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6050H
Calibration Bath
PN 3729208
March 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
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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
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Table of Contents
Title Page
Before You Start .................................................................................... 1
Symbols Used ................................................................................... 1
Safety Information .............................................................................. 2
Cautions ............................................................................................ 6
How to Contact Fluke Calibration .......................................................... 7
Product Introduction .............................................................................. 8
Specifications and Environmental Conditions ....................................... 9
Specifications .................................................................................... 9
Environmental Conditions .................................................................. 10
Quick Start ............................................................................................. 10
Unpacking .......................................................................................... 10
Set Up ................................................................................................ 11
Power ................................................................................................ 11
Set the Temperature .......................................................................... 11
Installation ............................................................................................. 13
Bath Environment .............................................................................. 13
“Dry-out” Period ................................................................................. 14
Bath Preparation and Filling .............................................................. 14
Probe ................................................................................................. 14
Power ................................................................................................ 15
Tipping Prevention Brackets Installation ........................................... 15
Installation on a Concrete Floor ..................................................... 15
Bath Use ................................................................................................ 16
General .............................................................................................. 17
Comparison Calibration ..................................................................... 17
Calibration of Multiple Probes ............................................................ 18
Parts and Controls ................................................................................. 18
Front Panel ........................................................................................ 18
Bath Tank and Lid ............................................................................. 20
Back Panel ........................................................................................ 22
General Operation ................................................................................. 24
Bath Fluid .......................................................................................... 24
Safety ............................................................................................ 24
Heat Transfer Salt ......................................................................... 24
Stirring ............................................................................................... 25
Power ................................................................................................ 25
Heater ................................................................................................ 26
Fluid Drain ......................................................................................... 26
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6050H
User's Guide
Temperature Controller ..................................................................... 26
Controller Operation .............................................................................. 27
Bath Temperature .............................................................................. 27
Reset Cutout ...................................................................................... 27
Temperature Set-point ....................................................................... 29
Programmable Set-points .............................................................. 29
Set-point Value .............................................................................. 30
Set-point Vernier ............................................................................ 30
Temperature Scale Units ................................................................... 31
Secondary Menu ............................................................................... 32
Heater Power ..................................................................................... 32
Proportional Band .............................................................................. 33
Cutout ................................................................................................ 35
Controller Configuration ..................................................................... 36
Probe Parameters .............................................................................. 36
R0 .................................................................................................. 36
ALPHA ........................................................................................... 36
Operating Parameters ....................................................................... 36
Cutout Reset Mode ........................................................................ 37
Stir Mode Select ............................................................................ 37
Stir Set-point .................................................................................. 38
Heat Up Power .............................................................................. 38
Serial Interface Parameters ............................................................... 39
BAUD Rate .................................................................................... 39
Sample Period ............................................................................... 40
Duplex Mode ................................................................................. 40
Linefeed ......................................................................................... 41
IEEE-488 Parameters ........................................................................ 41
IEEE-488 Address ......................................................................... 41
Calibration Parameters ...................................................................... 42
CTO ............................................................................................... 42
CO and CG .................................................................................... 42
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 ......................................................................... 47
Power Control Functions ................................................................... 50
Calibration Procedure ............................................................................ 51
Calibration Points .............................................................................. 51
Measuring the Set-point Error ........................................................... 51
Computing R0 and ALPHA ................................................................ 52
Calibration Example .......................................................................... 52
Maintenance .......................................................................................... 54
Troubleshooting ..................................................................................... 55
Troubleshooting Table ....................................................................... 55
Comments ......................................................................................... 59
EMC Directive ................................................................................ 59
Low Voltage Directive (Safety) ....................................................... 59
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List of Tables
Table Title Page
1. Symbols ..................................................................................................... 1
2. Interface Command Summary .................................................................. 47
3. Power Control Commands ........................................................................ 50
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6050H
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List of Figures
Figure Title Page
1. 6050H Bath Cross Section (Optional Cart Shown) ................................... 8
2. Tipping Prevention Bracket Installation ..................................................... 16
3. Front Panel ................................................................................................ 18
4. Bath and Lid Components ......................................................................... 20
5. Back Panel Features ................................................................................. 23
6. Controller Operation Flow Chart ................................................................ 28
7. Bath Temperature Fluctuation at Various Proportional Band Settings ...... 33
8. Serial Communication Cable Wiring .......................................................... 44
9. Calibration Example .................................................................................. 53
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6050H
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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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6050H
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P Conforms to European Union directives.
Conforms to relevant Australian EMC standards.
Fuse
This product complies with the WEEE Directive marking requirements. The affixed label
indicates that you must not discard this electrical/electronic product in domestic
~
Safety Information
DISCLAIMER: Fluke Calibration manufactures baths for the purpose of
temperature calibration. Baths used for applications other than calibration are
used at the discretion and sole responsibility of the customer. Hart Scientific
cannot accept any responsibility for the use of baths for any application other
than temperature calibration.
Use this instrument only as specified in this manual. Otherwise, the protection
provided by the instrument may be impaired.
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.
The following definitions apply to the terms “Warning” and “Caution”.
“WARNING” identifies conditions and actions that may pose hazards to the user.
“CAUTION” identifies conditions and actions that may damage the in- strument
being used.
WWARNING
To avoid personal injury, follow these guidelines.
GENERAL
• Appropriate personal safety protection should be worn by
the operator at all times while using the bath.
• Fluke Calibration does not recommend that user’s drain the
salt from the bath. Fluke Calibration provides the service of
draining salt from the bath. If draining the bath salt is
necessary, contact an Authorized Service Center (see the
How to Contact Fluke Calibration section) for an RMA and
instructions on returning the bath. Insure that the control
probe is removed from the bath before the salt solidifies. If
the control probe is not removed before shipping the bath,
the control probe may be damaged during shipping and the
Service Centers assume no liability for damage incurred
during shipping.
• DO NOT use the instrument for any application other than
calibration work. The instrument was designed for
temperature calibration. Any other use of the unit may cause
unknown hazards to the user.
• DO NOT use the unit in environments other than those listed
in the user’s guide.
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Calibration Bath
Before You Start
• DO NOT overfill the bath. Overflowing extremely hot fluid
may be harmful to the operator. See 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.
• If this equipment is used in a manner not specified by the
manufacturer, the protection provided by the equipment
may be impaired.
• Before initial use, or after transport, or after storage in
humid or semi-humid environments, or anytime the
instrument has not been energized for more than 10 days,
the instrument needs to be energized for a “dry-out” period
of 2 hours before it can be assumed to meet all of the safety
requirements of the IEC 1010-1. If the product is wet or has
been in a wet environment, take necessary measures to
remove moisture prior to applying power such as storage in
a low humidity temperature chamber operating at 50 °C for
4 hours or more.
• DO NOT operate high temperature baths (500 °C) near
flammable materials. Extreme temperatures could ignite the
flammable material.
• Overhead clearance is required. Do not place the instrument
under a cabinet or other structure. Always leave enough
clearance to allow for safe and easy insertion and removal
of probes.
• The instrument is intended for indoor use only.
• Ensure that you check the appropriate OSHA and local fire
code regulations for proper equipment required to suppress
a fire for the Salt utilized in the bath.
BURN HAZARD
• High temperatures may be present in this equipment. Fires
and severe burns may result if personnel fail to observe
safety precautions.
• Ensure the bath DOES NOT contain any water and has been
completely dried prior to filling with salt. Any trapped water
can cause a steam explosion resulting in personal injury. If
the bath has recently been filled with water, ensure the
inside of the drain tube is dry prior to filling the bath with
salt.
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6050H
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• When immersing any object in the bath, ensure that you are
not introducing anything into the bath that will react with the
bath salt. Ensure that probes are DRY and free of
contaminants. Read the MSDS (Material Safety Data Sheet)
for the salt used. If you are still unsure if the material you
are going to introduce into the bath will react with the salt,
refer to the individual MSDS sheets for the three
components that make up the salt.
• The bath is provided with an access cover. The access
cover can be modified to allow the probes being calibrated
to be inserted through the access cover. The bath should be
operated with the access cover on at all times. Operating the
bath without the access cover reduces stability, increases
out gassing of fluids, and increases the possibility of
personal injury or fire hazard.
• When removing probes from the bath DO NOT wipe probes
down with a paper towel. If the bath setpoint is high, the salt
can cause the paper towel to ignite in your hand. Provide a
safe surface and situation for the probes to cool prior to
cleaning the salt from the probes.
• The bath generates extreme temperatures. Precautions must
be taken to prevent personal injury or damage to objects.
Probes may be extremely hot when removed from the bath.
Cautiously handle probes to prevent personal injury.
Carefully place probes on a heat resistant surface or rack
until they are at room temperature.
• Be extremely careful when filling the bath with salt and
bringing it up to temperature. Salt expands with
temperature. It is easy to add salt, but extremely dangerous
to remove hot molten salt because the bath is over filled. DO
NOT fill the bath above the indicated fill line when the
stirring is on. It will overflow.
ELECTRICAL HAZARD
• These guidelines must be followed to ensure that the safety
mechanisms in this instrument will operate properly. This
instrument must be plugged into an outlet 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. Additionally, the
instrument has a Permanent Earth Ground that must be
connected during use. Consult a qualified electrician. DO
NOT use an extension cord or adapter plug.
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Calibration Bath
Before You Start
• DO use a 30 mA ground fault interrupt device. This unit
contains a liquid. A ground fault device is advised in case
liquid 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.
• Keep all combustible materials away from the bath when
using salt. Operate the bath on a heatproof surface such as
concrete. Provide a means of safety for containing any spill,
which may occur.
BATH SALT
• Salt used in this unit 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 unit 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 unit operation.
Ensure that the soft cutout is adjusted to the fluid
characteristics of the application. Failing to set the cutout to
the limits of the bath fluid can result in fire hazards and
personal injury.
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6050H
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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 liquid may damage the
electrical system. Be sure to allow for thermal expansion of
the fluid as the bath temperature increases. See the Bath
Preparation and Filling section, for specific instructions.
• Read the Bath Use section, before placing the bath into
service.
• 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 unit.
• Only authorized personnel should perform the Factory Reset
Sequence 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.
• The bath is a precision instrument. Although it has been
designed for optimum durability and trouble free operation, it
must be handled with care. Position the bath before the tank is
filled with salt.
• 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.
• DO ensure the salt is cleaned from the probes prior to
immersing the probe in the next bath. Clean your probe
between each bath to avoid contamination between bath
fluids.
• Under filling the bath may reduce the bath performance and
may possibly damage the bath.
• When calibrating PRTs always follow correct calibration
procedure and calibrate from high temperatures to low
temperatures with the appropriate triple point of water checks.
Never immerse a wet or cold PRT into a bath filled with hot
fluid. Severe damage to the PRT may result as well as personal
injury to the calibration technician.
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Calibration Bath
How to Contact Fluke Calibration
• This bath is not designed to be portable. Therefore, moving
the bath once it has been installed should be kept to a
minimum. NEVER MOVE A BATH THAT IS FULL OF “HOT”
FLUID. This action could be extremely dangerous and could
result in personal injury to the person moving the bath. If the
bath is going to be placed in an area where it may need to be
moved frequently, Fluke Calibration sells a special cart
designed to accommodate the bath. However, even with a cart
the bath should not be moved full of “hot” fluid. The fluid can
splash causing injury or if the bath and cart tip, the “hot” fluid
could cause damage to the surrounding area and personnel.
• If the bath must be moved, allow the salt to solidify and cool.
Care must be used when moving the bath with the fluid
solidified in the bath. The control probe can easily be
damaged. Two people are required to safely move the bath.
One person should lift the bath by the tower, while the second
person lifts from underneath the bath tank.
• The control probe must be inserted through the lid into the
bath fluid and plugged into the socket at the back of the bath.
DO NOT operate the bath without the control probe properly
inserted and attached. The bath will not operate correctly
without the control probe. Injury to operating personnel and
permanent damage to the bath could occur.
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
• Anywhere in the world: +1-425-446-6110
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6050H
User's Guide
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 6050H is a constant temperature bath intended mainly for
the application of temperature calibration. However, its high stability and the
availability of factory modifications make it suitable for other uses as well.
.
Figure 1. 6050H Bath Cross Section (Optional Cart Shown)
8
6050 cross section.eps
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Calibration Bath
Specifications and Environmental Conditions
Specifications and Environmental Conditions
Specifications
6050H
Range 180 °C to 550 °C †
±0.002 °C at 200 °C (salt)
Stability
±0.004 °C at 300 °C (salt)
±0.008 °C at 550 °C (salt)
Uniformity
Temperature Setting Digital display with push-button data entry
Set-Point Resolution 0.01 °C; high-resolution mode, 0.00018 °C
Display Temperature Resolution 0.01 °C
Digital Setting Accuracy ±1 °C
Digital Setting Repeatability ±0.02 °C
Heaters 400/1200/2000 Watts
Access Opening 5" x 10" (127 x 254 mm)
Depth 12" (305 mm)
Wetted Parts 304 stainless steel
Power 230 VAC (±10 %), 50/60 Hz, 10 A, 2200 W
Volume 7.1 gallons (27 liters), requires 112 lb. of bath salt
Weight 180 lb. (82 kg)
Size
Automation Package
±0.005 °C at 200 °C (salt)
±0.020 °C at 550 °C (salt)
28.5" H x 20.4" W x 24.5" D
(724 x 518 x 622 mm)
Interface-it software and RS-232 computer
interface are available for setting bath
temperature via remote computer. For IEEE-488,
add the
2001-IEEE to the automation package.
Safety
OVERVOLTAGE (Installation) CATEGORY II,
Pollution Degree 2 per IEC61010-1
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6050H
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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
• 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
WCaution
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 6050H 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:
• Bath
• Access Hole Cover
• Controller Probe
• Manual
• Report of Test
If you are missing any item, please contact Fluke Calibration.
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Calibration Bath
Quick Start
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. Remember that the bath
operates at very high temperatures.
Fill the bath tank with salt. (See the Heat Transfer Salt section.) Refer to sections
Bath Use through Parts and Controls for more information on bath setup and
use.
The control probe must be inserted through the lid into the bath and plugged into
the socket at the back of the bath. DO NOT operate the bath without the control
probe properly installed.
Power
Plug the bath power cord into a mains outlet of the proper voltage, frequency,
and current capability. See the Specifications section for power details.
Additionally, a separate ground connection is provided and required to
permanently connect the instrument to earth ground for added operator safety.
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.
Bath temperature display
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
Set-point 1, 25.0 °C currently used
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6050H
User's Guide
Press “SET” to select this memory and access the set-point value.
Access set-point value
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
New set-point value
Store new set-point, access vernier
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 “MED” or “HIGH” to allow the bath to more quickly reach
a higher temperature. The higher heater settings 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 cutout 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.
Current vernier value
Bath temperature display
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Calibration Bath
Installation
Installation
WCaution
Read the Bath Use section before placing the bath in service.
Incorrect handling can damage the bath and void the warranty.
This bath is not designed to be portable. Therefore, moving the bath once it has
been installed should be kept to a minimum.
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 is going to be placed in an area where it will need to be moved
frequently, Fluke Calibration sells a special cart designed to accommodate the
bath. Thus making the bath much more portable. However, even with a cart the
bath should not be moved full of “hot” fluid. The fluid can splash causing injury or
if the bath and cart tip, the “hot” fluid could cause damage to the surrounding
area and personal injury to personnel.
WCaution
Care must be used when moving the bath with the fluid
solidified in the bath. The control probe can easily be damaged.
If the bath must be moved, all the salt to solidify and cool. To safely move the
bath, two people are required. One person should lift the bath by the tower, while
the second person slides their hands underneath the bath tank and lifts the bath.
Bath Environment
DO NOT place under a cabinet or other structure. Allow for
overhead clearance.
The 6050H 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.
Because the bath is designed for operation at high temperatures, keep all
flammable and meltable materials away from the bath. Although the bath is well
insulated, top surfaces do become hot. Beware of the danger of accidental fluid
spills. We recommend placing the bath on a heat-proof surface such as concrete
with plenty of clear space around the bath.
If the bath is operated at high temperatures, a fume hood should be used to
remove any vapors given off by hot bath fluid.
WCaution
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6050H
User's Guide
“Dry-out” Period
WWarning
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 “dry-out” period of 1-2 hours before
it can be assumed to meet all of the safety requirements of the
IEC 1010-1. If the product is wet or has been in a wet
environment, take necessary measures to remove moisture
prior to applying power such as storage in a low humidity
temperature chamber operating at 50 °C for 4 hours or more.
Bath Preparation and Filling
The Model 6050H Bath is only intended to be used with salt. Bath salt is
available from Hart Scientific and other sources.
Bath salt is discussed in detail in the Bath Fluid section.
Remove any access hole cover from the bath and check the tank for foreign
matter (dirt, remnant packing material, etc.).
Before filling the bath make sure the drain is well plugged (see Figure 4 and
Figure 5). When using heat transfer salt you must follow a special procedure in
filling and heating the bath because the salt is solid at lower temperatures. See
the Heat Transfer Salt section.
Probe
Disconnect power to the stirrer if at any time the material in the bath is solid and
prevents the stirrer from turning. Fill the bath with clean unpolluted salt. Fill the
bath carefully through the large square access hole to a level that will allow for
stirring and thermal expansion. Under-filling may reduce bath performance and
may possibly damage the bath heater. The salt should never exceed a height of
1/2” below the top of the tank. See Figure 4 for reference to the fluid level with
regards to the top of the tank and the lid of the bath. Carefully monitor the bath
fluid level as the bath temperature rises to prevent overflow or splashing. Use
caution to prevent bath fluid from spilling on the stir motor while filling.
WCaution
Underfilling may reduce bath performance and may possibly
damage the bath.
Inspect the bath controller probe (see Figure 4). It 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. Contact the factory.
Insert the probe into the 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”.
14
Page 23
Calibration Bath
Installation
Power
With the bath power switch off (see Figure 3), plug the bath into an AC mains
outlet of the appropriate voltage, frequency, and current capacity (see the
Specifications section for power details). A separate ground connection is
provided and required to permanently connect the instrument to earth ground for
added operator safety.
Be sure the stirring motor power cord is plugged into the “STIRRER” socket at
the back of the bath (see Figure 5).
Tipping Prevention Brackets Installation
WWarning
Fluke Calibration recommends installing the bath on a heatresistant non-flammable surface.
In order to create the safest possible conditions under use, your bath comes
equipped with Tipping Prevention Brackets. The installation of the brackets is
required for compliance with the International Safety Standard IEC 61010-1,
Section 7.3, Stability, which applies to the stability of the bath under normal
operating conditions.
Installation on a Concrete Floor
Using a concrete drill and concrete drill bit, drill three 1/4 inch x 1 1/4 inch deep
(approximately 6.5 mm x 32 mm) holes in the concrete floor using the bracket to
mark the hole placement. Drop the flare anchor bolt into the hole. Tightening the
screw expands the anchor in the drilled hole and secures the bracket. Ensure
that the bracket is installed in such a way as to ensure the bath will have a
minimum of 6 inches of clearance for air circulation (see Figure 2). Screw the
brackets securely to the floor.
Installation of The Bath
Slide the back casters of the bath completely into the bracket caster slots (see
Figure 2). Lock the front casters of the bath. Check that the bath is securely
locked into the brackets by gently pushing on the bath. Proceed to fill the bath
with the applicable bath fluid after reading the entire User's Guide. If you have
any questions concerning installation of the tipping prevention brackets, please
contact an Authorized Service Center (see the How to Contact Fluke Calibration
section).
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6050H
Wall
Caster Slots
User's Guide
tip.eps
Figure 2. Tipping Prevention Bracket Installation
Bath Use
Read before placing 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
16
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Calibration Bath
Bath Use
General
The 6050H bath is intended tob used with heat transfer salt only. Refer to the
MSDS (Material Safety Data Sheet) for information specific to the salt 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 remove the salt from the probe 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. Modify the access cover to accept
probes for calibration. The bath should be covered at all times. Allowing the
access cover to be open during the calibration process reduces the stability and
accuracy of the test and increases the outgassing of the fluid which can cause
safety concerns for attending personnel.
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. 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.
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6050H
User's Guide
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 by the
metrologist. 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.
Parts and Controls
Front 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.
18
Figure 3. Front Panel
figure 2.eps
Page 27
Calibration Bath
Parts and Controls
1. The digital display is an important part of the temperature controller. It
displays the set-point temperature and bath temperature as well as the
various other bath functions, settings, and constants. The display shows
temperatures in values according to the selected scale units °C or °F.
2. 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 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.
3. The on/off switch controls power to the entire bath including the stirring
motor.
4. The control indicator is a two color light emitting diode (LED). This indicator
lets the user visually see the ratio of heating to cooling. When the indicator is
red the heater is on and when the indicator is green the heater is off and the
bath is cooling.
5. The heater power switch is used to select the appropriate heater power levels
for heating and controlling temperatures.
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6050H
User's Guide
Bath Tank and Lid
The bath tank and lid assembly includes (see Figure 4):
the tank
the control probe
the stirring motor
the access holes
the access hole cover
the drain tube
WWarning
The drain is for factory use only.
Figure 4. Bath and Lid Components
bathlid.eps
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Calibration Bath
Parts and Controls
1. The bath tank is constructed of stainless steel. It is very resistant to
oxidation in the presence of most chemicals and over a wide range of
temperatures.
2. The control probe provides the temperature feedback signal to the
controller allowing the controller to maintain a constant temperature. The
control probe is a precision platinum resistance thermometer (PRT). The
control probe is delicate and must be handled carefully. The probe is
placed in the small hole in the top of the bath so that the probe tip is fully
immersed in the bath fluid. The probe cable connects to the bath at the
probe connector on the back panel.
3. The stirring motor is mounted on the bath tank lid. It drives the stirring
propeller to provide mixing of the bath fluid. Proper mixing of the fluid is
important for good constant temperature stability. The stirring motor
power cord plugs into the back of the bath at the power socket labelled
“STIRRER”.
4. On the bath lid is a large rectangular access hole and a small circular
access hole. These holes are used for placement of thermometers and
devices into the bath. When possible the access holes should be
covered.
5. An access hole cover is recommended to cover the large square access
opening in the top of the bath. This improves bath temperature stability,
prevents excess fluid evaporation or fumes and increases safety with hot
fluid. The user may drill or cut holes in the cover to accommodate the
instruments to be calibrated or immersed in the bath. Spare covers are
available from Hart Scientific.
6. The drain tube, located at the lower left corner of the bath, is for factory
use only.
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6050H
User's Guide
Back Panel
The back panel has six standard features and two optional features (see
Figure 4):
The back panel of the bath contains the following features (see Figure 5):
the bath power cord
the stirring motor power socket
the internal fuses
the probe socket
the RS-232 interface connector (optional)
the IEEE-488 interface connector (optional)
the drain tube
WWarning
The drain tube is for factory use only.
1. The bath power cord extends from the back of the bath. It provides power for
the bath temperature controller, the heaters, and the stirring motor. The cord
is plugged into an AC mains socket of 230 VAC (±10 %), 10 A, 50/60 Hz.
2. The stirring motor power cord plugs into the socket labelled “STIRRER”.
Power to the stirring motor is switched on by the POWER switch on the
control panel.
3. The system and heater fuses are internal. Never replace a fuse with one of a
rating greater than that specified. The heater fuses protect against shorted
heaters.
4. The control probe plugs into the bath at the socket on the back of the bath
labelled “PROBE”.
5. 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 labelled “RS-232”.
6. 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 labelled “IEEE-488”.
7. The drain is for factory use only, but must be tightly sealed when the bath is
in use.
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Calibration Bath
Parts and Controls
Figure 5. Back Panel Features
back_panel.eps
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.
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6050H
User's Guide
General Operation
Bath Fluid
Heat transfer salt is intended to be used with the 6050H bath. Other fluids
should not be used.
Safety
Always consider the safety issues associated with using salt in the Warnings and
Cautions sections of the Safety Information section (see the Safety Information
section of this manual). Obviously where there are extreme temperatures there
can be danger to personnel and equipment. Salt may also be hazardous for other
reasons. Some salt 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.
Salt may be flammable or pose a fire hazard and require special fire safety
equipment and procedures.
Environmentally hazardous salts require special disposal according to
applicable federal or local laws after use.
Heat Transfer Salt
Heat transfer salt is often used at high bath temperatures. Salt has a very high
upper temperature limit and a wide useful temperature range. New bath salt
melts around 145 °C however its viscosity is such that its functional range is from
around 180 °C up to the upper limit of the bath. The melting temperature will
change as the salt ages or becomes contaminated. When the bath is not in use
we recommend keeping the temperature above 230 °C to prevent excessive
amounts of salt from freezing on the stir shaft and other cooler parts of the tank.
Viscosity is low, especially at higher temperatures. Salt when melted has very
low electrical resistivity. Salt may be corrosive to some materials. Salt will quickly
oxidize the coating on galvanized metal. Carbon steel may be used with salt up
to 450 °C. Beyond this temperature stainless steel is recommended.
Keep all combustible materials away from the bath when using
salt. Operate the bath on a heat-proof surface such as concrete.
Provide a means of safely containing any spills which may
occur.
The greatest safety concern with liquid salt is with its high temperature. The fluid
provides a source of heat which can ignite or destruct materials. Especially
dangerous are spills since the hot fluid is difficult to contain. Salt may also cause
steam explosions if it comes into contact with water or other volitile fluids. Using
salt requires special caution. Read carefully the information and safety data
sheets provided with the salt. Use of a fume hood is recommended to remove
any products of decomposition or oxidation.
WCaution
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Calibration Bath
General Operation
Because salt is solid at room temperature special procedures are required in
using the bath with salt. Before filling the bath with solid salt disconnect the
stirring motor to prevent it from being damaged. (See the Stir Mode Select
section.)
WCaution
Never allow the stir motor to run with solid material in the bath.
Restraining the motor from turning may over-heat and damage
the motor. Use HIGH heat (Heater Switch) and “LO” Heat Up
Power with solid salt. A Fast Start Heater Model 2024 may be
used to aid in the melting of solid salt. See the Stir Mode Select
section.
Solid salt has poor thermal conductivity. The 6050H bath uses a special "soft
start" program to prevent the heaters from being overheated until the salt is
completely molten. This program controls the heater duty cycle at 25 % until the
bath temperature reaches 200 °C. To allow the bath to control below 200 °C the
soft start feature must be deactivated (see the Stir Mode Select section, Stir Set-
point section, and Heat Up Power section.)
Salt is supplied in a pink granular form. Fill the bath gradually as the salt heats
and melts. Because of the heat required to melt the salt this is a slow process
and may take 10 hours or more. Fill the bath until the liquid is a few inches below
the lid. The level will rise as much as two inches as it is heated to the upper
temperature limit.
Stirring
Power
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. When the salt in the
bath is solid, it is very important that the stirrer power be disconnected until the
salt melts. Otherwise, the stirrer will likely over-heat and be damaged.
Power to the bath is provided by an AC mains supply. See the Specifications
section for power details. See Figure 5. 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
stirring 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.
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6050H
User's Guide
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 (see Figure 3) 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 “MED” and “HIGH” heater power
settings are used to more quickly heat the bath fluid up to the desired operating
temperature. These heater power settings may also be required for control at
higher temperatures. The “HIGH” setting is used to heat solid salt. The “LOW”
setting is used when controlling at lower temperatures, and for scanning at
slower rates. When controlling at the “MED” or “HIGH” heater power settings
instead of “LOW” the proportional band may need to be increased (typically two
or four times) to compensate for the increase in power gain. Otherwise the
temperature may oscillate.
Fluid Drain
The drain at the back of the bath (see Figure 5) is for factory use only. During
operation of the bath the drain plug must be screwed on tightly.
Temperature Controller
The bath temperature is controlled by Fluke Calibration’s unique hybrid
digital/analog temperature controller (see Figure 3). 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.
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Calibration Bath
Controller Operation
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.
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 6.
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,
The temperature display function may be accessed from any other function by
pressing the “EXIT” button.
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.
Bath temperature in degrees Celsius
Indicates cutout condition
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6050H
User's Guide
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
28
Figure 6. Controller Operation Flow Chart
figure 7.eps
Page 37
Calibration Bath
Controller Operation
The display will indicate the reset function.
Press “SET” once more to reset the cutout.
Reset cutout
This action also switches the display 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 “cutout”. 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:
1. select the set-point memory
2. adjust the set-point value
cutout reset function
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.
Access set-point memory
Increment memory
Bath temperature in degrees Celsius
Set-point memory 1, 25.0°C currently used
To change the set-point memory press “UP”
or “DOWN”.
New set-point memory 4, 40.0°C
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Press “SET” to accept the new selection and access the set-point value.
Accept selected set-point memory
Set-point Value
The set-point value can be set with a resolution of 0.01 °C. The user may want to
adjust the set-point slightly to achieve a more precise bath temperature. The setpoint vernier allows the temperature to be adjusted below or above the
set-point by a small amount with very high resolution. Each of the 8 stored setpoints has an associated vernier setting. The vernier is accessed from the setpoint 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.
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.
Increment memory
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.
Set-point 4 value in °C
New set-point value
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.
30
Current vernier value in °C
Page 39
Calibration Bath
Controller Operation
Increment memory
Next press “EXIT” to return to the temperature display or “SET” to access the
temperature scale units selection.
Access scale units
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.
Access set-point memory
New vernier setting
Bath temperature
Set-point memory
Access set-point value
Set-point value
Access vernier
Vernier setting
Access scale units selection
Press “UP” or “DOWN” to change the units.
change units
=
Scale units currently selected
New units selected
=
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User's Guide
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 (see Figure 6).
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
To exit out of the secondary menu press “EXIT”. To continue on to the
proportional band setting function press “SET”.
Heater power in percent
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Calibration Bath
Controller Operation
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 7. 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.
Figure 7. Bath Temperature Fluctuation at Various Proportional Band Settings
figure 8.eps
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.
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.
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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.
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.
+ Access heater power in secondary menu
Access proportional band
To change the proportional band press “UP” or “DOWN”.
=
Decrement display
Heater power in percent
Proportional band setting
New proportional band setting
=
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
34
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Calibration Bath
Controller Operation
Cutout
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.
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.
+ Access heater power in secondary menu
Access proportional band
=
Access cutout set-point
=
To change the cutout set-point press “UP” or “DOWN”.
Heater power in percent
Proportional band setting
Cutout set-point
Decrement display
=
New cutout set-point
35
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6050H
User's Guide
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,
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.
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
Operating Parameters
The operating parameters menu is indicated by,
Probe parameters menu
-1
.
Press “UP” to enter the menu. The operating parameters menu contains the
cutout reset mode parameter, the stirrer mode select, and stirrer set-point.
36
Operating parameters menu
Page 45
Calibration Bath
Controller Operation
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,
Press “SET” to access the parameter setting. Normally the cutout is set for
manual mode.
To change to manual reset mode press “UP” and then “SET”.
Stir Mode Select
This parameter along with the Stir set-point allows the user to set the
temperature at which the stir motor is activated. This setting is generally used
when salt is used for the bath medium. For example, you can set the mode to
“auto” and the temperature to 200 °C. This allows the stir motor to shut off and
turn on only when the salt is a liquid (>200 °C) preventing the stir motor from
overheating and or being damaged.
=
=
cutout reset mode parameter
cutout set for automatic reset
cutout set for manual reset
The parameter is indicated by, Stir mode selection
parameter
Press “SET” to access the parameter setting.
=
To change the setting to always on press the “UP” or “DOWN” buttons and then
“SET”. When set to “Str=ON” the stir motor comes on regardless of the
temperature set in the stir set-point parameter.
Stir Mode Select defaults to “Auto” each time the power of the bath
is cycled off and back on. Therefore, this parameter has to be set
each time the bath is powered on if “Str-ON” is the desired mode of
operation.
Stir motor is set for automatic activation at the stir
set-point temperature.
Note
37
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6050H
User's Guide
Stir Set-point
The stir set-point allows setting of the temperature above which the stir motor
activates when the stir activation is set to automatic.
To access the paramter press “SET” from the stir activation parameter. Set-point
mode selection parameter is indicated by,
Press “SET” to access the parameter value.
=
Press “UP” or “DOWN” to change the value and then “SET” to enter the new
value.
Heat Up Power
This section applies to controller parameters, not to High/Low setting
of the front panel heater switch.
Stir motor activation set-point parameter
Stir motor activation set-point
Note
The Heat Up Power or “soft start” feature allows heat transfer salt to be melted in
the bath without overheating the heaters. When salt solidifies it shrinks leaving
gaps between the solid salt and the sides of the bath. Applying full power to the
heaters while the salt is solid can cause the heaters to overheat since there is
poor heat conduction between the walls of the bath and the solid salt. The Heat
Up Power feature prevents the heaters from overheating by limiting the power.
When the Heat Up Power is set to ‘Low’, the heaters operate at 25% power until
the temperature reaches 200°C and is completely melted. While the solid salt is
being heated the control LED flashes. The heater switch setting should be set to
HIGH enabling all the heaters to provide adequate power to melt the salt and to
melt it as quickly as possible. Once the temperature exceeds 200°C, the heaters
operate at full power again and the control LED glows red constantly until the setpoint temperature is reached. The Heat Up Power always defaults to ‘Low’ when
the bath is switched on.
The heat up power option is indicated by,
Heat up power option
Press “SET” to access the parameter value.
=
Low power heat up mode for heat transfer salt
=
38
High power heat up mode
Page 47
Calibration Bath
Controller Operation
Press “UP” or “DOWN” to change the option and then press “SET” to store the
setting.
Note
When using salt as the fluid be sure to always set this option to LO
to maximize the lifetime of the heaters.
Serial Interface Parameters
The serial RS-232 interface parameters menu is indicated by,
Serial RS-232 interface parameters menu
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.
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.
Serial BAUD rate parameter
Current BAUD rate
New BAUD rate
39
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6050H
User's Guide
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,
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.
m
Serial sample period parameter
Current sample period (seconds)
=
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.
The mode may be changed using “UP” or “DOWN” and pressing “SET”.
=
=
=
New sample period
Serial duplex mode parameter
Current duplex mode setting
New duplex mode setting
40
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Calibration Bath
Controller Operation
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.
=
The mode may be changed using “UP” or “DOWN” and pressing “SET”.
=
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,
Press “SET” to enter the menu.
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,
Serial linefeed parameter
Current linefeed setting
New linefeed setting
IEEE-488 parameters menu
Press “SET” to access the address setting.
=
Adjust the value with “UP” or “DOWN” and then use “SET” to set the address to
the displayed value.
IEEE-488 interface address
Current IEEE-488 interface address
New IEEE-488 interface address
=
41
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6050H
User's Guide
Calibration Parameters
The operator of the bath controller has access to a number of the bath calibration
constants namely CTO, C0, CG, 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 so that 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.
WCaution
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 calibration parameters menu is indicated by,
Press “SET” five times to enter the menu. The display now shows:
CTO
Parameter CTO sets the calibration of the over-temperature cutout. This
parameter is not adjusted through software. It is adjusted with an internal
potentiometer. The following values are set by the factory: 565 °C ±5 °C.
CO and CG
These parameters calibrate the accuracy of the bath set-point. They are
programmed at the factory when the bath is calibrated and the values are
entered onto the Report of Test.
Do not alter the value of these parameters. If improved bath
accuracy is needed, calibrate R0 and ALPHA according to the
procedure given in the Calibration section.
To restore these values, press “SET” to display,
Calibration parameters menu
Note
Press “SET” to show the current value of C0.
Use the “UP” and “DOWN” keys until the value displayed matches the C0 value
on the Report of Calibration. Press “SET” to store the value.
42
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Calibration Bath
Controller Operation
The display now shows,
Press “SET” to show the current value of Cg. Use the “UP and ”DOWN" keys
until the value displayed matches the Cg value on the Report of Calibration.
Press “SET” to store the value. The display now shows,
H and L
These parameters set the high and low set-point limits of the bath. These
parameters are factory set to the following: High 550 °C ±0 °C, Low 0 °C ±0 °C.
Note
DO NOT change the values of these parameters from the factory set
values. To do so may present danger of the bath overheating and
causing damage or fire.
To adjust, press “SET” to show the current value of H. Use the “UP” and “DOWN”
keys until the value matches the factory settings listed above. Press “SET to
store the value.
The display now shows,
Press “SET” to show the current value of L. Use the “UP” and “DOWN” keys
until the value matches the factory settings listed above. Press “SET” to store
the value.
The display now shows,
Press “EXIT” to return to displaying the temperature.
43
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6050H
User's Guide
Digital Communication Interface
If supplied with the option, the 6050H 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 may be controlled. To
enable the digital interface to control the heater the “HEATER” switch must be
set to the “LOW” position.
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 Controller
Operation section with the exception of the BAUD rate setting.
Wiring
The serial communications cable attaches to the bath through the DB-9
connector at the back of the instrument. Figure 8 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 8. Serial Communication Cable Wiring
figure 9.eps
Page 53
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.
The serial interface parameters menu is outlined in Figure 6. To enter the serial
parameter “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 pre-programmed 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 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 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”.
45
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6050H
User's Guide
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 serial
interface 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.
46
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Calibration Bath
Digital Communication Interface
Interface Commands
The various commands for accessing the bath controller functions via the digital
interfaces are listed in this section (see Table 2). 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.
In the table 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 are ignored. Backspace (BS,
ASCII 8) may be used to erase the previous character. A terminating CR is
implied with all commands.
Table 2. 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
Set temperature units to
Fahrenheit
u[nits]=c u=c
u[nits]=f u=f
Command
Example
Returned
Returned
Example
Acceptable
Values
Range
Configuration
Secondary Menu
Read proportional band
setting
Set proportional band to n pr[op-band]=n pr=8.83 Depends on
Read cutout setting c[utout] c c: 9999 {x},{xxx} c: 620 C, in
Set cutout setting: c[utout]=n/r[eset]
pr[op-band] pr pb: 999.9 pb: 15.9
Configuration
47
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6050H
User's Guide
Command Description Command Format
Set cutout to n degrees c[utout]=n c=500 Temperatur
Reset cutout now c[utout]=r[eset] c=r
Read heater power (duty
cycle)
Configuration Menu
Probe Menu
Read R0 calibration
parameter
Set R0 calibration parameter
to n
Read ALPHA calibration
parameter
Set ALPHA calibration
parameter to n
Operating Parameters Menu
po[wer] po po: 9999 po: 1
r[0] r r0: 999.999 r0: 100.578
r[0]=n r=100.324 98.0 to
al[pha] al al: 9.9999999 al: 0.0038573
al[pha]=n al=0.00384
Command
Example
33
Returned
.00370 to
Returned
Example
Acceptable
Values
e Range
104.9
.00399
Read cutout mode cm[ode] cm cm: {xxxx} cm: AUTO
Set cutout mode: cm[ode]=r[eset]/a[ut
o]
Set cutout to be reset
manually
Command Description
Set cutout to be reset
automatically
Read stirrer mode smod smod smod:{xxxx} smod:AUTO
Set stirrer mode: smod=o[n]/a[uto] ON or
Set stirrer to on smod=o[n] smod=o
Set stirrer to automatic smod=a[uto] smod=a
Read stirrer set-point sset sset sset:999.99 {C or F} set:150.0C
Set stirrer set-point sset=n sset=450 instrument
Serial Interface Menu
cm[ode]=r[eset] cm=r
Command Format Command
cm[ode]=a[uto] cm=a
RESET or
AUTO
Example
Returned
Returned
Example
Acceptable
Values
AUTO
range
Read serial sample setting sa[mple] sa sa: 9 sa: 1
Set serial sampling setting to
n
seconds
sa[mple]=n sa=0 0 to 4000
48
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Calibration Bath
Digital Communication Interface
Command Description Command Format
Set serial duplex mode: du[plex]=f[ull]/h[alf] FULL or
Set serial duplex mode to
full
Set serial duplex mode to
half
Set serial linefeed mode: lf[eed]=on/of[f] ON or OFF
Set serial linefeed mode to
on
Set serial linefeed mode to
off
Calibration Menu
Read C0 calibration
parameter
Set C0 calibration parameter
to n
Read CG calibration
parameter
du[plex]=f[ull] du=f
du[plex]=h[alf] du=h
lf[eed]=on lf=on
lf[eed]=of[f] lf=of
*c0 *c0 b0: 9 b0: 0
*c0=n *c0=0 –999.9 to
*cg *cg bg: 999.99 bg: 156.25
Command
Example
Returned
Returned
Example
Acceptable
Values
HALF
999.9
Set CG calibration
parameter to n
Read low set-point limit
value
Set low set-point limit to n *tl[ow]=n *tl=-80 –999.9 to
Read high set-point limit
value
Set high set-point limit to n *th[igh]=n *th=205 –999.9 to
Miscellaneous (not on
menus)
Read firmware version
number
Read structure of all
commands
Read heater fn f1 f1:9 f1:1
*cg=n *cg-156.25 –999.9 to
999.9
*tl[ow] *tl tl: 999 tl: –80
999.9
*th[igh] *th th: 999 th: 205
999.9
*ver[sion] *ver ver.9999,9.99 ver.2100,3.56
h[elp] h list of commands
49
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6050H
User's Guide
Command Description Command Format
Set heater fn=1/0 (1=on, 0=off)
(n=1 or 2)
Set heater to off fn=0 f1=0
Set heater to on fn=1 f1=1
Legend:
Note:
[ ] Optional Command data
{ } Returns either information
n Numeric data supplied by user
9 Numeric data returned to user
x Character data returned to user
When DUPLEX is set to FULL and a command is sent to READ, the command is returned followed by a
carriage return and linefeed. Then the value is returned as indicated in the RETURNED column.
Command
Example
0 or 1
Returned
Returned
Example
Power Control Functions
The digital interface is capable of controlling the heating 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, the front panel controls are disabled
by switching the heater switch to “LOW”. Otherwise, the interface would not be
able to switch the heater functions off. The 6050H bath has two control functions
with the digital interface. These control functions are for heaters settings Med
and High.
Acceptable
Values
To control the heaters with the digital interface the front panel heater switch must
be set to “LOW”. The heater function is controlled with the “F1" and ”F2"
commands. These commands are either set to “0" or ”1" according to Table 4.
The default settings are “F1=0" and ”F2=0" which is “LOW”. Sending a command
without a parameter returns the state, “1" for on or ”0" for off.
Table 3. Power Control Commands
Power F1 F2
400 W 0 0
1200 W 1 0
2000 W x 1
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Page 59
Calibration Bath
Calibration Procedure
Calibration Procedure
Note
This procedure is to be considered a general guideline. Each
laboratory should write their own procedure based on their
equipment and their quality program. Each procedure should be
accompanied by an uncertainty analysis also based on the
laboratory's equipment and environment.
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 R0 and ALPHA so that the temperature of the bath
as measured with a standard thermometer agrees more closely with the bath
set-point. 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 R0 and ALPHA are adjusted to minimize the set-point error
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 farther apart the calibration temperatures the larger the
calibrated temperature range, but the calibration error is also greater over the
range. For instance, if 50 °C and 150 °C are chosen as the calibration
temperatures, then the bath may achieve an accuracy of ±0.03 °C over the range
40 to 160 °C. Choosing 80 °C and 120 °C may allow the bath to have a better
accuracy of maybe ±0.01 °C over the range 75 to 125 °C but outside that range
the accuracy may be only ±0.05 °C.
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, t
. Wait for the bath to reach the set-point and allow 15 minutes to
L
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, err
which is the actual bath temperature minus the set-point temperature. For
example, if the bath is set for a lower set-point of t
a measured temperature of 49.7 °C then the error is –0.3 °C.
Next, set the bath for the upper set-point, t
bath temperature and compute the error, err
was set for 150 °C and the thermometer measured 150.1 °C giving an error of
+0.1 °C.
,
L
=50 °C and the bath reaches
L
, and, after stabilizing, measure the
H
. For example, suppose the bath
H
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Computing R0 and ALPHA
Before computing the new values for R0 and ALPHA the current values must be
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 R0’ and ALPHA’ are computed by entering the old values
for R0 and ALPHA, the calibration temperature set-points t
temperature errors err
For example, if R0 and ALPHA were previously set for 100.000 and 0.0038500
respectively and the data for t
values R0’ and ALPHA’ would be computed as 100.193 and 0.0038272
respectively. Program the new values R0 and ALPHA into the controller. Check
the calibration by setting the temperature to t
again. If desired the calibration procedure may be repeated again to further
improve the accuracy.
and errH into the following equations:
L
, tH, errL, and errH were as given above, the new
L
and tH and measuring the errors
L
and tH, and the
L
Calibration Example
The bath is to be used between 75 and 125 °C and it is desired to calibrate the
bath as accurately as possible for operation within this range. The current values
for R0 and ALPHA are 100.000 and 0.0038500 respectively. The calibration
points are chosen to be 80.00 and 120.00 °C. The measured bath temperatures
are 79.843 and 119.914 °C respectively. Refer to Figure 9 for applying equations
to the example data and computing the new probe constants.
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Calibration Procedure
Figure 9. Calibration Example
figure 10.eps
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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.
• The bath should be cleaned regularly to prevent a buildup of oil, salt, or dust.
Use a paint safe cleaning agent on all painted surfaces. Solvents such as
Trichloroethylene or Acetone may dull or dissolve the paint. The stainless
steel surfaces may be cleaned with solvents as necessary to remove salt.
• The stirring motor should be clean to allow proper cooling. Normally only the
outside surfaces will require any attention. If the inside of the motor has
become heavily loaded with salt or dust, blow it out with compressed air.
Follow normal safety procedures when using pressurized gasses.
• 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
user can set up a maintenance schedule based on the data specific to the
application.
• Salt requires little maintenance. There is very little evaporation with salt.
Periodic fluid level checks are sufficient.
• If a hazardous material is spilled 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 salt used in the bath 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 Hart, 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.
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Calibration Bath
Troubleshooting
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.
• 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.
Troubleshooting
In the event the bath 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 bath seems
faulty or the problem cannot otherwise be solved, then contact an Authorized
Service Center for assistance. Opening the unit without contacting an Authorized
Service Center may void the warranty.
Troubleshooting Table
Problem Causes and Solutions
The heater indicator LED stays red but the
temperature does not increase
The controller display flashes
the heater does not operate
“CUToUT”
and
If the display does not show “cutout” and shows the
correct bath temperature, consider the following
possibilities:
Insufficient heating. Insufficient heating may be
caused by the heater power setting being too low,
especially at higher operating temperatures. Switching
to the higher heater power switch setting, if available,
may solve the problem.
No heating. This is caused by blown heater fuses
and/or burned out heaters. Check the heater fuses to
make sure that they are still good. Access the heater
fuses by removing the L-shaped panel covering the
display electronics. If they are blown, and continue to
blow when replaced, the heaters may be shorted. If
you suspect that the heaters are shorted or burned
out, contact an Authorized Service Center for
assistance.
If the display flashes “CUToUT” alternately with the
correct process temperature, check the following:
Wrong cutout setting. The cutout disconnects power
to the heaters when the bath temperature exceeds the
cutout set-point. This causes the bath 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 operator manually resets the cutout.
Check that the cutout set-point is adjusted to 10 or
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Problem Causes and Solutions
The display flashes “CUToUT” alternately
with an incorrect process temperature
20°C above the desired maximum bath operating
temperature and that the cutout mode is set as
desired.
Continuous cutout. 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, the cutout circuitry may
be faulty. Try performing the Factory Reset Sequence
explained below.
Factory Reset Sequence Hold the “SET” and “EXIT”
keys down at the same time while powering up the
unit. The display shows “-init”, the model number, and
the firmware version. Each of the controller
parameters and calibration constants must be reprogrammed. The values can be found on the Report
of Calibration that was shipped with the instrument.
Low battery. 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. Access the battery by
removing the L-shaped panel covering the display
electronics.
Corrupt controller memory. If the problem reoccurs
after the battery is replaced, initialize the memory by
performing a Factory Reset Sequence (described in a
previous solution).
The controller displays the wrong
temperature and the bath continually heats
or cools regardless of the set-point value
Defective control probe. The bath control probe may
be disconnected, burned out, or shorted. Check first
that the probe is connected properly to the socket in
the rear of the bath labeled “PROBE”.
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. 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 its current
temperature.
Corrupt controller memory. Initialize the memory by
performing a Factory Reset Sequence (described in a
previous solution).
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Troubleshooting
Problem Causes and Solutions
If the controller appears to operate normally except
that the bath’s temperature does not agree with the
temperature measured by the user’s reference
thermometer to within the specified accuracy, consider
the following:
Erroneous parameters. Check that the calibration
parameters are all correct according to the Report of
Calibration. If not, reprogram the constants. If the
controller does not keep the correct parameters, the
memory backup battery may be weak causing errors
The controller controls or attempts to
control at an inaccurate temperature
in data. See “Low Battery” in a previous solution.
Poor uniformity. There may be an actual difference
between the bath’s control probe and the reference
thermometer due to excess gradients in the bath.
Check that the bath has an adequate amount of fluid
in the tank and that the stirrer is operating properly.
Also check that the reference thermometer and
control probe are both fully inserted into the bath to
minimize temperature gradient errors.
Defective control probe. Check that the control probe
has not been struck, bent, or damaged. Refer to the
previous solution for how to check the probe’s
resistance.
The controller shows that it is controlling at
the proper temperature, but the bath
temperature is unstable
The controller alternately heats for a while
then cools
If the bath does not achieve the expected degree of
temperature stability when measured using a
thermometer, consider the following:
Wrong proportional band setting. If the proportional
band is set too narrow, the bath will oscillate causing
poor stability. In this case, increase the width of the
proportional band.
If the proportional band setting is too wide, the longterm stability of the bath is affected. In this case
decrease the width of the band.
Bath salt is too thick. Make sure that the bath salt
used is less than 50 centistokes (10 is ideal) at the
temperature at which the bath is controlling. Check
the salt manufacturer’s specifications.
Defective control probe. Check that the control probe
has not been struck, bent, or damaged. Refer to the
previous solution for how to check the probe’s
resistance.
Wrong proportional band setting. If the proportional
band is set too narrow, the bath will oscillate between
too much heating and too much cooling causing
instability. Increase the width of the proportional band
until the temperature stabilizes.
Stir motor does not function
Improper setting or normal operation. See Section
9.11.2, Stir Mode Select, for proper stir mode settings.
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Problem Causes and Solutions
Note
Stir Mode Select defaults to “Auto” each
time the power of the bath is cycled off
and back on. Therefore, this parameter
has to be set each time the bath is
powered on if “Str-ON” is the desired
mode of operation.
If stir motor still does not function, contact
an Authorized Service Center for
assistance.
Note
Before performing the memory check, you
need to record the controller calibration
parameters (found in the CAL menu of the
instrument) and any user-adjusted
parameters that you have changed (such
as the programmable set points and
proportional band).
The controller does not maintain controller
parameters or parameters are reset each
time the power to the unit is removed.
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 useradjustable parameters into the
controller.
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Troubleshooting
Comments
EMC Directive
Fluke Calibration's equipment has been tested to meet the European
Electromagnetic Compatibility Directive (EMC Directive, 89/336/EEC). The
Declaration of Conformity for your instrument lists the specific standards to which
the unit was tested.
Low Voltage Directive (Safety)
In order to comply with the European Low Voltage Directive (73/23/EEC), Hart
Scientific equipment has been designed to meet the EN 61010-1 and EN 610102-010 standards.
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