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 International Electrical Symbols
SymbolDescription
AC (Alternating Current)
AC-DC
Battery
1 Before you start
Symbols used
CE Complies with European Union Directives
DC
Double Insulated
Electric Shock
Fuse
PE Ground
Hot Surface (Burn Hazard)
Read the User’s Manual (Important Information)
Off
On
1
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6055 Calibration Bath
User’s Guide
SymbolDescription
Canadian Standards Association
OVERVOLTAGE (Installation) CATEGORY II, Pollution Degree 2 per IEC1010-1 re
fers to the level of Impulse Withstand Voltage protection provided. Equipment of
OVERVOLTAGE CATEGORY II is energy-consuming equipment to be supplied from
the fixed installation. Examples include household, office, and laboratory appliances.
tures baths for the purpose of temperature calibration. Baths used for ap
plications 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.
The following definitions apply to the terms “Warning” and “Caution”.
-
-
-
1.2.1
• “Warning” identifies conditions and actions that may pose hazards to the
user.
• “Caution” identifies conditions and actions that may damage the instru-
ment being used.
Warnings
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.
•
Hart Scientific does not recommend that user’s drain the salt from the
bath. Hart Scientific provides the service of draining salt from the bath. If
draining the bath salt is necessary, contact an Authorized Service Center
(see Section 1.3) for an RMA and instructions on returning the bath. In
sure that the control probe is removed from the bath before the salt solidi
fies. Solidification in the bath can take up to several days. 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.
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-
2
Page 9
1 Before you start
Safety information
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.
DO NOT overfill the bath. Overflowing extremely hot fluid may be harm
•
ful to the operator. See Section 7.5, Filling the bath, for specific instruc
tions.
Follow all safety guidelines listed in the user’s manual.
•
Calibration Equipment should only be used by Trained Personnel.
•
If this equipment is used in a manner not specified by the manufacturer,
•
the protection provided by the equipment may be impaired.
Before initial use, or after transport, or after storage in humid or semi-hu
•
mid environments, or anytime the instrument has not been energized for
more than 10 days, the instrument needs to be energized for a “dry-out”
period of 2 hours before it can be assumed to meet all of the safety re
quirements of the IEC 1010-1. If the product is wet or has been in a wet
environment, take necessary measures to remove moisture prior to 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 materi-
als. Extreme temperatures could ignite the flammable material.
• Overhead clearance is required. Do not place the instrument under a cabi-
net or other structure. Always leave enough clearance to allow for safe
and easy insertion and removal of probes.
• The instrument is intended for indoor use only.
• Ensure that you check the appropriate OSHA and local fire code regula-
tions 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 explo
sion 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.
•
When immersing any object in the bath, ensure that you are not introduc
ing 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
-
-
3
Page 10
6055 Calibration Bath
User’s Guide
the individual MSDS sheets for the three components that make up the
salt.
The bath is provided with an access cover. The cover should remain on
•
the bath whenever possible. Operating the bath without the access cover
reduces stability, increases out gassing of fluids, and increases the possi
bility 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 stated in the specifications of this guide. The power cord
of the instrument is equipped with a three-pronged grounding plug for
your protection against electrical shock hazards. It must be plugged directly into a properly grounded three-prong receptacle. The receptacle
must be installed in accordance with local codes and ordinances. Consult
a qualified electrician. DO NOT use an extension cord or adapter plug.
•
DO use a ground fault interrupt device. This 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 rat
ing and type. If you have questions, contact an Authorized Service Center
(see Section 1.3).
•
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. Oper
ate the bath on a heatproof surface such as concrete. Provide a means of
safety for containing any spill, which may occur.
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-
4
Page 11
1 Before you start
Safety information
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 ap
plication. Failing to set the cutout to the limits of the bath fluid can result
in fire hazards and personal injury.
-
1.2.2
Cautions
Always operate this instrument at room temperature between 41°F and
•
104°F (5°C to 40°C). Allow sufficient air circulation by leaving at least 6
inches (15 cm) 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 Section 7.5, Filling the bath, for specific instructions.
• Read Section 5, Bath Use, before placing the unit into service.
• DO NOT change the values of the bath calibration constants from the fac-
tory set values. The correct setting of these parameters is important to the
safety and proper operation of the 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 op
timum 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 in
struments 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 con
tamination 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
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5
Page 12
6055 Calibration Bath
User’s Guide
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 per
sonal injury to the calibration technician.
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 ex
tremely dangerous and could result in personal injury to the person mov
ing the bath. The fluid can splash causing injury or if the bath tips, 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. Four people are required to safely
move the bath.
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.
-
-
-
1.3Authorized Service Centers
Please contact one of the following authorized Service Centers to coordinate
service on your Hart product:
Fluke, Hart Scientific Division
799 E. Utah Valley Drive
American Fork, UT 84003-9775
USA
Phone: +1.801.763.1600
Telefax: +1.801.763.1010
E-mail: support@hartscientific.com
Fluke Nederland B.V.
Customer Support Services
Science Park Eindhoven 5108
5692 EC Son
NETHERLANDS
Phone: +31-402-675300
Telefax: +31-402-675321
E-mail: ServiceDesk@fluke.nl
6
Page 13
Fluke Int'l Corporation
Service Center - Instrimpex
Room 2301 Sciteck Tower
22 Jianguomenwai Dajie
Chao Yang District
Beijing 100004, PRC
CHINA
Phone: +86-10-6-512-3436
Telefax: +86-10-6-512-3437
E-mail: xingye.han@fluke.com.cn
Fluke South East Asia Pte Ltd.
Fluke ASEAN Regional Office
1 Before you start
Authorized Service Centers
Service Center
60 Alexandra Terrace #03-16
The Comtech (Lobby D)
118502
SINGAPORE
Phone: +65 6799-5588
Telefax: +65 6799-5588
E-mail: antng@singa.fluke.com
When contacting these Service Centers for support, please have the following
information available:
•
Model Number
•
Serial Number
•
Voltage
•
Complete description of the problem
7
Page 14
2Introduction
The 6055 Calibration Bath is a highly stable constant temperature salt bath. It
has been designed for calibrating liquid-in-glass thermometers or other types of
long thermometers against a known temperature standard such as a Standard
Platinum Resistance Thermometer (SPRT).
The 6055 calibration bath provides the following features:
A deep fluid tank (test well is 3.88 inches in diameter and has 17 inches
•
of fluid depth).
A highly temperature stable low gradient environment typically a nominal
•
stability of ±0.005°C with salt. The fluid is well stirred and environmen
tally protected to minimize gradients.
The fluid level is near the top of the test well to facilitate calibration of
•
liquid-in-glass thermometers without needing to compensate for stem ef
fect.
2 Introduction
-
-
• The bath provides two calibration modes; temperature control mode and
temperature drift mode. The temperature control mode uses a hybrid digital and analog PI controller with lock in amplifier design. The temperature
and other functions are selected with the four button keypad to a hundredth of a degree and finer with a digital vernier adjustment. The Drift
mode bypasses the controller with heater power manually controlled by
the variable transformer.
9
Page 15
3 Specifications and environmental conditions
3Specifications and environmental
conditions
3.1Specifications
Specifications
Range
Stability
Uniformity
Temperature Setting
Set-Point Resolution
Display Temperature
Resolution
Digital Setting Accuracy
Digital Setting Repeatability
Heaters
Working Area
Wetted Parts
Power
Volume
Size
Weight
Distance from Line of Sight to
Top of Fluid
Safety
200 °C to 550 °C (392 °F to 1022 °F)
± 0.003 °C at 200 °C (salt)
± 0.010 °C at 550 °C (salt)
± 0.005 °C at 200 °C (salt)
± 0.010 °C at 550 °C (salt)
Digital display with push-button entry
0.01 °C, high resolution 0.00018 °C
0.01 °C
±1°C
±0.01°C
260 to 2080 W
107 mm diameter (4.2 in), 432 mm deep (17 in), removable SST lid,
special viewing channel for LIG sighting
304 stainless steel
230 V ac (± 10 %), 50/60 Hz, 15 A
19.8 liters, 43 kg of bath salt (5.2 gal, 95 lb)
57.2 cm D x 77.5 cm W x 152.4 cm H (22.5 x 30.5 x 60 in)
70.8 kg (156 lb)
15.9 mm (5/8 in)
OVERVOLTAGE (Installation) CATEGORY II, Pollution Degree 2
per IEC1010-1
3.2Environmental conditions
Although the instrument has been designed for optimum durability and trou
ble-free operation, it must be handled with care. The instrument should not be
operated in an excessively dusty or dirty environment. Maintenance and clean
ing recommendations can be found in the Maintenance Section of this manual.
The instrument operates safely under the following conditions:
•
ambient temperature range: 5–50°C (41–122°F)
•
ambient relative humidity: maximum 80% for temperature <31°C, de
creasing linearly to 50% at 40°C
•
pressure: 75kPa–106kPa
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-
-
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6055 Calibration Bath
User’s Guide
mains voltage within ±10% of nominal
•
vibrations in the calibration environment should be minimized
•
altitude less than 2000 meters
•
12
Page 17
4Installation
CAUTION: READ SECTION 5 ENTITLED BATH USE before placing the
bath in service. Incorrect handling can damage the bath and void the war
ranty.
This section provides the steps required to set up and operate the 6055 bath.
This section should be used as a general overview and reference and not as a
substitute for the remainder of the manual. Please read Sections5 through7
carefully before operating the bath.
WARNING: Never move a bath that is full of “hot” fluid. This action is
extremely dangerous and can result in personal injury and possible dam
age to the surrounding area.
4 Installation
Unpacking
-
-
The bath comes on a cart. This cart is for ease of operation, but in no way im
plies that the bath is portable. This bath is extremely dangerous when filled
with salt. Follow the safety guidelines set forth in the Before you start section.
The bath should never be picked up with liquid salt in the tank. If the bath
needs to be picked up, allow the salt to solidify and cool. Four people are
needed to safely lift the bath. Lift the bath where the bath and the cart meet.
CAUTION: Use caution as this bath is top heavy.
4.1Unpacking
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 the following components are present:
•
6055 Bath
•
Control Probe
•
Power Cord
-
•
Immersion Heater
•
Report of Test
•
Carousel (optional)
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6055 Calibration Bath
User’s Guide
4.2Comments concerning the use of salt
CAUTION: Do not use the control heaters to melt granular salt when fill
ing the bath. The control heaters can be damaged if used in such a man
ner. Use the immersion heater (with a power of about 1000 watts) to melt
the salt. Do not turn the POWER on until the tank is 3/4 full of melted salt.
4.3Bath environment
The Model 6055 bath is a precision instrument that must be located in an ap
propriate environment. The location should be free from drafts, extreme tem
peratures, extreme temperature changes, and dirt. Use the levelers to ensure that
the bath is level. Allow free air space around the bath to allow surface heat to
convect away freely. A fume hood should be used for ventilation of fumes.
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.
If used at high temperatures, a fume hood should be used to remove any vapors
given off by hot bath fluid.
4.4“Dry-out” period
-
-
-
-
The melting period for salt serves as a “dry-out” period for the heaters of this
bath. During this time period all of the safety requirements of the IEC 1010-1
CAN NOT beassumedtobemet.
4.5Power
Plug the bath power cord into a mains outlet of the proper voltage, frequency,
and current capability as stated in the Specifications. Set the “HEATER” switch
on the front panel to position “LOW” and turn the bath on using the front panel
“POWER” switch. The bath turns on and begins to heat or cool to reach the
previously programmed temperature set-point. The front panel LED display in
dicates the actual bath temperature.
4.6Setup
The probe used with the Model 6055 is a precision PRT sensor. The probe
should not be bent or damaged in any way. Plug the probe into the probe con
nector on the rear panel of the bath.
Plug the stirrer into the receptacle marked “STIRRER POWER” located on the
rear panel of the bath. This receptacle is switched on with the instruments con
trol after the instrument reaches 200°C.
-
-
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14
Page 19
4.7Setting the temperature
In the following discussion and throughout this manual 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.
100.00 CBath temperature display
4 Installation
Setting the temperature
When “SET” is pressed the display shows the set-point memory that is cur
rently being used and its value. Eight set-point memories are available.
S
1. 150.0Set-point 1, 150.0 °C currently used
Press “SET” to select this memory and access the set-point value.
S
C 150.00Current value of set-point 1, 150.00°C
Press “UP” or “DOWN” to change the set-point value.
U
C 160.00New set-point value
Access set-point selection
Access set-point value
Increment display
-
Press “SET” to accept the new value and display the vernier value. The bath be
gins heating or cooling to the new set-point.
S
0.00000Current vernier value
Press “EXIT” and the bath temperature will be displayed again.
E
100.00 CBath temperature display
Store new set-point, access vernier
Return to the temperature display
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15
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6055 Calibration Bath
User’s Guide
The bath heats or cools until it reaches the new set-point temperature. Set the
heater switch to position “HIGH” to allow the bath to more quickly reach a
higher temperature. The “HIGH” setting may be necessary to reach higher tem
peratures and control at high temperatures.
When setting the set-point temperature be careful not to exceed the temperature
limit or the bath fluid. The over-temperature cut-out should be correctly set to
prevent this from happening. See Section 8.8.
To obtain optimum control stability adjust the proportional band as discussed in
Section 8.7.
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Page 21
5Bath Use
CAUTION: READ THIS SECTION before placing the bath in service.
Incorrect handling can damage the bath and void the warranty.
5 Bath Use
General
The information in this section is for general information only. It is not de
signed to be the basis for calibration laboratory procedures. Each laboratory
will need to write their own specific procedures.
5.1General
Be sure to select the correct fluid for the temperature range of the calibration.
Bath fluids should be selected to operate safely with adequate thermal proper
ties to meet the application requirements. Also, be aware that some fluids ex
pand and could overflow the bath if not watched. Refer to General Operation,
Section 7, for information specific to fluid selection and to the MSDS sheet
specific to the fluid selected. Generally, baths are set to one temperature and
used to calibrate probes only at that single temperature. This means that the
type of bath fluid does not have to change. Additionally, the bath can be left energized reducing the stress on the system.
The bath generates extreme temperatures. Precautions must be taken to prevent
personal injury or damage to objects. Probes may be extremely hot or cold
when removed from the bath. Cautiously handle probes to prevent personal injury. Carefully place probes on a heat/cold resistant surface or rack until they
are at room temperature. It is advisable to wipe the probe with a clean soft cloth
or paper towel before inserting it into another bath. This prevents the mixing of
fluids from one bath to another. If the probe has been calibrated in liquid salt,
carefully wash the probe in warm water and dry completely before transferring
it to another fluid. Always be sure that the probe is completely dry before inserting it into a hot fluid. Some of the high temperature fluids react violently to
water or other liquid mediums. Be aware that cleaning the probe can be danger
ous if the probe has not cooled to room temperature. Additionally, high temper
ature 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.
5.2Comparison 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, al
low 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 cali
brate multiple probes is that the probes do not need to be identical in construc
tion. The fluid in the bath allows different types of probes to be calibrated at
-
-
-
17
Page 22
6055 Calibration Bath
User’s Guide
the same time. However, stem effect from different types of probes is not to
tally 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 Hart Scien
tific, 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 dur
ing calibration at high temperatures, a heat shield could be used just below the
probe handle. This heat shield could be as simple as aluminum foil slid over the
probe before inserting it in the bath or as complicated as a specially designed
reflective metal apparatus.
When calibrating over a wide temperature range, better results can generally be
achieved by starting at the highest temperature and progressing down to the
lowest temperature.
Probes can be held in place in the bath by using probe clamps or drilling holes
in the access cover. Other fixtures to hold the probes can be designed. The object is to keep the reference probe and the probe(s) to be calibrated as closely
grouped as possible in the working area of the bath. Bath stability is maximized
when the bath working area is kept covered.
In preparing to use the bath for calibration start by:
• Placing the reference probe in the bath working area.
• Placing the probe to be calibrated, the UUT, in the bath working area as
close as feasibly possible to the reference probe.
5.3Calibration 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.
18
Page 23
Page 24
6055 Calibration Bath
HEATINGPOWER
User’s Guide
6.2Power panel
The Power Panel (Figure 2) controls include: 1) the power switch and indicator,
2) the boost heater and indicator, 3) the mode select switch and indicators, 4)
the control heating select switch, and 5) the drift adjust control.
1)The “ON/OFF” power switch powers up the bath. The switch is a DPST
2)The boost heating provides an additional 900 watts for rapidly changing
3)The mode select switch selects between the Temperature Control and
type that opens both legs of the ac mains power source. A red indicator
light shows that power is on.
between temperatures. The boost heating indicator shows whether the
boost heater is on or off. The boost heater is powered through the tem
perature controller triac to prevent exceeding the desired set temperature.
The boost heater indicator flashes when the set temperature has been
reached as a reminder to turn it off for control.
Temperature Drift modes. The indicator light shows which mode is functioning. The Temperature Control position selects the temperature controller panel. In Temperature Drift mode, the heater control is via the
Drift Adjust control and the heating select switch.
Boost Heating
Indicator
BOOST
HEATER
OFF
ON
OFF
4)The control heating switch selects the control heater power positions; off
Boost Heating
Switch
2
through 4. Select the lowest reasonable value for normal control condi-
Mode Select
Switch
3
OFF
Temperature Drift
Mode Indicator
TEMPERATURE DRIFT
MODE SELECT
TEMPERATURE CONTROL
LOW
HIGH
Drift Adjust
Control
5
DRIFT ADJUST
40
30
20
10
0
50
PERCENT
60
100
70
80
90
Power
Indicator
Figure 2 Power panel
20
1
Power
Switch
Heating
4
Switch
Temperature Control
Mode Indicator
Page 25
6 Parts and controls
Power panel
1
2
4
5
7
8
6
Figure 3 Back panel
21
Page 26
6055 Calibration Bath
User’s Guide
tions depending on bath temperature. The switch simply adds more heat
ers into the circuit until the desired power is attained. Position 2 is
variable using the Drift Adjust control.
5)The drift adjust control is a variable transformer that adjusts the position
1 control heater through 0 to 100% of its power range. The additional
power required for higher temperatures may be added in steps by select
ing heating 2, 3, 4, etc. Positions 2 + 3 + 4 + 5 will not achieve the maxi
mum possible temperatures. Boost + 2 is the next increment. Boost + 2 +
3 and so on can be used as required.
6.3Back panel
The Back Panel (Figure 3) includes: 1) the probe connector, 2) the stirrer power
outlet, 4) the power cord, 5) the heater power connector, 6) the serial number,
7) optional RS-232 connector, and 8) optional IEEE-488 GPIB connector.
1)The probe connector on the back panel is used for the temperature controller probe.
2)The stirrer power connection provides ac power to the stirring motor and
cooling fan.
3)The system fuses are internal (one fuse for each leg of the ac mains
power). Only replace fuses with those of the same rating and type.
-
-
-
4)The power cord.
5)The heater power outlet supplies power to the control and boost heaters
that are attached to the top plate of the bath tank. The connector allows
the assembly to be easily removed if required.
6)The serial number is located at the top right corner of the back panel.
When consulting with an Authorized Service Center, refer to the serial
number.
7)Optional DB-9 connector for interfacing the instrument to a computer or
terminal with a serial RS-232 cable.
8)Optional GPIB connector for interfacing the instrument to a computer or
terminal using IEEE-488 communications.
22
Page 27
Two modes of temperature control
7General operation
The components, features and operational theory of the Model 6055 calibration
bath are described in this section.
The Model 6055 calibration bath is shown in block diagram form in Figure 4
on page 24. This diagram illustrates the primary features of the bath system and
their function, which are described as follows.
7.1Two modes of temperature control
There are two modes of temperature control available with the Model 6055.
The Temperature Control mode or the Temperature Drift mode may be selected
by a switch on the front panel.
7.1.1Temperature control mode
The Temperature Control Mode uses a hybrid digital/analog PI temperature
controller with a lock-in-amplifier. The bath stability is very high with this controller. The temperature is selected using the four button keypad on the front
panel. Temperatures from 150 to 550°C may be selected directly to a hundredth
of a degree. Finer adjustment is available using the vernier adjustment. Accuracy of the setting is typically ±0.5°C or better.
7 General operation
The controller pulses AC current to the control heaters in a time modulated
fashion to compensate for heat gains and losses to the system. A two color LED
on the control panel glows red when the heaters are on and glows green when
they are off and cooling is taking place. (Note: The cooling required for control
is supplied through heat loss to ambient).
The temperature control probe uses a 100 ohm PRT. Plug the probe into the
rear of the control unit.
The heaters are internal to the tank. They are arranged electrically to provide
the 4 control heating positions plus an off position. The additional boost heat
ing position is accessed from a separate switch on the control panel.
7.1.2Temperature drift mode
When using the Temperature Drift mode, the heater may be set manually to al
low the temperature to drift very slowly (a few millidegrees C per minute) over
the desired range. This allows the control noise to be eliminated although
greater skill is required in making calibrations. The heater power is adjusted by
means of a variable transformer located on the control panel. It allows position
one of the heater selection switch to be continually variable from 0 to 100%.
Positions 2, 3, 4 and Boost add their full value of heat incrementally to the ad
justed value of position 1.
-
-
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6055 Calibration Bath
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COOOLING
FAN
STIRRER
17" DEEP
3.88" DIA
FLOW TEST WELL
CONSTANT LEVEL
DRAIN
BATH TANK
PROBE
BOOST
HEATER
CONTROL MODE
HEATING
DIGITAL DISPLAY
HI
MODE
315.00 C
OFF
SELECT
DRIFT MODE
INSULATED
FLUID TANK
WARNING: DRAIN IS FOR FACTORY USE ONLY!
Figure 4 System diagram
24
CONTROLLER
TEMPERATURE
DRIFT
ADJUST
CONTROL
INDICATOR
VARIABLE
TRANSFORMER
Page 29
7.2Bath fluid
Heat transfer salt works with the 6055 bath up to 550°C. Other fluids
SHOULD NOT be used with the 6055 bath.
7.3Fluid system
The fluid system consists of the insulated tank, the stirrer assembly, the drain,
the overflow test well, and the fluid. The heaters and probe, which are part of
the control system, are physically internal to the tank.
7 General operation
Bath fluid
The tank and other wetted parts are made of stainless steel. The stirrer is at
tached to the tank top plate of the bath and its motor receives additional cooling
from a fan to keep from overheating and to increase the lifetime at high bath
temperatures. The stirrer directly drives three 2-inch diameter stirring propel
lers. The down draft from the propellers forces the fluid through the overflow
test well. The stirring motor plugs into the rear of the control unit. (See Figure
5onpage26.)
The over-flow test well serves to provide a constant depth of fluid at an essentially constant height near the well opening. Variations in fluid volume due to
thermal expansion and evaporation do not effect measurements within reasonable volume ranges. The fluid expelled from the tank is controlled to flow past
the control heaters first before entering the main tank for thermal management.
WARNING: The drain is for factory use only.
7.4Fluid Drain
The drain on the bottom of the bath (see Figure 4 on page 24) is for factory use
only. During operation of the bath the drain plug must be screwed on tightly.
-
-
7.5Filling the bath
The bath is shipped dry. Check inside of the test well for foreign matter and re
move it to avoid interference with operation.
7.5.1Using heat transfer salt
7.5.1.1The first salt load
Salt comes in small bead or granular form which is initially pink in color. Ap
proximately 70 pounds are required for the installation.
The following procedure is required if the bath is empty and will be filled with
bead or granular salt.
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25
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6055 Calibration Bath
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Figure 5 System diagram
26
Page 31
7 General operation
Filling the bath
Use an immersion heater (with a power of about 1000 watts) to melt the
•
salt.
Do not use the control heaters to melt the granular salt or they will be
•
damaged.
Inspect the drain to be sure it is fully sealed.
•
Insert the immersion heater into the test well and fill the remaining space
•
with the granular salt.
As the salt melts, it will run into the main tank. As this occurs continually
•
fill the test well with more salt.
CAUTION: Danger of serious burns exists. Use extreme care and use ap
propriate safety equipment.
As this process continues and the tank is nearing its full level, turn the POWER
switch ON and set the temperature to about 200°C with the MODE SELECT
switched to TEMPERATURE CONTROL. The stirrer will not turn on until the
bath has actually reached the cut in temperature of 175 to 225°C. The melting
point of the salt is about 150°C. Increase the temperature of the main tank and
add more salt until the salt depth reaches about 3.5 inches from the tank top
plate at 250°C (without pumping).
7.5.1.2Melting the salt
The following process is to be followed to melt salt in a bath which has previously had salt installed and has cooled.
• Turn on the unit and set the temperature to the desired starting point (at
least 200°C).
• Turn the heater to the maximum position of 4 and turn on the boost
heater.
•
The controller will limit the duty cycle of the heaters to 25% until the salt
reaches about 200°C.
-
•
As the heat expands the solid salt, you will hear some cracking noises
which should not cause concern.
•
When the stirrer cut in temperature is reached the stirrer will turn on and
begin to pump the molten salt into the test well.
•
If the thermometer holding fixture was removed previously, it may be re
placed at this time.
•
The bath is now ready for operation.
-
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7.6Stirring
Stirring of the bath salt is very important for stable temperature control. The
salt must be mixed well for good temperature uniformity and fast controller re
sponse. The stirrer is precisely adjusted for optimum performance.
7.7Power
-
Power to the bath is provided by an AC mains supply as specified in the speci
fications. Power to the bath passes through a filter to prevent switching spikes
from being transmitted to other equipment.
To turn on the bath switch the control panel power switch to the “ON” position.
The stir motor will turn on, the LED display will begin to show the bath tem
perature, and the heater will turn on or off until the bath temperature reaches
the programmed set-point.
When powered on the control panel display will briefly show a four digit num
ber. 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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28
Page 33
8Controller 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 dis
play 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 propor
tional band, set the cut-out set-point, and program the probe calibration param
eters, operating parameters, optional serial and IEEE-488 interface
configuration, and controller calibration parameters. Operation of the primary
functions is summarized in Figure 6.
8.1Bath 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,
8 Controller operation
Bath temperature
-
-
-
25.00 C
The temperature display function may be accessed from any other function by
pressing the “EXIT” button.
8.2Reset cut-out
If the over-temperature cut-out has been triggered then the temperature display
will alternately flash,
Cut-out
The message continues to flash until the temperature is reduced and the cut-out
is reset.
The cut-out has two modes — automatic reset and manual reset. The mode de
termines how the cut-out is reset which allows the bath to heat up again. When
in automatic mode, the cut-out resets itself as soon as the temperature is low
ered below the cut-out set-point. With manual reset mode the cut-out must be
reset by the operator after the temperature falls below the set-point.
When the cut-out is active and the cut-out mode is set to manual (“reset”) then
the display flashes “Cut-out” until the user resets the cut-out. To access the
reset cut-out function press the “SET” button.
Bath temperature in degrees Celsius
Indicates cut-out condition
-
-
S
The display indicates the reset function.
Access cut-out reset function
29
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6055 Calibration Bath
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EXIT
Cutout Active
EXIT
EXIT
Display
Temperature
SET
Reset Cutout
SET
Select Setpoint
SET
Adjust Setpoint
EXIT
EXIT
EXIT
Secondary Functions
+
SET
EXIT
Display Power
SET
Set Proportional Band
SET
Set Cutout Temp.
SET
SET
EXIT
Adjust Vernier
EXIT
SET
EXIT
Set Scale °C/°F
SET
Configuration Menu
SET
EXITEXITEXITEXITEXIT
UP
Probe
Menu
SET
R0
SETSETSET
Adj. R0
SET/EXITSET/EXITSET/EXITSET/EXIT
ALPHA
SET
Adj. ALPHA
SET/EXITSET/EXIT
DOWN
EXITEXITEXIT
EXIT
Operating
Parameters
Menu
SETSETSETSET
Cutout
Reset Mode
SET
Adj. Cutout
Reset Mode
Stirrer
Mode Select
SET
Adj. Stirrer
Mode
Stirrer
Setpoint
SET
Adj. Stirrer
Setpoint
SET/EXIT
Heatup
Power
SET
Adj. Heatup
Power
SET/EXIT
UPUPUP
DOWNDOWNDOWN
EXIT
EXIT
EXIT
EXIT
Serial
Interface
Menu
BAUD
Rate
Adjust
BAUD Rate
Sample
Period
SET
Adj. Sample
Period
SET/EXIT
Duplex
Mode
SET
Adj. Duplex
Mode
SET/EXIT
Linefeed
SET
Adjust
Linefeed
SET/EXIT
EXIT
EXIT
EXIT
IEEE-488
Interface
Menu
Device
Address
SET
Adj. Device
Address
SET/EXIT
IEEE-488
Option Installed
EXIT
Calibration
Adjust CTO
SET
Adjust C0
SET/EXIT
SET
DO NOT CHANGE THESE VALUES. SEE MANUAL
Adjust CG
SET/EXIT
SET
Adjust H
SET/EXIT
Menu
X 5
CTO
C0
EXIT
CG
EXIT
H
EXIT
Figure 6 Controller operation flowchart
30
Interface
Option Installed
L
SET
Adjust L
SET/EXIT
EXIT
Page 35
8 Controller operation
Temperature set-point
rESEt ?
Press “SET” once more to reset the cut-out.
S
This will also switch the display to the set temperature function. To return to
displaying the temperature press the “EXIT” button. If the cut-out is still in the
over-temperature fault condition the display continues to flash “cut-out”.
The bath temperature must drop a few degrees below the cut-out set-point be
fore the cut-out can be reset.
Reset cut-out
Cut-out reset function
8.3Temperature set-point
The bath temperature can be set to any value within the range as given in the
specifications with a high degree of resolution. 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 cut-out 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, and (3) adjust the vernier, if desired.
-
8.3.1Programmable 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.
To set the bath temperature one must first select the set-point memory. This
function is accessed from the temperature display function by pressing “SET”.
The number of the set-point memory currently being used is shown at the left
on the display followed by the current set-point value.
25.00 C
S
Access set-point memory
1. 25.0
To change the set-point memory press “UP” or “DOWN”.
U
Increment memory
4. 40.0
Bath temperature in degrees Celsius
Set-point memory 1, 25.0°C currently used
New set-point memory 4, 40.0°C
Press “SET” to accept the new selection and access the set-point value.
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6055 Calibration Bath
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S
Accept selected set-point memory
8.3.2Set-point value
The set-point value may be adjusted after selecting the set-point memory and
pressing “SET”. The set-point value is displayed with the units, C or F, at the
left.
C 40.00
If the set-point value need not be changed then press “EXIT” to resume dis
playing the bath temperature. To adjust the set-point value press “UP” or
“DOWN”.
U
Increment display
C 42.50
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.
Set-point 4 value in°C
-
New set-point value
S
Accept new set-point value
8.3.3Set-point vernier
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
set-point vernier allows one to adjust the temperature below or above the
set-point 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 num
ber with five digits after the decimal point. This is a temperature offset in de
grees of the selected units, C or F.
0.00000
To adjust the vernier press “UP” or “DOWN”. Unlike most functions the ver
nier 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
vernierasitisdisplayed.
U
Increment display
Current vernier value in°C
-
-
-
32
0.00090
New vernier setting
Page 37
8 Controller operation
Temperature scale units
Next press “EXIT” to return to the temperature display or “SET” to access the
temperature scale units selection.
S
Access scale units
8.4Temperature scale units
The temperature scale units of the controller may be set by the user to degrees
Celsius (°C) or Fahrenheit (°F). The units will be used in displaying the bath
temperature, set-point, vernier, proportional band, and cut-out set-point.
The temperature scale units selection is accessed after the vernier adjustment
function by pressing “SET”. From the temperature display function access the
units selection by pressing “SET” 4 times.
25.00 C
S
1. 25.0
S
Access set-point memory
Access set-point value
Bath temperature
Set-point memory
C 25.00
S
0.00000
S
Un= C
Press “UP” or “DOWN” to change the units.
U
Un= F
Press “SET” to accept the new selection and resume displaying the bath
temperature.
S
Access vernier
Access scale units selection
Change units
Set the new units and resume temperature display
Set-point value
Vernier setting
Scale units currently selected
New units selected
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8.5Secondary menu
Functions which are used less often are accessed within the secondary menu.
The secondary menu is accessed by pressing “SET” and “EXIT” simulta
neously and then releasing. The first function in the secondary menu is the
heater power display. (See Figure 6.)
8.6Heater 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 di
rectly from the digital display. By knowing the amount of heating 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 heat-
ing 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.
S+E
12 Pct
To exit out of the secondary menu press “EXIT”. To continue on to the proportional band setting function press “SET”.
E
Return to temperature display
Access heater power in secondary menu
Heater power in percent
8.7Proportional 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 bot
tom of the proportional band the heater output is 100%. At the top of the pro
portional 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.
-
-
34
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 ex
cessively 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 propor
-
-
Page 39
8 Controller operation
Proportional band
tional band is too narrow the bath temperature may swing back and forth be
cause the controller overreacts to temperature variations. For best control
stability the proportional band must be set for the optimum width.
The optimum proportional band width depends on several factors among which
are fluid volume, fluid characteristics (viscosity, specific heat, thermal conduc
tivity), 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 propor
tional band width are the fluid viscosity and thermal noise due to difference in
temperature between the fluid and ambient. The proportional band should be
wider when the fluid viscosity is higher because of the increased response time
and also when noise is greater.
Proportional Band too NarrowProportional Band too Wide
-
-
-
Optimum Proportional Band
Figure 7 Bath temperature fluctuations at various proportional band settings
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 control
ler 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.
S+E
12 Pct
Access heater power in secondary menu
Heater power in percent
-
S
Access proportional band
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6055 Calibration Bath
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Pb=0.101C
To change the proportional band press “UP” or “DOWN”.
D
Pb=0.060C
To accept the new setting and access the cut-out set-point press “SET”. Press
ing “EXIT” will exit the secondary menu ignoring any changes just made to the
proportional band value.
S
8.8Cut-out
As a protection against software or hardware fault, shorted heater triac, or user
error, the bath is equipped with an adjustable heater cut-out device that will
shut 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 cut-out 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.
Proportional band setting
Decrement display
New proportional band setting
-
Accept the new proportional band setting
If the cut-out is activated because of excessive bath temperature then power to
the heater will be shut off and the bath will cool. The bath will cool until it
reaches a few degrees below the cut-out set-point temperature. At this point the
action of the cut-out is determined by the setting of the cut-out mode parameter.
The cut-out has two modes — automatic reset or manual reset. If the mode is
set to automatic, then the cut-out will automatically reset itself when the bath
temperature falls below the reset temperature allowing the bath to heat up
again. If the mode is set to manual, then the heater will remain disabled until
the user manually resets the cut-out.
The cut-out 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 cut-out set-point.
S+E
12 Pct
S
Access proportional band
Access heater power in secondary menu
Heater power in percent
36
Page 41
8 Controller operation
Controller configuration
Pb=0.101C
S
Access cut-out set-point
CO= 210C
To change the cut-out set-point press “UP” or “DOWN”.
D
Decrement display
CO= 95C
To accept the new cut-out set-point press “SET”.
S
The next function is the configuration menu. Press “EXIT” to resume displaying the bath temperature.
Accept cut-out set-point
Proportional band setting
Cut-out set-point
New cut-out set-point
8.9Controller 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 cut-out set-point function by pressing
“SET”. The display will prompt with “COnFIG”. Press “SET” once more.
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”. See Figure 6.
8.10Probe parameters
The probe parameter menu is indicated by,
PrObE
Press “SET” to enter the menu. The probe parameters menu contains the pa
rameters, R0 and ALPHA, which characterize the resistance-temperature rela
tionship of the platinum control probe. These parameters may be adjusted to
improve the accuracy of the bath. This procedure is explained in detail in Sec
tion 10.
The probe parameters are accessed by pressing “SET” after the name of the pa
rameter 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” will cause the parameter to
be skipped ignoring any changes that may have been made.
Probe parameters menu
-
-
-
-
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6055 Calibration Bath
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8.10.1R0
This probe parameter refers to the resistance of the control probe at 0°C. Nor
mally this is set for 100.000 ohms.
8.10.2ALPHA
This probe parameter refers to the average sensitivity of the probe between 0
and 100°C. Normally this is set for 0.00385°C
8.11Operating parameters
The operating parameters menu is indicated by,
PAr
Press “SET” to enter the menu. The operating parameters menu contains the
cut-out reset mode parameter.
8.11.1Cut-out reset mode
The cut-out reset mode determines whether the cut-out resets automatically
when the bath temperature drops to a safe value or must be manually reset by
the operator.
Operating parameters menu
-
-1
.
The parameter is indicated by,
CtorSt
Press “SET” to access the parameter setting. Normally the cut-out is set for
manual mode.
Cto=rst
To change to automatic reset mode press “UP” and then “SET”.
Cto=Auto
Cut-out reset mode parameter
Cut-out set for manual reset
Cut-out set for automatic reset
8.11.2Stir mode select
This parameter along with the Stirrer Set-point allows the user to set the tem
perature at which the stirrer 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 stirrer motor to shut off
and turn on only when the salt is a liquid (>200°C) preventing the stirrer motor
from overheating and damage.
-
38
The parameter is indicated by,
Page 43
8 Controller operation
Operating parameters
Str Act
Press “SET” to access the parameter setting.
Str=Auto
To change the setting to always on press the “UP” or “DOWN” buttons and
then “SET”. When set to “Str=On” the stirrer motor comes on with the bath
power regardless of the temperature set in the stirrer set-point parameter.
8.11.3Stir set-point
Allows setting of the temperature above which the stirrer motor will activate
when the stirrer activation is set to automatic.
To access the paramter press “SET” from the stirrer activation parameter.
Set-point mode selection parameter is indicated by,
Str SEtStirrer motor activation set-point parameter
Press “SET” to access the parameter value.
Stirrer mode selection parameter
Stirrer is set for automatic activation at the stirrer set-point
temperature.
Str=200
Press “UP” or “DOWN” to change the value and then “SET” to enter the new
value.
NOTE: Stir Mode Select defaults to “
bath is cycled off and back on. Therefore, this parameter has to be set
each time the bath is powered on if “
eration.
8.11.4Heat up power
NOTE: This section applies to controller parameters, not to the High/Low
setting of the front panel heater switch.
This feature helps lengthen the lifetime of the heaters when using heat transfer
salt as the bath fluid. The heater power will be limited to less than 30% while
the salt is solid at low temperatures to prevent the heaters from overheating.
Once the temperature reaches 200°C the heaters can then operate at 100%
power.
Stirrer motor activation set-point
” each time the power of the
” is the desired mode of op
-
HEAt UPHeat up power option
Press “SET” to access the parameter value.
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6055 Calibration Bath
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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.
8.12Serial interface parameters
The optional serial RS-232 interface parameters menu is indicated by,
HU=LOLow power heat up mode for heat transfer salt
HU=HIHigh power heat up mode
SErIAL
The serial interface parameters menu contains parameters which determine the
operation of the serial interface. These controls only apply to baths fitted with
the serial interface. The parameters in the menu are — baud rate, sample period, duplex mode, and linefeed.
8.12.1Baud 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,
BAUd
Press “SET” to choose to set the baud rate. The current baud rate value will
then be displayed.
1200 b
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.
Serial RS-232 interface parameters menu
Serial baud rate parameter
Current baud rate
40
2400 b
Press “SET” to set the baud rate to the new value or “EXIT” to abort the opera
tion and skip to the next parameter in the menu.
New baud rate
-
Page 45
8.12.2Sample 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 measure
ments transmitted from the serial interface. If the sample rate is set to 5, for in
stance, 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,
8 Controller operation
Serial interface parameters
-
-
SAmPLE
Press “SET” to choose to set the sample period. The current sample period
value will be displayed.
SA= 1
Adjust the value with “UP” or “DOWN” and then use “SET” to set the sample
rate to the displayed value.
SA= 60
8.12.3Duplex 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 will be immediately echoed or transmitted back to the device of origin. With half duplex the commands will be executed but not echoed.
The duplex mode parameter is indicated by,
dUPL
Serial sample period parameter
Current sample period (seconds)
New sample period
Serial duplex mode parameter
Press “SET” to access the mode setting.
dUP=FULL
The mode may be changed using “UP” or “DOWN” and pressing “SET”.
dUP=HALF
8.12.4Linefeed
The final parameter in the serial interface menu is the linefeed mode. This pa
rameter 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,
LF
Current duplex mode setting
New duplex mode setting
-
Serial linefeed parameter
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6055 Calibration Bath
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Press “SET” to access the linefeed parameter.
LF= On
The mode may be changed using “UP” or “DOWN” and pressing “SET”.
LF= OFF
Current linefeed setting
New linefeed setting
8.13IEEE-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,
IEEE
Press “SET” to enter the menu.
8.13.1IEEE-488 address
The IEEE-488 interface must be configured to use the same address as the external communicating device. The address is indicated by,
IEEE-488 parameters menu
AddrESS
Press “SET” to access the address setting.
Add= 22
Adjust the value with “UP” or “DOWN” and then use “SET” to set the address
to the displayed value.
Add= 15
IEEE-488 interface address
Current IEEE-488 interface address
New IEEE-488 interface address
8.14Calibration parameters
The operator of the bath controller has access to a number of the bath calibra
tion constants, namely CTO, C0, CG, H, and L. These values are set at the fac
tory 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 avail
able 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.
-
-
-
42
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8 Controller operation
Calibration parameters
CAUTION: DO NOT change the values of the bath calibration constants
from the factory set values. The correct setting of these parameters is im
portant to the safety and proper operation of the bath.
The calibration parameters menu is indicated by,
-
CAL
Press “SET” five times to enter the menu.
8.14.1CTO
Parameter CTO sets the calibration of the over-temperature cut-out. This is not
adjustable by software but is adjusted with an internal potentiometer. For the
6055 bath this parameter should read between 560 and 570.
8.14.2CO and CG
These parameters calibrate the accuracy of the bath set-point. These are programmed at the factory when the bath is calibrated. Do not alter the value of
these parameters. If the user desires to calibrate the bath for improved accuracy
then calibrate R0 and ALPHA according to the procedure given in Section 10.
8.14.3H and L
These parameters set the upper and lower set-point limits of the bath. DO NOT
change the values of these parameters from the factory set values. To do so may
present danger of the bath overheating and causing damage or fire.
Calibration parameters menu
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9 Digital communication interface
9Digital communication interface
If supplied with the option, the 6055 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.
9.1Serial communications
Serial communications
The bath may be installed with an RS-232 serial interface that allows serial dig
ital communications over fairly long distances. With the serial interface the user
may access any of the functions, parameters and settings discussed in Section7
with the exception of the BAUD rate setting. The serial interface operates with
8 data bits, 1 stop bit, and no parity. The use of a shielded communications ca
ble is recommended.
9.1.1Wiring
The serial communications cable attaches to the bath through the DB-9 connector on the back panel. 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.
9.1.2Setup
Before operation, the serial
interface of the bath must first
be set up by programming the
BAUD rate and other configu
ration parameters. These pa
rameters are programmed
within the serial interface
menu. The serial interface pa
rameters menu is outlined in
Figure 6.
-
-
-
-
-
To enter the serial parameter
programming mode first press
“EXIT” while pressing “SET”
and release to enter the sec
ondary menu. Press “SET” re
peatedly until the display
reads “ProbE” .Thisisthe
menu selection. Press “UP”
-
-
Figure 8 Serial Cable Wiring Diagram
45
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6055 Calibration Bath
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repeatedly until the serial interface menu is indicated with “SErIAL”. Finally
press “SET” to enter the serial interface parameters menu. In the serial interface
parameters menu are the baud rate, sample rate, duplex mode, and linefeed
parameters.
9.1.2.1Baud 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.
9.1.2.2Sample period
The sample period is the next parameter in the menu and prompted with “SAm
PLE”. 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, for instance, 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.
9.1.2.3Duplex 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 will be immediately echoed or transmitted back to the device of origin. With half duplex
the commands will be executed but not echoed. The default setting is full duplex. The mode may be changed using “UP” or “DOWN” and pressing “SET”.
9.1.2.4Linefeed
The final parameter in the serial interface menu is the linefeed mode. This pa
rameter enables (“On”)ordisables(“OFF”) transmission of a linefeed charac
ter (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”.
-
-
-
46
9.1.3Serial operation
Once the cable has been attached and the interface set up properly the control
ler will immediately begin transmitting temperature readings at the pro
grammed rate. The serial interface operates with 8 data bits, 1 stop bit, and no
parity. 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 inter
-
-
-
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9 Digital communication interface
IEEE-488 communication (optional)
face commands are discussed in Section 9.3. All commands are ASCII charac
ter strings terminated with a carriage-return character (CR, ASCII 13).
9.2IEEE-488 communication (optional)
The IEEE-488 interface is available as an option. Baths supplied with this op
tion 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.
9.2.1Setup and address selection
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”.Thisis
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.
-
-
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”.
9.2.2IEEE-488 operation
Commands may now be sent via the IEEE-488 interface to read or set the tem
perature or access other controller functions. All commands are ASCII charac
ter strings and are terminated with a carriage-return (CR, ASCII 13). Interface
commands are listed below.
9.3Interface commands
The various commands for accessing the bath controller functions via the digi
tal interfaces are listed in this section (see Table 1). These commands are used
with both the RS-232 serial interface and the IEEE-488 GPIB interface. In ei
ther case the commands are terminated with a carriage-return character. The in
terface 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 (set-point 1) to
50.00 degrees.
-
-
-
-
-
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6055 Calibration Bath
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Table 1 Interface command summary
Command
Command Description
Display Temperature
Read current set-points[etpoint]sset: 9999.99 {C or F}set: 150.00 C
Set current set-point to ns[etpoint]=ns=450Instrument
Read vernierv[ernier]vv: 9.99999v: 0.00000
Set vernier to nv[ernier]=nv=.00001Depends on
Read temperaturet[emperature]tt: 9999.99 {C or F}t: 55.69 C
Read temperature unitsu[nits]uu: xu: c
Set temperature units:u[nits]=c/f
Set temperature units to Celsiusu[nits]=cu=c
Set temperature units to
Fahrenheit
Secondary Menu
Read proportional band settingpr[op-band]prpb: 999.9pb: 15.9
Set proportional band to
n
Format
u[nits]=fu=f
pr[op-band]=npr=8.83Depends on
Command
ExampleReturned
Returned
Example
Acceptable
Values
Range
Configuration
CorF
Configuration
Read cut-out settingc[utout]cc: 9999 {x},{xxx}c: 620 C, in
Read high set-point limit value*th[igh]*thth: 999th: 205
Set high set-point limit to
Miscellaneous (not on menus)
Read firmware version number*ver[sion]*verver.9999,9.99ver.2100,3.56
Read structure of all commandsh[elp]hlist of commands
Read Heater 1f1f1f1:9f1:1
Set Heater 1f1=1/01or0
n
n
*c0=n*c0=0–999.9 to 999.9
n
*cg=n*cg=406.25–999.9 to 999.9
*tl[ow]=n*tl=-80–999.9 to 999.9
*th[igh]=n*th=205–999.9 to 999.9
ON or OFF
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Interface command summary cont.
Command
Command Description
Set heater 1 to onf1=
Set heater 1 to offf1=
Read Heater 2f2f2f2:9f2:0
Set Heater 2f2=1/01or0
Set Heater 2 to onf2=
Set Heater 2 to offf2=
Read Heater 3f3f3f3:9f3:1
Set Heater 3f3=1/01or0
Set Heater 3 to onf3=
Set Heater 3 to offf3=
Read Heater 4f4f4f4:9f4:1
Set Heater 4f4=1/01or0
Set Heater 4 to onf4=
Set Heater 4 to offf4=
Read Boost Heaterf5f5f5:9f5:1
Set Boost Heaterf5=1/01or0
Format
n
n
n
n
n
n
n
n
Command
ExampleReturned
f1=1
f1=0
f2=1
f2=0
f3=1
f3=0
f4=1
f4=0
Returned
Example
Acceptable
Values
Set Boost Heater to onf5=
Set Boost Heater to offf5=
Legend:[] Optional Command data
Note:When DUPLEX is set to FULL and a command is sent to READ, the command is returned followed by a
n
n
{} Returns either information
n Numeric data supplied by user
9 Numeric data returned to user
x Character data returned to user
carriage return and linefeed. Then the value is returned as indicated in the RETURNED column.
f5=1
f5=0
50
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In Table 1, characters or data within brackets, “[” and “]”, are optional for the
command. A slash, “/”, denotes alternate characters or data. Numeric data, de
noted by “n”, may be entered in decimal or exponential notation. Characters are
shown in lower case although upper case may be used. Spaces may be added
within command strings and will simply be ignored. Backspace (BS, ASCII 8)
may be used to erase the previous character. A terminating CR is implied with
all commands.
9.4Power commands
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 dis
abled by 1) switching the heater control to “OFF”, and 2) switching the boost
heater switch to “OFF”. Otherwise, the interface would not be able to switch
these functions off. The 6055 bath has five control functions with the digital in
terface. These are controls for heaters 1, 2, 3, and 4, each 225 W, and the boost
heater which is 900 W. Heater 1 power could be varied with the DRIFT control
on the front panel. The boost heater should only be used for quickly heating the
bath up to a high temperature and not for controlling at a constant temperature.
9 Digital communication interface
Power commands
-
-
-
Serial commands “F1” through “F5” control the heaters 1 through 4 and the
boost heater individually. These commands are used to turn the heaters on or
off or to read the states of the heaters. Sending a command with parameter “1”
turns the heater on. Parameter “0” turns the heater off. No parameter returns the
state, “1” for on or “0” for off. For example “F1=1”<RETURN> turns on
heater 1. “F1”<RETURN> (no parameter) will return “f1:1” or “f1:0” depending on whether heater 1 is on or off respectively.
Since unlike the front panel heater control, which turns on multiple heaters to
achieve the desired power level, the interface commands control the heaters in
dividually, multiple commands must be issued to set the desired amount of
power. Table 2 lists the commands which should be given to set various power
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6055 Calibration Bath
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levels. Power is variable with the front panel DRIFT control when heater 1 (F1)
is turned on.
Table 2 Power Commands
POWERF1F2F3F4F5
OFF00000
0–225 W LOW10000
225–450 W
MEDIUM
450–675 W
MEDIUM HIGH
675–900 W HIGH11110
1800 W BOOST11111
11000
11100
9.5Heater settings for control
Suggested heater control settings for various ranges are suggested below.
RangeControls
150°C–250°CLOW - Heater 1 on, heaters 2–4 and boost heater off
250°C–350°CMEDIUM - Heaters 1 and 2 on, heater 3, 4, and boost heater off
350°C–450°CMEDIUM HIGH - Heaters 1–3 on and heater 4 and boost heater off
450°C–550°CHIGH - Heaters 1–4 and boost heater on
52
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10Calibration procedure
10 Calibration procedure
Calibration points
In some instances the user may want to calibrate the bath to improve the tem
perature 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 temper
ature 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.
10.1Calibration 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 will be
obtained when using bath temperatures which are just within the most useful
operating range of the bath. The further apart the calibration temperatures the
larger will be the calibrated temperature range but the calibration error will also
be greater over the range. If for instance 50°C and 150°C are chosen as the cali-
bration temperatures then the bath may achieve an accuracy of say ±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.
-
-
10.2Measuring the set-point error
The first step in the calibration procedure is to measure the temperature errors
(including sign) at the two calibration temperatures. First set the bath to the
lower set-point which we will call t
. Wait for the bath to reach the set-point
L
and allow 15 minutes to stabilize at that temperature. Check the bath stability
with the thermometer. When both the bath and the thermometer have stabilized
measure the bath temperature with the thermometer and compute the tempera
ture error err
which is the actual bath temperature minus the set-point temper
L
ature. If for example the bath is set for a lower set-point of t
bath reaches 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
and after stabilizing measure the
H
. For our example we will suppose
H
the bath was set for 150°C and the thermometer measured 150.1°C giving an
errorof+0.1°C.
10.3Computing 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
=50°C and the
L
-
-
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6055 Calibration Bath
User’s Guide
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 re
stored 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
t
H
, and the temperature errors errLand errHinto the following equations,
L
-
and
⎡
R
010′=
ALPHA
err terr t
⎢
⎣
′=
−
HLLH
tt
−
HL
⎡
ALPHA t errALPHA t err
+−+
()()11
⎢
⎣
ALPHAR
HLLH
tt
HL
If for example R0 and ALPHA were previously set for 100.000 and 0.0038500
respectively and the data for t
L,tH
new values R0′ and ALPHA′ would be computed as 100.193 and 0.0038272 re
spectively. 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.
10.4Calibration 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.
⎤
+
⎥
⎦
⎤
+
−
1⎥ALPHA
⎦
,errL,anderrHwere as given above then the
and tHand measuring the errors
L
-
54
Page 58
R0= 100.000
ALPHA = 0.0038500
t
= 80.00°C
L
measured t = 79.843°C
t
= 120.00°C
H
measured t = 119.914°C
Compute errors,
err
= 79.843 - 80.00°C = -0.157°C
L
err
= 119.914 - 120.00°C = -0.086°C
H
10 Calibration procedure
Calibration example
Compute R
⎡
R
0
⎢
⎣
,
0
0 08680 00157120 0
−−−
(. ). (. ) .
xx
120 080 0
Compute ALPHA,
⎡
ALPHA′=
+−−+(..)(.)(..)(1 0 00385 120 0015710 0038580 0xx
⎢
⎣
Figure 9 Calibration example
−
..
0 00385′=
.
120 080 0
−
..
⎤
+
1 100 000100115
⎥
=..
⎦
−
0 086
.)
⎤
+
1 0 003850 0038387
..
⎥
=
⎦
55
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11Maintenance
11 Maintenance
The calibration instrument has been designed with the utmost care. Ease of op
eration 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 operat
•
ing 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 salt. 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 oils.
• The stirring motor should be clean to allow proper cooling. Normally
only the outside surfaces require any attention. If the inside of the motor
has become heavily loaded with salt, blow it out with compressed air. Follow normal safety procedures when using pressurized gasses.
• Salt expands and contracts with temperature. Be sure that the correct
amount of salt is used for the temperature. If the bath is used at a lower
temperature and then raised to a higher temperature, some of the molten
salt may need to be carefully removed to prevent overflow.
-
-
• 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. Af
ter 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 usually sufficient.
•
If a hazardous material is spilt on or inside the equipment, the user is re
sponsible for taking the appropriate decontamination steps as outlined by
the national safety council with respect to the material. MSDS sheets ap
plicable to all fluids used in the baths should be kept in close proximity to
the instrument.
•
If the mains supply cord becomes damaged, replace it with a cord with
the appropriate gauge wire for the current of the bath. If there are any
questions, contact an Authorized Service Center for more information.
-
-
-
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6055 Calibration Bath
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WARNING: When checking the over-temperature cut-out, 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.
Before using any cleaning or decontamination method except those rec
•
ommended by Hart, users should check with an Authorized Service Cen
ter 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 equip
•
ment design, the operation of the bath may be impaired or safety hazards
may arise.
The over-temperature cut-out should be checked every 6 months to see
•
that it is working properly. In order to check the user selected cut-out, fol
low the controller directions (Section 8.2) for setting the cut-out. Both the
manual and the auto reset option of the cut-out should be checked. Set the
bath temperature higher than the cut-out. Check to see if the display
flashes cut-out and the temperature is decreasing.
-
-
-
-
• The constant temperature bath depends upon the certain qualities of the
fluid medium in order to maintain a uniform and stable temperature environment.
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12Troubleshooting
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 sec
tion carefully and attempt to understand and solve the problem. If the bath
seems faulty or the problem cannot otherwise be solved, then contact an Autho
rized Service Center for assistance. Opening the unit without contacting an Au
thorized Service Center may void the warranty.
12.1Troubleshooting
ProblemCauses and Solutions
12 Troubleshooting
Troubleshooting
-
-
-
The heater indicator LED
stays red but the temper
ature does not increase
The controller display
flashes “CUToUT” and
the heater does not
operate
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 (see Section 1.3) 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 tempera
ture 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 “RE
SET”, the heater only comes on again when the temperature is reduced and the
operator manually resets the cutout. (Refer to Section 8.11.1.)
Check that the cutout set-point is adjusted to 10 or 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 be
low 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 con
stants must be re-programmed. The values can be found on the Report of Cali
bration that was shipped with the instrument.
-
-
-
-
-
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ProblemCauses and Solutions
The display flashes
“CUToUT” alternately
with an incorrect process
temperature
The controller displays
the wrong temperature
and the bath continually
heats or cools regardless
of the set-point value
The controller controls or
attempts to control at an
inaccurate temperature
Low battery. A problem could exist with the memory back-up battery. If the bat
tery voltage is insufficient to maintain the memory, data may become scrambled
causing problems. A nearby large static discharge may also affect data in mem
ory. 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).
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 be
tween 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).
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 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.
-
-
-
60
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 long-term stability of the bath is
affected. In this case decrease the width of the band. (Refer to Section 8.7.)
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 in
stability. Increase the width of the proportional band until the temperature stabi
lizes. (Refer to Section 8.7.)
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-
Page 63
ProblemCauses and Solutions
12 Troubleshooting
Comments
Stir motor does not
function
The controller does not
maintain controller parameters or parameters
are reset each time the
power to the unit is
removed
Improper setting or normal operation. See Section 8.11.2, Stir Mode Select, for
proper stir mode settings.
Auto
Note: Stir Mode Select defaults to “
bath is cycled off and back on. Therefore, this parameter has to be set each
time the bath is powered on if “
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).
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 a Hart Scientific Authorized Service Center for assistance.
5. After replacing the battery, you must reprogram the calibration and user-adjustable parameters into the controller.
Str-ON
” each time the power of the
” is the desired mode of operation.
12.2Comments
12.2.1EMC Directive
Hart Scientific’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.
12.2.2Low 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 IEC 1010-1 (EN
61010-1) and the IEC 1010-2-010 (EN 61010-2-010) standards.
Via Acquanera, 29 22100 Como
tel. 031.526.566 (r.a.) fax 031.507.984
info@calpower.it www.calpower.it
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