Hart Sceintific 9113 User manual

Model 9113
Portable Furnace
User Manual
HART
SCIENTIFIC
Rev. 721801

© Copyright,1991 All rights reserved
Hart Scientific
799 E. Utah Valley Drive
American Fork, Utah 84003-9775
Telephone [phone] • Fax [phone]
Internet: http://www.hartscientific.com
2

WARNING
To ensure the safety of operating personnel, and to avoid damage to this equipment:
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
HIGHVOLTAGE
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.
WARNING
HIGH TEMPERATURES PRESENT
in this equipment
FIRES AND SEVERE BURNS
may result if personnel fail to observe safety precautions.
WARNING
To ensure the safety of personnel, and to avoid damage to equipment:
DO NOT use this unit for any application other than calibration work.
DO NOT use this unit in environments other than those listed in the user’s manual.
Continuous use of this equipment at high temperatures for extended periods of time
requires caution.
Completely unattended high temperature operation is not recommended for
safety reasons.
Components and heater lifetimes can be shortened by continuous high temperature operation.
Follow all safety guidelines listed in the user’s manual.
c

WARNING
THIS EQUIPMENT SHOULD ONLY BE USED BY TRAINED PERSONNEL.
d

Table of Contents
1 Introduction ................................7
2 Specifications and Environmental Conditions .............8
2.1 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2 Environmental Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3 Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3 Safety Guidelines ............................ 10
4 Quick Start ................................ 11
4.1 Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.2 Set-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.3 Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
5 Installation ................................ 12
5.1 Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.2 Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.3 “Dry-out” Period . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.4 Equilibration Block Installation . . . . . . . . . . . . . . . . . . . . . . . . . . 12
6 Parts and Controls ........................... 13
6.1 Top Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
6.1.1 Temperature Controller ................................... 13
6.1.1.1 Temperature Adjustment Up/Down Keys ..................... 13
6.1.2 Power Switch ........................................ 14
6.1.3 Fan Light Indicator ...................................... 14
6.1.4 Probe Cooling Tubes .................................... 14
6.1.5 Handles ........................................... 14
6.1.6 Cooling Vents ........................................ 15
6.2 Equilibration Block Assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6.2.1 Temperature Control and Cut-out Sensors ......................... 15
6.3 Back Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6.3.1 Power Cable ......................................... 15
6.3.2 Fuse ............................................. 15
6.3.3 RS-232 Port (Optional) ................................... 15
7 General Operation ............................ 18
7.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
7.2 Operating the Temperature Controller . . . . . . . . . . . . . . . . . . . . . . 18
v

7.2.1 Over Temperature Cut-out ................................. 19
8 Digital Communications Interface (optional) .............20
8.1 Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
8.2 Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
9 Test Probe Calibration .........................21
9.1 Calibration Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
9.1.1 Direct Calibration ...................................... 21
9.1.2 Comparison Calibration ................................... 21
9.1.3 Calibration of Multiple Probes ................................ 22
9.2 Furnace Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
9.2.1 Vertical Gradient ...................................... 22
9.2.2 Stabilization and Accuracy ................................. 22
10Maintenance ...............................23
11TroubleShooting ............................24
11.1 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
11.2 Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Figures and Tables
Table 1 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 1 Top Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 2 Temperature Controller (enlarged view) . . . . . . . . . . . . . . . . . . . 14
Figure 3 Equilibration Block Assembly . . . . . . . . . . . . . . . . . . . . . . . . 16
Figure 4 Back Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 5 Serial Communications Wiring Diagram . . . . . . . . . . . . . . . . . . . 20
Figure 6 Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
vi

1 Introduction
The model 9113 Portable Calibration Furnace was
designed specifically for calibrating PRT’s, fiber optic
sensorsandthermocouplesatthehighertemperature
ranges up to 1100°C. The furnace utilizes an equili-
bration block capable of making comparison meas-
urements.Temperaturestabilityisbetterthan±0.75°C
throughout the range and the gradient between wells
at full insertion is less than 1.0°C (±0.25°C).
The temperature control system utilizes a digital con-
troller with a type K thermocouple control sensor.An
RS-232 interface is optional. The controller displays
thesettemperatureandtheactualtemperaturesimul-
taneously.Thedisplaysshowtemperaturetothenear-
est degree in °C or °F (normally shipped in °C, may
be changed to °F). The temperature is set with con-
venient up and down buttons on the front panel.
The furnace is protected from excessive temperature
with an over-temperature cut-out.The cut-out is relay
operated and independent from the temperature con-
troller to protect against the possibility of thermal
runaway due to a shorted solid state relay which
controls the heater.
Introduction
9113 Portable Furnace Manual Rev. 721801 7

2 Specifications and Environmental
Conditions
2.1 Specifications
See Table 1.
2.2 Environmental Conditions
Although the instrument has been designed for opti-
mum durability and trouble-free operation, it must be
handled with care. The instrument should not be
operatedinanexcessivelydustyordirtyenvironment.
Maintenance and cleaning recommendations can be
found in the Maintenance Section of this manual.
The instrument operates safely under the following
conditions:
•temperature range: 5–50°C (41–122°F)
•ambient relative humidity: 15–50%
•pressure: 75kPa–106kPa
•mains voltage within ±10% of nominal
•vibrations in the calibration environment
should be minimized
•altitude does not effect the performance or
safety of the unit
2.3 Warranty
The 9113 calibration furnace is covered by a 1 year
warranty that takes effect 10 days after the product is
Operating Range: 200°C to 1100°C
Stability: ±0.75°C
Test Well: 1.3" Dia.X 10.5" Deep. Available inserts size the well for best thermal
contact with the probe.
Inserts: Special high temperature alloy. Standard inserts include a reference
and a test hole.One insert is included with the 9113 with 1 hole for
0.25" dia.probes and one for 0.28" dia.standard. Additional custom
drilled inserts are available with holes sizes starting at 3/16" (probe
size fit).Insert block dimension is 1.25" dia.X 6" long.
Interface: Optional, RS-232 serial interface for computer controlled operation
Cooling: Built in fan keeps enclosure cool and assists cool down after high
temperatue use
Size: 17.5 H X 13" W X 7" D
Weight: 22 lb.
Table 1 Specifications
Specifications and Environmental Conditions
8 Manual Rev. 721801 Hart Scientific

shipped. This warranty excludes breakage of the
quartz tube. The manufacturer will provide parts and
labor without charge for repair or replacement of the
instrumentduetodefectsinmaterialor workmanship.
Thewarranty willnot applyiftheproducthas notbeen
used according to the instruction manual or has been
tampered with by the user.For service or assistance,
please contact the manufacturer.
Hart Scientific, Inc.
799 East Utah Valley Drive
American Fork, UT 84003
Phone: [phone]  Fax: [phone]
Internet: http://www.hartscientific.com
Specifications and Environmental Conditions
9113 Portable Furnace Manual Rev. 721801 9

3 Safety Guidelines
•Operate the instrument in room temperatures
between 5-50°C (41-122°F). Allow sufficient
air circulation by leaving at least 6 inches of
space between the furnace and nearby ob-
jects. Overhead clearance needs to allow for
safe and easy insertion and removal of probes
for calibration. If the furnace is equipped with
cooling coils, use cold water circulation when
the furnace is used above 600°C.
•The furnace is a precision instrument. Al-
though it has been designed for optimum du-
rability and trouble free operation, it must be
handled with care. The instrument should not
be operated in wet, oily, dusty or dirty environ-
ments. It is important to keep the well of the
instrument free of any foreign matter. Do not
operate near flammable materials.
•Do not use fluids to clean out the well.
•The furnace generates extreme temperatures.
Precautionsmustbe takentopreventpersonal
injury or damage to objects. Probes may be
extremely hotwhen removedfromthe furnace.
Cautiously handle probes to prevent personal
injury. Carefully place probes on a heat resis-
tant surface or rack until they are at room
temperature.
•Use only a grounded AC mains supply of the
appropriate voltage to power the instrument.
The furnace requires 8 amps at 115 VAC
(±10%), single phase, 50\60 Hz.(optional 230
VAC (±10%))
•Before initial use, after transport, and anytime
the furnace has not been energized for more
than 10 days, the instrument needs to be en-
ergized for a “dry-out” period of 1-2 hours
before it can be assumed to meet all of the
safety requirements of the IEC 1010-1.
•The instrument is equipped with operator ac-
cessible fuses. If a fuse blows, it may be due
to a power surge or failure of a component.
Replace the fuse once. If the fuse blows a
second time, it is likely caused by failure of a
component part. If this occurs, contact Hart
Scientific Customer Service. Always replace
the fuse with one of the same rating, voltage,
and type.Never replace the fuse with one of a
higher current rating.
•If a mains supply power fluctuation occurs,
immediately turn off the furnace.Power bumps
from brown-outs and black-outs can damage
the instrument. Wait until the power has stabi-
lized before re-energizing the furnace.
Safety Guidelines
10 Manual Rev. 721801 Hart Scientific

4 Quick Start
4.1 Unpacking
Unpack the furnace carefully and inspect it for any
damage that may have occurred during shipment. If
there is shipping damage, notify the carrier immedi-
ately.
Verify that the following components are present:
•9113 Furnace
•Model 3189, Equilibration Block Assembly
•Equilibration Block Assembly Removal Tool
•Power Cord
•Manual
Theequilibrationblockassemblyispackedseparately
in order to protect the quartz tube from breakage
during shipment. The equilibration block assembly
should not be installed into the furnace until it has
been placed in location.
4.2 Set-up
Place the furnace on a flat surface with at least 6
inches of free space around the instrument. Plug the
powercordintoagroundedmainsoutlet.Observethat
the nominal voltage corresponds to that indicated on
the back of the furnace.
Carefully insert the equilibration block into the well
using the removal tool to lower the block in place.The
well must be clear ofany foreign objects, dirt, and grit
before the equilibration block is inserted.
Turnonthepowertothefurnacebytogglingthepower
switch on. The controller display should illuminate
after 3 seconds. After a brief self-test the controller
should begin normal operation. If the unit fails to
operate please check the power connection.
The display begins to show the well temperature and
the well heater starts operating to bring the tempera-
ture of the well to the set-point temperature.
4.3 Power
Plug the furnace power cord into a mains outlet of the
propervoltage, frequency,andcurrentcapability.Typi-
cally this outlet is 115 VAC (±10%), 50/60 Hz or 230
VAC (±10%), 50/60 Hz.Turn the furnace on using the
front panel on/off switch. The furnace turns on and
begins to heat to the previously programmed tem-
perature set-point. The front panel LED display indi-
cates the actual furnace temperature.
Quick Start
9113 Portable Furnace Manual Rev. 721801 11

5 Installation
5.1 Location
Thefurnaceisintendedtobeusedinanyenvironment
which is clean, safe and reasonably free from drafts.
Thebest resultsfromthefurnace willbe realized ifthe
temperature fluctuations in the room are not exces-
sive.A minimum of 6 inches free air space around the
furnace must be allowed.This will allow air exchange
to safely remove excess heat from the furnace.
DANGER
This furnace is intended for high temperature
use and consequently a fire danger exists. Keep
away from flammable materials and keep fire ex-
tinguishing equipment near by.
5.2 Power
The furnace’s nominal voltage is 115 VAC (±10%), 8
amps, single phase, 50/60 Hz. A six foot 16 AWG, 2
conductor with ground, removable power cord is pro-
vided.Be sure an adequate ground is provided.
5.3 “Dry-out”Period
Before initial use, after transport, and any time the
instrument has not been energized for more than 10
days, the instrument will need to be energized for a
“dry-out”periodof1–2hoursbeforeitcanbeassumed
to meet all of the safety requirements of the IEC
1010-1.
5.4 Equilibration Block
Installation
After the furnace has generally been installed, the
equilibration block may be inserted. Carefully insert
the block into the quartz tube. See Figure 1 on page
13.Extreme care should be taken installing theEquili-
brationBlocksinceitisveryheavyandthequartztube
is very fragile. Care must be taken to prevent dirt,
insulation, or other foreign materials from getting be-
tween the block and the quartz tube or it might break
during heat up due to thermal expansion differences.
The fit between the block and the tube is typically
loose in order to accommodate this expansion. A
handle is provided to insert the block.It consists of a
stainless steel rod with a 1/4-20 threaded end which
is screwed into the top of the block. The block is then
lowered down over the control and cut-out sensors
using the handle and allowed to rest on the ceramic
fiberinsulationonthebottomofthewell.Youwillnotice
that there are grooves on either side of the block for
the sensors to slide into.The grooves have a tapered
openingatthebottomtofacilitateentryofthesensors.
WARNING
When the furnace must be moved for any rea-
son, remove the block assembly to prevent
breakage of the quartz tube.
Installation
12 Manual Rev. 721801 Hart Scientific

6 Parts and Controls
6.1 Top Panel
See Figure 1.
The heater is made of a fiber ceramic insulating
material with the heating element imbedded. The
heater is cylindrical in shape and is enclosed in an
aluminumcasewithadditionalceramicfiberinsulation
surrounding it. The heater provides about 850 watts
of heating power. The heater is primarily a radiating
device and is rated for a maximum furnace operating
temperature of 1100°C. Realize, however, that the
highertheoperatingtemperaturethelowerthelifetime
of any high temperature heater. Limiting the number
of hours at the extreme high end of the temperature
range to only the time required for calibrations will
increase the longevity of your furnace heating ele-
ment.
6.1.1 Temperature Controller
The temperature controller (see Figure 2 for detail) is
a full PID micro-processor based instrument as indi-
cated. It is set to cover the range of 0 to 1100°C. It
features two LED type displays. The upper display
normally indicates the actual temperature while the
lower display indicates the set temperature. The dis-
plays are also utilized in setup and alarm functions.
Other indicators include the OP1 and OP2 indicator
lights.The OP1 indicator lights when the heater is on.
The “M” indicator flashes if the sensor fails. If the
sensor opens, the heaters will shut off.
The OP2 and “R” are not functional in this unit.
6.1.1.1 Temperature Adjustment Up/Down
Keys
See Figure 2. The up and down arrow keys are used
to increase and decrease the set temperature, select
CALIBRATION FURNACE
9113
HART
SCIENTIFIC
A/M PAR
Cooling Vents
Covers Power
Switch
Temperature
Controller
Probe Cooling
Tubes
Fan Light HandlesFurnace Core
Opening
OP1
OP2
RM
Figure 1 Top Panel
Parts and Controls
9113 Portable Furnace Manual Rev. 721801 13

between°C and°F,andotherfunctions.Aquicksingle
stroke will increment or decrement the temperature
setting. Holding the buttons down causes a gradual
acceleration of the temperature setting. When these
buttonsareusedtoadjustotherfunctionsor“parame-
ters”, they are used in conjunction with the “PAR”
button.
6.1.2 Power Switch
The power switch is located on the right side of the
furnace just under the temperature controller. The
bottom is pressed inward revealing the bright reddish
colored portion indicating the switch is actuated on.
Note that the internal fan is wired ahead of the power
switch so that it will stay on until the fan thermostat
determines that the unit is cooled even though the
main power may have been turned off. This way the
outer surfaces of the enclosure will not be heated to
dangerous levels from stored heat.The fan does not
come on until the internal temperature rises ade-
quately to actuate the thermostat.
6.1.3 Fan Light Indicator
Thefanlightindicatorcomeson whenthe fan thermo-
stat reaches about 40°C inside the chassis and actu-
ates.This light will stay on as a reminder to leave the
power connected until the unit has sufficiently cooled.
6.1.4 Probe Cooling Tubes
Two probe cooling tubes are built into the model 9113
furnace. They have the capacity of cooling up to two
3/8 inch diameter probes with out any danger to the
furnace, facility or other equipment in the area. Avoid
laying hot probes on surfaces which are flammable or
may be damaged by high heat.
6.1.5 Handles
Handles are provided on each end of the furnace to
allow transport of the unit as needed. Remove the
equilibration block before moving any distance as a
precaution against breakage.
A/M PAR
OP1
OP2
RM
Sensor Failure
Indicator
Actual
Temperature
Set
Temperature
Temperature/Function
Adjustment
Heater
Indicator Parameter
Button Attachment
Screw
Figure 2 Temperature Controller (enlarged view)
Parts and Controls
14 Manual Rev. 721801 Hart Scientific

6.1.6 CoolingVents
The cooling vents in the top and in the front and rear
covers provide inlets for air to circulate through the
chassis and keep it cool. The air is expelled through
the rear of the chassis at the fan exit.
6.2 Equilibration Block
Assembly
See Figure 3.
The equilibration block is intended to stabilize the
temperature fluctuations and to conduct heat be-
tween the test wells in order to equalize them. The
whole assembly is supported by a quartz tube and
fiber ceramic insulation.Two grooves along the sides
of the block provide contact with the control thermo-
couple and the over-temperature cut-out thermocou-
ple. All heated materials are quartz, ceramic fiber, or
INCONEL (alloy 600 or other related high oxidation
resistant metals).
The top view of the block reveals 3 holes; the test
probe hole, the reference thermometer hole, and the
removal tool hole. The standard equilibration block is
sized for .25 and .28 inch diameter probes, however,
custom options are possible. The block removal tool
hole is a 1/4-20 threaded hole to allow a similarly
threaded tool to be inserted for the ease of insertion
and removal of the block.
6.2.1 Temperature Control and
Cut-out Sensors
The temperature control sensor is a type K as indi-
cated. It is grounded to the INCONEL sheath. The
probe is normally inserted as shown in Figure 3.It fits
in a slot along the thermal equilibration block as
indicated.
The cut-out sensor is the same as the control sensor.
It is inserted along the groove on the opposite side
from the control thermocouple. It helps prevent the
heater elements from overheating thus prolonging
their life.
6.3 Back Panel
See Figure 4.
The nomenclature on the rear panel of the furnace
provides important information to the user in case
service is required. Note that the manufacturer (Hart
Scientific, Inc.), manufacturers location (American
Fork, Utah 84003, USA) and model number data
specific to this unit are provided. Refer to the Model
and Serial numbers whenever service is required.
6.3.1 Power Cable
The furnace is provided with a 16 gauge two conduc-
torwithgroundmoldedcordset.Thecordsetisremov-
able for convenience in moving the unit.
6.3.2 Fuse
The fuses used are 10 amp fuses. They protect the
system 115 VAC power and are easily accessed from
the rear of the furnace.If the furnace fails to operate,
check these first.
6.3.3 RS-232 Port (Optional)
An RS-232 serial port is available as an option for
computer control of the furnace. It is located on the
rear panel of the unit as shown. See Digital Commu-
nications Interface, Section 8.
Parts and Controls
9113 Portable Furnace Manual Rev. 721801 15

Top View of
Equilibration Block
Removal Tool
Hole (1/4-20 Thread)
Quartz Tube
Ceramic Fiber
Insulation
Probe Holes
Equilibration
Block
Thermocouple, Type K
Cutout Probe
Thermocouple, Type K
Control Probe
Embeded Radient
Heating Coils
Ceramic Fiber
Insulation
TEST WELLS
Test Probe
Reference
Thermometer
Figure 3 Equilibration Block Assembly
Parts and Controls
16 Manual Rev. 721801 Hart Scientific

F
U
S
E
F
U
S
E
F
U
S
E
F
U
S
E
SYSTEM
FUSES RS-232
Made in USA
Model 9113
115 VAC 50/60 Hz
850 Watts
Fuse 10 Amp, 250 V F
HART
SCIENTIFIC
HART
SCIENTIFIC
American Fork
Utah 84003
Serial No:
Model No:
Before opening
disconnect mains.
Vor Öffnen des Gehäuses
Netzstecker ziehen.
Avant d’ouvrir l’appereil
retirez la fichemâle.
Figure 4 Back Panel
Parts and Controls
9113 Portable Furnace Manual Rev. 721801 17

7 General Operation
7.1 Overview
The model 9113 is a temperature controlled furnace
utilizingafullPIDmicro-processorbasedtemperature
controller with a type K thermocouple temperature
sensor.The temperature controller sends a time pro-
portional signal to the solid state relay (triac) which
regulates the current to the heater. The object of
temperature control is the equilibration blockwith test
wells containing the reference probe and the test
sensor to be calibrated inside. This block provides a
thermalmasswhichtendstostabilizethetemperature
and reduce the gradients between the test wells.The
furnace cabinet contains ventilation holes as well as
a fan controlled by a thermostat.This cooling capabil-
ity prevents the surface of the enclosure from getting
hot. In the event that the fans should fail, a second
thermostat is installed in the cabinet which will shut
down the furnace heaters if the cabinet exceeds a
safe temperature.
7.2 Operating the Temperature
Controller
Operatingthemodel9113isstraightforwardonceyou
have grasped all the basic principles.
Temperature selection accomplished by using the up
and down arrow keys on the front of the temperature
controller. The lower display will indicate the new
temperaturesettingwhiletheupperdisplayshowsthe
actual temperature. When scanning from one tem-
perature to another you will notice that the tempera-
ture controller seems to be ahead of the temperature
of the equilibration block. This is because the tem-
peraturecontrolsensorisneartheoutsideoftheblock
for rapid control response and it takes some time for
the heat to conduct into the center. Depend on your
external temperature monitor to establish when the
equilibration block has reached the desired tempera-
ture and achieved stability.
The actual temperature indication made by the tem-
perature controller is not intended to be a calibration
reference, but to merely provide a general indication
of the furnace temperature. NIST traceable standard
thermometers are available and should be used in
makingcomparisonmeasurements.Forlessstringent
measurements, you may make a calibration of the
controller and control probe at particular temperature
points and use that with reasonable accuracy for a
time.
WARNING
Take care that all sensors used as references or
being calibrated in the furnace are capable of
withstanding the desired temperature range to
be used.
For best results, all reference or sample probes
should be inserted into the full depth of the well. At
this position, the stability is the highest and the gradi-
ents are the lowest. Hart Scientific recommends that
each user satisfy themselves as to what the uncer-
taintiesare intermsofstabilityandgradientsbetween
the test wells.Variations inequipment, probe size and
configuration,etc.will haveeffectsonthese important
factors. A solid (unstirred) mass such as in a furnace
is subject to heat losses from the probe stem which
varies from probe to probe and temperature to tem-
perature.Typically, stabilities are better than ±0.75°C.
For calibrations that must be less than full insertion
into the test well, make your own comparisons be-
tween the reference and test cell at that depth to
establish the uncertainties.
The furnace can be used throughout the temperature
range of 100 to 1100°C. Lower temperatures are
sluggish however. High integrating values are re-
quired to maintain controller stability (1200 sec) at the
lower temperatures.
WARNING
Take extreme care in handling hot probes. The
extreme temperatures generated in a furnace of
this type can cause serious personal injury. Do
not touch them on external surfaces of the fur-
nace or set them on any other surfaces unable
to withstand those temperatures. A fire hazard
exists.
General Operation
18 Manual Rev. 721801 Hart Scientific

7.2.1 Over Temperature Cut-out
The over temperature cut-out protects the furnace
from exceeding its own safe operating range. The
cut-out is factory set to about 1125°C. The cut-out
controlsarelaywhichiswiredinserieswiththeheater
circuit. The cut-out is provided as a safety backup in
case the temperature controller or the triac circuit
driven by the temperature controller fails causing
thermal runaway.
General Operation
9113 Portable Furnace Manual Rev. 721801 19

8 Digital Communications Interface
(optional)
Ifsuppliedwiththeoption,the9113furnaceiscapable
of being controlled by other equipment through the
digital interface.
8.1 Wiring
The serial communications cable attaches to the fur-
nace through the DB-9 connector at the back of the
instrument.Figure 5 shows the pin-out ofthe connec-
torandsuggestedcablewiring.Toeliminatenoise,the
serial cable should be shielded with low resistance
between the connector (DB-9) and the shield.
8.2 Example
First, make the appropriate cable assembly for your
computer system. Connect the appropriate connec-
tors to your computer and to the furnace. Load
GWBASIC.Then load the program TC847.BAS.Run
the program. Set the Baud Rate on the Controller of
the 9113 to 9600. Next set the address of your fur-
nace, it must be 10 or greater. Now you can set the
temperature or if needed the furnace parameters. A
listing of the parameters and their meaning are in the
following table.
PV process value (temperature)
SL setpoint
OP output power
XP proportional band
TI integration time
TD derivative time
CH Cycle time
To set a parameter, simply type in the parameter and
the value. Example, SL=800. This sets the control
temperature to 800°C.
The program suppliedis a demo program and may be
altered by you for your specific needs.
For details of controller operation, see the controller
manual supplied. (The controller manual is supplied
only with the RS-232 option.)
1NC
2RxD
3TxD
4NC
5 GND
6NC
7RTS
8CTS
9NC
1NC
2RxD
3TxD
4NC
5 GND
6NC
7RTS
8CTS
9NC
1NC
2RxD
3TxD
4NC
5 GND
6NC
7RTS
8CTS
9NC
2TxD
3RxD
4RTS
5CTS
6
7 GND
8
20
RS-232 Cable Wiring for
IBM PC and Compatibles
Instrument
Connector
(DB 9-Pin)
Instrument
Connector
(DB 9-Pin)
Computer (DTE)
Connector
(DB 25-Pin)
Computer (DTE)
Connector
(DB 9-Pin)
Figure 5 Serial Communications Wiring Diagram
Digital Communications Interface (optional)
20 Manual Rev. 721801 Hart Scientific