Fluke 7380 User manual

7380
Ultra Low Temp Bath
User’s Guide
January 2013
© 2013 Fluke Corporation. All rights reserved. Specifications are subject to change without notice.
All product names are trademarks of their respective companies.

Table of Contents
1 Before You Start . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Symbols Used . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.1 Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.2 Cautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3 Authorized Service Centers. . . . . . . . . . . . . . . . . . . . . . 5
2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3 Specifications and Environmental Conditions . . . . . . . . . 11
3.1 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2 Environmental Conditions. . . . . . . . . . . . . . . . . . . . . . 11
3.3 Warranty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4 Quick Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.1 Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.2 Set-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.3 Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.4 Setting the Temperature . . . . . . . . . . . . . . . . . . . . . . . 14
5 Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.1 Bath Environment . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.2 “Dry-out” Period . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.3 Bath Preparation and Filling . . . . . . . . . . . . . . . . . . . . 17
5.3.1 Filling With Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
5.4 Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
6 Bath Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.2 Comparison Calibration . . . . . . . . . . . . . . . . . . . . . . . 19
6.3 Calibration of Multiple Probes . . . . . . . . . . . . . . . . . . . 20
7 Parts and Controls . . . . . . . . . . . . . . . . . . . . . . . . 21
7.1 Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
7.2 Bath Tank and Lid . . . . . . . . . . . . . . . . . . . . . . . . . . 22
7.3 Back Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
i

8 General Operation . . . . . . . . . . . . . . . . . . . . . . . . 25
8.1 Heat Transfer Fluid . . . . . . . . . . . . . . . . . . . . . . . . . 25
8.1.1 Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
8.1.2 Viscosity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
8.1.3 Specific Heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
8.1.4 Thermal Conductivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
8.1.5 Thermal Expansion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
8.1.6 Electrical Resistivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
8.1.7 Fluid Lifetime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
8.1.8 Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
8.1.9 Cost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
8.1.10 Commonly Used Fluids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
8.1.10.1 Water (Distilled) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
8.1.10.2 Ethanol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
8.1.10.3 Mineral Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
8.1.10.4 Silicone Oil (Dow Corning 200.10, 200.20) . . . . . . . . . . . . . . . . . . . . . . 28
8.1.10.5 Halocarbon 0.8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
8.1.11 Fluid Characteristics Charts. . . . . . . . . . . . . . . . . . . . . . . . . . . 28
8.1.11.1 Limitations and Disclaimer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
8.1.11.2 About the Graph . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
8.2 Stirring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
8.3 Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
8.4 Heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
8.5 Refrigeration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
8.5.1 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
8.5.2 Important Refrigerant Information . . . . . . . . . . . . . . . . . . . . . . . 32
8.6 Temperature Controller . . . . . . . . . . . . . . . . . . . . . . . 33
9 Controller Operation . . . . . . . . . . . . . . . . . . . . . . . 35
9.1 Bath Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . 35
9.2 Temperature Set-point . . . . . . . . . . . . . . . . . . . . . . . . 35
9.2.1 Programmable Set-points . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
9.2.2 Set-point Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
9.2.3 Temperature Scale Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
9.3 Scan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
9.3.1 Scan Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
9.3.2 Scan Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
9.4 Secondary Menu. . . . . . . . . . . . . . . . . . . . . . . . . . . 39
9.5 Heater Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
9.6 Proportional Band . . . . . . . . . . . . . . . . . . . . . . . . . . 39
9.7 Cutout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
9.8 Controller Configuration . . . . . . . . . . . . . . . . . . . . . . 41
9.9 Operating Parameters . . . . . . . . . . . . . . . . . . . . . . . . 42
9.9.1 High Limit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
9.9.2 Low Limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
ii

9.9.3 Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
9.10 Serial Interface Parameters . . . . . . . . . . . . . . . . . . . . . 43
9.10.1 Baud Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
9.10.2 Sample Period. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
9.10.3 Duplex Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
9.10.4 Linefeed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
9.11 Calibration Parameters . . . . . . . . . . . . . . . . . . . . . . . 45
9.11.1 Hard Cutout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
9.11.2 R0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
9.11.3 ALPHA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
9.11.4 DELTA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
9.11.5 BETA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
10 Digital Communication Interface . . . . . . . . . . . . . . . . 47
10.1 Serial Communications . . . . . . . . . . . . . . . . . . . . . . . 47
10.1.1 Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
10.1.2 Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
10.1.2.1 BAUD Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
10.1.2.2 Sample Period. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
10.1.2.3 Duplex Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
10.1.2.4 Linefeed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
10.1.3 Serial Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
10.2 Interface Commands . . . . . . . . . . . . . . . . . . . . . . . . 49
11 Calibration Procedure . . . . . . . . . . . . . . . . . . . . . . 53
11.1 Calibration Procedure . . . . . . . . . . . . . . . . . . . . . . . . 53
11.1.1 Calibration Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
11.1.2 Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
12 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
13 Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . 57
13.1 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
13.2 CE Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
13.2.1 EMC Directive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
13.2.2 Low Voltage Directive (Safety) . . . . . . . . . . . . . . . . . . . . . . . . . 58
iii

iv
Figures
Figure 1 Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Figure 2 Back Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Figure 3 Chart of Various Bath Fluids . . . . . . . . . . . . . . . . . . . . . . . 30
Figure 4 Controller Operation Flowchart . . . . . . . . . . . . . . . . . . . . . 36
Figure 5 Serial Cable Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

v
Tables
Table 1 International Electrical Symbols . . . . . . . . . . . . . . . . . . . . . 1
Table 2 Table of Various Bath Fluids . . . . . . . . . . . . . . . . . . . . . . . 31
Table 3 Controller Communications Commands . . . . . . . . . . . . . . . . . 50
Table 3 Controller Communications Commands continued . . . . . . . . . . . 51

1 Before You Start
1.1 Symbols Used
Table 1 lists the International Electrical Symbols. Some or all of these symbols
may be used on the instrument or in this manual.
Symbol Description
AC (Alternating Current)
AC-DC
Battery
CE Complies with European Union Directives
DC
Double Insulated
Electric Shock
Fuse
PE Ground
Hot Surface (Burn Hazard)
Read the User’s Manual (Important Information)
Off
On
1
1 Before You Start
Symbols Used
Table 1 International Electrical Symbols

Symbol Description
Canadian Standards Association
OVERVOLTAGE (Installation) CATEGORY II, Pollution Degree 2 per IEC1010-1 re-
fers to the level of Impulse Withstand Voltage protection provided. Equipment of
OVERVOLTAGE CATEGORY II is energy-consuming equipment to be supplied from
the fixed installation. Examples include household, office, and laboratory appliances.
C-TIC Australian EMC Mark
The European Waste Electrical and Electronic Equipment (WEEE) Directive
(2002/96/EC) mark.
1.2 Safety Information
Use this instrument only as specified in this manual. Otherwise, the protection
provided by the instrument may be impaired.
The following definitions apply to the terms “Warning” and “Caution”.
•“Warning” identifies conditions and actions that may pose hazards to the
user.
•“Caution” identifies conditions and actions that may damage the instru-
ment being used.
1.2.1 Warnings
To avoid personal injury, follow these guidelines.
GENERAL
•DO NOT use the instrument for any application other than calibration
work. The instrument was designed for temperature calibration. Any other
use of the unit may cause unknown hazards to the user.
•DO NOT use the unit in environments other than those listed in the user’s
guide.
•DO NOT overfill the bath. Overflowing extremely cold or hot fluid may
be harmful to the operator. See Section 5.3, Bath Preparation and Filling,
for specific instructions.
•Follow all safety guidelines listed in the user’s manual.
•Calibration Equipment should only be used by Trained Personnel.
•If this equipment is used in a manner not specified by the manufacturer,
the protection provided by the equipment may be impaired.
•Before initial use, or after transport, or after storage in humid or semi-hu-
mid environments, or anytime the instrument has not been energized for
more than 10 days, the instrument needs to be energized for a "dry-out"
7380 Ultra Low Temp Bath
User’s Guide
2

period of 2 hours before it can be assumed to meet all of the safety re-
quirements of the IEC 1010-1. If the product is wet or has been in a wet
environment, take necessary measures to remove moisture prior to apply-
ing power such as storage in a low humidity temperature chamber operat-
ing at 50 degree centigrade for 4 hours or more.
•DO NOT operate high temperature baths (500°C) near flammable materi-
als. Extreme temperatures could ignite the flammable material.
•Overhead clearance is required. Do not place the instrument under a cabi-
net or other structure. Always leave enough clearance to allow for safe
and easy insertion and removal of probes.
•The instrument is intended for indoor use only.
BURN HAZARD
•Extremely cold temperatures may be present in this equipment. Freezer
burns and frostbite may result if personnel fail to observe safety precau-
tions.
•High temperatures may be present in this equipment. Fires and severe
burns may result if personnel fail to observe safety precautions.
ELECTRICAL HAZARD
•These guidelines must be followed to ensure that the safety mechanisms
in this instrument will operate properly. This instrument must be plugged
into a 115 VAC, 60Hz (230 VAC, 50Hz optional), AC only electric outlet.
The power cord of the instrument is equipped with a three-pronged
grounding plug for your protection against electrical shock hazards. It
must be plugged directly into a properly grounded three-prong receptacle.
The receptacle must be installed in accordance with local codes and ordi-
nances. Consult a qualified electrician. DO NOT use an extension cord or
adapter plug.
•DO use a ground fault interrupt device. This unit contains a liquid. A
ground fault device is advised in case liquid is present in the electrical
system and could cause an electrical shock.
•Always replace the power cord with an approved cord of the correct rat-
ing and type. If you have questions, contact a Hart Scientific Authorized
Service Center (see Section 1.3).
•High voltage is used in the operation of this equipment. Severe injury or
death may result if personnel fail to observe the safety precautions. Before
working inside the equipment, turn off the power and disconnect the
power cord.
BATH FLUIDS
•Fluids used in this unit may produce noxious or toxic fumes under certain
circumstances. Consult the fluid manufacturer’s MSDS (Material Safety
Data Sheet). Proper ventilation and safety precautions must be observed.
3
1 Before You Start
Safety Information

•The unit is equipped with a soft cutout (user settable firmware) and a hard
cutout (set at the factory). Check the flash point, boiling point, or other
fluid characteristic applicable to the circumstances of the unit operation.
Ensure that the soft cutout is adjusted to the fluid characteristics of the ap-
plication.
1.2.2 Cautions
•THE DRAIN VALVE MUST BE CLOSED ON THE BACK OF THE
BATH BEFORE ATTEMPTING TO FILL THE TANK WITH
FLUID.
•Always operate this instrument at room temperature between 41°F and
104°F (5°C to 40°C). Allow sufficient air circulation by leaving at least 6
inches (15 cm) of clearance around the instrument.
•DO NOT overfill the bath. Overflowing liquid may damage the electrical
system. Be sure to allow for thermal expansion of the fluid as the bath
temperature increases. See Section 5.3, Bath Preparation and Filling, for
specific instructions.
•No matter what fluid is used, DO NOT exceed the recommended fluid
viscosity.
•Read Section 6, Bath Use, before placing the unit into service.
•DO NOT change the values of the bath calibration constants from the fac-
tory set values. The correct setting of these parameters is important to the
safety and proper operation of the unit.
•The refrigeration may be damaged or the lifetime shortened if the
set-point temperature is set above 60°C for more than one hour with the
refrigeration manually on. Ensure that the refrigeration is off when the
unit is used above 60°C.
•The Factory Reset Sequence should be performed only by authorized
personnel if no other action is successful in correcting a malfunction. You
must have a copy of the most recent Report of Test to restore the test pa-
rameters.
•DO NOT operate this instrument in an excessively wet, oily, dusty, or
dirty environment.
•The unit is a precision instrument. Although it has been designed for opti-
mum durability and trouble free operation, it must be handled with care.
Position the unit before the tank is filled with fluid. Use the handles pro-
vided to move the unit. Due to the weight of the compressor, it may re-
quire two people to safely move the bath. If two people are used, place
one person in the front and one person in the back of the unit, carefully
slide hands under the unit and lift in unison. The area containing the com-
pressor will be heavier than the rest of the unit. Do not move a unit filled
with fluid.
•Most probes have handle temperature limits. Be sure that the probe handle
temperature limit is not exceeded in the air above the instrument.
7380 Ultra Low Temp Bath
User’s Guide
4

•The instrument and any thermometer probes used with it are sensitive in-
struments that can be easily damaged. Always handle these devices with
care. Do not allow them to be dropped, struck, stressed, or overheated.
COLD BATHS
•Refrigerated baths require that the condensing coil be cleaned periodi-
cally. Accumulation of dust and dirt on the condenser will result in pre-
mature failure of the compressor.
•Bath or compressor lifetime may be affected by:
♦Cycling the heat source through extreme temperature ranges (the full
temperature limit of the heat source). Cycling the instrument can cause
excessive stress on the compressors. Compressor manufacturers rec-
ommend, for longest lifetime, that the instrument be set at one temper-
ature and left on at that temperature.
♦Turning the instrument on and off frequently adds wear and tear to the
compressor.
•This bath has been equipped with a brownout and over voltage protection
device as a safety feature to protect the system components.
•Mode of Operation: This bath needs to be plugged into the line voltage
for at least 2 minutes before operation. This is only necessary for the first
time that the bath is energized or when it is moved from one location to
another. Turning the bath ON or OFF does not trigger the delay.
•If a High/Low voltage condition exists for longer than 5 seconds, the bath
de-energizes. The display flashes “LoLinE” while the contdition exists.
•Re-energization is automatic upon correction of the fault condition and af-
ter a delay cycle of about 2 minutes. If a fault condition exists upon appli-
cation of power, the bath will not energize.
•Under and Over Voltage Protection at 115 VAC
♦Voltage Cutout: ±12.5% (101 - 129 VAC)
♦Voltage Cut In: ±7.5% (106 - 124 VAC)
•Under and Over Voltage Protection at 230 VAC
♦Voltage Cutout: ±12.5% (203 - 257 VAC)
♦Voltage Cut In: ±7.5% (213 - 247 VAC)
1.3 Authorized Service Centers
Please contact one of the following authorized Service Centers to coordinate
service on your Hart product:
Fluke Corporation, Hart Scientific Division
799 E. Utah Valley Drive
5
1 Before You Start
Authorized Service Centers

American Fork, UT 84003-9775
USA
Phone: [phone]
Telefax: +1.801.763.1010
E-mail: [email protected]
Fluke Nederland B.V.
Customer Support Services
Science Park Eindhoven 5108
5692 EC Son
NETHERLANDS
Phone: [phone]
Telefax: [phone]
E-mail: [email protected]
Fluke Int'l Corporation
Service Center - Instrimpex
Room 2301 Sciteck Tower
22 Jianguomenwai Dajie
Chao Yang District
Beijing 100004, PRC
CHINA
Phone: [phone]
Telefax: [phone]
E-mail: [email protected]
Fluke South East Asia Pte Ltd.
Fluke ASEAN Regional Office
Service Center
60 Alexandra Terrace #03-16
The Comtech (Lobby D)
118502
SINGAPORE
Phone: [phone]
7380 Ultra Low Temp Bath
User’s Guide
6

Telefax: [phone]
E-mail: [email protected]
When contacting these Service Centers for support, please have the following
information available:
•Model Number
•Serial Number
•Voltage
•Complete description of the problem
7
1 Before You Start
Authorized Service Centers

2 Introduction
The Hart Scientific 7380 is an ultra low temp bath useful in temperature cali-
bration and other applications requiring stable temperatures. An innovative
state of the art solid-state temperature controller has been incorporated which
maintains the bath temperature with extreme stability. The temperature control-
ler uses a micro-controller to execute the many operating functions.
The user interface is provided by the 8-digit LED display and four
key-switches. Digital remote communication is available with an RS-232
interface.
The 7380 bath was designed to be compact and low cost without compromising
performance. The 7380 bath operates over a wide temperature range from
–80°C to 100°C.
9
2 Introduction

3 Specifications and Environmental
Conditions
3.1 Specifications
Range –80°C to 100°C
(–112°F to 212°F)
Ambient Operating Range 15°C to 25°C
(59°F to 77°F)
Stability (2 sigma) ±0.006°C at –80°C (ethanol)
±0.010°C at 0°C (ethanol)
±0.010°C at 100°C (oil 5012)
Uniformity ±0.008°C at –80°C (ethanol)
±0.012°C at 0°C (ethanol)
±0.012°C at 100°C (oil 5012)
Heating Time
†
25 minutes from 25°C to 100°C (oil 5010)
Cooling Time 130 minutes from 25°C to –80°C (ethanol)
Stabilization Time 15–20 minutes
Display Resolution 0.01°
Set-Point Accuracy ±0.5°C
Set-Point Repeatability ±0.01°C
Access Opening 3.25" x 4.5" (83 x 114 mm)
Immersion Depth 7" (180 mm) max
Volume 1 gallon (4 liters)
Refrigeration Cascade Two ¼ HP compressors
Heater Power 500 W
Automation Package Interface
-it software and RS-232 included
Power
†
115 V ac (±10%), 60 Hz, 15 A or 230 V ac (±10%), 50 Hz, 8 A,
1700 VA
Size 12" W x 30" H x 24" D
(305 x 762 x 610 mm)
Weight 115 lb. (52 kg)
Safety OVERVOLTAGE (Installation) CATEGORY II, Pollution Degree 2 per
IEC1010-1
†
Rated at listed 115 V (or optional 230 V)
3.2 Environmental Conditions
Although the instrument has been designed for optimum durability and trou-
ble-free operation, it must be handled with care. The instrument should not be
operated in an excessively dusty or dirty environment. Maintenance and clean-
ing recommendations can be found in the Maintenance Section of this manual.
11
3 Specifications and Environmental Conditions
Specifications

4 Quick Start
CAUTION: READ SECTION 6 TITLED BATH USE before placing the
bath in service. Incorrect handling can damage the bath and void the war-
ranty.
This chapter gives a brief summary of the steps required to set up and operate
the bath. This should be used as a general overview and reference and not as a
substitute for the remainder of the manual. Please read Section 5 through 8
carefully before operating the bath.
4.1 Unpacking
Unpack the bath carefully and inspect it for any damage that may have oc-
curred during shipment. If there is shipping damage, notify the carrier immedi-
ately. Verify that all components are present:
•7380 Bath
•RS-232 Cable
•Access Hole Cover
•Power Cord
•Manual
•Report of Test
If you are missing any item, please call a Hart Authorized Service Center (see
Section 1.3).
4.2 Set-up
CAUTION: The drain valve on the back of the bath must be closed before
attempting to fill the tank with fluid.
WARNING: The instrument is equipped with a soft cutout (user settable
firmware) and a hard cutout (set at the factory). Check the flash point,
boiling point, or other fluid characteristic applicable to the circumstances
of the unit operation. Ensure that the soft cutout is adjusted to the fluid
characteristics of the application. As a guideline, the soft cutout should be
set 10°C to 15°C below the flash point of the bath fluid. See Section 8.1,
Heat Transfer Fluid, for specific information on bath fluids and Section
9.7, Cutout.
Set up of the bath requires careful unpacking and placement of the bath, filling
the bath with fluid, and connecting power. Consult Section 5 for detailed in-
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Unpacking

structions for proper installation of the bath. Be sure to place the bath in a safe,
clean and level location. Fill the bath tank with an appropriate liquid. For oper-
ation at moderate bath temperatures, clean distilled water works well. For lower
temperatures, ethanol (denatured) works well but is NOT USABLE AT
HIGHER TEMPERATURES due to flammability.
Carefully pour the fluid into the bath tank through the large rectangular access
hole above the tank avoiding spilling any fluid. The fluid must not exceed a
height of 1/2 inch below the top of the tank or be less than 2 inches (50 mm)
below the top.
4.3 Power
Plug the bath power cord into a mains outlet of the proper voltage, frequency,
and current capability. See Section 3.1, Specifications, for power details. Refer
to and read the CAUTION at the front of this manual concerning brownout and
over voltage protection.
Turn the bath on using the front panel “POWER” switch. The bath begins to
heat or cool to reach the previously programmed temperature set-point. The
front panel LED display indicates the actual bath temperature. Set the cooling
switch to “OFF” for temperatures above approximately 50°C. Set the switch to
“ON” for lower temperatures. When the cooling switch has been turned on, the
first stage compressor powers up. The second stage comes on automatically
when proper conditions are met. This takes 2 to 4 minutes. The bath does not
begin to cool until the second stage starts.
4.4 Setting the Temperature
In the following discussion and throughout this manual a solid box around the
word SET, UP, DOWN or EXIT indicates the panel button to press while the
dotted box indicates the display reading on the front panel. Explanation of the
button function or display reading is written at the right.
To view or set the bath temperature set-point proceed as follows. The front
panel LED display normally shows the actual bath temperature.
24.68 C Bath temperature display
When “SET” is pressed the display shows the set-point memory that is cur-
rently being used and its value. Eight set-point memories are available.
SAccess set-point selection
1. 25.0 Set-point 1, 25.0°C currently used
Press “SET” to select this memory and access the set-point value.
7380 Ultra Low Temp Bath
User’s Guide
14

SAccess set-point value
C 25.00 Current value of set-point 1, 25.00°C
Press “UP” or “DOWN” to change the set-point value.
UIncrement display
C 30.00 New set-point value
Press SET to accept the new value. The bath begins heating or cooling to the
new set-point.
SStore new set-point
Press “EXIT” and the bath temperature is displayed again.
EReturn to the temperature display
24.73 C Bath temperature display
The bath heats or cools until it reaches the new set-point temperature. Turn off
the cooling to reach and control at higher temperatures.
When setting the set-point temperature be careful not to exceed the temperature
limit of the bath fluid.
To obtain optimum control stability adjust the proportional band as discussed in
Section 9.6.
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Setting the Temperature