouple temperature monitoring circuit which shuts off the
heater if the temperature exceeds the cut-out set-point.
The controller allows the operator to set the bath temperature with high
resolution, set the cut-out, adjust the proportional band, monitor the heater output
power, and program the controller configuration and calibration parameters.
The controller may be operated in temperature units of degrees Celsius or
Fahrenheit. The controller is operated and programmed from the front control
panel using the four key switches and digital LED display. The controller may
also be optionally equipped with a serial RS-232 or IEEE-488 GPIB digital
interface for remote operation. Operation of the controller using the front control
panel is discussed following in the Controller Operation section. Operation using
the digital interfaces is discussed in the Digital Communications Interface
section.
When the controller is set to a new set-point the bath heats or cools to the new
temperature. Once the new temperature is reached the bath usually takes 10–15
minutes for the temperature to settle and stabilize. There may be a small
overshoot or undershoot of about 0.5 °C.
30
Calibration Bath
Controller Operation
Controller Operation
This section discusses in detail how to operate the bath temperature controller
using the front control panel. Using the front panel key switches and LED display
the user may monitor the bath temperature, set the temperature set-point in
degrees C or F, monitor the heater output power, adjust the controller
proportional band, set the cut-out set-point, and program the probe calibration
parameters, operating parameters, serial and IEEE-488 interface configuration,
and controller calibration parameters. Controller operations are summarized in
the flow chart in Figure 7.
Bath Temperature
The digital LED display on the front panel allows direct viewing of the actual bath
temperature. This temperature value is what is normally shown on the display.
The units, C or F, of the temperature value are displayed at the right. For
example,
25.00 C
The temperature display function may be accessed from any other function by
pressing the “EXIT” button.
Bath temperature in degrees Celsius
Reset Cutout
If the over-temperature cutout has been triggered, then the temperature display
alternately flashes,
The message continues to flash until the temperature is reduced and the cutout
is reset.
The cutout has two modes — automatic reset and manual reset. The mode
determines how the cutout is reset which allows the bath to heat up again. When
in automatic mode, the cutout resets itself as soon as the temperature is lowered
below the cutout set-point. With manual reset mode the cutout must be reset by
the operator after the temperature falls below the set-point.
When the cutout is active and the cutout mode is set to manual reset, the display
flashes “Cutout” until the user resets the cutout. To access the reset cutout
function press the “SET” button.
Access cutout reset function
The display will indicate the reset function.
Cut-out
Indicates cutout condition
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User's Guide
32
Figure 7. Controller Operation Flow Chart
figure 7.eps
Calibration Bath
Controller Operation
cutout reset function
Press “SET” once more to reset the cutout.
Reset cutout
The display is also switched to the set temperature function. To return to
displaying the temperature press the “EXIT” button. If the cutout is still in the
over-temperature fault condition, the display continues to flash “Cut-out”. The
bath temperature must drop a few degrees below the cutout set-point before the
cutout can be reset.
Temperature Set-point
The bath temperature can be set to any value within the range and with
resolution as given in the specifications. The temperature range of the particular
fluid used in the bath must be known by the operator and the bath should only be
operated well below the upper temperature limit of the liquid. In addition, the
cutout temperature should also be set below the upper limit of the fluid.
Setting the bath temperature involves three steps:
rESEt ?
1. select the set-point memory
2. adjust the set-point value
3. adjust the vernier if desired.
Programmable Set-points
The controller stores 8 set-point temperatures in memory. The set-points can be
quickly recalled to conveniently set the bath to a previously programmed
temperature set-point.
To set the bath temperature one must first select the set-point memory. This
function is accessed from the temperature display function by pressing “SET”.
The number of the set-point memory currently being used is shown at the left on
the display followed by the current set-point value.
25.00 C
Access set-point memory
1.
25.0
Bath temperature in degrees Celsius
Set-point memory 1, 25.0°C currently used
To change the set-point memory press “UP”
or “DOWN”.
4. 40.0
New set-point memory 4, 40.0°C
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User's Guide
Press “SET” to accept the new selection and access the set-point value.
Set-point Value
The set-point value may be adjusted after selecting the set-point memory and
pressing “SET”. The set-point value is displayed with the units, C or F, at the left.
Accept selected set-point memory
If the set-point value need not be changed then press “EXIT” to resume
displaying the bath temperature. Press “UP” or “DOWN” to adjust the set-point
value.
When the desired set-point value is reached press “SET” to accept the new value
and access the set-point vernier. If “EXIT” is pressed instead then any changes
made to the set-point will be ignored.
Accept new set-point value
Set-point Vernier
The set-point value can only be set with a resolution of 0.01 °C. The user may
want to adjust the set-point slightly to achieve a precise bath temperature. The
set-point vernier allows one to adjust the temperature below or above the setpoint by a small amount with very high resolution. Each of the 8 stored set-points
has an associated vernier setting. The vernier is accessed from the set-point by
pressing “SET”. The vernier setting is displayed as a 6 digit number with five
digits after the decimal point. This is a temperature offset in degrees of the
selected units, C or F.
C
C
40.00
42.50
Set-point 4 value in °C
New set-point value
34
0.00000
To adjust the vernier press “UP” or “DOWN”. Unlike most functions the vernier
setting has immediate effect as the vernier is adjusted. “SET” need not be
pressed. This allows one to continually adjust the bath temperature with the
vernier as it is displayed.
0.00090
Next press “EXIT” to return to the temperature display or “SET” to access the
temperature scale units selection.
Access scale units
Current vernier value in °C
New vernier setting
Calibration Bath
Controller Operation
Temperature Scale Units
The temperature scale units of the controller may be set by the user to degrees
Celsius (°C) or Fahrenheit (°F). These units are used in displaying the bath
temperature, set-point, vernier, proportional band, and cutout set-point.
The temperature scale units selection is accessed after the vernier adjustment
function by pressing “SET”. From the temperature display function access the
units selection by pressing “SET” 4 times.
25.00 C
Access set-point memory
1.
25.0
Access set-point value
C
25.00
Bath temperature
Set-point memory
Set-point value
Access vernier
Access scale units selection
Press “UP” or “DOWN” to change the units.
Press “SET” to accept the new selection and resume displaying the bath
temperature.
Set the new units and resume temperature display
Secondary Menu
Functions which are used less often are accessed within the secondary menu.
The secondary menu is accessed by pressing “SET” and “EXIT”
simultaneously and then releasing. The first function in the secondary menu is
the heater power display.
0.00000
Un= C
Un= F
Vernier setting
Scale units currently selected
New units selected
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User's Guide
Heater Power
The temperature controller controls the temperature of the bath by pulsing the
heater on and off. The total power being applied to the heater is determined by
the duty cycle or the ratio of heater on time to the pulse cycle time. This value
may be estimated by watching the red/green control indicator light or read
directly from the digital display. By knowing the amount of heating to the bath the
user can tell if the bath is heating up to the set-point, cooling down, or controlling
at a constant temperature. Monitoring the percent heater power lets the user
know how stable the bath temperature is. With good control stability the percent
heating power should not fluctuate more than ±1 % within one minute.
The heater power display is accessed in the secondary menu. Press “SET” and
“EXIT” simultaneously and release. The heater power will be displayed as a
percentage of full power.
+ Access heater power in secondary menu
12
To exit out of the secondary menu press “EXIT”. To continue on to the
proportional band setting function press “SET”.
Proportional Band
In a proportional controller such as this the heater output power is proportional to
the bath temperature over a limited range of temperatures around the set-point.
This range of temperature is called the proportional band. At the bottom of the
proportional band the heater output is 100 %. At the top of the proportional band
the heater output is 0. Thus as the bath temperature rises the heater power is
reduced, which consequently tends to lower the temperature back down. In this
way the temperature is maintained at a fairly constant temperature.
The temperature stability of the bath depends on the width of the proportional
band. See Figure 8. If the band is too wide the bath temperature will deviate
excessively from the set-point due to varying external conditions. This is because
the power output changes very little with temperature and the controller cannot
respond very well to changing conditions or noise in the system. If the
proportional band is too narrow the bath temperature may swing back and forth
because the controller overreacts to temperature variations. For best control
stability the proportional band must be set for the optimum width.
The optimum proportional band width depends on several factors among which
are fluid volume, fluid characteristics (viscosity, specific heat, thermal
conductivity), heater power setting, operating temperature, and stirring. Thus the
proportional band width may require adjustment for best bath stability when any
of these conditions change. Of these, the most significant factors affecting the
optimum proportional band width are heater power setting and fluid viscosity.
Pct
Heater power in percent
36
Calibration Bath
Controller Operation
Figure 8. Bath Temperature Fluctuation at Various Proportional Band Settings
figure 8.eps
The proportional band should be wider when the higher power setting is used so
that the change in output power per change in temperature remains the same.
The proportional band should also be wider when the fluid viscosity is higher
because of the increased response time.
The proportional band width is easily adjusted from the bath front panel. The
width may be set to discrete values in degrees C or F depending on the selected
units. The optimum proportional band width setting may be determined by
monitoring the stability with a high resolution thermometer or with the controller
percent output power display. Narrow the proportional band width to the point at
which the bath temperature begins to oscillate and then increase the band width
from this point to 3 or 4 times wider. Table 3 lists typical proportional band
settings for optimum performance with a variety of fluids at selected
temperatures.
Table 3. Proportional Band- Fluid Table
Fluid Temperature Heater Setting Proportional Band
Water 30.0 °C Low 0.04 °C
Water 60.0 °C Low 0.04 °C
Eth-Gly 50 % 35.0 °C Low 0.05 °C
Eth-Gly 50 % 60.0 °C Low 0.05 °C
Eth-Gly 50 % 100.0 °C High 0.4 °C
Oil (5cs) 35.0 °C Low 0.1 °C
Oil (5cs) 60.0 °C Low 0.2 °C
Oil (5cs) 100 °C Low 0.2 °C
Stability
±
0.001°C
±
0.001°C
±
0.001°C
±
0.001°C
±
0.002°C
±
0.003°C
±
0.002°C
±
0.003°C
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User's Guide
The proportional band adjustment may be accessed within the secondary menu.
Press “SET” and “EXIT” to enter the secondary menu and show the heater
power. Then press “SET” to access the proportional band.
To change the proportional band press “UP” or “DOWN”.
+ Access heater power in secondary menu
Heater power in percent
12
Pct
Access proportional band
Proportional band setting
Pb=0.101C
Cutout
Pb=0.060C
To accept the new setting and access the cutout set-point press “SET”. Pressing
“EXIT” exits the secondary menu ignoring any changes just made to the
proportional band value.
Accept the new proportional band setting
As a protection against software or hardware fault, shorted heater triac, or user
error, the bath is equipped with an adjustable heater cutout device that shuts off
power to the heater if the bath temperature exceeds a set value. This protects
the heater and bath materials from excessive temperatures and, most
importantly, protects the bath fluids from being heated beyond the safe operating
temperature preventing hazardous vaporization, breakdown, or ignition of the
liquid. The cutout temperature is programmable by the operator from the front
panel of the controller. It must always be set below the upper temperature limit of
the fluid and no more than 10 degrees above the upper temperature limit of the
bath.
If the cutout is activated because of excessive bath temperature then power to
the heater shuts off and the bath cools. The bath cools until it reaches a few
degrees below the cutout set-point temperature. At this point the action of the
cutout is determined by the setting of the cutout mode parameter. The cutout has
two selectable modes — automatic reset or manual reset. If the mode is set to
automatic, the cutout automatically resets itself when the bath temperature falls
below the reset temperature allowing the bath to heat up again. If the mode is set
to manual, the heater remains disabled until the user manually resets the cutout.
New proportional band setting
38
The cutout set-point may be accessed within the secondary menu. Press
“SET” and “EXIT” to enter the secondary menu and show the heater power.
Then press “SET” twice to access the cutout set-point.
Calibration Bath
Controller Operation
+ Access heater power in secondary menu
Heater power in percent
12
Pct
Access proportional band
Proportional band setting
Pb=0.101C
Access cutout set-point
Cutout set-point
To change the cutout set-point press “UP” or “DOWN”.
CO= 110C
CO=
To accept the new cutout set-point press “SET”.
Accept cutout set-point
The next function is the configuration menu. Press “EXIT” to resume displaying
the bath temperature.
Controller Configuration
The controller has a number of configuration and operating options and
calibration parameters which are programmable via the front panel. These are
accessed from the secondary menu after the cutout set-point function by
pressing “SET.” There are 5 sets of configuration parameters — probe
parameters, operating parameters, serial interface parameters, IEEE-488
interface parameters, and controller calibration parameters. The menus are
selected using the “UP” and “DOWN” keys and then pressing “SET”.
Probe Parameters
The probe parameter menu is indicated by,
75C
New cutout set-point
PrObE
Press “SET” to enter the menu. The probe parameters menu contains the
parameters, R0 and ALPHA, which characterize the resistance-temperature
relationship of the platinum control probe. These parameters may be adjusted to
improve the accuracy of the bath. This procedure is explained in detail in the
Calibration Procedure section.
The probe parameters are accessed by pressing “SET” after the name of the
parameter is displayed. The value of the parameter may be changed using the
“UP” and “DOWN” buttons. After the desired value is reached press “SET” to set
the parameter to the new value. Pressing “EXIT” causes the parameter to be
skipped ignoring any changes that may have been made.
Probe parameters menu
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User's Guide
R0
This probe parameter refers to the resistance of the control probe at 0 °C.
Normally this is set for 100.000 ohms.
ALPHA
This probe parameter refers to the average sensitivity of the probe between 0
and 100 °C. Normally this is set for 0.00385 °C-1.
Operating Parameters
The operating parameters menu is indicated by,
Press “SET” to enter the menu. The operating parameters menu contains the
cutout reset mode setting.
Cutout Reset Mode
The cutout reset mode determines whether the cutout resets automatically when
the bath temperature drops to a safe value or must be manually reset by the
operator.
The parameter is indicated by,
CtorSt
Press “SET” to access the parameter setting. Normally the cutout is set for
manual mode.
Cto=rSt
To change to manual reset mode press “UP” and then “SET”.
Cto= Auto
PAr
Operating parameters menu
cutout reset mode parameter
cutout set for manual reset
cutout set for automatic reset
40
Serial Interface Parameters
The serial RS-232 interface parameters menu is indicated by,
SErIAL
The serial interface parameters menu contains parameters which determine
the operation of the serial interface. These controls only apply to baths fitted
with the serial interface. The parameters in the menu are — baud rate,
sample period, duplex mode, and linefeed.
Serial RS-232 interface parameters menu
Calibration Bath
Controller Operation
Baud Rate
The baud rate is the first parameter in the menu. The baud rate setting
determines the serial communications transmission rate.
The baud rate parameter is indicated by,
Press “SET” to choose to set the baud rate. The current baud rate value will then
be displayed.
The baud rate of the bath serial communications may be programmed to
300,600,1200, or 2400 baud. Use “UP” or “DOWN” to change the baud rate
value.
Press “SET” to set the baud rate to the new value or “EXIT” to abort the
operation and skip to the next parameter in the menu.
Sample Period
The sample period is the next parameter in the serial interface parameter menu.
The sample period is the time period in seconds between temperature
measurements transmitted from the serial interface. If the sample rate is set to 5,
the bath transmits the current measurement over the serial interface
approximately every five seconds. The automatic sampling is disabled with a
sample period of 0. The sample period is indicated by,
BAUd
1200 b
2400 b
Serial baud rate parameter
Current baud rate
New baud rate
SAmPLE
Press “SET” to choose to set the sample period. The current sample period value
will be displayed.
Adjust the value with “UP” or “DOWN” and then use “SET” to set the sample rate
to the displayed value.
SA= 1
SA= 60
Serial sample period parameter
Current sample period (seconds)
New sample period
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User's Guide
Duplex Mode
The next parameter is the duplex mode. The duplex mode may be set to full
duplex or half duplex. With full duplex any commands received by the bath via
the serial interface are immediately echoed or transmitted back to the device of
origin. With half duplex the commands are executed but not echoed. The duplex
mode parameter is indicated by,
Press “SET” to access the mode setting.
dUPL
Serial duplex mode parameter
dUP=FULL
The mode may be changed using “UP” or “DOWN” and pressing “SET”.
dUP=HALF
Linefeed
The final parameter in the serial interface menu is the linefeed mode. This
parameter enables (on) or disables (off) transmission of a linefeed character (LF,
ASCII 10) after transmission of any carriage-return. The linefeed parameter is
indicated by,
Press “SET” to access the linefeed parameter.
LF= On
The mode may be changed using “UP” or “DOWN” and pressing “SET”.
LF= OFF
IEEE-488 Parameters
Baths may optionally be fitted with an IEEE-488 GPIB interface. In this case the
user may set the interface address within the IEEE-488 parameter menu. This
menu does not appear on baths not fitted with the interface. The menu is
indicated by,
LF
Current duplex mode setting
New duplex mode setting
Serial linefeed parameter
Current linefeed setting
New linefeed setting
42
IEEE
Press “SET” to enter the menu.
IEEE-488 parameters menu
Calibration Bath
Controller Operation
IEEE-488 Address
The IEEE-488 interface must be configured to use the same address as the
external communicating device. The address is indicated by,
AddrESS
Press “SET” to access the address setting.
Add= 22
Adjust the value with “UP” or “DOWN” and then use “SET” to set the address to
the displayed value.
Add= 15
Calibration Parameters
The operator of the bath controller has access to a number of the bath calibration
constants namely CTO, B0, BG, H, and L. These values are set at the factory
and must not be altered. The correct values are important to the accuracy and
proper and safe operation of the bath. Access to these parameters is available to
the user only in the event that the controller’s memory fails the user may restore
these values to the factory settings. The user should have a list of these
constants and their settings with the manual.
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.
IEEE-488 interface address
Current IEEE-488 interface address
New IEEE-488 interface address
WCaution
The calibration parameters menu is indicated by,
Press “SET” five times to enter the menu
CTO
Parameter CTO sets the calibration of the over-temperature cutout. This is not
adjustable by software but is adjusted with an internal potentiometer.
BO and BG
These parameters calibrate the accuracy of the bath set-point. These are
programmed at the factory when the bath is calibrated. Do not alter the value of
these parameters. If the user desires to calibrate the bath for improved accuracy
then calibrate R0 and ALPHA according to the procedure given in the Calibration
Procedure section.
H and L
These parameters set the upper and lower set-point limits of the bath. DO NOT
change the values of these parameters from the factory set values. To do so may
present danger of the bath exceeding its temperature range causing damage or
fire.
CAL
Calibration parameters menu
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User's Guide
Digital Communication Interface
If supplied with the option, the bath is capable of communicating with and being
controlled by other equipment through the digital interface. Two types of digital
interface are available — the RS-232 serial interface and the IEEE-488 GPIB
interface.
With a digital interface the bath may be connected to a computer or other
equipment. This allows the user to set the bath temperature, monitor the
temperature, and access any of the other controller functions, all using remote
communications equipment. In addition the heater power setting and cooling
capacity may be controlled using the interface. To enable the heater to be
switched to high using the interface the “HEATER” switch must be set to the
“LOW” position. The cooling power switch must be set to OFF to enable remote
control.
Serial Communications
The bath may be installed with an RS-232 serial interface that allows serial digital
communications over fairly long distances. With the serial interface the user may
access any of the functions, parameters and settings discussed in the Interface
Commands section with the exception of the BAUD rate setting. The serial
interface uses 8 data bits, 1 stop bit, and no parity.
Wiring
The serial communications cable attaches to the bath through the DB-9
connector at the back of the instrument. Figure 9 shows the pin-out of this
connector and suggested cable wiring. To eliminate noise, the serial cable should
be shielded with low resistance between the connector (DB-9) and the shield.
44
Figure 9. Serial Cable Wiring
figure 9.eps
Calibration Bath
Digital Communication Interface
Setup
Before operation the serial interface of the bath must first be set up by
programming the baud rate and other configuration parameters. These
parameters are programmed within the serial interface menu.
To enter the serial parameter programming mode first press “EXIT” while
pressing “SET” and release to enter the secondary menu. Press “SET”
repeatedly until the display reads “ProbE”. This is the menu selection. Press “UP”
repeatedly until the serial interface menu is indicated with “SErIAL”. Finally press
“SET” to enter the serial parameter menu. In the serial interface parameters
menu are the baud rate, the sample rate, the duplex mode, and the linefeed
parameter.
Baud Rate
The baud rate is the first parameter in the menu. The display will prompt with the
baud rate parameter by showing “BAUd”. Press “SET” to choose to set the baud
rate. The current baud rate value will then be displayed. The baud rate of the
serial communications may be programmed to 300,600,1200, or 2400 baud. The
baud rate is preprogrammed to 1200 baud. Use “UP” or “DOWN” to change the
baud rate value. Press “SET” to set the baud rate to the new value or “EXIT” to
abort the operation and skip to the next parameter in the menu.
Sample Period
The sample period is the next parameter in the menu and prompted with
“SAmPLE”. The sample period is the time period in seconds between
temperature measurements transmitted from the serial interface. If the sample
rate is set to 5, the bath transmits the current measurement over the serial
interface approximately every five seconds. The automatic sampling is disabled
with a sample period of 0. Press “SET” to choose to set the sample period.
Adjust the period with “UP” or “DOWN” and then use “SET” to set the sample
rate to the displayed value.
Duplex Mode
The next parameter is the duplex mode indicated with “dUPL”. The duplex mode
may be set to half duplex (“HALF”) or full duplex (“FULL”). With full duplex any
commands received by the thermometer via the serial interface are immediately
echoed or transmitted back to the device of origin. With half duplex the
commands are executed but not echoed. The default setting is full duplex. The
mode may be changed using “UP” or “DOWN” and pressing “SET”.
Linefeed
The final parameter in the serial interface menu is the linefeed mode. This
parameter enables (“On”) or disables (“OFF”) transmission of a linefeed
character (LF, ASCII 10) after transmission of any carriage-return. The default
setting is with linefeed on. The mode may be changed using “UP” or “DOWN”
and pressing “SET”.
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Serial Operation
Once the cable has been attached and the interface set up properly the controller
immediately begins transmitting temperature readings at the programmed rate.
The set-point and other commands may be sent to the bath via the seriainterface
to set the bath and view or program the various parameters. The interface
commands are discussed in the Interface Commands section. All commands are
ASCII character strings terminated with a carriage-return character (CR, ASCII
13).
IEEE-488 Communication (optional)
The IEEE-488 interface is available as an option. Baths supplied with this option
may be connected to a GPIB type communication bus which allows many
instruments to be connected and controlled simultaneously. To eliminate noise,
the GPIB cable should be shielded.
Setup
To use the IEEE-488 interface first connect an IEEE-488 standard cable to the
back of the bath. Next set the device address. This parameter is programmed
within the IEEE-488 interface menu.
To enter the IEEE-488 parameter programming menu first press “EXIT” while
pressing “SET” and release to enter the secondary menu. Press “SET”
repeatedly until the display reaches “PrObE”. This is the menu selection. Press
“UP” repeatedly until the IEEE-488 interface menu is indicated with “IEEE”. Press
“SET” to enter the IEEE-488 parameter menu. The IEEE-488 menu contains the
IEEE-488 address parameter.
IEEE-488 Interface Address
The IEEE-488 address is prompted with “AddrESS”. Press “SET” to program the
address. The default address is 22. Change the device address of the bath if
necessary to match the address used by the communication equipment by
pressing “UP” or “DOWN” and then “SET”.
IEEE-488 Operation
Commands may now be sent via the IEEE-488 interface to read or set the
temperature or access other controller functions. All commands are ASCII
character strings and are terminated with a carriage-return (CR, ASCII 13).
Interface commands are listed below.
Interface Commands
The various commands for accessing the bath controller functions via the digital
interfaces are listed in this section (see Table 4). These commands are used with
both the RS-232 serial interface and the IEEE-488 GPIB interface. In either case
the commands are terminated with a carriage-return character. The interface
makes no distinction between upper and lower case letters, hence either may be
used. Commands may be abbreviated to the minimum number of letters which
determines a unique command. A command may be used to either set a
parameter or display a parameter depending on whether or not a value is sent
with the command following a “=” character. For example “s”<CR> will return the
current set-point and “s=50.00”<CR> will set the set-point to 50.00 degrees.
46
Calibration Bath
Digital Communication Interface
In the following list of commands, characters or data within brackets, “[” and “]”,
are optional for the command. A slash, “/”, denotes alternate characters or data.
Numeric data, denoted by “n”, may be entered in decimal or exponential notation.
Characters are shown in lower case although upper case may be used. Spaces
may be added within command strings and will simply be ignored. Backspace
(BS, ASCII 8) may be used to erase the previous character. A terminating CR is
implied with all commands.
Table 4. Interface Command Summary
Command Description Command Format
Display Temperature
Read current set-point s[etpoint] s set: 9999.99 {C or F} set: 150.00 C
Set current set-point to n s[etpoint]=n s=450 Instrument
Read vernier v[ernier] v v: 9.99999 v: 0.00000
Set vernier to n v[ernier]=n v=.00001 Depends on
Read temperature t[emperature] t t: 9999.99 {C or F} t: 55.69 C
Read temperature units u[nits] u u: x u: c
Set temperature units: u[nits]=c/f C or F
Set temperature units to Celsius u[nits]=c u=c
Set temperature units to Fahrenheit u[nits]=f u=f
Secondary Menu
Read proportional band setting pr[op-band] pr pr: 999.9 pr: 15.9
Set proportional band to n pr[op-band]=n pr=8.83 Depends on
Command
Example
Returned
Returned
Example
Acceptable
Values
Range
Configuration
Configuration
Read cutout setting c[utout] c c: 9999 {x},{xxx} c: 620 C, in
Set cutout setting: c[utout]=n/r[eset]
Set cutout to n degrees c[utout]=n c=500 Temperature
Range
Reset cutout now c[utout]=r[eset] c=r
Read heater power (duty cycle) po[wer] po po: 9999 po: 1
Configuration Menu
Probe Menu
Read R0 calibration parameter r[0] r r0: 999.999 r0: 100.578
Set R0 calibration parameter to n r[0]=n r=100.324 98.0 to 104.9
Read ALPHA calibration parameter al[pha] al al: 9.9999999 al: 0.0038573
Set ALPHA calibration parameter to n al[pha]=n al=0.0038433 .00370 to
.00399
Operating Parameters Menu
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User's Guide
Read cutout mode cm[ode] cm cm: {xxxx} cm: AUTO
Set cutout mode: cm[ode]=r[eset]/a[uto] RESET or
AUTO
Set cutout to be reset manually- cm[ode]=r[eset] cm=r
Command Description
Set cutout to be reset automatically cm[ode]=a[uto] cm=a
Serial Interface Menu
Read serial sample setting sa[mple] sa sa: 9 sa: 1
Set serial sampling setting to n
seconds
Set serial duplex mode: du[plex]=f[ull]/h[alf] FULL or HALF
Set serial duplex mode to full du[plex]=f[ull] du=f
Set serial duplex mode to half du[plex]=h[alf] du=h
Set serial linefeed mode: lf[eed]=on/of[f] ON or OFF
Set serial linefeed mode to on lf[eed]=on lf=on
Set serial linefeed mode to off lf[eed]=of[f] lf=of
Calibration Menu
Read B0 calibration parameter *b0 *b0 b0: 9 b0: 0
Set B0 calibration parameter to n *b0=n *b0=0 –999.9 to 999.9
Read BG calibration parameter *bg *bg bg: 999.99 bg: 156.25
Command Format Command
Example
sa[mple]=n sa=0 0 to 4000
Returned
Returned
Example
Acceptable
Values
Set BG calibration parameter to n *bg=n *bg-156.25 –999.9 to 999.9
Read low set-point limit value *tl[ow] *tl tl: 999 tl: –80
Set low set-point limit to n *tl[ow]=n *tl=-80 –999.9 to 999.9
Read high set-point limit value *th[igh] *th th: 999 th: 205
Set high set-point limit to n *th[igh]=n *th=205 –999.9 to 999.9
Miscellaneous (not on menus)
Read firmware version number *ver[sion] *ver ver.9999,9.99 ver.2100,3.56
Read structure of all commands h[elp] h list of commands
Read Heater f1 f1 f1:9 f1:1
Set Heater f1=1/0 0 or 1
Set heater to low f1=n f1=0
Set heater to high f1=n f1=1
Read Refrigeration f2 f2 f2:9 f2:0
Set Refrigeration f2=1/0 0 or 1
Set Refrigeration to on f2=n f2=1
Set Refrigeration to off f2=n f2=0
48
Calibration Bath
Digital Communication Interface
Read Expansion Valve 1 f3 f3 f3:9 f3:1
Set Expansion Valve 1 f3=1/0 0 or 1
Set Expansion Valve 1 to on f3=n f3=1
Set Expansion Valve 1 to off f3=n f3=0
Read Cooling Power f4 f4 f4:9 f4:1
Set Back Pressure f4=1/0 0 or 1
Set back pressure on f4=n f4=1
Set back pressure off f4=n f4=0
Legend: [ ] Optional Command data
{ } Returns either information
n Numeric data supplied by user
9 Numeric data returned to user
x Character data returned to user
Note:
When DUPLEX is set to FULL and a co mmand is sent to READ, the command is returned followed by a carriage return and linefeed. Then the value is ret urned as indicated in the RET URNED
column.
Power Control Functions
The digital interface is capable of controlling the heating and cooling functions so
that the bath can be remotely operated at any temperature within the range of the
bath. To allow the interface to control the heating and the cooling, the front panel
controls are disabled by 1) switching the heater switch to LOW, and 2) switching
the refrigeration switch to OFF. Otherwise, the interface would not be able to
switch these functions off. The bath has four control functions with the digital
interface. These are heater power high/low, cooling on/off, expansion valve
open/closed, and back pressure valve open/closed.
Heater Control
To control the heater with the digital interface the front panel heater switch must
be set to LOW (500 W). The heater function is controlled with the “F1" command.
Setting the “F1" parameter to 0 sets the heater to LOW (500 W) and setting it to 1
sets the heater to HIGH (1000 W). Sending “F1" with no value causes the
controller to return a value showing what the heater setting is. When the heater
setting is changed a pop is heard as the heater relay opens or closes.
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User's Guide
Cooling Control
To control the refrigeration power with the digital interface the front panel
refrigeration switch must be off. The refrigeration power function is controlled with
the “F2" command. Setting the “F2" value to 0 turns the refrigeration off and
setting it to 1 turns it on. “F2" alone returns 0 or 1 showing the state of the
refrigeration power control.
The “F3" command controls the cooling temperature (expansion valve). This
valve adjusts the cooling temperature which sets the cooling capacity. Setting
”F3" to 1 opens the valve (on or high) and 0 closes the valve (off or low). A
command with no value returns the current setting. With the valve closed, the
cooling temperature is set with the cooling temperature knob labeled “LOW”. This
should be adjusted for approximately 0–1 psi if the bath is to be used as low as –
40°C. The knob labeled “HIGH” controls the cooling temperature when the
expansion valve is on. This should be adjusted for approximately 65 psi. These
values are typical but may be adjusted as required for specific applications. The
low range must be set to a lower pressure (temperature) than the high range
valve.
The “F4" command controls the back pressure bypass valve. When the valve is
open the cooling capacity is significantly reduced. Cooling capacity may need to
be reduced at higher temperatures. Adjust the back pressure valve manually with
the bypass valve closed until the duty cycle at the desired bath temperature is
within 10–30 %. This setting may be bypassed automatically by opening the
bypass valve. Table 5 summarizes the control functions for heating and cooling.
Function Command 0 1
Heater F1 low high
Refrigeration F2 off on
Expansion valve F3 off on
Back pressure bypass F4 off on
Full Remote Operation
The back pressure valve knob is used to control the cooling power of the bath at
higher temperatures. Normally, it is enabled for manual operation and it is
adjusted to its full counterclockwise range for maximum cooling power.
For full remote operation, the following steps need to be followed.
1. Set the temperature of the bath to 25 °C.
2. Set the low cooling power to its maximum psi but no more than 90 psi.
3. When the bath stabilizes, adjust the back pressure valve so that the duty
cycle is about 8 %.
4. Set the cooling power back to 2 psi.
Table 5. Serial Power Control Functions
50
You are now ready to control the bath remotely according to the ranges
recommended in the following table. The suggested ranges overlap and are not
absolute values.
Calibration Bath
Calibration Procedure
Table 6. Remote Operation Ranges and Settings
Range Heater Refrigeration
–40 to 0°C Low On Off On
–10 to 20°C Low On On On
10 to 40°C Low On On Off
40 to 110°C High Off Off Off
High Cooling
Valve
Calibration Procedure
In some instances the user may want to calibrate the bath to improve the
temperature set-point accuracy. Calibration is done by adjusting the controller
probe calibration constants R
measured with a standard thermometer agrees more closely with the bath setpoint. The thermometer used must be able to measure the bath fluid temperature
with higher accuracy than the desired accuracy of the bath. By using a good
thermometer and carefully following procedure the bath can be calibrated to an
accuracy of better than 0.02 °C over a range of 100 degrees.
Calibration Points
In calibrating the bath R
at each of two different bath temperatures. Any two reasonably separated bath
temperatures may be used for the calibration. However, best results are obtained
when using bath temperatures which are just within the most useful operating
range of the bath. The further apart the calibration temperatures the larger will be
the calibrated temperature range but the calibration error will also be greater over
the range. If for instance 0 °C and 100 °C are chosen as the calibration
temperatures then the bath may achieve an accuracy of maybe ±0.03 °C over
the range –10 to 110 °C. Choosing 30 °C and 70 °C may allow the bath to have a
better accuracy of maybe ±0.01 °C over the range 25 to 75 °C but outside that
range the accuracy may be only ±0.05 °C.
and ALPHA so that the temperature of the bath as
0
and ALPHA are adjusted to minimize the set-point error
0
Back Pressure
Valve
Measuring the Set-point Error
The first step in the calibration procedure is to measure the temperature errors
(including sign) at the two calibration temperatures. First set the bath to the lower
set-point which we will call t
15 minutes to stabilize at that temperature. Check the bath stability with the
thermometer. When both the bath and the thermometer have stabilized measure
the bath temperature with the thermometer and compute the temperature error
which is the actual bath temperature minus the set-point temperature. If for
err
L
example the bath is set for a lower set-point of t
measured temperature of –0.3 °C then the error is –0.3 °C.
Next, set the bath for the upper set-point t
temperature and compute the error err
bath was set for 100 °C and the thermometer measured 100.1 °C giving an error
of +0.1 °C.
. Wait for the bath to reach the set-point and allow
L
=0 °C and the bath reaches a
L
and after stabilizing measure the bath
H
. For this example we will suppose the
H
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User's Guide
Computing R0 and ALPHA
Before computing the new values for R
known. The values may be found by either accessing the probe calibration menu
from the controller panel or by inquiring through the digital interface. The user
should keep a record of these values in case they may need to be restored in the
future. The new values R
for R
temperature errors err
If for example R0 and ALPHA were previously set for 100.000 and 0.0038500
respectively and the data for t
new values R
respectively. Program the new values R
the calibration by setting the temperature to t
again. If desired the calibration procedure may be repeated again to further
improve the accuracy.
and ALPHA the current values must be
0
and ALPHA are computed by entering the old values
0
and ALPHA, the calibration temperature set-points tL and tH, and the
0
and errH into the following equations:
L
, tH, errL, and errH were as given above then the
L
and ALPHA would be computed as 99.885 and 0.0038302
0
and ALPHA into the controller. Check
0
and tH and measuring the errors
L
Calibration Example
The bath is to be used between 25 and 75 °C and it is desired to calibrate the
bath as accurately as possible for operation within this range. The current values
and ALPHA are 100.000 and 0.0038500 respectively. The calibration
for R
0
points are chosen to be 30.00 and 80.00 °C. The measured bath temperatures
are 29.843 and 79.914 °C respectively. Refer to Figure 10 for applying equations
to the example data and computing the new probe constants.
52
Calibration Bath
Maintenance
Maintenance
The calibration instrument has been designed with the utmost care. Ease of
operation and simplicity of maintenance have been a central theme in the
product development. Therefore, with proper care the instrument should require
very little maintenance. Avoid operating the instrument in dirty or dusty
environments.
• A battery is used to maintain operating parameters in the unit. All operating
parameters, including calibration parameters should be checked on a regular
basis to insure accuracy and proper operation of the instrument. See the
troubleshooting section for the procedure on checking the status of the
battery.
• If the outside of the bath becomes soiled, it may be wiped clean with a damp
cloth and mild detergent. Do not use harsh chemicals on the surface which
may damage the paint.
• Periodically check the fluid level in the bath to ensure that the level has not
dropped. A drop in the fluid level affects the stability of the bath. Changes in
fluid level are dependent upon several factors specific to the environment in
which the equipment is used. A schedule cannot be outlined to meet each
environmental setting. Therefore, the first year the bath should be checked
weekly with notes kept as to changes in bath fluid. After the first year, the
Figure 10. Calibration Example
figure 10.eps
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User's Guide
• Heat transfer medium lifetime is dependent upon the type of medium and the
• Depending on the cleanliness of the environment, the internal parts (parts
user can set up a maintenance schedule based on the data specific to the
application.
environment. The fluid should be checked at least every month for the first
year and regularly thereafter. This fluid check provides a baseline for
knowledge of bath operation with clean, usable fluid. Once some fluids have
become compromised, the break down can occur rapidly. Particular attention
should be paid to the viscosity of the fluid. A significant change in the
viscosity can indicate that the fluid is contaminated, being used outside of its
temperature limits, contains ice particles, or is close to a chemical
breakdown. Once data has been gathered, a specific maintenance schedule
can be outline for the instrument. Refer to the General Operation section for
more information about the different types of fluids used in calibration baths.
behind the front cover only) of the cold bath should be cleaned and/or
checked at least every month for dust and dirt. Particular attention should be
paid to the condensing coil fins. The fins should be vacuumed or brushed free
of dust and dirt on a regular basis. Dust and dirt inhibit the operation of the
condensing coil and thus compromise the performance and lifetime of the
cooling system.
• If a hazardous material is spilt on or inside the equipment, the user is
responsible for taking the appropriate decontamination steps as outlined by
the national safety council with respect to the material. MSDS sheets
applicable to all fluids used in the baths should be kept in close proximity to
the instrument.
• If the mains supply cord becomes damaged, replace it with a cord with the
appropriate gauge wire for the current of the bath. If there are any questions,
contact an Authorized Service Center for more information.
• Before using any cleaning or decontamination method except those
recommended by Fluke Calibration, users should check with an Authorized
Service Center to be sure that the proposed method will not damage the
equipment.
• If the instrument is used in a manner not in accordance with the equipment
design, the operation of the bath may be impaired or safety hazards may
arise.
• The over-temperature cutout should be checked every 6 months to see that it
is working properly. In order to check the user selected cutout, follow the
controller directions for setting the cutout. Both the manual and the auto reset
option of the cutout should be checked. Set the bath temperature higher than
the cutout. Check to see if the display flashes cutout and the temperature is
decreasing.
WWarning
When checking the over-temperature cutout, be sure that the
temperature limits of the bath fluid are not exceeded. Exceeding
the temperature limits of the bath fluid could cause harm to the
operator, lab, and instrument.
54
Calibration Bath
Troubleshooting
Troubleshooting
This section contains information on troubleshooting and CE Comments.
Troubleshooting Table
In the event that the instrument appears to function abnormally, this section may
help to find and solve the problem. Several possible problem conditions are
described along with likely causes and solutions. If a problem arises, please read
this section carefully and attempt to understand and solve the problem. If the
probe seems faulty or the problem cannot otherwise be solved, contact an
Authorized Service Center for assistance. Be sure to have the model number and
serial number of your instrument available.
Problem Causes and Solutions
The display does not show “cutout” nor displays an
incorrect bath temperature, but the controller
otherwise appears to operate normally. The problem
may be either insufficient heating or no heating at all
or too much cooling. Insufficient heating may be
caused by the heater power setting being too low,
The heater indicator LED stays red but the
temperature does not increase
especially at higher operating temperatures. Switching
to the higher heater power switch setting, if available,
may solve the problem. Try reducing cooling capacity
by increasing the cooling temperature, switching the
cooling power switch to “LOW”, or switching off the
cooling altogether. One or more burned out heaters or
blown heater fuses may also cause this problem. If
the heaters seem to be burned out, contact an
Authorized Service Center for assistance.
The controller display flashes “cutout” and
the heater does not operate
The display will flash “cutout” alternately with the
process temperature. If the process temperature
displayed seems grossly in error, consult the problem
“The display flashes “cutout” and an incorrect process
temperature”. Normally, the cutout disconnects power
to the heater when the bath temperature exceeds the
cutout set-point causing the temperature to drop back
down to a safe value. If the cutout mode is set to
“AUTO”, the heater switches back on when the
temperature drops. If the mode is set to “RESET”, the
heater only comes on again when the temperature is
reduced and the cutout is manually reset by the
operator. Check that the cutout set-point is adjusted to
10 or 20 °C above the maximum bath operating
temperature and that the cutout mode is set as
desired. If the cutout activates when the bath
temperature is well below the cutout set-point or the
cutout does not reset when the bath temperature
drops and it is manually reset, then the cutout circuitry
may be faulty or the cutout thermocouple sensor may
be faulty or disconnected. Contact an Authorized
Service Center for assistance.
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The display flashes “cutout” and an
incorrect process temperature
Problem Causes and Solutions
The problem may be that the controller’s voltmeter
circuit is not functioning properly. A problem could
exist with the memory back-up battery. If the battery
voltage is insufficient to maintain the memory, data
may become scrambled causing problems. A nearby
large static discharge may also affect data in memory.
The memory may be reset by holding the “SET” and
“EXIT” keys down while power to the controller is
switched on. The display shows “—init—” indicating
the memory is being initialized. At this point, each of
the controller parameters and calibration constants
must be reprogrammed into memory. You can obtain
the calibration constants from the test results sheet of
the calibration report.
If the problem reoccurs, the battery should be
replaced. Contact an Authorized Service Center for
assistance. If initializing the memory does not remedy
the problem, there may be a failed electronic
component. Contact an Authorized Service Center for
assistance.
The displayed process temperature is in
error and the controller remains in the
cooling or the heating state at any set-point
value
Possible causes may be either a faulty control probe
or erroneous data in memory. The probe may be
disconnected, burned out, or shorted. Check that the
probe is connected properly. The probe may be
checked with an ohmmeter to see if it is open or
shorted. The probe is a platinum 4-wire Din 43760
type, therefore, the resistance should read 0.2 to 2.0
ohms between pins 1 and 2 on the probe connector
and 0.2 to 2.0 ohms between pins 3 and 4. The
resistance should read from 100 to 300 ohms
between pins 1 and 4 depending on the temperature.
If the probe is defective, contact an Authorized
Service Center for assistance.
If the problem is not the probe, erroneous data in
memory may be the cause. Re-initialize the memory
as discussed in the problem “The display flashes
“cutout” and an incorrect process temperature” above.
If the problem remains, the cause may be a defective
electronic component, contact an Authorized Service
Center for assistance.
56
Calibration Bath
Troubleshooting
Problem Causes and Solutions
The controller operates normally except when controlling at a specified set-point. At this set-point, the
temperature does not agree with that measured by the
user’s reference thermometer to within the specified
accuracy. This problem may be caused by an actual
difference in temperature between the points where
the control probe and thermometer probe measure
temperature, by erroneous bath calibration
parameters, or by a damaged control probe.
Check that the bath has an adequate amount of fluid
in the tank and that the stirrer is operating properly.
The controller controls or attempts to
control at an inaccurate temperature
Check that the thermometer probe and control probe
are both fully inserted into the bath to minimize
temperature gradient errors.
Check that the calibration parameters are all correct
according to the certification sheet. If not, reprogram
the constants. The memory backup battery may be
weak causing errors in data as described in the
problem ‘The display flashes “cutout” and an incorrect
process temperature’.
Check that the control probe has not been struck,
bent, or damaged. If the cause of the problem remains
unknown, contact an Authorized Service Center for
assistance.
The controller shows that the output power
is steady but the process temperature is
unstable
The controller alternately heats for a while
then cools
The controller erratically heats then cools,
control is unstable
If the bath temperature does not achieve the expected
degree of stability when measured using a
thermometer, try adjusting the proportional band to a
narrower width as discussed in the Proportional Band
section.
This oscillation is typically caused by the proportional
band being too narrow. Increase the width of the
proportional band until the temperature stabilizes as
discussed in the Proportional Band section.
If both the bath temperature and output power do not
vary periodically but in a very erratic manner, the
problem may be excess noise in the system. Noise
due to the control sensor should be less than
0.001 °C. However, if the probe has been damaged or
has developed an intermittent short, erratic behavior
may exist. Check for a damaged probe or poor
connection between the probe and bath.
Intermittent shorts in the heater or controller electronic
Circuitry may also be a possible cause. Contact an
Authorized Service Center for assistance.
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User's Guide
The bath does not achieve low
temperatures
The controller does not maintain controller
parameters or parameters are reset each
time the power to the unit is removed
Problem Causes and Solutions
This problem can be caused by too much heating or
not enough cooling. Check that the control indicator
glows green showing that the controller is attempting
to cool. The heaters may be disabled as a test by
temporarily removing the heater fuses.
Maximize cooling by switching the cooling on, setting
the cooling power to high, if applicable, and setting the
cooling temperature to 10-15 °C below the bath setpoint (see the chart on the bath). Insufficient cooling
may be caused by lack of refrigerant because of a
leak in the system.
Note: Before performing the memory check, you need
to record the controller calibration parameters (found
in the CAL menu of the instrument) and any useradjusted parameters that you have changed (such as
the programmable set points and proportional band).
Memory Check
Doing a memory check is the easiest way to verify the
ability of the battery to maintain controller parameters.
1. Power off the instrument.
2. Disconnect the instrument from AC power for 10
seconds.
3. Reconnect the AC power and power on the
instrument.
4. If the display shows InIT and/or the cycle count
shows a low number such as 0002, the battery is
spent and should be replaced. Contact an
Authorized Service Center for assistance.
5. After replacing the battery, you must reprogram
the calibration and user-adjustable parameters
into the controller.
58
Comments
EMC Directive
Fluke Calibration's equipment has been tested to meet the European
Electromagnetic Compatibility Directive (EMC Directive, 89/336/EEC). Selection
of Light Industrial of Heavy Industrial compliance has been based on the
intended use of the instrument. Units designed for use in a calibration laboratory
have been tested to Light Industrial Standards. Units designed to be used in the
"field" have been tested to both Light Industrial and Heavy Industrial Standards.
The Declaration of Conformity for your instrument lists the specific standards to
which the unit was tested.
Calibration Bath
Troubleshooting
Low Voltage Directive (Safety)
In order to comply with the European Low Voltage Directive (73/23/EEC), Fluke
Calibration equipment has been designed to meet the IEC 1010-1 (EN 61010-1)
and the IEC 1010-2-010 (EN 61010-2-010) standards.
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User's Guide
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