Fluke Calibration 6054 User Manual

Via Acquanera, 29 22100 Como
tel. 031.526.566 (r.a.) fax 031.507.984

[e-mail] www.calpower.it

6054

Calibration Bath

October 2013
© 2013 Fluke Corporation. All rights reserved. Specifications are subject to change without notice.
All product names are trademarks of their respective companies.

User Manual

WARNING

To ensure the safety of operating personnel, and to avoid damage to this unit:

DO NOT operate this unit without a properly grounded, properly polarized power cord.

DO NOT connect this unit to a non-grounded, non-polarized outlet.

DO use a ground fault interrupt device.

WARNING

HIGH TEMPERATURES PRESENT

in this equipment.

FIRES and SEVERE BURNS

may result if personnel fail to observe safety precautions.

WARNING

HIGH VOLTAGE

is used in the operation of this equipment.

SEVERE INJURY or DEATH

may result if personnel fail to observe safety precautions.

Before working inside the equipment, turn power off and disconnect power cord.

Consult the fluid manufacturer’s MSDS (Material Safety Data Sheet).

SAFETY PRECAUTIONS MUST BE OBSERVED.

WARNING

Fluids used in this bath may produce

NOXIOUS OR TOXIC FUMES

under certain circumstances.

PROPER VENTILATION AND

c

d

TABLE OF CONTENTS

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3 Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.1 Two Modes of Temperature Control . . . . . . . . . . . . . . . . . . . . . . 11

3.1.1 The Temperature Control Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.1.2 The Temperature Drift Mode: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.1.3 The Fluid system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.2 Description Of Features and Controls . . . . . . . . . . . . . . . . . . . . . 12

3.2.1 The Controller Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3.2.2 The Power Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

3.2.3 The Rear Panel: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

4 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

4.1 Receiving and Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

4.2 Installation Location Requirements . . . . . . . . . . . . . . . . . . . . . . 16

4.2.1 Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

4.2.2 Electrical Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

4.2.3 Safety Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

4.3 Setup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

4.3.1 Filling the Bath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

4.3.1.1 Filling the Bath With Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

4.3.2 Draining the Oil from the Bath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

5 Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . 18

5.1 Quick Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

6 Controller Operation . . . . . . . . . . . . . . . . . . . . . . . . . 19

6.1 Bath temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

6.2 Reset Cutout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

6.3 Temperature Set-point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

6.3.1 Programmable Set-points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

6.3.2 Set-point Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

6.3.3 Set-point vernier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

6.4 Temperature Scale Units. . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

6.5 Secondary Menu. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

6.6 Heater Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

6.7 Proportional Band . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

6.8 Cutout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

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6.9 Controller Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

6.10 Probe Parameters Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

6.10.1 R0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

6.10.2 ALPHA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

6.11 Operating Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

6.11.1 Cutout Reset Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

6.11.2 Stirrer Mode Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

6.11.3 Stirrer set-point. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

6.12 Serial Interface Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . 25

6.12.1 BAUD Rate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

6.12.2 Sample Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

6.12.3 Duplex Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

6.12.4 Linefeed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

6.13 IEEE-488 Parameters Menu . . . . . . . . . . . . . . . . . . . . . . . . . . 26

6.13.1 IEEE-488 Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

6.14 Calibration Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

6.14.1 CTO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

6.14.2 CO and CG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

6.14.3 H and L. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

6.15 Operation Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

7 Digital Communication Interface . . . . . . . . . . . . . . . . . . . 28

7.1 Serial Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

7.1.1 Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

7.1.2 Setup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

7.1.2.1 BAUD rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

7.1.2.2 Sample Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

7.1.2.3 Duplex Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

7.1.2.4 Linefeed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

7.1.3 Serial Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

7.2 IEEE-488 Communication (optional) . . . . . . . . . . . . . . . . . . . . . . 29

7.2.1 Setup and Address Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

7.2.2 IEEE-488 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29

7.3 Interface Commands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

7.4 Power Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

7.5 Heater Settings for Control. . . . . . . . . . . . . . . . . . . . . . . . . . . 32

8 Bath Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

8.1 Calibration Points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

8.2 Measuring the Set-point Error . . . . . . . . . . . . . . . . . . . . . . . . . 34

8.3 Computing R0 and ALPHA . . . . . . . . . . . . . . . . . . . . . . . . . . 34

8.4 Calibration Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

9 Bath Heat Transfer Fluid . . . . . . . . . . . . . . . . . . . . . . . 35

vi

9.1 Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

9.2 Viscosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

9.3 Specific heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

9.4 Thermal Conductivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

9.5 Thermal Expansion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

9.6 Electrical Resistivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

9.7 Fluid lifetime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

9.8 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

9.9 Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

9.9.1 Commonly used fluids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36

9.9.2 Water. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

9.9.3 Ethylene Glycol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

9.9.4 Mineral Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

9.9.5 Silicone oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

9.9.6 Heat Transfer Salt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

9.10 Fluid Characteristics Charts . . . . . . . . . . . . . . . . . . . . . . . . . . 39

9.10.1 Limitations and Disclaimer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

9.10.2 About the Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

10 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

10.1 The Heater Indicator LED Stays Red But The Temperature Does Not In-

crease. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

10.2 The Controller Display Flashes “CUT-OUT” And The Heater Does Not Oper-

ate. 41

10.3 The Display Flashes “CUT-OUT” And An Incorrect Process Temperature. . . 41

10.4 The Displayed Process Temperature Is In Error And The Controller Remains In

The Cooling Or Heating State At Any Set-point Value. . . . . . . . . . . . . . . . . 42

10.5 The Controller Controls Or Attempts To Control At An Inaccurate Tempera

ture. 42

10.6 The Controller Shows That The Output Power Is Steady But The Process Temper

ature Is Unstable.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

10.7 The Controller Alternately Heats For A While Then Cools. . . . . . . . . . . 42

10.8 The Controller Erratically Heats Then Cools, Control Is Unstable. . . . . . . . 42

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vii

1 Introduction

Introduction

The Hart Scientific Model 6054 Calibration Bath is a
highly stable constant temperature liquid bath. It has
been designed for calibrating liquid and glass ther
mometers or other types of long thermometers
against a known temperature standard such as a
Standard Platinum Resistance Thermometer
(SPRT).

The 6054 calibration bath provides the following fea
tures:

A deep fluid tank (test well is 7.5 inches in di

•

ameter and has 24 inches of fluid depth).

It provides a highly temperature stable low gra

•

dient environment typically a nominal stability
of ±0.005°C with oils. The fluid is well stirred

and environmentally protected to minimize
gradients.

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-

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The fluid level is near the top of the test well to

•

facilitate calibration of liquid and glass ther
mometers without needing to compensate for
stem effect.

The bath provides two calibration modes. An

•

electronically controlled mode uses a hybrid
digital and analog PI controller with lock in am
plifier design. The temperature and other func
tions are selected with the four button keypad
to a hundredth of a degree and finer with a digi
tal vernier adjustment. The Drift mode by
passes the controller with heater power
manually controlled with variable transformer.

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-

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9

Specifications

2 Specifications

Table 1

Power Required . . . . . . . . . 230 VAC; 60 Hz; 15 Amps max.

Bath Temperature Range . . . . 50°C to 325°C

Temperature Stability. . . . . . .

Temperature Uniformity . . . . .

Controller Accuracy . . . . . . .

Test Well Area . . . . . . . . . . 7.5-inches dia X 24-inches deep

Heater . . . . . . . . . . . . . . Electrical, 5 positions; 1=off, 2=250, 3=500, 4=750 & 5=1,000 watts at

Boost Heater . . . . . . . . . . . 750watts

Heat Transfer Liquid . . . . . . . Fluids compatible with stainless steel may be used. (e.g. oils such as

Exterior Dimensions . . . . . . . Height 56" X Width 31" X FB 23"

Weight . . . . . . . . . . . . . . 156 Lbs.

Specifications

±0.005°C to 200°C, ±0.010°C to 325°C

±0.005°C max

±0.5°C

240 VAC line

Dow Corning 710 and 210H or Hart Salt)

10

3 Theory of Operation

Theory of Operation

The components, features and operational theory of
the Model 6054 calibration bath are described in this
section.

3.1 Two Modes of
Temperature Control

Two modes of temperature control are available with
the model 6054. The TEMPERATURE CONTROL
mode or the TEMPERATURE DRIFT mode may be
selected by a switch on the front panel.

3.1.1 The Temperature Control Mode

The control mode uses a hybrid digital/analog PI tem­perature controller with lock-in-amplifier. The bath
stability is very high with this controller. The tempera­ture is selected using a four button keypad on the front
panel. Temperatures from 0.00 to 325.00°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.

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.
It is a totally separateunit for ease of replacement.It is
inserted into the top of the bath near the stirring motor
as shown and plugs into the rear of the control unit.

The heaters are external to the tank. They are ar
ranged electrically to provide the 4 control heating po
sitions plus an off position. The additional boost
heating position is accessed from a separate switch
on the control panel.

3.1.2 The Temperature Drift Mode:

In the Temperature Drift mode the heater may be set
manually to allow the temperature to drift very slowly

(a few milli-°C per minute) over the desired range.
This allows the control noise to be eliminated al
though 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 po
sition one of the heater selection switch to be continu
ally variable from 0 to 100% Positions 2, 3, 4 and
Boost add their full value of heat incrementally to the
adjusted value of position 1.

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-

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3.1.3 The Fluid system

The fluid system consists of the insulated tank, the
stirrer assembly, the condensate drain, the overflow
test well, and the fluid itself. The heaters and probe,
which are part of the control system, are physically
external to the tank.

The tank and other wettedparts are made of stainless
steel for compatibility with most practical
thermostating fluids.The stirrer is attached to the tank
top plate of the bath and its motor receives additional
cooling from a fan to keep from overheating and in­crease lifetime at high bath temperatures. The stirrer
directly drives four 2-inch diameter stirring propellers.
The down draft from the propellers forces the bath
fluid through the overflow test well.The stirring motor
plugs into the rear of the control unit.(See Figure 3 on
page 14.)

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 volatilization will 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

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tank for thermal management.

A drain is provided for convenience in changing the
bath fluid. (See draining the tank.)

The condensate drain collects condensed oil vapor
and oil that has expanded over the top of the tank
walls.Tubes on either side of the drainat the bottom of
the bath allow the liquid to be collected into a pan. Be
sure this pan is in place at all times to prevent oil from
draining onto the floor The condensate pan must be

11

Theory of Operation

EXIT — Used to exit from a menu. When EXIT is
pressed any changes made to the displayed value will
be ignored.

3) The control indicator is a two color light emitting di
ode (LED).This indicatorlets theuser visually see the
ratio of heating to cooling. When the indicator is red
the heater is on, and when it is green the heater is off
and the bath is cooling.

3.2.2 The Power Panel

The Power Panel (Figure 2) controls include; 1) The

Mode Select switch and indicators, 2) the Drift Ad
just control 3) the control Heating select switch, 4)
the Power switch and indicator, and 5) the Boost
Heater and indicator.

1) The MODE SELECT switch selects between the
Temperature Control and Drift Adjust modes. Lights
show which mode is functioning. The Temperature
Control position selects the temperature controller to
operate and the desired temperature is selected on
the controller panel. In the Temperature Drift mode

heater control is via the Drift Adjust control and the
Heating select switch.

2) The DRIFT ADJUST control is a variable trans

-

former that adjusts the Low control heater through 0
to 100% of its power range. The additional power re

-

­quired for higher temperatures may be added in steps
by selecting heating positions Medium, Medium High,
and High, as required.

3) The control HEATING switch selects control heater
power positions 1 through 5. Select the lowest rea
sonable value for normal control conditions depend

-

­ing on bath temperature. The switch simply adds

-

more heaters into the circuit until the desired power is
attained. Position 2 is variable using the Drift Adjust
control.

4) The POWER (On-Off) switch powers up the bath.
The switch is a DPST type that opens both legs of the
230 volt power source. A red indicator light shows that
power is on.

5) The BOOST HEATING provides an additional 750
watts for slewing between temperatures. The Boost
Heating Indicator shows whether the boost heater is
on or off. The boost heater is powered through the

Boost Heating

Indicator

Power

Indicator

Figure 2

BOOST

HEATER

OFF

ON

OFF

Power panel

Boost Heating

Switch

5

4

Power

Switch

Mode Select

Switch

1

Temperature Drift

Mode Indicator

TEMPERATURE DRIFT

MODE SELECT

TEMPERATURE CONTROL

OFF

3

Heating

Switch

LOW

HEATINGPOWER

HIGH

Temperature Control

Mode Indicator

20

Drift Adjust

Control

2

DRIFT ADJUST

40

30

10

0

50

PERCENT

60

70

80

90

100

13

Theory of Operation

1

2

3

8

4

7

E

F

S

U

E

S

U

F

F

U

S

U

F

E

S

E

6

Figure 3

Back panel

14

5

Theory of Operation

temperature controller triac to prevent exceeding the
desired set temperature. The boost heater indicator
will flash when the set temperature has been reached
as a reminder to turn it off for control.

3.2.3 The Rear Panel:

The Rear Panel has many features (see Figure 3). 1)
The PROBE connector, 8) STIRRER POWER outlet,

7) FUSES, 6) Power Connection, 5) ELECTRONICS
FUSE INTERNAL notation, 2) Unit SERIAL NO. no
tation, 3) optional SERIAL PORT and, 4) optional
IEEE-488 PORT.

1) The PROBE connector on the back panel is used
for the temperature controller probe.

2) The unit SERIAL NO.is located at the top right cor
ner of the back panel. When consulting with the fac

-

­tory, refer to the serial number.

3) SERIAL PORT (optional)

4) IEEE-488 PORT (optional)

5) The ELECTRONICS FUSE is located inside the
cabinet and is a 1/4 amp fuse. To replace the elec

­tronic fuse, remove the cover over the controller.

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6) The POWER CORD connector

7) The SYSTEM FUSES are 15 amps slow blow (one
fuse for each leg of the 230 VAC). The heater fuses
are located internally and are 10 amp, 250 VAC.

8) The STIRRER POWER connection provides 230
VAC to the stirring motor and its cooling fan.

15

Installation

4 Installation

The Model 6054 bath can be readily installed given
due care to the following instructions.

4.1 Receiving and Inspection

Upon receipt of the bath, inspect it to see that there is
no obvious damage from shipment. If any damage is
observed, notify the carrier at once for an inspector to
check out the damage.

Verify that all of the items ordered have been shipped.
Notify Hart Scientific immediately if there are any dis
crepancies.

4.2 Installation Location
Requirements

4.2.1 Environment

The model 6054 bath is a precision instrument that
must be located in an appropriate environment. The
location should be free from drafts, extreme tempera­tures and temperature changes, dirt, etc. The bath
must be level, use the levelers. Allow free air space
around the bath to allow surface heat to convect away
freely. Ventilation ofoil fumes will require a fumehood.

4.2.2 Electrical Power

Install the bath in an inherently fire safe area. There
should not be any material around that will ignite by
setting hot probes and thermometers on it or by spill
age of the hot bath fluid.

The best floor surface is concrete. If concrete is un
available, the surface should be protected in some
way from inadvertent spillage.

Do Not install thebath near flammable wall materials.

We recommend installing the bath under a fume hood
to safely remove oil fumes. It also will help to remove

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excess heat.It is best to direct oilfumes away from the
user when using.

Keep all flammable liquids, fumes, gasses, etc. away
from the bath to prevent ignition.

Keep fire safety equipment specific to the type of me­dium handy in case they are needed.

Safe handling equipment such as leather gloves
(such as welding gloves), face shields, long apron etc.
are required for reasonable safety.

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-

4.3 Setup

Inspect the probe.It should not be bent or damaged in
any way.The probe used with the Model 6054is apre
cision PRT sensor.

The probe is to be plugged into its connector on the
rear of the bath and inserted fully into the hole located
near the stirrer motor inside the motor cover.

-

The bath requires 208-240 VAC single phase power.
The higher voltage is used forrunning the heaters and
is required to reduce the current to reasonable levels.
The power connected at the junction box on the rear
of the bath. The two hot legs are wired to the brown
and blue wires, and the ground to the green/yellow
wire according to standard convention.

4.2.3 Safety Considerations

The Hart model 6054 bath is a high temperature bath.
Although safety has been a concern in its design,
there are several installation and operational consid
erations to prevent fire and burns.

16

Plug the stirrer into the receptacle located on the rear
panel of the bath marked STIRRER POWER. This re
ceptacle is switched on with the unit’s main power.

Attach a drain line to the overflow drain tube at the
rear of the bath behind the strirer.Use a line compati
ble with the selected fluid and maximum bath temper
ature to be used. Run the line to a similarly adequate
sump.

-

-

-

4.3.1 Filling the Bath

-

The bath is shipped dry. Check inside of the test well
for foreign matter and remove it to avoid interference
with operation.

Installation

4.3.1.1 Filling the Bath With Oil

To fill the bath with oil, first be sure the drain is fully
closed off. Check the drain assembly for tight fittings.
Pour in the heat transfer fluid until it reaches a 1-inch
depth from the top of the top plate.Note: Actual depth
depends on the thermal expansion of the oil and the
anticipated temperature range. The fluid volume of
the tank is approximately 2800 cubic inches to the
level of the primary overflow. The flowing fluid level

can be adjusted somewhat by adding to or removing
fluid.The fluid levelduring pumping should be flowing
over the rim.

The bath is now ready for operation.

4.3.2 Draining the Oil from the Bath

17

Operating Instructions

5 Operating Instructions

Operating the model 6054 constant temperature bath
is not complex, but must be done according to the fol
lowing instructions.

The system must be installed and the bath filled ac
cording to the instructions in the previous section.

5.1 Quick Start

With the bath fluid in the bath and the control probe in
place, the bath is ready to be turned on. When
switched on, the stirring motor, the controller display
ing the bath temperature, and the heater will come on.
Now set the bath to the desired temperature using the
buttons to set the temperature controller. This is ac
complished by pressing the SET button and then us­ing the UP and DOWN buttons to reach the desired
set temperature. Once the set-point desired is dis­played, press the SET button to set the bath to the
new temperature and then press the EXIT button to
return to the temperature display (refer to the Temper­ature Controller User Flow chart Figure 4). The bath
will heat to the set temperature and begin to control.
Allow several minutes for the bath to stabilize at the
control set-point.

The heater power switch should be set to the lowest
position necessary to provide adequate power to con
trol. Obviously, higher bath temperatures will require
higher heater settings. The boost heater may be

switched on to bring the bath up to higher tempera

-

-

-

-

-

tures quickly. It mustbe switched off when the temper
ature is reached.

To achieve optimum control stability the proportional
band may require adjustment. The ideal proportional
band setting varies with temperature, heater setting,
and fluid type.

It is advised that you operate the 6054 bath with an
access cover or thermometer holder in place. At most
temperatures, control stability is improved with the
cover in place. At high temperatures, the use of the
cover also improves safety.

To accelerate bath cooling after operation at a higher
temperature, the access cover may be removed to al­low greater air cooling. It also may be possible to
make use of a dip chiller or auxiliary cooling coil to de­crease cooling times.

If the Temperature Drift mode is desired, select that
position after adjusting the Drift Adjust to 0% to elim­inate jumps in temperature, then adjust to the antici­pated heating position. Use a bridge and strip chart
recorder or other adequate means to establish the
desired temperature drift rate as the Drift Adjustcon­trol is adjusted upward. Select the LOW control
heater position for the minimum amount of heat and
add heat in increments with positions MEDIUM, ME
DIUM HIGH and HIGH as needed.

-

-

-

18

6 Controller Operation

Controller Operation

This Section discusses in detail how to operate the
bath temperature controller using the front control
panel. Using the front panel key switches and LED
display the user may monitor the bath temperature,
set the temperature set-point in degrees C or F, moni
tor the heater output power, adjust the controller pro
portional band, set the cutout set-point, and program
the probe calibration parameters, operating parame
ters, serial and IEEE-488 interface configuration, and
controller calibration parameters. Operation ofthe pri
mary functions is summarized in Figure 4.

6.1 Bath temperature

The digital LED display on the front panel allows di
rect viewing of the actual bath temperature. This tem­perature value is what is normally shown on the
display. The units, C or F, of the temperature value are
displayed at the right. For example,

25.00 C

The temperature display function may be accessed
from any other function by pressing the “EXIT” button.

Bath temperature in degrees
Celsius

6.2 Reset Cutout

If the over-temperature cutout has been triggered
then the temperature display will alternately flash,

Cut-out

The message will continue to flash until the tempera
ture is reduced and the cutout is reset.

Indicates cut-out condition

until the user resets the cutout. To access the reset
cutout function press the “SET” button.

-

-

-

-

-

S

The display will indicate the reset function.

Press “SET” once more to reset the cutout.

This will also switch the display to the set temperature
function. To return to displaying the temperature
press the “EXIT” button. If the cutout is still in the
over-temperature fault condition the display will con­tinue to flash “cutout”. The bath temperature must
drop a few degrees below the cutout set-point before
the cutout can be reset.

Access cutout reset function

rESEt ?

Reset cutout

Cutout reset function

6.3 Temperature Set-point

The bath temperature can be set to any value within
the range as given inthe specifications with ahigh de­gree of resolution. The temperature range of the par
ticular 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 ad
dition, the cutout temperature should also be set be
low 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.

-

-

-

The cutout has two modes — automatic reset and
manual reset.The mode determines how the cutout is
reset which allows the bath to heat up again. When in
automatic mode, the cutout will reset itself as soon as
the temperature is lowered below the cutout set-point.
With manual reset mode the cutout must be reset by
the operator after the temperature falls below the
set-point.

When the cutout is active and the cutout mode is set
to manual (“reset”) then the display will flash “cutout”

6.3.1 Programmable Set-points

The controller stores 8 set-point temperatures in
memory. The set-points can be quickly recalled to
conveniently set the bath to a previously programmed
temperature.

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

19

Controller Operation

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

EXITEXITEXIT EXIT EXIT

UP

Probe
Menu

SET

R0

SET SET SET

SET

Adj. ALPHA

SET/EXIT SET/EXIT

EXIT EXIT EXIT

Adj. R0

SET/EXIT SET/EXIT SET/EXIT SET/EXIT

ALPHA

EXIT

DOWN

Operating

Parameters

Menu

SET SET SET SET

Cutout

Reset Mode

SET

Adj. Cutout
Reset Mode

Stirrer

Mode Select

SET

Adj. Stirrer

Mode

Stirrer

Setpoint

SET

Adj. Stirrer

Setpoint

SET/EXIT

UP UP UP

DOWN DOWN DOWN

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

Menu

Adjust CTO

SET

Adjust C0

SET/EXIT

SET

DO NOT CHANGE THESE VALUES. SEE MANUALDO NOT CHANGE THESE VALUES. SEE MANUAL

Adjust CG

SET/EXIT

SET

Adjust H

SET/EXIT

Interface

Option Installed

SET

X5

CTO

C0

EXIT

CG

EXIT

H

EXIT

L

EXIT

Figure 4

Controller Operation Flowchart

20

Adjust L

SET/EXIT

Controller Operation

is shown at the left on the display followed by the cur
rent 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

Press “SET” to accept the new selection and access
the set-point value.

S

Accept selected set-point memory

Bath temperature in degrees
Celsius

Set-point memory 1, 25.0°C
currently used

New set-point memory 4,

40.0°C

-

6.3.3 Set-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 temper
ature 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 ver
nier is accessed from the set-point by pressing “SET”.
The vernier setting is displayed as a 6 digit number
with five digits after the decimal point. This is a tem
perature offset in degrees of the selectedunits, C or F.

0.00000

To adjust the vernier press “UP” or “DOWN”. Unlike
most functions the vernier setting has immediate ef
fect as the vernier is adjusted. “SET” need not be
pressed.This allows one to continuallyadjust the bath
temperature with the vernier as it is displayed.

U

Increment display

Current vernier value in°C

-

-

-

-

6.3.2 Set-point Value

The set-point value may be adjusted after selecting
the set-point memory and pressing “SET”. The
set-point value is displayed with the units, C or F, at
the left.

C 40.00

If the set-point value need not be changed then press
“EXIT” to resume displaying 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.

S

Accept new set-point value

Set-point 4 value in°C

New set-point value

0.00090

Next press “EXIT”to return to the temperature display
or “SET”to access the temperature scale units selec­tion.

S

Access scale units

New vernier setting

6.4 Temperature 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 tem
perature, set-point, vernier, proportional band, and
cutout set-point.

The temperature scale units selection is accessed af
ter the vernier adjustment function by pressing “SET”.
From the temperature display function access the
units selection by pressing “SET” 4 times.

Bath temperature

S

25.00 C

Access set-point memory

-

-

1. 25.0

Set-point memory

21

Controller Operation

S

Access set-point value

C 25.00

S

Access vernier

Set-point value

percent heating power should not fluctuate more than
±1% within one minute.

The heater power display is accessed in the second
ary menu. Press “SET” and “EXIT” simultaneously
and release. The heater power will be displayed as a
percentage of full power.

-

0.00000

S

Access scale units selection

Un= C

Press “UP” or “DOWN” to change the units.

U

Change units

Un= F

Press “SET” to accept the new selection and resume
displaying the bath temperature.

S

Set the new units and resume temperature
display

Vernier setting

Scale units currently selected

New units selected

6.5 Secondary 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 4.)

6.6 Heater Power

The temperature controller controls the temperature
of the bath by pulsing the heater on and off. The total
power being applied to the heater is determined by
the duty cycle or the ratio of heater on time to the
pulse cycle time. This value may be estimated by
watching the red/green control indicator light or read
directly from the digital display. By knowing the
amount of heating the user can tell if the bath is heat
ing up to the set-point, cooling down, or controlling at
a constant temperature. Monitoring the percent
heater power will let the user know how stable the
bath temperature is. With good control stability the

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

6.7 Proportional Band

In a proportional controller such as this the heater
output power is proportional to the bath temperature
over a limited range of temperatures around the
set-point. This range of temperature is called the pro­portional band.At the bottom of the proportional band
the heater output is 100%. At the top of the propor­tional band the heater output is 0. Thus as the bath
temperature rises the heater power is reduced, which
consequently tends to lower the temperature back
down. In this way the temperature is maintained at a

-

-

fairly constant temperature.

The temperature stability of the bath depends on the
width of the proportional band. See Figure 5. 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 proportional band is too narrow the
bath temperature may swing back and forth because
the controller overreacts to temperature variations.
For best control stability the proportional band must
be set for the optimum width.

The optimum proportional band width depends on
several factors among which are fluid volume, fluid
characteristics (viscosity, specific heat, thermal con
ductivity), operating temperature, and stirring. Thus
the proportional band width may require adjustment
for best bath stability when any of these conditions

-

-

22

Controller Operation

Proportional Band too Narrow Proportional Band too Wide

Optimum Proportional Band

Figure 5

change. Of these, the most significant factors affect­ing the optimum proportional 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.

The proportional band width is easily adjusted from
the bath front panel.The width may be set to discrete
values in degrees C or F depending on the selected
units. The optimum proportional band width setting
may be determined by monitoring the stability with a
high resolution thermometer or with the controller
percent output powerdisplay. 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

Bath temperature flucuations at various proportional band settings.

Access heater power in secondary
menu

12 Pct

Heater power in percent

S

To change the proportional band press “UP” or
“DOWN”.

D

To accept the new setting and access the cutout
set-point press “SET”. Pressing “EXIT” will exit the
secondary menu ignoring any changes just made to
the proportional band value.

S

Access proportional band

Pb=0.101C

Decrement display

Pb=0.060C

Accept the new proportional band setting

Proportional band setting

New proportional band setting

6.8 Cutout

As a protection against software or hardware fault,
shorted heater triac, or user error, the bath is
equipped with an adjustable heater cutout device that
will shut off power to the heater if the bath tempera
ture exceeds a set value.This protects the heater and
bath materials from excessive temperatures and,

-

23

Controller Operation

most importantly, protects the bath fluids from being
heated beyond the safe operating temperature pre
venting hazardous vaporization, breakdown, or igni
tion of the liquid. The cutout temperature is
programmable by the operator from the front panel of
the controller. It must always be set below the upper
temperature limit of the fluid and no more than 10 de
grees above the upper temperature limit of the bath.

-

-

-

S

The next function is the configuration menu. Press
“EXIT” to resume displaying the bath temperature.

Accept cutout set-point

6.9 Controller Configuration

If the cutout 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 cutout set-point
temperature. At this point the action of the cutout is
determined by the setting of the cutout mode parame
ter. The cutout has two modes — automatic reset or
manual reset. If the mode is set to automatic, then the
cutout will automatically reset itself when the bath
temperature falls below the reset temperature allow
ing the bath toheat up again.If the mode isset to man
ual, then the heater will remain disabled until the user
manually resets the cutout.

The cutout set-point may be accessed within the sec­ondary menu. Press “SET” and “EXIT” to enter the
secondary menu and show the heater power. Then
press “SET” twice to access the cutout set-point.

S+E

12 Pct

S

S

To change the cutout set-point press “UP” or
“DOWN”.

Access proportional band

Pb=0.101C

Access cutout set-point

CO= 210C

Access heater power in secondary
menu

Heater power in percent

Proportional band setting

Cutout set-point

The controller has a number of configuration and op
erating options and calibration parameters which are
programmable via the front panel. These are ac
cessed from the secondary menu after the cutout
set-point function by pressing “SET”. The display will

-

-

-

prompt with “COnFIG”. Press “SET” once more.
There are 5 sets ofconfiguration parameters — probe
parameters, operating parameters, serial interface
parameters, IEEE-488 interface parameters, and
controller calibration parameters. The menus are se
lected using the “UP” and “DOWN” keys and then
pressing “SET”. See Figure 4.

-

-

-

6.10 Probe Parameters Menu

The probe parameter menu is indicated by,

PrObE

Press “SET” to enter the menu. The probe parame­ters menu contains the parameters, R0 and ALPHA,
which characterize the resistance-temperature rela
tionship of the platinum control probe.These parame
ters may be adjusted to improve the accuracy of the
bath.This procedure is explained in detail inSection.

The probe parameters are accessed by pressing
“SET” after the name of the parameter is displayed.
The value of theparameter 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

-

-

D

To accept the new cutout set-point press “SET”.

24

Decrement display

CO= 95C

New cutout set-point

6.10.1 R0

This probe parameter refers to the resistance of the
control probe at 0°C. Normally this is set for 100.000
ohms.

Controller Operation

6.10.2 ALPHA

This probe parameter refers to the average sensitivity
of the probe between 0 and 100°C. Normally this is
set for 0.00385°C

-1

.

6.11 Operating Parameters

The operating parameters menu is indicated by,

PAr

Press “SET” to enter the menu. The operating param
eters menu contains the cutout reset mode parame
ter.

6.11.1 Cutout Reset Mode

The cutout reset mode determines whether the cutout
resets automatically when the bath temperature
drops to a safe value or must be manually reset by the
operator.

Operating parameters menu

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.

-

-

6.11.3 Stirrer 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,

Stirrer mode selection parame
ter

Stirrer is set for automatic acti
vation at the stirrer set-point
temperature.

-

-

The parameter is indicated by,

CtorSt

Press “SET” to access the parameter setting.
Normally the cutout is set for automatic mode.

Cto=Auto

To change to manual reset mode press “UP” and then
“SET”.

Cto=rSt

Cutout reset mode parameter

Cutout set for automatic reset

Cutout set for manual reset

6.11.2 Stirrer Mode Select

This parameter along with the Stirrer set-point allow
the user to set the temperature 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) prevent
ing the stirrer motor from overheating and damage.

The parameter is indicated by,

Str SEt

Press “SET” to access the parameter value.

Str=200

Press “UP” or “DOWN” to change the value and then
“SET” to enter the new value.

Stirrer motor activation set-point
parameter

Stirrer motor activation set-point

6.12 Serial Interface
Parameters

The serial RS-232 interface parameters menu is indi
cated by,

SErIAL

The serial interface parameters menu contains pa
rameters which determine the operation of the serial
interface. These controls only apply to baths fitted

-

with the serial interface. The parameters in the menu
are — BAUD rate, sample period, duplex mode, and
linefeed.

Serial RS-232 interface param
eters menu

-

-

-

25

Controller Operation

6.12.1 BAUD Rate

The BAUD rate is the first parameter in the menu.The
BAUD rate setting determines the serial communica
tions transmission rate.

The BAUD rate parameter is indicated by,

BAUd

Press “SET”to choose to set the BAUD rate. The cur
rent 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.

2400 b

Press “SET” to set the BAUD rate to the new value or
“EXIT” to abort the operation and skip to the next pa­rameter in the menu.

Serial BAUD rate parameter

Current BAUD rate

New BAUD rate

6.12.2 Sample Period

The sample period is the next parameter in the serial
interface parameter menu. The sample period is the
time period in seconds between temperature mea
surements transmitted from the serial interface. If the
sample rate is set to 5 for instance then the bath will
transmit the current measurement over the serial in
terface approximately every five seconds. The auto
matic sampling is disabled with a sample period of 0.
The sample period is indicated by,

SAmPLE

Press “SET” to choose to set the sample period. The
current sample period value will be displayed.

Serial sample period parameter

6.12.3 Duplex Mode

The next parameter is the duplex mode. The duplex

-

-

mode may be set to full duplex or half duplex.With full
duplex any commands received by the bath via the
serial interface will be immediately echoed or trans
mitted 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

Press “SET” to access the mode setting.

dUP=FULL

The mode may be changed using “UP” or “DOWN”
and pressing “SET”.

dUP=HALF

Serial duplex mode parameter

Current duplex mode setting

New duplex mode setting

-

6.12.4 Linefeed

The final parameter in the serial interface menu is the
linefeed mode. This parameter enables (on) or dis­ables (off) transmission of a linefeed character (LF,
ASCII 10) after transmission of any carriage-return.
The linefeed parameter is indicated by,

-

Press “SET” to access the linefeed parameter.

-

-

The mode may be changed using “UP” or “DOWN”
and pressing “SET”.

LF

LF= On

LF= OFF

Serial linefeed parameter

Current linefeed setting

New linefeed setting

SA= 1

Adjust the value with “UP” or “DOWN” and then use
“SET” to set the sample rate to the displayed value.

SA= 60

26

Current sample period (sec
onds)

New sample period

-

6.13 IEEE-488 Parameters
Menu

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 in
terface. The menu is indicated by,

-

Controller Operation

IEEE

Press “SET” to enter the menu.

IEEE-488 parameters menu

6.13.1 IEEE-488 Address

The IEEE-488 interface must be configured to use the
same address as the external communicating device.
The address is indicated by,

AddrESS

Press “SET” to access the address setting.

Add= 22

Adjust the value with “UP” or “DOWN” and then use
“SET” to set the address to the displayed value.

Add= 15

IEEE-488 interface address

Current IEEE-488 interface ad
dress

New IEEE-488 interface ad­dress

-

The calibration parameters menu is indicated by,

CAL

Press “SET” five times to enter the menu.

Calibration parameters menu

6.14.1 CTO

Parameter CTO sets the calibration of the over-tem
perature cutout. This is not adjustable by software but
is adjusted with an internal potentiometer. For the
6054 bath this parameter should read between 560
and 570.

6.14.2 CO 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.

-

6.14 Calibration Parameters

The operator of the bath controller has access to a
number of the bath calibration constants, namely
CTO, C0, CG, H, and L. These values are set at the
factory and must not be altered. The correct values
are important to the accuracy and proper and safe op­eration of the bath. Access to these parameters is
available to the user only so that in the event that the
controller’s memory fails the user may restore these
values to the factory settings.The user should have a
list of these constants and their settings with the man
ual.

DO NOT change the values of the bath calibration
constants from the factory set values.The correct
setting of these parameters is important to the
safety and proper operation of the bath.

6.14.3 H and L

These parameters set the upper and lower set-point
limits of the bath. DO NOT change the values of these
parameters from the factory set values. To do so may
present danger of the bath overheating and causing
damage or fire.

6.15 Operation Summary

­A complete flowchart of controller operation is shown

in Figure 4. This chart may be reproduced and used
as a reference and operating guide.

27

Digital Communication Interface

9NC

9NC

7 Digital Communication Interface

If supplied with the option, the 6025/6035 bath is ca
pable 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.

7.1 Serial Communications

The bath may be installed with an RS-232 serial inter
face that allows serial digital communications over
fairly long distances. With the serial interface the user
may access any of the functions, parameters and set
tings discussed in Section 6 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 cable is recommended.

7.1.1 Wiring

The serial communications cable attaches to the bath
through the D-9 connector on the back panel.Figure 6
shows the pin-out of this connector and suggested
cable wiring.

7.1.2 Setup

Before operation, the serial interface of the bath must
first be set up by programming the BAUD rate and
other configuration parameters. These parameters
are programmed within the serial interface menu. The
serial interface parameters menu is outlined in Figure

4 on page 20.

-

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 communica

­tions 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.

-

7.1.2.2 Sample Period

The sample period is the next parameter in the menu

-

and prompted with “SAmPLE”. The sample period is
the time period in seconds between temperature
measurements transmitted from the serial interface.If
the sample rate is set to 5 for instance then the bath
will transmit the current measurement over the serial

RS-232 Cable Wiring for

IBM PC and Compatibles

6054 Controller

Connector

(DB 9-Pin)

1NC
2 RxD
3 TxD
4NC
5 GND
6NC
7RTS
8 CTS
9NC

Computer (DTE)

Connector

(DB 25-Pin)

2 TxD
3 RxD
4RTS
5 CTS
6
7 GND
8
20

To enter the serial parameter programming mode first
press “EXIT” while pressing “SET” and release to en
ter the secondary menu. Press “SET” repeatedly until
the display reads “ProbE”.This is the menu selection.
Press “UP” repeatedly until the serial interface menu
is indicated with “SErIAL”. Finally press “SET” to enter
the serial interface parameters menu. In the serial in
terface parameters menu are the BAUD rate, sample
rate, duplex mode, and linefeed parameters.

7.1.2.1 BAUD rate

The BAUD rate is the first parameter in the menu.The
display will prompt with the BAUD rate parameter by

28

-

-

6054 Controller

Connector

(DB 9-Pin)

1NC
2 RxD
3 TxD
4NC
5 GND
6NC
7RTS
8 CTS

Figure 6

Computer (DTE)

Connector

(DB 9-Pin)

1NC
2 RxD
3 TxD
4NC
5 GND
6NC
7RTS
8 CTS

Serial Cable Wiring Diagram

Digital Communication Interface

interface approximately every five seconds.The auto
matic sampling is disabled with a sample period of 0.
Press “SET” to choose to set the sample period. Ad
just the period with “UP” or “DOWN” and then use
“SET” to set the sample rate to the displayed value.

7.1.2.3 Duplex Mode

The next parameter is the duplex mode indicated with
“dUPL”. The duplex mode may be set to half duplex
(“HALF”) or full duplex (“FULL”). With full duplex any
commands received by the bath via the serial inter
face 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”.

7.1.2.4 Linefeed

The final parameter in the serial interface menu is the
linefeed mode. This parameter enables (“On”) or dis
ables (“OFF”) transmission of a linefeed character
(LF, ASCII 10) after transmission of any carriage-re­turn. The default setting is with linefeed on. The mode
may be changed using “UP”or “DOWN”and pressing
“SET”.

7.1.3 Serial Operation

Once the cable has been attached and the interface
set up properly the controller 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 thebath via the serial
interface to set the bath and view or program the vari
ous parameters. The interface commands are dis
cussed in Section 7.3. All commands are ASCII
character strings terminated with a carriage-return
character (CR, ASCII 13).

7.2 IEEE-488 Communication
(optional)

The IEEE-488 interface is available as an option.
Baths supplied with this option may be connected to a
GPIB type communication bus which allows many in
struments to be connected and controlled simulta
neously.

-

-

-

-

7.2.1 Setup 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 pro
grammed within the IEEE-488 interface menu. To en
ter the IEEE-488 parameter programming menu first
press “EXIT” while pressing “SET” and release to en
ter the secondary menu. Press “SET” repeatedly until
the display reaches “PrObE”.This is the menu selec
tion. Press “UP” repeatedly until the IEEE-488 inter
face 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 ad
dress is 22. Change the device address of the bath if
necessary to match the address used by the commu
nication equipment by pressing “UP” or “DOWN” and
then “SET”.

-

-

-

-

-

-

-

7.2.2 IEEE-488 Operation

Commands may now be sent via the IEEE-488 inter­face to read or set the temperature or access other
controller functions. All commands are ASCII charac­ter strings and are terminated with a carriage-return
(CR, ASCII 13). Interface commands are listed below.

-

7.3 Interface Commands

-

-

-

-

The various commands for accessing the bath con
troller functions via the digital interfaces are listed in
this section (see Ta bl e 2 ).These commands are used
with both the RS-232 serial interface and the
IEEE-488 GPIB interface. In either case the com
mands are terminated with a carriage-return charac
ter.The interface makes no distinction between upper
and lower case letters, hence either may be used.
Commands may be abbreviated tothe minimum num
ber 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 “=” charac
ter. 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.

In Ta bl e 2 , characters or data within brackets, “[” and
“]”, are optional for the command.A slash, “/”, denotes

-

-

-

-

-

29

Digital Communication Interface

Table 2

Command Description

Communications Commands

Command
Format

Command
Example Returned

Returned
Example

Acceptable
Values

Display Temperature

Read current set-point s[etpoint] s set: 9999.99 {C or F} set: 150.00 C

Set current set-point to n s[etpoint]=n s=450 Instrument Range

Read vernier v[ernier] v v: 9.99999 v: 0.00000

Set vernier to n v[ernier]=n v=.00001 Depends on

Read temperature t[emperature] t t: 9999.99 {C or F} t: 55.69 C

Read temperature units u[nits] u u: x u: c

Set temperature units: u[nits]=c/f

Set temperature units to

u[nits]=c u=c

Configuration

C or F

Celsius
Set temperature units to

u[nits]=f u=f

Fahrenheit

Secondary Menu

Read proportional band setting pr[op-band] pr pr: 999.9 pr: 15.9

Set proportional band to

Read cutout setting c[utout] c c: 9999 {x},{xxx} c: 620 C, in

Set cutout setting: c[utout]=n/r[eset]

n

Set cutout tondegrees

Reset cutout now

Read heater power

(duty cycle)

pr[op-band]=n pr=8.83 Depends on

Configuration

c[utout]=n c=500 Temperature

Range

c[utout]=r[eset] c=r

po[wer] po po: 9999 po: 1

Configuration Menu

Probe Menu

Read R0 calibration parameter r[0] r r0: 999.999 r0: 100.578

n

Set R0 calibration parameter to

Read ALPHA calibration parameter al[pha] al al: 9.9999999 al: 0.0038573

Set ALPHA calibration parameter to

Operating Parameters Menu

Read cutout mode cm[ode] cm cm: {xxxx} cm: AUTO

Set cutout mode: cm[ode]=r[eset]/a[uto]

Set cutout to be reset
manually-

Set cutout to be reset
automatically

Read Stirrer Mode smod smod smod: {xxxx} smod: AUTO

Set Stirrer Mode: smod=o/a

Set striier activation
mode to on

Set striier activation
mode to auto

Read Stirrer Set-Point sset sset sset: 9999.99 {C or F} sset: 160.00C

Set Stirrer Set-Point to

Serial Interface Menu

Read serial sample setting sa[mple] sa sa: 9 sa: 1

Set serial sampling setting to
seconds

Set serial duplex mode: du[plex]=f[ull]/h[alf]

n

n

Set serial duplex mode to full
Set serial duplex mode to half

Set serial linefeed mode: lf[eed]=on/of[f]

r[0]=n r=100.324 98.0 to 104.9

n

al[pha]=n al=0.0038433 .00370 to .00399

RESET or AUTO

cm[ode]=r[eset] cm=r

cm[ode]=a[uto] cm=a

ON or AUTO

smod=o smod=o

smod=a smode=a

sset=n sset=160 instrument range

sa[mple]=n sa=0 0 to 4000

FULL or HALF

du[plex]=f[ull] du=f

du[plex]=h[alf] du=h

ON or OFF

30

Communications Commands, cont.

Digital Communication Interface

Command

Command Description

Set serial linefeed mode to on
Set serial linefeed mode to off

Calibration Menu

Read C0 calibration parameter *c0 *c0 c0: 9 c0: 0

Set C0 calibration parameter to

Read CG calibration parameter *cg *cg cg: 999.99 cg: 406.25

Set CG calibration parameter to

Read low set-point limit value *tl[ow] *tl tl: 999 tl: –80

Set low set-point limit to

Read high set-point limit value *th[igh] *th th: 999 th: 205

Set high set-point limit to

Miscellaneous (not on menus)

Read firmware version number *ver[sion] *ver ver.9999,9.99 ver.2100,3.56

Read structure of all commands h[elp] h list of commands

Read Heater 1 f1 f1 f1:9 f1:1

Set Heater 1 f1=1/0 1 or 0

Set heater 1 to on
Set heater 1 to off

Read Heater 2 f2 f2 f2:9 f2:0

Set Heater 2 f2=1/0 1 or 0

Set Heater 2 to on
Set Heater 2 to off

Read Heater 3 f3 f3 f3:9 f3:1

Set Heater 3 f3=1/0 1 or 0

Set Heater 3 to on
Set Heater 3 to off

Read Heater 4 f4 f4 f4:9 f4:1

Set Heater 4 f4=1/0 1 or 0

Set Heater 4 to on
Set Heater 4 to off

Read Boost Heater f5 f5 f5:9 f5:1

Set Boost Heater f5=1/0 1 or 0

Set Boost Heater to on
Set Boost Heater to off
Legend:

Note:

n

n

Format

lf[eed]=on lf=on

lf[eed]=of[f] lf=of

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

f1=

n

f1=

n

f2=

n

f2=

n

f3=

n

f3=

n

f4=

n

f4=

n

f5=

n

f5=

n

[] Optional Command data

{} Returns either information

n Numeric data supplied by user

9 Numeric data returned to user

x Character data returned to user

When DUPLEX is set to FULL and a command is sent to READ, the command is returned followed by a carriage
return and linefeed. Then the value is returned as indicated in the RETURNED column.

Command
Example Returned

f1=1

f1=0

f2=1

f2=0

f3=1

f3=0

f4=1

f4=0

f5=1

f5=0

Returned
Example

Acceptable
Values

alternate characters or data. Numeric data, denoted
by “n”, may be entered in decimal or exponential nota
tion. Bold type characters are literal characters while
normal type symbolizes data. 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 terminat
ing CR is implied with all commands.

-

7.4 Power Commands

The digital interface is capable of controlling the heat
ing functions so that the bath can be remotely oper

-

-

ated at any temperature within the range of the bath.

To allow the interface to control the heating, the front

-

panel controls are disabled by 1) switching the heater
control to “OFF”, and 2) switching the boost heater

31

Digital Communication Interface

switch to “OFF”

able to switch these functions off. The 6054 bath has
five control functions with the digital interface. These
are controls for heaters 1, 2, 3, and 4, each 250 W,
and the boost heater which is 1000 W. Heater 1 power
is variable 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.

Serial commands “F1” through “F5” control the heat
ers 1 through 4 and the boost heater individually.
These commands are used to turn the heaters on or
off or to read thestates of the heaters.Sending a com
mand with parameter “1” turns the heater on.Parame
ter “0” turns the heater off. No parameter returns the
state, “1” for on or “0” for off.For example “F1=1”<RE
TURN> turns on heater 1. “F1”<RETURN> (no pa

.Otherwise, the interface would not be

rameter) 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 heat
ers individually, multiple commands mustbe issued to
set the desired amount of power.Ta b le 4 lists the com
mands which should be given to set various power
levels. Power is variable with the front panel DRIFT

-

-

-

-

-

control when heater 1 (F1) is turned on.

7.5 Heater Settings for Control

Suggested heater control settings for various ranges
are suggested in Ta bl e 5 below.

-

-

Table 4

POWER F1 F2 F3 F4 F5

OFF 00000

0–250 W LOW 10000

250–500 W
MEDIUM

500–750 W
MEDIUM HIGH

750–1000 W
HIGH

‘750 W BOOST 11111

32

Heater Power Settings

11000

11100

11110

Table 5

Range Controls
50°C–125°C LOW - Heater 1 on, heaters 2–4

125°C–200°C MEDIUM - Heaters 1 and 2 on,

200°C–275°C MEDIUM HIGH - Heaters 1–3 on

275°C–325°C HIGH - Heaters 1–4 and boost

Suggested Heater Settings

and boost heater off

heater 3, 4, and boost heater off

and heater 4 and boost heater off

heater on

8 Bath Calibration

Bath Calibration

In some instances the user may want to calibrate the
bath to improve the temperature set-point accuracy.
Calibration is done by adjusting the controller probe
calibration constants R0 and ALPHA so that the tem
perature of the bath as measured with a standard
thermometer agrees more closely with the bath
set-point. The thermometer used must be able to
measure the bath fluid temperature with higher accu
racy 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.

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

8.1 Calibration Points

In calibrating the bath R0 and ALPHA are adjusted to

-

-

minimize the set-point error at each of two different
bath temperatures. Any two reasonably separated
bath temperatures may be used for the calibration
however best results will be obtainedwhen using bath
temperatures which are just within the most useful
operating range of the bath.The further apart the cali
bration 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 calibration temperatures
then the bath may achieve an accuracy of say
±0.03°C over the range 40 to 160°C. Choosing 80°C

-

Compute errors,

err

= 79.843 - 80.00°C = -0.157°C

L

err

= 119.914 - 120.00°C = -0.086°C

H

Compute R

⎡

0086 800 0157 1200

−−−

R

(. ) . (. ) .

0

⎢
⎣

Compute ALPHA,

ALPHA

Figure 7

′=

Calibration Example

,

0

xx

1200 80 0

−

..

⎡

+−−+(. .)(.)(. .)(1 0 00385 120 0 0157 1 0 00385 80 0xx

⎢
⎣

1200 80 0

000385′=

.

..

−

⎤

+

1 100 000 100115

⎥
⎦

=..

0086

.)

−

⎤

1 0 00385 0 0038387

..

+

⎥
⎦

=

33

Bath Calibration

and 120°C may allow the bath to have a better accu
racy of maybe ±0.01°C over the range75 to 125°C but
outside that range theaccuracy may be only±0.05°C.

8.2 Measuring the Set-point
Error

The first step in the calibration procedure is to mea
sure the temperature errors (including sign) at the two
calibration temperatures. First set the bath to the
lower set-point which we will callt

.Wait forthe bath to

L

reach the set-point and allow 15 minutes to stabilize
at that temperature. Check the bath stability with the
thermometer.When both the bath and the thermome
ter have stabilized measure the bath temperature
with the thermometer and compute the temperature
error err

which is the actual bath temperature minus

L

the set-point temperature. If for example the bath is
set for a lower set-point of t

=50°C and the bath

L

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

and after

H

stabilizing measure the bath temperature and com­pute the error err

. For our example we will suppose

H

the bath was set for 150°C and the thermometer mea­sured 150.1°C giving an error of +0.1°C.

8.3 Computing R0 and ALPHA

Before computing the new values for R0 and ALPHA
the current values must be known.The values may be
found by either accessing the probe calibration menu
from the controller panel or by inquiring through the
digital interface. The user should keep a record of
these values in case they may need to be restored in

-

the future. The new values R0′ and ALPHA′ are com

­puted by entering the old values for R0 and ALPHA,
the calibration temperature set-points t
the temperature errors err

and errHinto the following

L

and tH, and

L

equations,

err t err t

R

010⎡=

⎡
⎢
⎣

−

HL LH

tt

−

HL

ALPHA R

⎤

+

⎥
⎦

-

ALPHA

⎡=

⎡
⎢
⎣

HL LH

tt

−

HL

+

⎤

1

ALPHA

⎥
⎦

ALPHA t err ALPHA t err

+−+

()()11

If for example R0 and ALPHA were previously set for

-

100.000 and 0.0038500 respectively and the data for
t

, errL, and errHwere as given above then the new

L,tH

values R0′ and ALPHA′ would be computed as

100.193 and 0.0038272 respectively. Program the
new values R0 and ALPHA into the controller. Check
the calibration by setting the temperature to t

and t

L

H

and measuring the errors again.If desired the calibra­tion procedure may be repeated again to further im­prove the accuracy.

8.4 Calibration Example

The bath is to be used between 75 and 125°C and it is
desired to calibrate the bath as accurately as possible
for operation within this range. The current values for
R0 and ALPHA are 100.000 and 0.0038500 respec
tively. 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 7
for applying equations to the example data and com
puting the new probe constants.

-

-

34

9 Bath Heat Transfer Fluid

Bath Heat Transfer Fluid

Many fluids will work with 6054 bath.Choosing a fluid
requires consideration of many important character
istics of the fluid. Among these are temperature
range, viscosity, specific heat, thermal conductivity,
thermal expansion, electrical conductivity, fluid life
time, safety, and cost.

9.1 Temperature Range

One of the most important characteristics to consider
is the temperature range of the fluid. Few fluids work
well throughout the entire temperature range of the
bath. The temperature at which the bath is operated
must always be within the safe and useful tempera
ture range of the fluid used. The lower temperature
range of the fluid is determined either by the freeze
point of the fluid or the temperature at which the vis­cosity becomes too great. The upper temperature is
usually limited by vaporization, flammability, or chem­ical breakdown of the fluid. Vaporization of the fluid at
higher temperatures may adversely affect tempera­ture stability because of cool condensed fluid dripping
into the bath from the lid.

compensate for the reduced response time. Other

-

-

-

wise the temperature may begin to oscillate.

9.3 Specific heat

Specific heat is the measure of the heat storage abil
ity of the fluid. Specific heat, to a small degree, affects
the control stability. It also affects the heating and
cooling rates. Generally, a lower specific heat means
quicker heating and cooling. The proportional band
may require some adjustment depending on the spe
cific heat of the fluid.

-

-

-

9.4 Thermal Conductivity

Thermal conductivity measures how easily heat flows
through the fluid. Thermal conductivity of the fluid af­fects the control stability, temperature uniformity, and
temperature settling time. Fluids with higher conduc­tivity distribute heat more quickly and evenly improv­ing bath performance.

The bath temperature should be limited by setting the
safety cutout so that the bath temperature cannot ex
ceed the safe operating temperature limit of the fluid.

9.2 Viscosity

Viscosity is a measure of the thickness of a fluid or
how easily it can be poured and mixed. Viscosity af
fects the temperature uniformity and stability of the
bath. With lower viscosity, fluid mixing is better there
fore creating a more uniform temperature throughout
the bath. This improves the bath response time which
allows it to maintain a more constant temperature. For
good control the viscosity should be less than 10
centistokes. The practical upper limit of allowable vis
cosity is about 50 centistokes. Viscosity greater than
this causes very poor control stability because of poor
stirring and may also overheat or damage the stirring
motor. Viscosity may vary greatly with temperature,
especially with oils.

When using fluids with higher viscosities the control
ler proportional band may need to be increased to

-

-

-

9.5 Thermal Expansion

Thermal expansion describes how much the volume
of the fluid changes with temperature. Thermal ex
pansion of the fluid must be considered since the in
crease in fluid volume as the bath temperature
increases may cause overflow. Excessive thermal ex
pansion may also be undesirable in applications
where constant liquid level is important. Many fluids
including oils have significant thermal expansion.

-

-

-

9.6 Electrical Resistivity

-

-

Electrical resistivity describes how well the fluid insu
lates against the flow of electric current. In some ap
plications, such as measuring the resistance of bare
temperature sensors, it may be important that little or
no electrical leakage occur through the fluid. In such
conditions choose a fluid with very high electrical re
sistivity.

-

-

-

35

Bath Heat Transfer Fluid

9.7 Fluid lifetime

Many fluids degrade over time because of vaporiza
tion, water absorption, gelling, or chemical break
down. Often the degradation becomes significant
near the upper temperature limit of the fluid, substan
tially reducing the fluid’s lifetime.

9.8 Safety

When choosing a fluid always consider the safety is
sues associated. Obviously where there are extreme
temperatures there can be danger to personnel and
equipment. Fluids may also be hazardous for other
reasons. Some fluids may be considered toxic. Con
tact with eyes, skin, or inhalation of vapors may cause
injury.A proper fume hood must be used if hazardous
or bothersome vapors are produced.

Fluids may be flammable and require special fire
safety equipment and procedures.

An important characteristic of the fluid to consider is
the flash point. The flash point is the temperature at
which there is sufficient vapor given off so that when
there is adequate oxygen present and an ignition
source is applied the vapor will ignite. This does not
necessarily mean that fire will be sustained at the
flash point. The flash point may be either of the open
cup or closed cup type. Either condition may occur in
a bath situation.

The open cup flash point is measured under the con
dition of vapors escaping the tank. The closed cup
flash point is measured with the vapors being con
tained within the tank. Since oxygen and an ignition
source is less available inside the tank the closed cup
flash point will belower than the opencup flash point.

Remember also that environmentally hazardous flu
ids require special disposal according to applicable
federal or local laws after use.

9.9 Cost

Cost of bath fluids may vary greatly, from cents per
gallon for water to hundreds of dollars per gallon for
synthetic oils. Cost may be an important consider
ation when choosing a fluid.

9.9.1 Commonly used fluids

-

-

-

-

-

Below is a description of some of the more commonly
used fluids and their characteristics.

9.9.2 Water

Water is often used because of its very low cost, its
availability, and its excellent temperaturecontrol char
acteristics. Water has very low viscosity and good
thermal conductivity and heat capacity which makes
it among the best fluids for good control stability at
lower temperatures. Temperature stability is much
poorer at higher temperatures because water con
denses on the lid, cools and drips into the bath.Water
is safe and relatively inert. The electrical conductivity
of water may prevent its use in some applications.
Water has a limited temperature range, from a few de
grees above 0°C to a few degrees below 100°C. At
higher temperatures evaporation becomes signifi­cant. Water used in the bath should be distilled or
deionized to prevent mineral deposits. Consider using
an algicide chemical in the water to prevent contami­nation.

-

-

-

9.9.3 Ethylene Glycol

The temperature range of water may be extended by
using a solution of 1 part water and 1 part ethylene
glycol (antifreeze).The characteristics of the ethylene

-

-

glycol-water solution are similar to water but with
higher viscosity. Use caution with ethylene glycol
since this fluid is very toxic. Ethylene glycol must be
disposed of properly.

9.9.4 Mineral Oil

­Mineral oil or paraffin oil is often used at moderate

temperatures above the range of water. Mineral oil is
relatively inexpensive. At lower temperatures mineral
oil is quite viscous and control may be poor. At higher
temperatures vapor emission becomes significant.
The vapors may be dangerous and use of a fume
hood is highly recommended. As with most oils ,min

-

eral oil will expand as temperature increases, there
fore, be careful not to fill the bath too full that it
overflows when heated. The viscosity and thermal
characteristics of mineral oil is poorer than water so
temperature stability will not be as good. Mineral oil
has very low electrical conductivity. Use caution with

-

-

36

Bath Heat Transfer Fluid

Table 6

Halocarbon 0.8
#5019

Methanol –96°C (fr) 60°C (b) 54°C 1.3 @ –35°C

Water 0°C (fr) 95°C (b) NONE 1 @ 25°C

Ethylene
Glycol—50%
#5020

Mineral Oil 40°C (v) 190°C (fl) 190°C 15 @ 75°C

Dow Corning

200.5
Silicone Oil

Dow Corning

200.10
#5012

Dow Corning

200.20
#5013

Dow Corning

200.50
Silicone Oil

Dow Corning
550
#5016

Dow Corning
710
#5017

Dow Corning
210-H
Silicone Oil

Table of Bath Fluids

Fluid

(# = Hart

Part No.)

Lower

Temperatur

e Limit*

–90°C (v)** 70°C (e) NONE 5.7 @ –50°C

–35°C (fr) 110°C (b) NONE 7 @ 0°C

–40°C (v)** 133°C (fl, cc) 133°C 5 @ 25°C 0.92 @ 25°C 0.4 0.00028 @

–35°C (v)** 165°C (fl, cc) 165°C 10 @ 25°C

7°C (v) 230°C (fl, cc) 230°C 20 @ 25°C 0.949 @ 25°C 0.370 @ 40°C

25°C (v) 280°C (fl, cc) 280°C 20 @ 25°C 0.96 @ 25°C 0.4 0.00037 @

70°C (v) 232°C (fl, cc)

80°C (v) 302°C (fl, oc) 302°C 50 @ 80°C

66°C (v) 315°C (fl, oc) 315°C 50 @ 66°C

Upper

Temperatur

e Limit*

300°C (fl, oc)

Flash
Point

232°C 50 @ 70°C

Viscosity

(centistokes)

0.8 @ 40°C

0.5 @ 70°C

0.66 @ 0°C

0.45 @ 20°C

0.4 @ 75°C

2 @ 50°C

0.7 @ 100°C

5 @ 125°C

3 @ 135°C

10 @ 104°C

7 @ 204°C

14 @ 204°C

mineral oil since it is flammable and may also cause
serious injury if inhaled or ingested.

Specific

Specific

Gravity

1.71 @ 40°C 0.2 0.0004 0.0011

0.810 @ 0°C

0.792 @ 20°C

1.00 1.00 0.0014 0.0002 @

1.05 0.8 @ 0°C 0.001

0.87 @ 25°C

0.84 @ 75°C

0.81 @ 125°C

0.934 @ 25°C 0.43 @ 40°C

1.07 @ 25°C 0.358 @ 40°C

1.11 @ 25°C 0.363 @ 40°C

0.96 @ 25°C 0.34 @

Heat

(cal/g/°C)

0.6 0.0005 @

0.48 @ 25°C

0.53 @ 75°C

0.57 @ 125°C

0.45 @ 100°C

0.482 @
200°C

0.393 @
100°C

0.420 @
200°C

0.386 @
100°C

0.433 @
200°C

0.454 @
100°C

0.505 @
200°C

100°C

Thermal
Conductivity
(cal/s/cm/°C)

20°C

0.00025 @
25°C

25°C

0.00032 @
25°C

0.00034 @
25°C

25°C

0.00035 @
25°C

0.00035 @
25°C

0.0003 0.00095 100 @ 25°C

Thermal

Expansion

(cm/cm/°C)

0.0014 @
25°C

25°C

0.0007 @
50°C

0.00105 1000 @ 25°C

0.00108 1000 @ 25°C

0.00107 1000 @ 25°C

0.00104 1000 @ 25°C

0.00075 100 @ 25°C

0.00077 100 @ 25°C

very high electrical resistivity. Silicone oils are fairly
safe and non-toxic. Silicone oils are fairly expensive.

Resistivity

12

(10

-cm )

5 @ 25°C

10 @ 150°C

50 @ 150°C

50 @ 150°C

50 @ 150°C

1 @ 150°C

1 @ 150°C

1 @ 150°C

9.9.5 Silicone oil

Silicone oils are available which offer a much wider
operating temperature range than mineral oil. Like
most oils, silicone oils have temperature control char
acteristics which are somewhat poorer than water.
The viscosity changes significantly with temperature
and thermal expansion also occurs. These oils have

9.9.6 Heat Transfer Salt

Heat transfer salt is often used at high bath tempera
tures.Salt has a very highupper temperature limit and

-

a wide useful temperature range. Salt may be used
from its freezing point at 145°C up to the upper tem
perature limit of thebath. Viscosity islow, especially at
higher temperatures. Salt when melted has very low
electrical resistivity. Salt may be corrosive to some

-

-

37

Bath Heat Transfer Fluid

–100°C 0°C 100°C 200°C 300°C 400°C 500°C 600°C

Silicone Oil

710

Silicone Oil

200.50

Silicone Oil

200.20

Silicone Oil

200.10

Silicone Oil

200.05

Silicone Oil

550

Halocarbon

0.8

Mineral Oil

Water

Methanol

Ethylene Glycol

50/50 with H O

2

Bath Salt

PP

PP

PP

PP

PP

10 CS

FR (Pure)

FR

FR

10 CS

FL 12°C

10 CS

10 CS

10 CS

10 CS

EP

BP

BP

BP

FL 133°C

FR

10 CS

10 CS

FL 163°C

10 CS

FL 302°CPP

FL 280°C

FL 232°C

FL 230°C

FL 177°C

Shaded area represents usable range of fluid starting at 50
centistokes. Lighter shading represents decreasing viscosity, while
vaporization and decomposition increase.

Black area represents liquid range with excessive viscosity.

Range over which a fume hood is recommended.

Figure 8

Chart showing usable range of various fluids.

materials. Salt will quickly oxidize the coating on gal
vanized metal. Carbon steel may be used with salt up
to 450°C. Beyond this temperature stainless steel is
recommended.

Decomposition
Starts

BP - Boiling Point
CS - Centistokes
EP - Evaporation Point, fluid loss

due to evaporation too high.
FL - Flash Point
FR - Freeze Point
PP - Pour Point

-

CAUTION: Keep all combustible materials away
from the bath when using salt. Operate the bath
on a heat-proof surface such as concrete.Provide
a means of safely containing any spills which may
occur.

The greatest safety concern with liquid salt is with its
high temperature. The fluid provides a source of heat

38

Bath Heat Transfer Fluid

which can ignite or destroy materials. Especially dan
gerous are spills since the hot fluid is difficult to con
tain. Salt may also cause steam explosions if it comes
into contact with water. Using salt requires special
caution. Read carefully the information and safety
data sheets provided with thesalt. Use ofa fume hood
is recommended to remove any products of decom
position or oxidation.

Because salt is solid atroom temperature special pro
cedures are required in using the bath with salt. The
bath has been designed so that the stir motor will not
turn on until the bath has reached the temperature for
the salt to liquify.

Solid salt has poor thermal conductivity. Only operate
the bath with the “HEATER” switch on position “LOW”
until the salt is melted. Using higher heater power may
over-heat and damage the bath heaters.The heaters
will only run at 25% power until the bath reaches
200°C. This helps to protect the heaters during melt
ing of the salt. This is especially possible when heat­ing salt which has solidified and contracted leaving
gaps between the bath walls and the salt.

Salt is supplied in a pink granular form. Fill the bath
gradually as the salt heats and melts. Because of the
heat required to melt the salt this is a slow process
and may take 10 hours or more. Fill the bath until the
liquid is a few inches below the lid. The level will rise
as much as two inches as it is heated to the upper
temperature limit.

9.10 Fluid Characteristics

-

-

-

-

-

9.10.1 Limitations and Disclaimer

The information given in this manual regarding fluids
is intended only to be used as a general guide in
choosing a fluid.Though every effort has been made
to provide correct information we cannot guarantee
accuracy of data or assure suitability of a fluid for a
particular application.Specifications may change and
sources sometimes offer differing information. Hart
Scientific cannot be liable for any personal injury or
damage to equipment, product or facilities resulting
from the use of these fluids.The user of the bath is re
sponsible for collecting correct information, exercis
ing proper judgement, and insuring safe operation.
Operating near the limits ofcertain properties such as
the flash point or viscosity can compromise safety or
performance. Your company’s safety policies regard
ing flash points,toxicity, and such issues must be con
sidered. You are responsible for reading the MSDS
(material safety data sheets)and acting accordingly.

-

-

-

-

9.10.2 About the Chart

The fluid chart (Figure 8 on page 38) visually illus­trates some of the important qualities of the fluids
shown.

Temperature Range: The temperature scale is shown
in degrees Celsius.The fluids’general range of appli­cation is indicated by the shaded bands. Qualities in­cluding pour point, freeze point, important viscosity
points, flash point, boiling point and others may be
shown.

Charts

Ta bl e 6 and Figure 8 on pages 37 and 38 have been

created to provide help in selecting a heat exchange
fluid media foryour constant temperature bath.These
charts provide both a visual and numerical represen
tation of most of the physical qualities important in
making a selection. The list is not all inclusive. There
may be other useful fluids not shown in this listing.

The charts include information on a variety of fluids
which are often used as heat transfer fluid in baths.
Because of the temperature range some fluids may
not be useful with your bath.

Freezing Point: The freezing point of a fluid is an obvi
ous limitation to stirring. As the freezing point is ap
proached high viscosity may also limit performance.

Pour Point: This represents a handling limit for the

-

fluid.

Viscosity: Points shown are at 50 and 10 centistokes
viscosity. When viscosity is greater than 50 centi
stokes stirring is very poor and the fluid is unsatisfac
tory for bath applications. Optimum stirring generally
occurs at 10 centistokes and below.

Fume Point: This is the point at which a fume hood is
recommended. This point is very subjective in nature
and is impacted by individual tolerance to different
fumes and smells, how well the bath is covered, the
surface area of the fluid in the bath, the size and venti
lation of the facility where the bath is located and other

-

-

-

-

-

39

Bath Heat Transfer Fluid

conditions.We assume the bath is well covered at this
point. This is also subject to company policy.

Flash Point: This is the point at which ignition may oc
cur.The point shown may be either the open or closed
cup flash point. Refer to the flash point discussion in

Section.

Boiling Point: At or near the boiling point of the fluid
the temperature stability is difficult to maintain.

Fuming or evaporation is excessive. Large amounts
of heater power may be required because of the heat

-

of vaporization.

Decomposition: The temperature may reach a point
at which decomposition of the fluid begins. Further in
creasing the temperature may accelerate decompo

-

-

sition to the point of danger or impracticality.

40

10 Troubleshooting

Troubleshooting

In the event that the user of the 6054 bath encounters
difficulty in operation this section may help to find and
solve the problem. Several possible problem condi
tions are described along with likely causes and solu
tions. If a problem arises please read this section
carefully and attempt to understand and solve the
problem. If the bath seems faulty or the problem can
not otherwise be solved, then contact the factory for
assistance.

10.1 The Heater Indicator LED Stays

Red But The Temperature Does

Not Increase.

Here the display does not show “cut-out” nor displays
an incorrect bath temperature, but the controller oth­erwise appears to operate normally. The problem
may be either insufficient heating or no heating at all.
Insufficient heating may be caused by the heater
power setting being too low, especially at higher oper­ating temperatures. Switching to a higher heater
power switch setting may solve the problem. If one or
more of the heaters are burned out, it also may cause
this problem. If this seems the case contact the fac­tory for assistance.

If the heater seems not to be receiving power at all,
then first check the heater fuse. If the fuse is burned
out, then try replacing the fuse with a new one (of the
same rating) and then check to see if the bath re
sumes normal operation. If the fuse blows gain then
there may be a shorted heater. Contact the factory. If
the fuse was not blown in the first place then the prob
lem may be a faulty solid-state relay or mechanical re
lay. Contact the factory for assistance.

10.2 The Controller Display Flashes

“CUT-OUT” And The Heater

Does Not Operate.

cut-out disconnects power to the heater when the
bath temperature exceeds the cut-out set-point. This

-

-

-

will cause the temperature to drop back down to a
safe value. If the cut-out mode is set to “AUTO” then
the heater will switch back on when the temperature
drops. If the mode is set to “RESET” then the heater
will only come on again when the temperature is re
duced and the cut-out is manually reset by the opera
tor. See Section 6.8. Check that the cut-out set-point
is adjusted to 10 or 20°C above the desired bath oper
ating temperature and that the cut-out mode is set as
desired.

If the cut-out activates when the bath temperature is
well belowthe cut-out set-point or the cut-out does not
reset when the bath temperature drops and it is man
ually reset, then the cut-out circuitry may be faulty or
the cut-out thermocouple sensor may be faulty or dis­connected. Contact the factory for assistance.

-

-

-

-

10.3 The Display Flashes

“CUT-OUT” And An Incorrect

Process Temperature.

The problem may be that the controller’s voltmeter cir
cuit is not functioning properly. This could be a prob
lem with the memory back-up battery. If the battery
power is insufficient to maintain the memory then
data may become scrambled causing problems. A

-

-

-

nearby large static discharge may also affect data in
memory. The memory may be reset by holding the
“SET” and “EXIT” keys down while power to the con
troller is switched on. The display will show “—init—”
indicating the memory is being initialized. At this
point, each of the controller parameters and calibra
tion constants must be reprogrammed into memory. If
this solves the problem but the same problem reoc
curs then the battery should be replaced. Contact the
factory. If initializing the memory does not remedy the
problem then there may be a failed electronic compo
nent. Contact the factory.

-

-

-

-

-

-

The display will flash “CUT-OUT” alternately with the
process temperature. If the process temperature dis
played seems grossly in error then also consult Sec

tion 6.8 after this procedure is followed. Normally the

-

-

41

Troubleshooting

10.4 The Displayed Process

Temperature Is In Error And

The Controller Remains In The

Cooling Or Heating State At

Any Set-point Value.

Possible causes of this problem may be either a faulty
control probe or erroneous data in memory. The
probe may be disconnected, burned out, or shorted.
Check that the probe is connected properly. The
probe may be checked with an ohmmeter to see if it is
open or shorted. The probe is a platinum 4-wire DIN
43760 type therefore the resistance should read 0.2
to 2.0 ohms between pins 1 and 2 on the probe con­nector and between pins 3 and 4. The resistance
should read 100 to 300 ohms between pins 1 and 4. If
the probe is defective contact the factory.

If the problem is not the probe then it may be caused
by erroneous data in memory. Re-initialize the mem­ory as discussed in Section 10.3 above. If the prob­lem remains then it may be caused by a defective
electronic component. Contact the factory.

10.5 The Controller Controls Or

Attempts To Control At An

gram the constants. It may be that the memory
backup battery is weak causing errors in data as de
scribed in Section 10.3.

Check that the control probe has not been struck,
bent, or damaged. If the causeof the problem remains
unknown then contact the factory.

10.6 The Controller Shows That The

Output Power Is Steady But

The Process Temperature Is

Unstable.

If the bath temperature does not achieve the expected
degree of stability when measured using a thermom­eter, try adjusting the proportional band to a narrower
width as discussed in Section 6.7.

10.7 The Controller Alternately

Heats For A While Then Cools.

This is typically oscillation caused by the proportional
band being too narrow. Increase the width of the pro­portional band until the temperature stabilizes as dis­cussed in Section 6.7.

-

Inaccurate Temperature.

Here the controller operates normally except when
the controller has reached stable control of the bath
temperature, the temperature does not agree with
that measured with the user’s reference thermometer
to within the specified accuracy. This problem may be
caused by an actual difference in temperature be­tween the points where the control probe and ther­mometer probe measure temperature or by
erroneous bath calibration parameters or a damaged
control probe.

Check that the bath has an adequate amount of fluid
in the tank and that the pump is operating causing
fluid to circulate completely. Check that the thermom­eter probe and control probe are both fully inserted
into the bath tominimize temperature gradient errors.

Check that the calibration parameters are all correct
according to the certification sheet. If not then repro

42

10.8 The Controller Erratically Heats

Then Cools, Control Is

Unstable.

If both the bath temperature and output power do not
vary periodically but in a very erratic manner, then the
problem may be excess noise in the system. Noise
due to the control sensor should be less than

0.001°C. However, if the probe has been damaged or
has developed an intermittent short, then this may
cause erratic behavior. Check for a damaged probe or
poor connection between the probe and bath. Inter­mittent shorts in the heater or controller electronic cir­cuitry may also be a possible cause. Contact the
factory if this seems to be the case.

-

Via Acquanera, 29 22100 Como
tel. 031.526.566 (r.a.) fax 031.507.984

[e-mail] www.calpower.it