Fluke 9140 User Manual

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Hart Scientific
9140
Dry-well Calibrator
User’s Guide
Rev. 5B1702
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Fluke Corporation, Hart Scientific Division
799 E. Utah Valley Drive • American Fork, UT 84003-9775 • USA Phone: +1.801.763.1600 • Telefax: +1.801.763.1010 E-mail: support@hartscientific.com
www.hartscientific.com
Subject to change without notice. • Copyright © 2005 • Printed in USA
Rev. 5B1702
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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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3 Specifications and Environmental Conditions . . . . . . . . . . 9
3.1 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2 Environmental Conditions . . . . . . . . . . . . . . . . . . . . . . 9
3.3 Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4 Quick Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1 Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.2 Set-Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.3 Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
4.4 Setting the Temperature . . . . . . . . . . . . . . . . . . . . . . . 12
5 Parts and Controls . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1 Rear Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.2 Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.3 Constant Temperature Block Assembly . . . . . . . . . . . . . . . 15
5.3.1 Constant Temperature Block . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.3.2 Probe Sleeves and Tongs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6 General Operation . . . . . . . . . . . . . . . . . . . . . . . . 17
6.1 Calibrator Set-Up . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.2 Changing Display Units . . . . . . . . . . . . . . . . . . . . . . . 17
6.3 Switching to 230 V Operation. . . . . . . . . . . . . . . . . . . . 17
6.4 Setting the Temperature . . . . . . . . . . . . . . . . . . . . . . . 18
6.5 Calibrating Probes. . . . . . . . . . . . . . . . . . . . . . . . . . 18
7 Controller Operation . . . . . . . . . . . . . . . . . . . . . . . 21
7.1 Well Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . 21
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7.2 Temperature Set-point . . . . . . . . . . . . . . . . . . . . . . . . 21
7.2.1 Programmable Set-points . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
7.2.2 Set-point Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
7.2.3 Temperature Scale Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
7.3 Scan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
7.3.1 Scan Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
7.3.2 Scan Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
7.4 Temperature Display Hold . . . . . . . . . . . . . . . . . . . . . 25
7.4.1 Hold Temperature Display . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
7.4.2 Mode Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
7.4.3 Switch Wiring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
7.4.4 Switch Test Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
7.5 Secondary Menu. . . . . . . . . . . . . . . . . . . . . . . . . . . 26
7.5.1 Heater Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
7.5.2 Proportional Band. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
7.6 Controller Configuration . . . . . . . . . . . . . . . . . . . . . . 29
7.6.1 Calibration Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
7.6.1.1 R0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
7.6.1.2 ALPHA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
7.6.1.3 DELTA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
7.7 Operating Parameters . . . . . . . . . . . . . . . . . . . . . . . . 30
7.8 Serial Interface Parameters . . . . . . . . . . . . . . . . . . . . . 30
7.8.0.1 Baud Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
7.8.1 Sample Period. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
7.8.1.1 Duplex Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
7.8.1.2 Linefeed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
8 Digital Communication Interface . . . . . . . . . . . . . . . . 33
8.1 Serial Communications . . . . . . . . . . . . . . . . . . . . . . . 33
8.1.1 Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
8.1.2 Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
8.1.2.1 Baud Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
8.1.2.2 Sample Period. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
8.1.2.3 Duplex Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
8.1.2.4 Linefeed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
8.1.3 Serial Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
8.2 Interface Commands . . . . . . . . . . . . . . . . . . . . . . . . 35
9 Test Probe Calibration . . . . . . . . . . . . . . . . . . . . . . 39
9.1 Comparison Methods . . . . . . . . . . . . . . . . . . . . . . . . 39
9.1.1 Calibrating a Single Probe . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
9.1.2 Comparison Calibration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
9.1.3 Calibration of Multiple Probes . . . . . . . . . . . . . . . . . . . . . . . . . 40
9.2 Dry-well Characteristics. . . . . . . . . . . . . . . . . . . . . . . 40
9.2.1 Vertical Gradient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
9.2.2 Heating and Cooling Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
9.2.3 Stabilization and Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
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10 Calibration Procedure . . . . . . . . . . . . . . . . . . . . . . 43
10.1 Calibration Points . . . . . . . . . . . . . . . . . . . . . . . . . . 43
10.2 Calibration Procedure . . . . . . . . . . . . . . . . . . . . . . . . 43
10.2.1 Compute DELTA: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
10.2.2 Compute R
10.2.3 Accuracy & Repeatability. . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
& ALPHA: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
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11 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
12 Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . 49
12.1 Troubleshooting Problems, Possible Causes, and Solutions . . . . 49
12.2 CE Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
12.2.1 EMC Directive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
12.2.2 Low Voltage Directive (Safety) . . . . . . . . . . . . . . . . . . . . . . . . . 50
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Figures

Figure 1 9140 Back Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 2 9140 Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Figure 3 Inserts available for the 9140 block assembly . . . . . . . . . . . . . . 15
Figure 4 Controller Operation Flowchart . . . . . . . . . . . . . . . . . . . . . 22
Figure 5 Well temperature fluctuation at various proportional band settings . . . 27
Figure 6 Serial Cable Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Figure 7 Typical Heating Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Figure 8 Typical Cooling Rate. . . . . . . . . . . . . . . . . . . . . . . . . . . 41
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Tables

Table 1 International Electrical Symbols . . . . . . . . . . . . . . . . . . . . . 1
Table 2 9140 controller communications commands. . . . . . . . . . . . . . . 36
Table 3 9140 controller communications commands continued . . . . . . . . . 37
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1 Before You Start
1.1 Symbols Used
Table 1 lists the symbols used on the instrument or in this manual and the meaning of each symbol.
Tabl e 1 International Electrical Symbols
Symbol Description
AC (Alternating Current)
AC-DC
Battery
Complies with European Union directives
1 Before You Start
Symbols Used
DC
Double Insulated
Electric Shock
Fuse
PE Ground
Hot Surface (Burn Hazard)
Read the User’s Manual (Important Information)
Off
On
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9140 Dry-well Calibrator
User’s Guide
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
The European Waste Electrical and Electronic Equipment (WEEE) Directive (2002/96/EC) mark.
1.2 Safety Information
Use the instrument only as specified in this manual. Otherwise, the protection provided by the instrument may be impaired. Refer to the safety information below and throughout the manual.
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.
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GENERAL
DO NOT use this instrument in environments other than those listed in the User’s Guide.
Inspect the instrument for damage before each use. DO NOT use the in
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strument if it appears damaged or operates abnormally.
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 dry-well has not been energized for more than 10 days, the instrument needs to be energized for a "dry-out" period of 2 hours before it can be assumed to meet all of the safety re
­quirements of the IEC 1010-1. If the product is wet or has been in a wet environment, take necessary measures to remove moisture prior to apply
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1 Before You Start
Safety Information
ing power such as storage in a low humidity temperature chamber operat ing at 50°C for 4 hours or more.
DO NOT use this instrument for any application other than calibration
work. The instrument was designed for temperature calibration. Any other use of the instrument may cause unknown hazards to the user.
Completely unattended operation is not recommended.
Overhead clearance is required. DO NOT place the instrument under a
cabinet or other structure. Always leave enough clearance to allow for safe and easy insertion and removal of probes.
If the instrument is used in a manner not in accordance with the equip
ment design, the operation of the dry-well may be impaired or safety haz ards may arise.
This instrument is intended for indoor use only.
BURN HAZARDS
DO NOT turn the instrument upside down with the inserts in place; the
inserts will fall out.
DO NOT operate near flammable materials.
Use of this instrument at HIGH TEMPERATURES for extended periods
of time requires caution.
DO NOT touch the well access surface of the instrument.
The block vent may be very hot due to the fan blowing across the heater
block of the dry-well.
The temperature of the well access is the same as the actual display tem-
perature, e.g. if the instrument is set to 700°C and the display reads 700°C, the well is at 700°C.
For top loading dry-wells, the top sheet metal of the dry-well may exhibit extreme temperatures for areas close to the well access.
The air over the well can reach temperatures greater that 200°C for high temperature (400°C and higher) dry-wells. Note: Probes and inserts may be hot and should only be inserted and removed from the instrument when the instrument is set at temperatures less than 50°C. Use extreme care when removing hot inserts.
DO NOT turn off the instrument at temperatures higher than 100°C. This could create a hazardous situation. Select a set-point less than 100°C and allow the instrument to cool before turning it off.
The high temperatures present in dry-wells designed for operation at 300°C and higher may result in fires and severe burns if safety precau tions are not observed.
For compliance with IEC 1010-1, it is recommended that the cutout mode always be set to the manual mode requiring user intervention to reset the instrument.
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9140 Dry-well Calibrator
User’s Guide
ELECTRICAL SHOCK
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.
If supplied with user accessible fuses, always replace the fuse with one of the same rating, voltage, and type.
Always replace the power cord with an approved cord of the correct rat
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ing and type.
HIGH VOLTAGE is used in the operation of this equipment. SEVERE INJURY or DEATH may result if personnel fail to observe safety precau
tions. Before working inside the equipment, turn power off and discon­nect power cord.
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1.2.2
CAUTIONS
Always operate this instrument at room temperature between 41°F and
122°F (5°C to 50°C). Allow sufficient air circulation by leaving at least 6 inches (15 cm) of clearance around the instrument. Overhead clearance is required. DO NOT place unit under any structure.
Component lifetime can be shortened by continuous high temperature op-
eration.
DO NOT leave the sleeve(s) in the instrument for prolonged periods. Due to the high operating temperatures of the instrument, the sleeves should be removed after each use and buffed with a Scotch-Brite® pad or emery cloth. (See Maintenance, Section .)
DO NOT apply any type of voltage to the display hold terminals. Apply ing a voltage to the terminals may cause damage to the controller.
DO NOT use fluids to clean out the well. Fluids could leak into electron ics and damage the instrument.
Never introduce any foreign material into the probe hole of the insert. Fluids, etc. can leak into the instrument causing damage.
DO NOT change the values of the calibration constants from the factory set values. The correct setting of these parameters is important to the safety and proper operation of the calibrator.
DO NOT slam the probe sheath in to the well. This type of action can cause a shock to the sensor and affect the calibration.
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1 Before You Start
Authorized Service Centers
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.
The Factory Reset Sequence (see Section 12.1, Troubleshooting) 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 Re port of Calibration to restore the calibration parameters.
DO NOT operate this instrument in an excessively wet, oily, dusty, or
dirty environment. Always keep the well and inserts clean and clear of foreign material.
The dry-well is a precision instrument. Although it has been designed for
optimum durability and trouble free operation, it must be handled with care. Always carry the instrument in an upright position to prevent the probe sleeves from dropping out. The convenient handle allows for hand carrying the instrument.
If a mains supply power fluctuation occurs, immediately turn off the in
strument. Power bumps from brown-outs could damage the instrument. Wait until the power has stabilized before re-energizing the instrument.
The probe and the block may expand at different rates. Allow for probe
expansion inside the well as the block heats. Otherwise, the probe may become stuck in the well.
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Most probes have handle temperature limits. Be sure that the probe handle
temperature limit is not exceeded in the air above the instrument. If the probe handle limits are exceeded, the probe may be permanently dam­aged.
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
American Fork, UT 84003-9775
USA
Phone: +1.801.763.1600
Telefax: +1.801.763.1010
E-mail: support@hartscientific.com
Fluke Nederland B.V.
Customer Support Services
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9140 Dry-well Calibrator
User’s Guide
Fluke Int'l Corporation
Science Park Eindhoven 5108
5692 EC Son
NETHERLANDS
Phone: +31-402-675300
Telefax: +31-402-675321
E-mail: ServiceDesk@fluke.nl
Service Center - Instrimpex
Room 2301 Sciteck Tower
22 Jianguomenwai Dajie
Chao Yang District
Beijing 100004, PRC
CHINA
Phone: +86-10-6-512-3436
Telefax: +86-10-6-512-3437
E-mail: xingye.han@fluke.com.cn
Fluke South East Asia Pte Ltd.
Fluke ASEAN Regional Office
Service Center
60 Alexandra Terrace #03-16
The Comtech (Lobby D)
118502
SINGAPORE
Phone: +65 6799-5588
Telefax: +65 6799-5588
E-mail: antng@singa.fluke.com
When contacting these Service Centers for support, please have the following information available:
Model Number
Serial Number
Voltage
Complete description of the problem
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2 Introduction
The Hart Scientific 9140 Mid-Range Field Calibrator may be used as a portable instrument or bench top temperature calibrator for calibrating thermocouple and RTD temperature probes. The 9140 is small enough to use in the field, and accurate enough to use in the lab.
The instrument features:
Rapid heating and cooling
Interchangeable multiple hole aluminum probe sleeves
Convenient hand strap
RS-232 interface capability
Built in programmable features include:
Temperature scan rate control
Temperature switch hold
Eight Setpoint memory
Adjustable readout in °C or °F
The temperature is accurately controlled by Hart’s hybrid analog/digital con­troller. The controller uses a precision platinum RTD as a sensor and controls the well temperature with a solid state relay (triac) driven heater.
The LED front panel continuously shows the current well temperature. The temperature may be easily set with the control buttons to any desired tempera­ture within the specified range. The instrument’s multiple fault protection de­vices insure user and instrument safety and protection.
The 9140 dry-well calibrator was designed for portability, low cost, and ease of operation. Through proper use the instrument will provide continued accurate calibration of temperature sensors and devices. The user should be familiar with the safety guidelines and operating procedures of the calibrator as de scribed in the instruction manual.
2 Introduction
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3 Specifications and Environmental Conditions
3 Specifications and Environmental
Conditions
3.1 Specifications
Specifications
The following table lists the specifications for this instrument. Accuracy speci fications are applicable for a one-year calibration interval. In line with normal prudent metrology practices, Hart Scientific recommends a short-cycle interval of six months for new units during the first year.
Power
Ambient Temperature
Operating Range
Resolution
Readout
Accuracy
Stability
Uniformity
Controller
Heater
Heating Time
Cooling Time
Cooling
Stabilization Time
Immersion Depth
Fault Protection
Test Wells
Exterior Dimension
Weight
Fuse Rating
Safety
115 VAC (±10%), 4.4 A or 230 VAC (±10%), 2.2 A, switchable 500 W
5–50°C (41–122°F)
35–350°C (95–662°F)
0.1°C or °F resolution
Switchable°C or °F
±
0.5°C (±0.9°F), in holes greater than 1/4" (6.35 mm) accuracy is ±1°C
(±1.8°F)
±
0.03°C at 50°C,±0.05°C at 350°C
±0.4°C typical, ±0.1°C with similarly sized wells
Digital controller with data retention
500W
12 minutes from ambient to 350°C
15 minutes from 350°C to 100°C
2 speed internal fan
7 minutes
124 mm (4.88 inches)
Sensor burnout and short protection, over temperature thermal cut-out, elec trical fuses
31.8 mm dia. x 123.7 mm deep (1.25" x 4.87"). Multi-hole inserts are available.
152.4 mm H x 85.7 mm W x 196.9 mm D (6" x 3.375" x 7.75")
2.7kg(6lbs.)
115 V: 6 A (fast acting), 250 V 230 V: 3.15 A (fast acting), 250 V
OVERVOLTAGE (Installation) CATEGORY II, Pollution Degree 2 per IEC1010-1
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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
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9140 Dry-well Calibrator
User’s Guide
operated in an excessively dusty or dirty environment. Maintenance and clean ing recommendations can be found in the Maintenance Section of this manual.
The instrument operates safely under the following conditions:
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
3.3 Warranty
Fluke Corporation, Hart Scientific Division (Hart) warrants this product to be free from defects in material and workmanship under normal use and service for a period as stated in our current product catalog from the date of shipment. This warranty extends only to the original purchaser and shall not apply to any product which, in Hart’s sole opinion, has been subject to misuse, alteration, abuse or abnormal conditions of operation or handling.
Software is warranted to operate in accordance with its programmed instruc­tions on appropriate Hart products. It is not warranted to be error free.
Hart’s obligation under this warranty is limited to repair or replacement of a product which is returned to Hart within the warranty period and is determined, upon examination by Hart, to be defective. If Hart determines that the defect or malfunction has been caused by misuse, alteration, abuse or abnormal condi­tions or operation or handling, Hart will repair the product and bill the pur­chaser for the reasonable cost of repair.
To exercise this warranty, contact an Authorized Service Center (see Section
1.3). Service Centers assume NO risk for in-transit damage.
THE FOREGOING WARRANTY IS PURCHASER’S SOLE AND EXCLU SIVE REMEDY AND IS IN LIEU OF ALL OTHER WARRANTIES, EX PRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY OR MERCHANTABILITY, OR FITNESS FOR ANY PARTICULAR PURPOSE OR USE. HART SHALL NOT BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAM AGES OR LOSS WHETHER IN CONTRACT, TORT, OR OTHERWISE.
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4 Quick Start
4.1 Unpacking
4 Quick Start
Unpacking
Unpack the dry-well carefully and inspect it for any damage that may have oc curred during shipment. If there is shipping damage, notify the carrier immediately.
Verify that the following components are present:
9140 Dry-well
Insert
Insert Removal Tool
Power Cord
Serial Cable
User's Guide
9930 Software Package
4.2 Set-Up
Place the calibrator on a flat surface with at least 6 inches of free space around the instrument. Plug the power cord into a grounded mains outlet. Observe that the nominal voltage corresponds to that indicated on the back of the calibrator.
Carefully insert the probe sleeve into the well. Probe sleeves should be of the smallest hole diameter possible still allowing the probe to slide in and out eas­ily. Sleeves of various sizes are available from Hart Scientific. The well must be clear of any foreign objects, dirt and grit before the sleeve is inserted. The sleeve is inserted with the two small tong holes positioned upward.
Turn on the power to the calibrator by toggling the switch on the power entry module. The fan should begin quietly blowing air through the instrument and 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 will begin to show the well temperature and the well heater will start operating to bring the temperature of the well to the set-point temperature. After using the calibrator, allow the well to cool by setting the temperature to 25°C and waiting for the instrument to reach temperature before turning the in strument off.
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4.3 Power
Plug the dry-well power cord into a mains outlet of the proper voltage, fre quency, and current capability. Refer to Section 3.1, Specifications, for power details. Turn the dry-well on using the rear panel “POWER” switch. The
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9140 Dry-well Calibrator
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dry-well will turn on and begin to heat to the previously programmed tempera ture set-point. The front panel LED display will indicate the actual dry-well temperature.
4.4 Setting the Temperature
Section 7.2 explains in detail how to set the temperature set-point on the cali brator using the front panel keys. The procedure is summarized here.
(1) Press “SET” twice to access the set-point value.
(2) Press “UP” or “DOWN” to change the set-point value.
(3) Press “SET” to program in the new set-point.
(4) Press “EXIT” to return to the temperature display.
When the set-point temperature is changed the controller will switch the well heater on or off to raise or lower the temperature. The displayed well tempera ture will gradually change until it reaches the set-point temperature. The well may require 5 to 10 minutes to reach the set-point depending on the span. An­other 5 to 10 minutes is required to stabilize within ±0.1°C of the set-point. Ul­timate stability may take 15 to 20 minutes more of stabilization time.
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5 Parts and Controls
The user should become familiar with the dry-well calibrator and its parts:
5.1 Rear Panel
Figure 1 on page 13.
Power Cord - At the rear of the calibrator is the removable power cord inlet that plugs into an IEC grounded socket.
Power Switch - The power switch is located on the power entry module
(PEM). The PEM also houses the fuses and the dual voltage selector. The PEM and Heater Voltage Switch (see below) allow the unit to be field switchable for 115 VAC (±10%) or 230 VAC (±10%) operation.
Heater Voltage Switch - To be used only when changing the input voltage. (See Section 6.3 for instructions on changing the input voltage.)
Note: The input voltage and heater voltage switch settings should always be the
same value.
Serial Port - A DB-9 male connector is present for interfacing the calibrator to a computer or terminal with serial RS-232 communications.
5 Parts and Controls
Rear Panel
Fan - The fan inside the calibrator runs continuously when the unit is being op­erated to provide cooling for the instrument. It has two speeds, a slow speed for control operation and a faster speed for rapid cooling. Slots at the top and
Figure 1 9140 Back Panel
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9140 Dry-well Calibrator
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around the two corners of the calibrator are provided for airflow. The area around the calibrator must be kept clear to allow adequate ventilation. The air flow is directed upward and as a result, can be extremely hot.
5.2 Front Panel
Figure 2 on page 14.
Controller Display - The digital display is an important part of the temperature controller because it not only displays set and actual temperatures but also vari ous calibrator functions, settings, and constants. The display shows tempera tures in units according to the selected scale °C or °F.
Controller Keypad - The four button keypad allows easy setting of the set-point temperature. The control buttons (SET, DOWN, UP, and EXIT) are used to set the calibrator temperature set-point, access and set other operating parameters, and access and set calibration parameters.
Setting the control temperature is done directly in degrees of the current scale. It can be set to one-tenth of a degree Celsius or Fahrenheit.
The functions of the buttons are as follows:
SET – Used to display the next parameter in the menu and to store parameters to the displayed value.
DOWN – Used to decrement the displayed value of parameters.
UP–Usedtoincrementthedisplayedvalue.
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Figure 2 9140 Front Panel
Page 21
Constant Temperature Block Assembly
5 Parts and Controls
EXIT – Used to exit a function and to skip to the next function. Any changes made to the displayed value are ignored.
5.3 Constant Temperature Block Assembly
Figure 3 on page 15.
5.3.1 Constant Temperature Block
The “Block” is made of aluminum and provides a relatively constant and accu rate temperature environment in which the sensor that is to be calibrated is in serted. A 1.25 inch diameter well is provided that may be used for sensors of that size or may be sleeved down with various sized multi-hole probe sleeves. Heaters surround the block assembly and provides even heat to the sensor. A high-temperature platinum RTD is imbedded at the base of the block assembly to sense and control the temperature of the block. The entire assembly is sus pended in an air cooled chamber thermally isolated from the chassis and electronics.
CAUTION: The block vent cover may be very hot due to the fan blowing
upward. Please use caution.
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5.3.2 Probe Sleeves and Tongs
The calibrator is supplied with a multi-hole aluminum probe sleeve for inser­tion into the calibrator well and tongs for removing sleeves. Probe sleeves of various hole sizes are available to allow the user’s probe to fit snugly into the well whatever the diameter of the probe.
One insert, whichever is ordered, is shipped with the unit:
Insert A (variety block): 1/2”, 3/8”,3/16”,1/8”, and 1/16” holes
Insert B (comparison block): 2 3/8”,2 1/4”, and 2 3/16” holes
Insert C (1/4” comparison block): 6 1/4” holes
or
Insert “A”
1/16"
1/2"
1/8"
Figure 3 Inserts available for the 9140 block assembly
1/4"
3/16"
3/8"
3/8"
3/16"
1/4"
Insert “B”
1/4"
3/16"
3/8"
1/4"
Insert “C”
6mm
3mm
4mm
Insert “D”
4mm
6mm
3mm
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Insert D (comparison block): 2 each at 3 mm, 4 mm, and 6 mm
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6 General Operation
6.1 Calibrator Set-Up
Place the calibrator on a flat surface with at least 6 inches of free space around the instrument. Overhead clearance is required. DO NOT place under a cabinet or other structure.Plug the power cord into a grounded mains outlet. Observe that the nominal voltage corresponds to that indicated on the back of the calibrator.
Gently insert the probe sleeve into the well. The probe sleeve should be of the smallest hole size possible while allowing the probe to slide in and out easily. Sleeves of various sizes are available from the manufacturer. The well must be clear of any foreign objects, dirt and grit before the sleeve is inserted. The sleeve is inserted with the two small tong holes positioned upward.
Turn on the power to the calibrator by toggling the switch at the rear of the in strument to the “l” (on) position. The fan will begin circulating air through the instrument. After a brief self test the controller should begin normal operation showing the well temperature. The block will heat or cool until it reaches the programmed set-point.
6 General Operation
Calibrator Set-Up
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6.2 Changing Display Units
The 9140 can display temperature in Celsius or Fahrenheit. The temperature units are shipped from the factory set to Celsius. To change to Fahrenheit or back to Celsius there are two ways:
1 - Press the “SET” and “UP” simultaneously. This will change display units.
2 - Press the “SET” key three times from the temperature display to show
Un= C
Press the “UP” or “DOWN” key to change units.
6.3 Switching to 230 V Operation
The 9140 is switchable from 115 VAC to 230 VAC 50/60 Hz. Switching the voltage can change the calibration, so it is recommended to recalibrate the unit after changing the input voltage.
To change from 115 VAC to 230 VAC:
Unplug the unit
With a small straight slot screwdriver remove the fuse holder located on the rear panel. Replace the two 6 amps fuses with 3 amp 250 V fuses.
Replace the fuse holder with the “230V” in the display window.
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NOTE: If the heater switch and the fuse holder do not both read 230V when
complete, the unit will eithernot heator only heat at a fraction of its capacity. If not done properly, the unit could become damaged and void the calibration and warranty.
CAUTION: DO NOT plug the unit into 230 V if the heater switch and fuse
holder read 115. This will cause the fuse to blow and may damage the in strument.
6.4 Setting the Temperature
Using the same straight slot screwdriver, move the heater switch to dis play “230V”. See the rear panel drawing in Figure 1 on page 13.
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Section 7.2 explains in detail how to set the temperature set-point on the cali brator using the front panel keys. The procedure is summarized here.
(1) Press “SET” twice to access the set-point value.
(2) Press “UP” or “DOWN” to change the set-point value.
(3) Press “SET” to program in the new set-point.
(4) Press “EXIT” to return to the temperature display.
When the set-point temperature is changed the controller will switch the well heater on or off to raise or lower the temperature. The cycle indicator, a two color LED, will also indicate on (red and heating) or off (green and cooling). The displayed well temperature will gradually change until it reaches the set-point temperature. The well may require 5 to 20 minutes to reach the set-point depending on the span. Another 5 to 10 minutes is required for the temperature to stabilize.
6.5 Calibrating Probes
The dry-well block provides a constant temperature environment in which probes may be compared. The probes inserted into the block may be compared to the well temperature displayed on the front panel of the calibrator. The probes should be inserted the full depth of the well since the temperature at the bottom of the well will most closely agree with the displayed temperature.
For greater accuracy the probes may be compared to a reference thermometer inserted into the block. The reference thermometer may be inserted into one hole while the probes to be calibrated are inserted into another. The drawback to this method is that because of temperature variations throughout the block there may be a small temperature difference between one hole and another which can cause errors.
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6 General Operation
Calibrating Probes
Using the same hole for the reference thermometer and the test probe may have better results. This however requires switching the probes which takes more time. One must allow a few minutes after inserting the probes for the tempera ture to stabilize before making measurements. Because of temperature varia
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­tions along the length of the well, best results are obtained when comparing probes of similar construction and inserting them the same depth into the well.
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7 Controller Operation
7 Controller Operation
Well Temperature
This chapter discusses in detail how to operate the dry-well temperature con troller using the front control panel. Using the front panel key-switches and LED display the user may monitor the well temperature, set the temperature set-point in degrees C or F, monitor the heater output power, adjust the control ler proportional band, and program the calibration parameters, operating pa rameters, and serial interface configuration. Operation of the functions and parameters are shown in the flowchart in Figure 4 on page 22. This chart may be copied for reference.
In the following discussion a button with the word SET, UP, EXIT or DOWN inside indicates the panel button while the dotted box indicates the display reading. Explanation of the button or display reading are to the right of each button or display value.
7.1 Well Temperature
The digital LED display on the front panel allows direct viewing of the actual well 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,
100.0 C
The temperature display function may be accessed from any other function by pressing the “EXIT” button.
Well temperature in degrees Celsius
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7.2 Temperature Set-point
The temperature set-point can be set to any value within the range and with res olution as given in the specifications. Be careful not to exceed the safe upper temperature limit of any device inserted into the well.
Setting the temperature involves two steps: (1) select the set-point memory and (2) adjust the set-point value.
7.2.1 Programmable Set-points
The controller stores 8 set-point temperatures in memory. The set-points can be quickly recalled to conveniently set the calibrator to a previously programmed temperature set-point.
To set the temperature one must first select the set-point memory. This function is accessed from the temperature display function by pressing “SET”. The number of the set-point memory currently being used is shown at the left on the display followed by the current set-point value.
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Figure 4 Controller Operation Flowchart
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7 Controller Operation
Temperature Set-point
100.0 C
S
Access set-point memory
1. 100.
To change to another set-point memory press “UP” or “DOWN”.
4. 300.
Press “SET” to accept the new selection and access the set-point value.
S
Accept selected set-point memory
7.2.2 Set-point Value
The set-point value may be adjusted after selecting the set-point memory and
pressing “SET”.
4. 200.
If the set-point value need not be changed then press “EXIT” to resume dis­playing the well temperature. To change the set-point value, press “SET” and then press “UP” or “DOWN.”
Well temperature in degrees Celsius
Set-point memory 1, 100°C currently used
New set-point memory 4, 300°C
Set-point 4 value in°C
220.0
When the desired set-point value is reached press “SET” to accept the new value and access the temperature scale units selection. If “EXIT” is pressed in stead then any changes made to the set-point will be ignored.
S
Accept new set-point value
New set-point value
7.2.3 Temperature Scale Units
The temperature scale units of the controller maybe set by the user to degrees Celsius (°C) or Fahrenheit (°F). The units are used in displaying the well tem perature, set-point, and proportional band.
Press “SET” after adjusting the set-point value to change display units.
Un= C Scale units currently selected
Press “UP” or “DOWN” to change the units.
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7.3 Scan
The scan rate can be set and enabled so that when the set-point is changed the dry-well heats or cools at a specified rate (degrees per minute) until it reaches the new set-point. With the scan disabled the dry-well heats or cools at the maximum possible rate.
7.3.1 Scan Control
The scan is controlled with the scan on/off function that appears in the main menu after the temperature scale units.
Un= F New units selected
Sc=OFF
Press “UP” or “DOWN” to toggle the scan on or off.
Sc=On
Press “SET” to accept the present setting and continue.
S
Accept scan setting
7.3.2 Scan Rate
The next function in the main menu is the scan rate. The scan rate can be set from .1 to 99.9°C/min. The maximum scan rate however is actually limited by the natural heating or cooling rate of the instrument. This is often less than 100°C/min, especially when cooling.
The scan rate function appears in the main menu after the scan control function. The scan rate units are in degrees per minute, degrees C or F depending on the selected units.
Sr= 10.0
Press“UP”or“DOWN”tochangethescanrate.
Sr= 2.0
Scan function off
Scan function on
Scan rate in°C/min
New scan rate
24
Press “SET” to accept the new scan rate and continue.
S
Accept scan rate
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7.4 Temperature Display Hold
The 9140 has a display hold function which allows action of an external switch to freeze the displayed temperature and stop the set-point from scanning. This is useful for testing thermal switches and cutouts. This section explains the functions available for operating the temperature hold feature. An example fol lows showing how to set up and use the hold feature to test a switch.
7.4.1 Hold Temperature Display
The hold feature is enabled by simply pressing the “UP” button. The hold tem perature display shows the hold temperature on the right and the switch status on the left. For the status “c” means the switch is closed and “o” means the switch is open. The status flashes when the switch is in its active position (op posite the normal position). The hold temperature shows what the temperature of the well was when the switch changed from its normal position to its active position. While the switch is in the normal position the hold temperature will follow the well temperature. Operation of the hold temperature display is out lined below.
7 Controller Operation
Temperature Display Hold
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143.5 C
U
Access hold display
c 144.8
To return to the normal well temperature display press “DOWN”.
7.4.2 Mode Setting
The Hold Function is always in the automatic mode. In this mode the normal position is set to whatever the switch position is when the set-point is changed. For example, if the switch is currently open when the set-point is changed, the closed position then becomes the new active position. The normal position is set automatically under any of the following conditions, (1) a new set-point number is selected, (2) the set-point value is changed, (3) a new set-point is set through the communications channels.
The operating mode of the temperature hold is set in the primary menu after the scan rate setting.
7.4.3 Switch Wiring
The thermal switch or cutout is wired to the calibrator at the two terminals in the front of the dry-well calibrator labeled “SWITCH HOLD”. The switch wires may be connected to the terminals either way. Internally the black termi
nal connects to ground. The red terminal connects to +5V through a 100 kΩ re
Well temperature display
Switch status and hold temperature
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sistor. The calibrator measures the voltage at the red terminal and interprets +5V as open and 0V as closed.
7.4.4 Switch Test Example
This section describes a possible application for the temperature hold feature and how the instrument is set up and operated.
Suppose you have a thermal switch which is supposed to open at about 75°C and close at about 50°C and you want to test the switch to see how accurate and repeatable it is. You can use the temperature hold feature and the scan function to test the switch. Measurements can be made by observing the display or, pref erably, by collecting data using a computer connected to the RS-232 port. To set up the test do the following steps.
1. Connect the switch wires to the terminals on the front of the dry-well and place the switch in the well.
2. Enable set-point scanning by setting the scan to “ON” in the primary menu (see section 7.3.1).
3. Set the scan rate to a low value, say 1.0°C/min. (see section 7.3.2). If the scan rate is too high you may lose accuracy because of transient temperature gradients. If the scan rate is too low the duration of the test may be longer than is necessary. You may need to experiment to find the best scan rate.
4. Set the first program set-point to a value below the expected lower switch temperature, say 40°C, in the program menu.
5. Set the second program set-point to a value above the expected upper switch temperature, say 90°C.
6. Set the program soak time to allow enough time to collect a number of data points, say 2 minutes.
7. Collect data on a computer connected to the RS-232 port. Refer to Section 8 for instructions on configuring the RS-232 communications interface.
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7.5 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.)
7.5.1 Heater Power
The temperature controller controls the temperature of the well 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. By knowing the amount of heating the user can tell if the calibrator is heating 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 well temperature
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7 Controller Operation
Secondary Menu
is. With good control stability the percent heating power should not fluctuate more than ±1% within one minute.
The heater power display is accessed in the secondary menu. Press “SET” and “EXIT” simultaneously and release. The heater power will be displayed as a percentage of full power.
100.0 C
S+E
Well temperature
Access heater power in secondary menu
SEC Flashes SEC for secondary menu and then displays the
heater power
12.0P
To exit out of the secondary menu press “EXIT”. To continue on to the propor­tional band setting function press “SET”.
Heater power in percent
7.5.2 Proportional Band
In a proportional controller such as this the heater output power is proportional to the well 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 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 level.
Proportional Band too Narrow Proportional Band too Wide
Optimum Proportional Band
Figure 5 Well temperature fluctuation at various proportional band settings
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The temperature stability of the well and response time depend on the width of the proportional band. If the band is too wide the well temperature will deviate excessively from the set-point due to varying external conditions. This is be cause 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 temperature may swing back and forth be cause the controller overreacts to temperature variations. For best control stabil ity the proportional band must be set for the optimum width.
The proportional band width is set at the factory to about 15.0°C. The propor tional band width may be altered by the user if he desires to optimize the con trol characteristics for a particular application.
The proportional band width is easily adjusted from the front panel. The width may be set to discrete values in degrees C or F depending on the selected units. The proportional band adjustment is 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.
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S+E
Access heater power in secondary menu
SEC Flashes SEC for secondary menu and then displays the
heater power
Heater power in percent
S
12.0P
Access proportional band
PROP Flashes Prop then displays the setting
4.1
To change the proportional band press “UP” or “DOWN”.
10.0
To accept the new setting press “SET”. Press “EXIT” to continue without stor ing the new value.
S
Accept the new proportional band setting
Proportional band setting
New proportional band setting
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7.6 Controller Configuration
7 Controller Operation
Controller Configuration
The controller has a number of configuration and operating options and calibra tion parameters which are programmable via the front panel. These are ac cessed from the secondary menu after the proportional band function by pressing “SET”. Pressing “SET” again enters the first of three sets of configu ration parameters — calibration parameters, operating parameters and serial in terface parameters. The menus are selected using the “UP” and “DOWN” keys andthenpressing“SET”.
7.6.1 Calibration Parameters
The operator of the instrument controller has access to a number of the calibra tion constants namely R0, ALPHA, and DELTA. These values are set at the factory and must not be altered. The correct values are important to the accu racy and proper and safe operation of the instrument. Access to these parame ters is available to the user so that in the event that the controller 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 instrument manual.
CAUTION: DO NOT change the values of the instrument calibration con-
stants from the factory set values. The correct setting of these parameters is important to the safety and proper operation of the instrument.
The calibration parameters menu is indicated by,
CAL Calibration parameters menu
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Press “SET” five times to enter the menu. The calibration parameters menu contains the parameters, R sistance-temperature relationship of the platinum control sensor. These parame ters may be adjusted to improve the accuracy of the calibrator. This procedure is explained in detail in Section 10, Calibration Procedure.
The calibration parameters are accessed by pressing “SET” after the name of the parameter is displayed. The value of the parameter may be changed using the “UP” and “DOWN” buttons. After the desired value is reached press “SET” to set the parameter to the new value. Pressing “EXIT” causes the parameter to be skipped ignoring any changes that may have been made.
7.6.1.1 R0
This probe parameter refers to the resistance of the control probe at 0°C. The value of this parameter is set at the factory for best instrument accuracy.
, ALPHA, and DELTA, which characterize the re
0
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7.6.1.2 ALPHA
This probe parameter refers to the average sensitivity of the probe between 0 and 100°C. The value of this parameter is set at the factory for best instrument accuracy.
7.6.1.3 DELTA
This probe parameter characterizes the curvature of the resistance-temperature relationship of the sensor. The value of this parameter is set at the factory for best instrument accuracy.
7.7 Operating Parameters
The operating parameters menu is indicated by,
PAr
The operating parameters menu contains NOTHING AT PRESENT.
Operating parameters menu
7.8 Serial Interface Parameters
The serial RS-232 interface parameters menu is indicated by,
SErIAL
Press “UP” to enter the menu. The serial interface parameters menu contains parameters which determine the operation of the serial interface. These controls only apply to instruments fitted with the serial interface. The parameters in the menu are — baud rate, sample period, duplex mode, and linefeed.
7.8.0.1 Baud Rate
The baud rate is the first parameter in the menu. The baud rate setting deter mines the serial communications transmission rate.
The baud rate parameter is indicated by,
bAUd Serial baud rate parameter
Press “SET” to choose to set the baud rate. The current baud rate value will then be displayed.
Serial RS-232 interface parameters menu
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2400 b
The baud rate of the serial communications may be programmed to 300, 600, 1200, 2400, 4800, or 9600 baud. The default factory setting is 2400 baud. Use “UP” or “DOWN” to change the BAUD rate value.
Current baud rate
Page 36
7 Controller Operation
Serial Interface Parameters
4800 b
Press “SET” to set the baud rate to the new value or “EXIT” to abort the opera tion and skip to the next parameter in the menu.
7.8.1 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 measure ments transmitted from the serial interface. If the sample rate is set to 5, the in strument transmits the current measurement over the serial interface approximately every five seconds. The automatic sampling is disabled with a sample period of 0. The sample period is indicated by,
SPEr
Press “SET” to choose to set the sample period. The current sample period value will be displayed.
SP= 1
Adjust the value with “UP” or “DOWN” and then use “SET” to set the sample rate to the displayed value. Press “EXIT” to continue without changes.
SP= 60
New baud rate
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Serial sample period parameter
Current sample period (seconds)
New sample period
7.8.1.1 Duplex Mode
The next parameter is the duplex mode. The duplex mode may be set to full du plex or half duplex. With full duplex any commands received by the calibrator via the serial interface are immediately echoed or transmitted back to the device of origin. With half duplex the commands are executed but not echoed. The du plex mode parameter is indicated by,
dUPL
Press “SET” to access the mode setting.
d=FULL
The mode may be changed using “UP” or “DOWN” and pressing “SET”.
d=HALF
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Serial duplex mode parameter
Current duplex mode setting
New duplex mode setting
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7.8.1.2 Linefeed
The final parameter in the serial interface menu is the linefeed mode. This pa rameter enables (on) or disables (off) transmission of a linefeed character (LF, ASCII 10) after transmission of any carriage-return. The linefeed parameter is indicated by,
LF
Press “SET” to access the linefeed parameter.
LF= On
The mode may be changed using “UP” or “DOWN” and pressing “SET”.
LF= OFF
Serial linefeed parameter
Current linefeed setting
New linefeed setting
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8 Digital Communication Interface
8 Digital Communication Interface
The dry-well calibrator is capable of communicating with and being controlled by other equipment through the digital serial interface.
With a digital interface the instrument may be connected to a computer or other equipment. This allows the user to set the set-point temperature, monitor the temperature, and access any of the other controller functions, all using remote communications equipment. Communications commands are summarized in
Table 2 on page 36.
8.1 Serial Communications
Serial Communications
The calibrator is installed with an RS-232 serial interface that allows serial dig ital communications over fairly long distances. With the serial interface the user may access any of the functions, parameters and settings discussed in Section 7 with the exception of the BAUD rate setting.
8.1.1 Wiring
The serial communications cable attaches to the calibrator through the D-9 con­nector at the back of the instrument. Figure 6 shows the pin-out of this connec­tor and suggested cable wiring. The serial cable should be shielded. If the unit is used in a heavy industrial setting the shielded cable must be limited to ONE meter.
8.1.2 Setup
Before operation the serial interface must first be set up by programming the BAUD rate and other configura tion parameters. These parameters are programmed within the serial inter face menu. The serial interface pa rameters menu is outlined in Figure 4 on page 22.
To enter the serial parameter program ming mode first press “EXIT” while pressing “SET” and release to enter the secondary menu. Press “SET” re peatedly until the display reads “CAL”. Press “UP” until the serial in terface menu is indicated with “SE rIAL”. Finally press “SET” to enter the serial parameter menu. In the se
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Figure 6 Serial Cable Wiring
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rial interface parameters menu are the BAUD rate, the sample rate, the duplex mode, and the linefeed parameter.
8.1.2.1 Baud Rate
The baud rate is the first parameter in the menu. The display will prompt with the baud rate parameter by 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 9140 serial communications may be programmed to 300, 600, 1200, 2400, 4800, or 9600 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.
8.1.2.2 Sample Period
The sample period is the next parameter in the menu and prompted with “SPEr”. 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 instrument will transmit the current measurement over the serial interface approximately every five seconds. The automatic sampling is disabled with a sample period of 0. Press “SET” to choose to set the sample pe­riod. Adjust the period with “UP” or “DOWN” and then use “SET” to set the sample rate to the displayed value.
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8.1.2.3 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 thermometer via the serial interface are immediately echoed or transmitted back to the device of origin. With half du plex the commands are executed but not echoed. The default setting is full du plex. The mode may be changed using “UP” or “DOWN” and pressing “SET”.
8.1.2.4 Linefeed
The final parameter in the serial interface menu is the linefeed mode. This pa rameter enables (“On”) or disables (“OFF”) transmission of a linefeed charac ter (LF, ASCII 10) after transmission of any carriage-return. The default setting is with linefeed on. The mode may be changed using “UP” or “DOWN” and pressing “SET”.
8.1.3 Serial Operation
Once the cable has been attached and the interface set up properly the control ler immediately begins transmitting temperature readings at the programmed rate. The serial communications uses 8 data bits, one stop bit, and no parity. The set-point and other commands may be sent via the serial interface to set the temperature set-point and view or program the various parameters. The inter
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face commands are discussed in Section. All commands are ASCII character strings terminated with a carriage-return character (CR, ASCII 13).
8.2 Interface Commands
8 Digital Communication Interface
Interface Commands
The various commands for accessing the calibrator functions via the digital in terfaces are listed in this section (see Table 2). These commands are used with the RS-232 serial interface. The commands are terminated with a carriage-re
­turn character. The interface makes no distinction between upper and lower case letters, hence either may be used. Commands may be abbreviated to the minimum number of letters which determines a unique command. A command may be used to either set a parameter or display a parameter depending on whether or not a value is sent with the command following a “=” character. For example “s”<CR> returns the current set-point and “s=150.0”<CR> sets the set-point to 150.0 degrees.
In the following list of commands, characters or data within brackets, “[” and “]”, are optional for the command. A slash, “/”, denotes alternate characters or data. Numeric data, denoted by “n”, may be entered in decimal or exponential notation. Characters are shown in lower case although upper case may be used. Spaces may be added within command strings and will simply be ignored. Backspace (BS, ASCII 8) may be used to erase the previous character. A termi­nating CR is implied with all commands.
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9140 Dry-well Calibrator
User’s Guide
Tabl e 2 9140 controller communications commands
Command Description
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=350 Instrument
Read temperature t[emperature] t t: 9999.9 {C or F} t: 55.6 C
Read temperature units u[nits] u u: x u: C
Set temperature units: u[nits]=c/f
Set temperature units to Celsius u[nits]=c u=c
Set temperature units to Fahrenheit
Read scan mode sc[an] sc sc: {ON or OFF} sc: ON
Set scan mode sc[an]=on/off sc=on ON or OFF
Read scan rate sr[ate] sr srat: 99.9 C/min srat:12.4 C/min
Set scan rate sr[ate]=n sr=1.1 .1 to 99.9
Read hold ho[ld] ho ho: open/closed, 99.9 {C
Secondary Menu
Read proportional band setting pr[op-band] pr pb: 999.9 pb: 15.9
Set proportional band to
Read heater power
(duty cycle)
Configuration Menu
Calibration Menu
Read R0 calibration parameter r[0] r r0: 999.999 r0: 100.7
Set R0 calibration parameter to
Read ALPHA calibration parameter
Set ALPHA calibration parameter to
n
Read DELTA calibration parameter
Read DELTA calibration parameter
Operating Parameters Menu
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]
Set serial duplex mode to full du[plex]=f[ull] du=f
Set serial duplex mode to half du[plex]=h[alf] du=h
n
Command Format
u[nits]=f u=f
pr[op-band]=n pr=8.83 Depends on
po[wer] po po: 999.9 po: 6.5
n
r[0]=n r=100.7 97.0 to 105
a[lpha] al al: 9.999999 al: 0.003865
a[lpha]=n al=0.003865 .002 to .006
d[elta] de de: 1.50
d[elta]=n de=1.37 de: 9.9999 0–3.0000
n
sa[mple]=n sa=0 0 to 999
Command Example Returned
or F}
Returned Example
ho: open,
30.5 C
Acceptable Values
Range
CorF
Configuration
FULL or HALF
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Tabl e 3 9140 controller communications commands continued
8 Digital Communication Interface
Interface Commands
Command Description
Set serial linefeed mode: lf[eed]=on/of[f]
Set serial linefeed mode to on lf[eed]=on lf=on
Set serial linefeed mode to off lf[eed]=of[f] lf=of
Miscellaneous Other Commands
Read firmware version number *ver[sion] *ver ver.9999,9.99 ver.9140,1.21
Read structure of all commands h[elp] h list of commands
Read ALL operating parameters all all list of parameters
Legend: [] Optional Command data
Note: When DUPLEX is set to FULL and a command is sent to READ, the command is returned followed by a
Command Format
{} Returns either information
n Numeric data supplied by user
9 Numeric data returned to user
x Character data returned to user
carriage return and linefeed. Then the value is returned as indicated in the RETURNED column.
Command Example Returned
Returned Example
Acceptable Values
ON or OFF
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9 Test Probe Calibration
For optimum accuracy and stability, allow the calibrator to warm up for 10 minutes after power-up and then allow adequate stabilization time after reach ing the set-point temperature. After completing operation of the calibrator, al low the well to cool by setting the temperature to 100°C for one-half hour before switching the power off.
9.1 Comparison Methods
For information on automating your testing, contact Hart Scientific.
9.1.1 Calibrating a Single Probe
Insert the probe to be calibrated into the well of the dry-well calibrator. The probe should fit snugly into the calibrator probe sleeve yet should not be so tight that it cannot be easily removed. Avoid any dirt or grit that may cause the probe to jam into the sleeve. Best results are obtained with the probe inserted to the full depth of the well. Once the probe is inserted into the well, allow ade­quate stabilization time to allow the test probe temperature to settle as de­scribed above. Once the probe has settled to the temperature of the well, it may be compared to the calibrator display temperature. The display temperature should be stable to within 0.1°C degree for best results.
9 Test Probe Calibration
Comparison Methods
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CAUTION: Never introduce any foreign material into the probe hole of
the insert. Fluids etc. can leak into the calibrator causing damage to the calibrator or binding and damage to your probe.
9.1.2 Comparison Calibration
Comparison calibration involves testing a probe against a similar reference probe. The advantage to this method is that better accuracy can be achieved since errors due to dry-well inaccuracy, stem effect, and drift can be reduced.
After inserting the probes to be calibrated, allow sufficient time for the probes to settle and the temperature of the dry-well to stabilize.
Both the reference probe and the probe under test should be the same size and construction. Using probes with different lengths, diameters and materials will have different stem effects causing an unknown temperature difference. All dry-wells have horizontal and vertical gradients that change with temperature . This is an unknown variable which can be factored out if probes are the same type, length, diameter, and material. Probes should be inserted to the same depth in the well.
The following procedure can be used to calibrate a probe against a reference while eliminating error due to temperature gradients between wells.
1. Place the reference probe in one well.
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9140 Dry-well Calibrator
User’s Guide
2. Place the probe to be calibrated, the unit under test (UUT), in another
3. With the reference inserted into one well and the probe under test in
4. Swap the locations of the reference probe and probe under test. Allow
5. Make another set of measurements of the reference probe and the probe
6. Average the two measurements of the reference probe. Average the two
7. You may now compare the averaged measurement of the probe under
For best results repeat the test several times at the same temperature and at dif ferent temperatures.
This method can be used with different types of probes but the user must deter­mine the uncertainty of the measurement.
well.
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serted into a second well, make measurements of each.
plenty of time for thermal settling.
under test.
measurements of the probe under test. Averaging the two measurements in this way eliminates error due to temperature gradients between the two wells.
test with the averaged measurement of the reference probe.
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9.1.3 Calibration of Multiple Probes
Fully loading the calibrator with probes increases the time required for the tem­perature to stabilize after inserting the probes. Be sure that the temperature has stabilized before starting the calibration.
Multiple probes may be calibrated simultaneously using either the direct or comparison calibration method. Stem effect will cause less error in the compar ison calibration method than with the direct calibration method.
9.2 Dry-well Characteristics
9.2.1 Vertical Gradient
There is a temperature gradient vertically in the test well. The heater has been applied to the block in such a way as to compensate for nominal heat losses out of the top of the dry-well and minimize vertical temperature gradients. How ever, actual heat losses will vary depending on the number and types of probes inserted into the calibrator and the block temperature. For best results, insert probes the full depth of well.
9.2.2 Heating and Cooling Rates
Figures 7 and 8 show typical heating cooling rates of the 9140 dry-well
calibrator.
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WARNING: DO NOT remove inserts when heating or when the unit is
hot.
9.2.3 Stabilization and Accuracy
The stabilization time of the dry-well calibrator will depend on the conditions and temperatures involved. Typically the test well will be stable to 0.1°C within 5 minutes of reaching the set-point temperature as indicated by the display. Ul
350
300
250
200
150
Block Temperature °C
100
Ambient
9 Test Probe Calibration
Dry-well Characteristics
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24
Figure 7 Typical Heating Rate
350
300
250
200
150
Block Temperature °C
100
Ambient
24
Figure 8 Typical Cooling Rate
6810
Time in Minutes
6810
Time in Minutes
12
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9140 Dry-well Calibrator
User’s Guide
timate stability will be achieved 10 to 20 minutes after reaching the set temperature.
Inserting a cold probe into a well will require another period of stabilizing de pending on the magnitude of the disturbance and the required accuracy. For ex ample, inserting a .25 inch diameter room temperature probe into a sleeve at 300°C will take 5 minutes to be within 0.1°C of its settled point and will take 10 minutes to achieve maximum stability.
Speeding up the calibration process can be accomplished by knowing how soon to make the measurement. It is recommended that typical measurements be made at the desired temperatures with the desired test probes to establish these times.
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10 Calibration Procedure
10 Calibration Procedure
Calibration Points
Sometimes the user may want to calibrate the dry-well to improve the tempera ture set-point accuracy. Calibration is done by adjusting the controller probe calibration constants R0 , ALPHA, and DELTA so that the temperature of the dry-well as measured with a standard thermometer agrees more closely with the set-point. The thermometer used must be able to measure the well temperature with higher accuracy than the desired accuracy of the dry-well. By using a good thermometer and following this procedure the dry-well can be calibrated to an accuracy of better than 0.5°C over its full range.
10.1 Calibration Points
In calibrating the dry-well, R0, ALPHA, and DELTA are adjusted to minimize the set-point error at each of three different dry-well temperatures. Any three reasonably separated temperatures may be used for the calibration. Improved results can be obtained for shorter ranges when using temperatures that are just within the most useful operating range of the dry-well. The farther apart the calibration temperatures, the larger will be the calibrated temperature range but the calibration error will also be greater over the range. If for instance 150°C to 350°C is chosen as the calibration range then the calibrator may achieve an ac­curacy of say ±0.3°C over the range 150 to 350°C. Choosing a range of 200°C to 300°C may allow the calibrator to have a better accuracy of maybe ±0.2°C over the range 175 to 325°C but outside that range the accuracy may be only ±0.5°C.
10.2 Calibration Procedure
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1. Choose three set points to use in the calibration of the R0, ALPHA, and DELTA parameters. These set points are generally 50.0°C, 200°C, and 350.0°C but other set points may be used if desired or necessary.
2. Set the dry-well to the low set-point. When the dry-well reaches the set-point and the display is stable, wait 15 minutes or so and then take a reading from the thermometer. Sample the set-point resistance by holding down the SET key and pressing the DOWN key. Write these values down as T respectively.
3. Repeat step 2 for the other two set points recording them as T and R3respectively.
4. Using the recorded data, calculate new values for the R DELTA parameters using the equations given below:
10.2.1 Compute DELTA:
ATT=−
32
BTT=−
21
1
and R2and T
2
, ALPHA, and
0
and R
1
3
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9140 Dry-well Calibrator
User’s Guide
C
D
ERR=−
FRR=−
delta
T
1-3
R
1-3
DOWN at the same time.)
where
T
and R1are the measured temperature and resistance at 50.0 °C
1
and R2are the measured temperature and resistance at 200.0 °C
T
2
and R3are the measured temperature and resistance at 350.0 °C
T
3
TTTT
3322
=
100
TTTT
2211
=
100
32
21
AF BE
=
DE CF
1
1
100 1001100
100 1001100
⎥ ⎦
⎤ ⎥
⎢ ⎣
⎢ ⎣
- Measured temperature using thermometer.
- Value of set-point resistance from display of 9140. (Press SET and
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10.2.2 Compute R0& ALPHA:
TT
=+
a T delta
11
=+
a T delta
33
Ra Ra
rzero
alpha
31 13
=
=
Ra Ra
11
1001100
TT
33
1001100
aa
13
RR
13
31 13
⎥ ⎦
⎤ ⎥
delta is the new value of DELTA computed above
5. Program the new values for DELTA (delta), R into the dry-well using the following steps.
a. Press the SET and EXIT keys at the same time and then press SET until R0 is displayed.
(rzero) & ALPHA (alpha)
0
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b. Press SET then use the UP or DOWN keys until the correct numerical setting is displayed. Press SET to accept the new value.
c. Repeat step b. for ALPHA and DELTA.
10.2.3 Accuracy & Repeatability
1. Check the accuracy of the dry-well at various points over the calibration range.
2. If dry-well does not pass specification at all set-points, repeat Calibration Procedure.
10 Calibration Procedure
Calibration Procedure
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11 Maintenance
The calibration instrument has been designed with the utmost care. Ease
of operation and simplicity of maintenance have been a central theme in the product development. Therefore, with proper care the instrument should require very little maintenance. Avoid operating the instrument in an oily, wet, dirty, or dusty environment.
If the outside of the instrument becomes soiled, it may be wiped clean
with a damp cloth and mild detergent. Do not use harsh chemicals on the surface which may damage the paint.
It is important to keep the well of the calibrator clean and clear of any for
eign matter. Do not use fluid to clean out the well.
The dry-well calibrator should be handled with care. Avoid knocking or
dropping the calibrator.
For dry-wells with removable probe sleeves, the sleeves can become cov
ered with dust and carbon material. If the buildup becomes too thick, it could cause the sleeves to become jammed in the wells. Avoid this build up by periodically buffing the sleeves clean.
If a sleeve should be dropped, examine the sleeve for deformities before
inserting it in the well. If there is any chance of jamming the sleeve in the well, file or grind off the protuberance.
Do not drop the probe stems into the well. This type of action can cause a
shock to the sensor.
If a hazardous material is spilt on or inside the equipment, the user is re-
sponsible for taking the appropriate decontamination steps as outlined by the national safety council with respect to the material.
If the mains supply cord becomes damaged, replace it with a cord with the appropriate gauge wire for the current of the instrument. If there are any questions, call Hart Scientific Customer Service for more informa tion.
Before using any cleaning or decontamination method except those rec ommended by Hart, users should check with Hart Scientific Customer Service to be sure that the proposed method will not damage the equip ment.
If the instrument is used in a manner not in accordance with the equip ment design, the operation of the dry-well may be impaired or safety haz ards may arise.
11 Maintenance
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Solutions
Troubleshooting Problems, Possible Causes, and
12 Troubleshooting
12 Troubleshooting
If problems arise while operating the 9140, this section provides some sugges tions that may help you solve the problem. A wiring diagram is also included.
12.1 Troubleshooting Problems, Possible Causes, and Solutions
In the event that the instrument appears to function abnormally, this section may help to find and solve the problem. Several possible problem conditions are described along with likely causes and solutions. If a problem arises, please read this section carefully and attempt to understand and solve the problem. If the problem cannot otherwise be solved, contact a Hart Scientific Authorized Service Center (see Section 1.3) for assistance. Be sure to have the model number, serial number, voltage, and problem description available.
Problem Possible Causes and Solutions
Incorrect tempera­ture reading
The instrument heats or cools too quickly or too slowly
Incorrect R0, ALPHA, and DELTA parameters. Find the value for R0, ALPHA, and DELTA on the Report of Calibration. Reprogram the parameters into the instrument (see Section , Calibration Parameters). Allow the instrument to stabilize and verify the accuracy of the temperature reading.
Controller locked up. The controller may have locked up due to a power surge or other aberration. Initialize the system by performing the Factory Reset Sequence.
Factory Reset Sequence. Hold the SET and EXIT buttons down at the same time while powering up the instrument. The instrument displays shows ‘-init-‘, the model number, and the firmware version. Each of the controller parameters and calibration constants must be reprogrammed. The values can be found on the Report of Calibration.
Incorrect scan and scan rate settings. The scan and scan rate settings may be set to unwanted values. Check the Scan and Scan Rate settings. The scan may be off (if the unit seems to be responding too quickly). The scan may be on with the Scan Rate set low (if unit seems to be responding too slowly).
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Unstable display
Improper line voltage. Verify that the voltage reading in the bottom of the unit matches the source voltage.
Wait. Allow the instrument to stabilize for a few minutes.
Proportional band may be incorrect. Refer to the proportional band on the Report
of Calibration.
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9140 Dry-well Calibrator
User’s Guide
Problem Possible Causes and Solutions
The display shows an error code
Temperature can not be set above a certain point
Display is reading incorrectly
Display flickers when the instru ment is turned off
The instrument does not reach temperature
Controller problem. The error messages signify the following problems with the controller.
Err 1
- a RAM error
Err 2
- a NVRAM error
Err 3
- a Structure error
Err 4
- an ADC setup error
Err 5
- an ADC ready error
Err 6
– a defective control sensor
Err 7
– a heater error
Initialize the system by performing the Factory Reset Sequence describe above.
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Incorrect High Limit parameter. The High Limit parameter may be set below 125°C. Check this value as described in Section 7.7, Operating Parameters.
The instrument was turned off at high temperatures and reenergized too quickly. Turn the instrument off until the display is completely off and then reenergize.
This is normal operation and is more prevalent at high temperatures due to Seebeck Coefficient of the thermoelectric cooling devices. Some time is required to fully dis
­charge the switching power supply and to complete the power off cycle.
The specifications for the instrument include an ambient temperature of 23°C. If the ambient temperature is above 23°C, the instrument may not be able to reach the lowest specified temperature. Check the ambient temperature if the instrument does not reach maximum temperature.
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12.2 CE Comments
12.2.1 EMC Directive
Hart Scientific's equipment has been tested to meet the European Electromag netic Compatibility Directive (EMC Directive, 89/336/EEC). The Declaration of Conformity for your instrument lists the specific standards to which the unit was tested.
12.2.2 Low Voltage Directive (Safety)
In order to,comply with the European Low Voltage Directive (73/23/EEC), Hart Scientific equipment has been designed to meet the IEC 1010-1 (EN 61010-1) and IEC 1010-2-010 (EN 61010-2-010) standards.
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