Guildline 5031 User manual

TECHNICAL MANUAL
FOR
MODEL 5031
AIR BATH
NOTICE
The contents and information contained in this manual are proprietary to
Guildline Instruments. They are to be used only as a guide to the operation
and maintenance of the equipment with which this manual was issued, and
may not be duplicated or transmitted by any means, either in whole or in
part, without the written permission of Guildline Instruments.
TM5031-D1-00
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TABLE OF CONTENTS
1. INTRODUCTION...................................................................................................1-1
1.1. SCOPE................................................................................................................................................... 1-1
1.2. GENERAL DESCRIPTION................................................................................................................ 1-2
1.3. FRONT PANEL INDICATORS AND CONTROLS......................................................................... 1-3
1.3.1. Power..................................................................................................................................................1-3
1.3.2. Heater ON and OFF............................................................................................................................1-3
1.3.3. High / Low..........................................................................................................................................1-3
1.3.4. Cooling ...............................................................................................................................................1-3
1.3.5. Temperature Set..................................................................................................................................1-3
1.4. REAR PANEL CONNECTORS AND CONTROLS......................................................................... 1-4
1.4.1. Line Input Connector..........................................................................................................................1-4
1.4.2. Voltage Selector..................................................................................................................................1-4
2. SPECIFICATIONS................................................................................................2-1
2.1. GENERAL SPECIFICATIONS.......................................................................................................... 2-1
3. OPERATING INSTRUCTIONS.............................................................................3-1
3.1. INSTALLATION.................................................................................................................................. 3-1
3.2. OPERATING NOTES.......................................................................................................................... 3-2
3.2.1. Heater Control Setting ........................................................................................................................3-2
3.2.2. Bath Temperature Selection................................................................................................................3-3
4. MAINTENANCE....................................................................................................4-1
4.1. PREVENTIVE MAINTENANCE....................................................................................................... 4-1
4.1.1. Cleaning..............................................................................................................................................4-1
4.1.2. Temperature Check.............................................................................................................................4-1
4.2. CORRECTIVE MAINTENANCE...................................................................................................... 4-1
4.2.1. Preliminary Checks.............................................................................................................................4-1
4.2.2. Temperature Control...........................................................................................................................4-1
4.2.3. Over Temperature...............................................................................................................................4-3
5. PRINCIPLES OF OPERATION ............................................................................5-1
5.1. INTRODUCTION ................................................................................................................................ 5-1
5.2. TEMPERATURE SENSITIVE OSCILLATOR................................................................................ 5-2
5.3. AMPLIFIER AND DETECTOR......................................................................................................... 5-2

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5.4. HEATER DRIVER............................................................................................................................... 5-3
5.5. OVER TEMPERATURE CIRCUIT................................................................................................... 5-3
5.6. POWER SUPPLY................................................................................................................................. 5-4

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TABLE OF FIGURES
FIGURE 1-1: FRONT VIEW....................................................................................................................................1-1
FIGURE 1-2: CONTROL PANEL............................................................................................................................1-3
FIGURE 5-1: HEATER CONTROL UNIT ..............................................................................................................5-1
FIGURE 5-2: TEMPERATURE SENSITIVE OSCILLATOR.................................................................................5-2
FIGURE 5-3: AMPLIFIER AND DETECTOR........................................................................................................5-2
FIGURE 5-4: HEATER DRIVER.............................................................................................................................5-3
FIGURE 5-5: OVER TEMPERATURE CIRCUIT...................................................................................................5-3
FIGURE 5-6: POWER SUPPLY...............................................................................................................................5-4

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LIST OF TABLES
TABLE 2-1: GENERAL SPECIFICATIONS...........................................................................................................2-1
TABLE 3-1: SUGGESTED CONTROL SETTINGS ................................................................................................3-3
TABLE 4-1: CONTROL CIRCUIT BOARD TESTING..........................................................................................4-2
TABLE 4-2: TRANSISTOR VOLTAGES................................................................................................................4-3

Section 1
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1-1
1. INTRODUCTION
Figure 1-1: Front View
1.1. SCOPE
This manual contains technical specifications, a detailed description, maintenance information,
and diagrams for the Guildline Instruments model 5031 Air Bath.

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1-2
1.2. GENERAL DESCRIPTION
The model 5031 Air Bath is a bench top high precision, variable temperature bath which
provides 0.08 m3(2.9 cu. ft.) of usable temperature controlled chamber. The internal temperature
is maintained by a solid state control system. The regulated temperature can be selected from a
digital switch control on the front control panel. The temperature range is from 15.00 C to
50.00 C with a resolution of 0.01 C and 0.03 C stability. The design assures minimal
thermal gradients within the chamber.
The air bath chamber is of stainless steel construction. This shielded enclosure is tied to earth
ground through the power cord to reduce electromagnetic interference. The circulation fan,
cooling unit and heater are separated from the air bath chamber to provide full and unimpeded
access to the bath chamber.
The design of the bath employs a fixed rate of cooling from a thermoelectric module and
balances this to the heating/cooling level required by turning a heater off and on rapidly. This
provides the required heating/cooling to balance the heat losses to ambient or the heat generated
by apparatus within the chamber.
To protect the contents of the chamber from overheating due to a malfunction of the temperature
control, there is an overriding over-temperature control that will disable the heating system if the
temperature exceeds 55 C 4 C.
Uses for the Programmable Air Bath include:
•Maintaining a constant temperature environment for reference resistors such as the Guildline
Instruments 9330 series resistors.
•Calibration of thermometers.
•Thermal stressing of precision materials.

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Figure 1-2: Control Panel
1.3. FRONT PANEL INDICATORS AND CONTROLS
The front panel indicators and controls are illustrated in Figure 1-2. They are provided to indicate
power status, heater operation and temperature status.
1.3.1. Power
The POWER switch controls AC line power to the air bath.
1.3.2. Heater ON and OFF
The HEATER indicator lamps indicate whether or not the heater is energised; alternating
illumination indicates that the bath has reached the pre-set operating temperature.
1.3.3. High / Low
This switch, in the HIGH position, energises the heater with full-wave current. In the
LOW position a diode in series with the heater provides half-wave operation and so
reduces the heater power to half the value obtained on the HIGH position. When
operating in the LOW position only one electrode of the neon lamps will glow, while in
the HIGH position both will be illuminated.
1.3.4. Cooling
Operation of the cooling switch will energise the circuit supplying current to the cooling
modules and also operate the fan, which cools their associated heat sink.
1.3.5. Temperature Set
The temperature setting is controlled by means of the four-digit thumbwheel switch. The
table enclosed with this manual indicates the control settings for temperatures over the
entire range of 15 C to 50 C. The effect of a one step change of these dials on the
temperature set point will vary depending upon their settings. The rate of change of
resistance setting vs. operating temperature is approximately -4%/C. The total resistance
of the 4-digit TEMPERATURE SET control is 200 more than the value indicated. For
example, if the operating temperature is 23 C when the control is set to 4000 (i.e.
resistance is 4200 ), then changing the control setting to 3832 (4000 - 4% of 4200) will
produce an operating temperature of approximately 24 C.

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1.4. REAR PANEL CONNECTORS AND CONTROLS
The rear panel connectors and controls include power entry, and line voltage selection.
1.4.1. Line Input Connector
The Line input connector is a standard male 3-prong AC connector, with an integral fuse. A
2 amp time delay fuse is provided for 115 VAC operation and a 1 amp time delay fuse is
provided for 230 VAC operation.
1.4.2. Voltage Selector
The line input voltage selector is a two-position switch that allows setting for a nominal line
voltage of either 115 VAC, or 230 VAC. The actual limits of the line voltage are
90-132 VAC or 200-264 VAC, 47-63 Hz.