Fluke 1502A User Manual

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Hart Scientific

1502A

Thermometer Readout

User’s Guide

Rev. 722101 ENG

Limited Warranty & Limitation of Liability

Each product from Fluke Corporation, Hart Scientific Division ("Hart") is warranted to be free from de fects in material and workmanship under normal use and service. The warranty period is three years for the Thermometer Readout. The warranty period begins on the date of the shipment. Parts, product re pairs, and services are warranted for 90 days. The warranty extends only to the original buyer or end-user customer of a Hart authorized reseller, and does not apply to fuses, disposable batteries or to any other product which, in Hart's opinion, has been misused, altered, neglected, or damaged by accident or abnor mal conditions of operation or handling. Hart warrants that software will operate substantially in accor dance with its functional specifications for 90 days and that it has been properly recorded on non-defective media. Hart does not warrant that software will be error free or operate without interrup tion. Hart does not warrant calibrations on the Thermometer Readout.

Hart authorized resellers shall extend this warranty on new and unused products to end-user customers only but have no authority to extend a greater or different warranty on behalf of Hart. Warranty support is available if product is purchased through a Hart authorized sales outlet or Buyer has paid the applicable international price. Hart reserves the right to invoice Buyer for importation costs of repairs/replacement parts when product purchased in one country is submitted for repair in another country.

Hart's warranty obligation is limited, at Hart's option, to refund of the purchase price, free of charge re pair, or replacement of a defective product which is returned to a Hart authorized service center within the warranty period.

To obtain warranty service, contact your nearest Hart authorized service center or send the product, with a description of the difficulty, postage, and insurance prepaid (FOB Destination), to the nearest Hart authorized service center. Hart assumes no risk for damage in transit. Following warranty repair, the product will be returned to Buyer, transportation prepaid (FOB Destination). If Hart determines that the failure was caused by misuse, alteration, accident or abnormal condition or operation or handling, Hart will provide an estimate or repair costs and obtain authorization before commencing the work. Following repair, the product will be returned to the Buyer transportation prepaid and the Buyer will be billed for the repair and return transportation charges (FOB Shipping Point).

Rev. 722101

THIS WARRANTY IS BUYER'S SOLE AND EXCLUSIVE REMEDY AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IM PLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. HART SHALL NOT BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL. OR CONSE QUENTIAL DAMAGES OR LOSSES, INCLUDING LOSS OF DATA, WHETHER ARISING FROM BREACH OF WARRANTY OR BASED ON CONTRACT, TORT, RELIANCE OR ANY OTHER THEORY.

Since some countries or states do not allow limitation of the term of an implied warranty, or exclusion or limitation of incidental or consequential damages, the limitations and exclusions of this warranty may not apply to every buyer. If any provision of this Warranty is held invalid or unenforceable by a court of com petent jurisdiction, such holding will not affect the validity or enforceability of any other provision.

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

1 Before You Start . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1 Symbols Used . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.2.1 Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.2.2 Cautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.3 Authorized Service Centers. . . . . . . . . . . . . . . . . . . . . . 4

2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

3 Specifications and Environmental Conditions . . . . . . . . . . 9

3.1 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3.2 Environmental Conditions . . . . . . . . . . . . . . . . . . . . . 10

4 Quick Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

4.1 Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

4.2 Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

4.3 Connecting the Probe . . . . . . . . . . . . . . . . . . . . . . . . 11

5 Parts and Controls . . . . . . . . . . . . . . . . . . . . . . . . 13

5.1 Front Panel Buttons . . . . . . . . . . . . . . . . . . . . . . . . . 13

5.2 Rear Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

6 General Operation . . . . . . . . . . . . . . . . . . . . . . . . 15

6.1 Selecting Units . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

6.2 Parameter Menus . . . . . . . . . . . . . . . . . . . . . . . . . . 15

6.3 Menu Lockout . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

6.4 Selecting the Probe Characterization . . . . . . . . . . . . . . . . 17

6.4.1 Setting the Probe Characterization Type . . . . . . . . . . . . . . . . . . . . 17

6.4.2 Setting the Characterization Coefficients. . . . . . . . . . . . . . . . . . . . 17

6.4.3 ITS-90 PRT and Coefficients . . . . . . . . . . . . . . . . . . . . . . . . . . 18

6.4.4 Callendar-Van Dusen (RTD) Conversion . . . . . . . . . . . . . . . . . . . . 20

6.4.5 IPTS-68 Conversion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

6.4.5.1 Setting the Characterization Coefficients. . . . . . . . . . . . . . . . . . . . . . . . 21

6.4.5.2 Testing the Coefficients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

6.5 Filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

6.6 Setting the Current . . . . . . . . . . . . . . . . . . . . . . . . . 22

6.7 Power Saver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

7 Digital Communications Interface . . . . . . . . . . . . . . . 23

7.1 Serial Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

7.1.1 Setting the Baud Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

7.1.2 Automatic Transmission of Measurements. . . . . . . . . . . . . . . . . . . 24

7.1.3 Time Stamp and System Clock . . . . . . . . . . . . . . . . . . . . . . . . . 24

7.1.4 Duplex Mode and Linefeed . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

7.2 GPIB Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

7.2.1 Setting the Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

7.2.2 Setting the Termination Character . . . . . . . . . . . . . . . . . . . . . . . 26

7.2.3 Time Stamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

7.3 Remote Commands . . . . . . . . . . . . . . . . . . . . . . . . . 26

7.3.1 Measurement Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

7.3.1.1 Reading Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

7.3.1.2 Automatically Transmitting Measurements . . . . . . . . . . . . . . . . . . . . . . 29

7.3.1.3 Selecting the Unit of Measurement. . . . . . . . . . . . . . . . . . . . . . . . . . . 29

7.3.1.4 Enabling the Time Stamp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

7.3.1.5 Setting the Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

7.3.2 Probe Characterization Commands . . . . . . . . . . . . . . . . . . . . . . . 29

7.3.2.1 Selecting the Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

7.3.2.2 Testing the Characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

7.3.3 Sample Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

7.3.3.1 Setting the Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

7.3.3.2 Setting the Probe Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

7.3.3.3 Setting the Power Saver. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

7.3.4 Communication Commands . . . . . . . . . . . . . . . . . . . . . . . . . . 31

7.3.4.1 Setting the Duplex Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

7.3.4.2 Setting the Linefeed Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

7.3.5 Calibration Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

7.3.5.1 Entering the Password . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

7.3.5.2 Setting the Menu Lockout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

7.3.5.3 Setting the Calibration Coefficients . . . . . . . . . . . . . . . . . . . . . . . . . . 32

7.3.5.4 Setting the Serial Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

7.3.6 Other Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

7.3.6.1 Instrument Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

7.3.6.2 Reading a List of Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

8 Calibration Procedure . . . . . . . . . . . . . . . . . . . . . . 35

8.1 Accessing the Calibration Parameters. . . . . . . . . . . . . . . . 35

8.2 Calibration Procedure . . . . . . . . . . . . . . . . . . . . . . . . 36

9 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

10 Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . 39

10.1 CE Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

10.1.1 EMC Directive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

10.1.1.1 Immunity Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

10.1.1.2 Emission Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

10.1.2 Low Voltage Directive (Safety) . . . . . . . . . . . . . . . . . . . . . . . . . 41

Figures

Figure 1 Connecting a four-wire probe . . . . . . . . . . . . . . . . . . . . . . 12

Figure 2 1502A Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Figure 3 1502A Back Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Figure 4 Parameter Menu Structure . . . . . . . . . . . . . . . . . . . . . . . . 16

Figure 5 Serial Cable Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

iii

Tables

Table1 International Electrical Symbols . . . . . . . . . . . . . . . . . . . . . 1

Table 2 Matching Certificate Values to 1502A ITS-90 Coefficients . . . . . . . 18

Table 3 Setting Coefficients Rtpw, a8, b8, a4, and b4 . . . . . . . . . . . . . . 19

Table 4 Setting Coefficients Rtpw, a5, and b5 . . . . . . . . . . . . . . . . . . 19

Table 5 Setting Coefficients R(273.16), a6, b6, c6, and d . . . . . . . . . . . . 20

Table 6 Command List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Table 6 Command List Continued . . . . . . . . . . . . . . . . . . . . . . . . 28

1 Before You Start

1.1 Symbols Used

Table 1 lists the symbols that may be used on the instrument or in this manual

Table 1 International Electrical Symbols

and the meaning of each symbol.

Symbol Description

AC (Alternating Current)

AC-DC

Battery

Complies with European Union Directives

1 Before You Start

Symbols Used

DC (Direct Current)

Double Insulated

Electric Shock

Fuse

PE Ground

Hot Surface (Burn Hazard)

Read the User’s Manual (Important Information)

Off

1502A Thermometer Readout

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 mark

The European Waste Electrical and Electronic Equipment (WEEE) Directive (2002/96/EC) mark.

1.2 Safety Information

Use this instrument only as specified in this manual. Otherwise, the protection provided by the instrument may be impaired. Refer to the safety information in Sections 1.2.1 and 1.2.2.

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 possible electric shock or personal injury, follow these guidelines.

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 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

guide.

DO NOT use this instrument in combination with any probe to measure the temperature or resistance of any device where the probe might come in contact with a conductor that is electrically energized. Severe electric shock, personal injury, or death may occur.

If this equipment is used in a manner not specified by the manufacturer, the protection provided by the equipment may be impaired.

1 Before You Start

Safety Information

Before initial use, or after transport, or after storage in humid or semi-humid environments, or anytime the instrument 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 requirements 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 applying power such as storage in a low humidity temperature chamber operating at 50°C for 4 hours or more.

Follow all safety guidelines listed in this user's guide.

Calibration Equipment should only be used by Trained Personnel.

To avoid possible burn hazards, follow these guidelines.

This instrument can measure extreme temperatures. Precautions must be taken to prevent personal injury or damage to objects. Probes may be extremely hot or cold. Cautiously handle probes to prevent personal injury. Carefully place probes on a heat/cold resistant surface or rack until they reach room temperature.

1.2.2

Cautions

To avoid possible damage to the instrument, follow these guidelines.

DO NOT change the values of the calibration constants from the factory set

values unless you are recalibrating the instrument. The correct setting of these parameters is important to the safety and proper operation of the instrument.

Allow sufficient air circulation by leaving at least 3 inches of space between the thermometer and nearby objects.

For CE compliance and for performance, use only the AC adapter shipped with the instrument. If the AC adapter needs to be replaced, contact an Authorized Service Center.

This instrument and thermometer probes are sensitive and can be easily dam aged. Always handle these devices with care. DO NOT allow them to be dropped, struck, stressed, or overheated.

Probes are fragile instruments which can be damaged by mechanical shock, over-heating, and absorption of moisture or fluids in the wires or hub. Damage may not be visibly apparent but nevertheless can cause drift, instability, and loss of accuracy. Observe the following precautions:

DO NOT allow probes to be dropped, struck, bent, or stressed.

DO NOT overheat probes beyond their recommended temperature range.

DO NOT allow any part of the probe other than the sheath to be immersed in fluid.

DO NOT allow the probe hub or wires to be exposed to excessive temperatures.

1502A Thermometer Readout

User’s Guide

Keep the probe wires clean and away from fluids.

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

Science Park Eindhoven 5108

5692 EC Son

NETHERLANDS

Phone: +31-402-675300

Telefax: +31-402-675321

E-mail: ServiceDesk@fluke.nl

Fluke Int'l Corporation

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

1 Before You Start

Authorized Service Centers

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

2 Introduction

The 1502A is a low-cost high-accuracy digital thermometer readout designed to be used with 25Ω and 100Ω RTDs and SPRTs. Its unique combination of fea

tures makes it suitable for a wide variety of applications from laboratory mea surement to industrial processes. Features of the 1502A include:

Measures 25Ω and 100Ω RTDs and SPRTs

•

Four-wire connection eliminates lead resistance effects

•

Accuracy: 0.006°C at 0°C

•

Resolution: 0.001°C

•

Fast one-second measurement cycle

•

Adjustable digital filter

•

Accepts ITS-90 characterization coefficients

•

Also accepts Callendar-Van Dusen and IPTS-68 coefficients

•

• Adjustable excitation current

• Displays temperature in Celsius, Fahrenheit, or Kelvin or displays resis-

tance in ohms

• Password protection of critical parameters

• Large, bright eight-digit LED display

• Serial RS-232 interface standard; IEEE-488 GPIB interface optional

• Detachable power cord

• Light weight, small and portable

•

Sturdy, reliable construction

2 Introduction

3 Specifications and Environmental Conditions

3 Specifications and Environmental

Conditions

3.1 Specifications

Specifications

Resistance Range

Resistance Accuracy, one year

Resistance Accuracy, short

1, 2

term

Temperature Range

Temperature Accuracy

Temperature Coefficient of Resistance

Resistance Resolution

Temperature Resolution

Probe

Probe Connection

Maximum acceptable lead resistance

Probe Characterizations

Probe Excitation Current

Measurement Period

Digital Filter

Communications

Display

Clock accuracy, typical

Operating Temperature Range

AC power

Size

1, 3, 4

to 400Ω, auto-ranging

0Ωto 20Ω: 0.0005 20Ωto 400Ω: 0.0025% (25 ppm) of reading

0Ωto 30Ω: 0.0005 30Ωto 400Ω: 0.0015% (15 ppm) of reading

–200°C to 962°C (–328°F to 1764°F)

–100°C: 0.004°C

0°C: 0.006°C 100°C: 0.009°C 200°C: 0.012°C 300°C: 0.015°C 400°C: 0.018°C 500°C: 0.021°C 600°C: 0.024°C

1 ppm/°C

to 20Ω: 0.0001

20Ωto 400Ω: 0.001

0.001°C

Nominal R(0.01°C): 25 RTD, PRT, or SPRT

4-wire with shield, 5-pin DIN connector

100

ITS-90 sub-ranges 4, 6, 7, 8, 9, 10, and 11 IPTS-68: R Callendar-Van Dusen: R0,

0.5 and 1 mA , user selectable, 2Hz

1 second

Exponential, 0 to 60 seconds time constant (user-selectable)

RS-232 serial standard IEEE-488 (GPIB) optional, conforms to IEEE-488.1, capability AH1, SH1, T6, L4, DC1

8-digit, 7-segment, yellow-green LED; 0.5 inch high characters

0.01%

Full accuracy: 16°C to 30°C Absolute: 0°C to 55°C

115 VAC ±10%, 50/60 Hz, 10 W, nominal, 1 A maximum 230 VAC ±10%, 50/60 Hz, 10 W, 1 A, nominal (optional) Detachable power cord

5.6 inches (14.3 cm) wide x 7.1 inches (18.1 cm) deep x 2.4 inches (6.1 cm) high

,α,δ,a4, and c

to 100

α, δ

, and

1502A Thermometer Readout

User’s Guide

Weight

Safety

Accuracy specifications apply within the recommended operating temperature range. Accuracy limits are

increased by a factor of the temperature coefficient outside this range.

Short-term accuracy includes nonlinearity and noise uncertainties. It does not include drift or calibration

uncertainties.

The temperature range may be limited by the sensor.

Temperature accuracy is for the 1502A only. It does not include probe uncertainty or probe characteriza

tion errors.

2.2 lb. (1.0 kg)

OVERVOLTAGE (Installation) CATEGORY II, Pollution Degree 2 per IEC 1010-1

3.2 Environmental Conditions

Although the instrument has been designed for optimum durability and trou ble-free operation, it must be handled with care. The instrument should not be operated in an excessively dusty or dirty environment. Maintenance and clean ing recommendations can be found in the Maintenance Section of this manual.

The instrument operates safely under the following conditions:

• Ambient temperature range: Absolute 0–55°C (32–131°F); [full accuracy

16–30°C (61–86°F)]

• Ambient relative humidity: maximum 80% for temperature < 31°C, de-

creasing linearly to 50% at 40°C

• Pressure: 75kPa–106kPa

• Mains voltage within ±10% of nominal

• Vibrations should be minimized

•

Altitude less than 2,000 meters

•

Indoor use only

4 Quick Start

This section briefly explains the basics of setting up and operating your 1502A thermometer readout.

4.1 Unpacking

Unpack the thermometer carefully and inspect it for any damage that may have occurred during shipment. If there is shipping damage, notify the carrier immediately.

Verify that the following components are present:

1502A Thermometer

•

Extra Probe Connector

•

Power Cord

•

• User’s Guide

• Probe (optional—must be purchased separately)

4.2 Power

4 Quick Start

Unpacking

Your 1502A is configured for either 115 VAC (±10%) operation or 230 VAC (±10%) operation. Be careful to only connect the 1502A to a mains supply of the correct voltage. Otherwise, the instrument may be damaged. The required voltage is indicated on the back of the 1502A. Power requirements are listed in Section 3.1, Specifications. The IEC type power cord connects to the back of the 1502A. The cord must be plugged in to a grounded outlet. The power switch is located at the back of the 1502A.

When the 1502A is powered on, wait briefly while it initializes. It will then be gin measuring and displaying temperature.

Because of the quality of the components used in the 1502A, it exhibits nearly negligible drift as it warms up. The warm-up drift is typically less than 5 ppm. Nevertheless, to ensure the best accuracy and stability, you may want to allow the 1502A to warm up for ten minutes before use.

Accurate measurement requires that the probe be connected properly to the in put and the correct probe characterization set.

4.3 Connecting the Probe

The RTD or SPRT probe connects to the back of the 1502A using a five-pin DIN plug. Figure 1 shows how a four-wire probe is wired to the five-pin DIN connector. One pair of wires attaches to pins 1 and 2 and the other pair attaches

1502A Thermometer Readout

User’s Guide

to pins 4 and 5. (Pins 1 and 5 source current and pins 2 and 4 sense the poten tial.) If a shield wire is present it should be connected to pin 3.

Probe Connector

Shield

RTD Sensor

Figure 1 Connecting a four-wire probe

A two-wire probe can also be used with the 1502A. It is connected by attaching one wire to both pins 1 and 2 of the plug and the other wire to both pins 4 and

5. If a shield wire is present it should be connected to pin 3. Accuracy may be significantly degraded using a two-wire connection because of lead resistance.

5 Parts and Controls

5.1 Front Panel Buttons

See Figure 2.

The front panel buttons are used to select units of measurement, access operat ing parameters, and alter operating parameters. The function of each button is as follows:

C/Probe—This button selects units of degrees Celsius. In conjunction with the Menu button, it selects the probe parameter menu.

F/Sample—This button selects units of degrees Fahrenheit. In conjunction with the Menu button, it selects the sample parameter menu.

K/Comm—This button selects units of Kelvin. In conjunction with the Menu button, it selects the communication parameter menu.

Ω/Exit (Cal)—This button selects resistance in ohms. While editing a parame- ter, it cancels the immediate operation and skips to the next parameter. If the Exit button is pressed for more than one-half second the menu is exited. In conjunction with the Menu button, it selects the calibration parameter menu.

5 Parts and Controls

Front Panel Buttons

Menu/Enter—This button allows one of the unit/menu buttons to select a menu. When editing a parameter, it accepts the new value and skips to the next operation.

L and R —When editing a numeric parameter, these buttons move between

digits. The selected digit flashes. U and D— When editing a parameter, these buttons increase or decrease the

value of the parameter or a selected digit.

84.981 C

PROBE

Figure 2 1502A Front Panel

SAMPLE

COMM

EXIT

ENTER

1502A

THERMOMETER READOUT

1502A Thermometer Readout

User’s Guide

5.2 Rear Panel

See Figure 3.

Serial Port - The DB-9 connector is for interfacing the thermometer to a com puter or terminal with serial RS-232 communications.

Probe Connector - At the rear of the thermometer is the probe connector. The probe must be connected for operation.

Power Switch - The power switch is located on the rear of the thermometer. The AC power switch turns the unit on and off.

AC Power - At the rear of the instrument is the removable power cord that plugs into a standard 115 VAC grounded socket. (230 VAC optional)

IEEE-488 Port (optional) - The GPIB connector is for interfacing the ther

mometer to a computer or terminal with IEEE-488 communications.

IEEE-488

RS-232

FLUKE CORPORATION

HART SCIENTIFIC DIVISION

www.hartscientific.com

POWER

201811

Figure 3 1502A Back Panel

PROBE

115 VAC 50/60 Hz 10 W

NO USER SERVICABLE PARTS

6 General Operation

This section explains basic operation of the 1502A Thermometer.

6.1 Selecting Units

Temperature can be displayed in degrees Celsius (indicated with “C”), degrees Fahrenheit (indicated with “F”), or Kelvin (indicated with “A” for absolute). The resistance of the sensor can also be displayed (indicated with “o”for

ohms). Simply press the appropriate unit button, C, F, K, or Ω to select the units.

6.2 Parameter Menus

Except for unit selection, all functions and operating parameters are accessed and edited within the parameter menus. There are four menus: the Probe pa rameter menu, Sample parameter menu, Comm (communication) parameter menu, and Cal (calibration) parameter menu. The arrangement of parameters in the menus is shown in Figure 4 on page 16.

Menus are selected by pressing the Menu/Enter button followed by the appropriate menu selection button. The name of the menu will briefly appear on the display. For example, the Probe menu is selected by pressing the Menu/Enter button (“SEt?” appears on the display) followed by the C/Probe button (“ProbE” appears). Selecting the Cal menu requires that you press the

Menu/Enter button then press the Ω/Exit button and hold it down for at least one second.

6 General Operation

Selecting Units

The Probe menu contains parameters for selecting the probe characterization and setting the characterization coefficients. These parameters are explained in

Section6.4.TheSample menu contains parameters for setting the filter and ex

citation current. These are explained in Sections 6.5 and 6.6. The Comm menu contains communication parameters such as the serial baud rate or IEEE-488 address. These are explained in Sections 7.1 and 7.2. The Cal menu contains the calibration parameters. These are explained in Section 8.1.

6.3 Menu Lockout

All menus can be locked out to prevent inadvertently changing parameters. By default, only the Cal menu is locked out. The lockout option is accessed in the Cal menu (see Section 8.1 “Accessing the Calibration Parameters”).

If menus are locked out you must enter the correct password (“2051”) to gain access. After you select the menu (see the previous section) the display will show “PA= 0000” and allow you to change the number to the correct pass

word. Use the L and R buttons to move between the password digits and the U and D buttons to increase or decrease the value of a digit. Press Enter

1502A Thermometer Readout

User’s Guide

Sample Comm (Cal)Probe

Set clockSet filterSet probe type Enter password

11.23.30FI= 4Pr= t90 PA= 0000

Set time stampSet currentSet coefficients Set menu lockout

ts= OFFCur= 1.0 LO=CaL

Set baud rateSet power saver Set CAL0

2400 bPS= OFF -0.0006

Press after changing a parameter

Enter

Press briefly to skip a parameter

Exit

Hold to exit the menu

Exit

Figure 4 Parameter Menu Structure

Set sample periodTest conversion Set CAL 100

00.00.01100.0000 +0.0128

Set duplex Set CAL 400

duP=FULL -0.0011

Set linefeed Factory reset

LF= ON rESEt?

Set GPIB address

Add= 22

Set GPIB EOS

E= LF

Selecting the Probe Characterization

6 General Operation

when all the digits are correct. If the password is entered correctly the first pa rameter in the menu will appear.

6.4 Selecting the Probe Characterization

Before the 1502A can measure temperature accurately it must know how to cal culate temperature from the resistance of the sensor. You must select a conver sion type and enter the proper characterization coefficients. There are several temperature conversion algorithms available. The one to use depends on the type of probe you are using and its calibration. The conversion algorithms use coefficients that characterize the sensor. Coefficients are determined when the probe is calibrated. SPRTs and PRTs often use the ITS-90 algorithms and are provided with ITS-90 characterization coefficients.

6.4.1 Setting the Probe Characterization Type

The probe characterization type and characterization coefficients are set in the Probe menu. Press the Menu button (“SEt?” appears), then the C/Probe button. The menu name, “ProbE”, will appear briefly then the characterization type. The probe characterization types are indicated on the display as follows:

Pr= t90 ITS-90

Pr= rtd Callendar-Van Dusen

Pr= t68 IPTS-68

Select the desired probe characterization type using the U and D buttons and pressing the Enter button. After the characterization type is selected the char acterization coefficients follow. The coefficients that appear depend on the probe type that was selected.

6.4.2 Setting the Characterization Coefficients

Probe characterization coefficients are set within the Probe menu after select ing the probe characterization type. Each coefficient appears with the name of a coefficient shown briefly followed by its value. For example,

+4.336079

For some coefficients, you only need to set the digits in the number. Other coef ficients also have a sign as shown above (positive sign appears as “ L and R buttons to move between the digits (and the sign). The selected

+”). Use the

1502A Thermometer Readout

User’s Guide

digit will flash. Use the U and D buttons to change a digit. Once the sign and digits are correct, press Enter to accept the number. If you decide to cancel any changes you have made, you may do so by pressing the Ω/Exit button. This will immediately skip to the next coefficient.

If the coefficient also requires an exponent, it will appear after setting the num ber as follows:

E -04

Increase or decrease the exponent using the U and D buttons. Once the expo nent is correct, press Enter to accept it.

6.4.3 ITS-90 PRT and Coefficients

The ITS-90 option is for PRTs calibrated and characterized using the Interna tional Temperature Scale of 1990 equations. The parameters that appear when

ITS-90 is selected are “R0.01", ”A", “b”, “C”, “d”, “A4", and ”b4". These should be set with the corresponding values that appear on the calibration certificate for the PRT. The parameter “R0.01" takes the triple point of water resistance, often labeled ”Rtpw" or “R(273.16K)” on the certificate. Parameters “A”, “b”, “C”, and “d” take the an,bn,cn, and d coefficients where n is a num- ber from 5 to 11. Parameters “A4" and ”b4" take the a4 and b4 coefficients or the a5 and b5 coefficients on the certificate. Any ITS-90 parameter of the

1502A that does not have a corresponding coefficient on the PRT’s certificate must be set to 0.

The following table shows which parameter to set for each of the coefficients that may appear on the certificate. The examples that follow demonstrate how to set the ITS-90 parameters for certain cases. (Note: If the certificate has two sets of coefficients, one set for “zero-power” calibration and one set for 1 mA calibration, use the coefficients for the 1 mA calibration.)

Tabl e 2 Matching Certificate Values to 1502A ITS-90 Coefficients

1502A ITS-90 Coefficient Certificate Value

A a5, a6, a7, a8, a9, a10, or a11

b b5, b6, b7, b8, or b9

Cc6orc7

A4 a4 or a5

b4 b4 or b5

Selecting the Probe Characterization

6 General Operation

Example 1:

A PRT was calibrated to ITS-90 and its calibration certificate states values for coefficients Rtpw, a4, b4, a8, and b8. Set the 1502A parameters with values from the certificate as follows.

Tabl e 3 Setting Coefficients Rtpw, a8, b8, a4, and b4

1502A Coefficient Certificate Value

R0.01 Rtpw

Aa8

bb8

A4 a4

b4 b4

Example 2:

A PRT was calibrated to ITS-90 and its calibration certificate states values for coefficients Rtpw, a5 and b5. Set the 1502A parameters with values from the certificate as follows:

Tabl e 4 Setting Coefficients Rtpw, a5, and b5

1502A Coefficient Certificate Value

R0.01 Rtpw

Aa5

bb5

A4 a5

b4 b5

1502A Thermometer Readout

User’s Guide

Example 3:

A PRT was calibrated to ITS-90 and its calibration certificate states values for coefficients R(273.16K), a6, b6, c6, and d. Set the 1502A parameters with val ues from the certificate as follows:

Tabl e 5 Setting Coefficients R(273.16), a6, b6, c6, and d

1502A Coefficient Certificate Value

R0.01 R(273.16K)

Aa6

Bb6

Cc6

A4 0.0

b4 0.0

6.4.4 Callendar-Van Dusen (RTD) Conversion

The RTD conversion uses the Callendar-Van Dusen equation:

⎧

rt C

°=

()

[]

⎧

⎪ ⎪

⎨ ⎪

⎪ ⎩

⎡

+− −

αδ

⎨

⎢

100 100

⎣

⎩ ⎧

⎡

−−

⎨

⎪

⎩

δβ

⎢

100 100

⎢

⎣

⎛ ⎜

⎝

tt t t

⎛ ⎜

⎝

⎫

⎤

⎞

⎟

⎬

⎥

⎠

⎦

⎭

⎛

⎞

⎛

⎞

−−

⎜

⎟

⎝

⎠

100

⎞

⎟

⎜

⎟

⎠

⎝

⎠

100

≥

⎫

⎤

t 0

⎥

⎬

⎥

⎦

⎭

The coefficients R0, α, β ,andδ can be set by the user. They are indicated as “r0”, “ALPHA”, “bEtA”, and “dELtA” on the display. The ALPHA coeffi

cient is scaled by a factor or 1000 to allow adequate resolution. For IEC-751 or DIN-43760 sensors, the coefficients for “r0”, “ALPHA”, “bEtA”, and “dELtA” should be 100.0, 0.00385055, 1.49979, and 0.1086 respectively.

Some probes may be provided with A, B, and C coefficients for the Callendar-Van Dusen equation in the following form:

()

≥

rt C

°=

()

[]

⎧

RAtB

()

⎨

RAtBtCt t

++ + −

1 100

[]

⎪

⎩

The A, B, and C coefficients can be converted to α, δ,andβ coefficients using the following formulas:

αδ β=+ =−

100

=−

100

6.4.5 IPTS-68 Conversion

The IPTS-68 characterization converts resistance to temperature according to the International Practical Temperature Scale of 1968. The applicable coeffi

cients are R You can also select the temperature scale (“SCALE”) as IPTS-68 (“68”) or ITS-90 (“90”). Selecting ITS-90 causes the temperature to be adjusted by a small amount equal to the difference between the ITS-90 and IPTS-68 tempera ture scales.

6.4.5.1 Setting the Characterization Coefficients

(“r0”), α (“ALPHA”), δ (“dELtA”), a4(“A4”), and c4(“C4”).

Selecting the Probe Characterization

6 General Operation

Probe characterization coefficients are set within the Probe menu after select ing the probe characterization type. Each coefficient appears with its name shown briefly followed by its value. For example,

+4.336079

For some coefficients, you only need to set the digits in the number. Other coefficients also have a sign as shown above (positive sign appears as “+”). Use the

L and R buttons to move between digits (and the sign). The selected digit will flash. Use the U and D buttons to change a digit. Once the sign and digits

are correct, press Enter to accept the number. If you decide you would like to cancel any changes you have made, you may do so by pressing the Ω/Exit but-

ton. This will immediately skip to the next coefficient.

If the coefficient also requires an exponent, it will appear after setting the number as follows:

E -04

Increase or decrease the exponent using the p and q buttons. Once the exponent is correct press Enter to accept it.

6.4.5.2 Testing the Coefficients

The 1502A provides a convenient method for testing the coefficients you have entered to make sure they have been entered correctly. This is done by calculat ing temperature for given resistances and comparing the results with tempera tures listed on the probe’s calibration report. This conversion test function is located at the end of the Probe menu. After setting the coefficients “tESt”ap pears briefly followed by the resistance value. You can change the resistance by

using the L and R buttons to move between digits and the U and D buttons to change a digit. After setting the resistance press Enter. The 1502A will cal culate and display the temperature corresponding to the resistance you entered.

1502A Thermometer Readout

User’s Guide

Compare this temperature with the temperatures listed on the probe calibration report to verify that the coefficients you entered are correct.

6.5 Filtering

While measuring temperature, the readings may appear to vary. This may be due to actual variations in temperature or electrical noise internal to the 1502A. The filter helps to smooth variations in the measurements and improve resolu tion. The drawback is that filtering tends to slow the response to changes in temperature. You can increase the filter time constant to further improve accu racy and resolution or decrease the time constant to reduce the response time. You can set it to any value between 0 and 60 seconds. A value of 0 disables the filter. The default time constant is 4 seconds.

To change the filter value, enter the Sample menu. This is done by first press ing the Menu button (“SEt?” appears) then pressing the F/Sample button. The display will briefly indicate “SA Par”, then “FILtEr”, then the current

filter value. Use the U and D buttons to increase or decrease the filter value then press Enter. The next parameter in the menu, the current, will then appear.

6.6 Setting the Current

You can select one of two options for the probe excitation current: 1.0 mA (default) or 0.5 mA. The current is set within the Sample menu. Press the Menu button (“SEt?” appears) then press the F/Sample button. The filter value will appear. Press Enter to continue. The display will briefly show “CurrEnt”

followed by the value for the current. You can use the Uand Dbuttons to change the value for the current. Press Enter to continue.

6.7 Power Saver

The power saver feature causes the display to blank after a period of no user ac tivity. The power saver feature can reduce operating current by as much as 100 mA. While the display is blanked a small illuminated dot appears on the left side of the display as an indication that the 1502A is still operating. Pressing any button on the front panel restores the display. You can program the power saver to activate after a specified period of time from 5 minutes to 60 minutes in intervals of 5 minutes. You can also disable the power saver feature com pletely. The power saver is off by default.

The power saver is programmed in the Sample menu. Press the Menu button (“SEt?” appears) then press the Sample menu button. Press Exit twice to skip to the power saver parameter. The display will briefly show “PO SA” followed

by the power saver setting. You can use the U and D buttons to change the power saver period (in minutes) or set it to OFF. Press Enter to continue.

7 Digital Communications Interface

Serial Interface

Remote communications allows an external device, such as a computer, to com municate with the 1502A to obtain measurement data and control its operation. Communication is accomplished with various commands issued to the 1502A through the RS-232 port or optional IEEE-488 port. A full list of commands is giveninSection7.3.

7.1 Serial Interface

The 1502A is equipped with an RS-232 serial port. The RS-232 interface is useful for connecting the 1502A to most any microcomputer. The RS-232 socket is located on the back panel of the 1502A. Wiring of the interface cable should be as shown in Figure 5 below. To eliminate noise, the serial cable should be shielded with low re sistance between the connector (DB-9) and the shield. The protocol for RS-232 communications is 8 data bits, 1 stop bit, and no parity. The RS-232 interface uses RTS and CTS for flow control.

7.1.1 Setting the Baud Rate

The 1502A must be set to the same baud rate as the remote device. The baud rate of the 1502A can be set to 1200, 2400, 4800, or 9600. The default is

2400. The baud rate is set in the Comm menu. Press the Menu button (“SEt?” appears) then press the K/Comm button. The display will briefly indicate “SErIAL”, then “bAUd”and then display the current baud

rate. Use the U and D buttons to increase or decrease the baud rate then press Enter. The next parameter in the Comm menu, the serial sample period, will then appear.

Figure 5 Serial Cable Wiring

1502A Thermometer Readout

User’s Guide

7.1.2 Automatic Transmission of Measurements

The 1502A can be programmed to automatically send measurements to a re mote printer or terminal. The transmission interval is set using the “SA PEr” sample period parameter. This is set in the Comm menu after the baud rate pa rameter. The display will briefly indicate “SA PEr” and then display the cur rent sample period. The sample period is specified in hours, minutes, and seconds. Setting the sample period to 0 disables automatic transmission of mea

surements. Use the L and R buttons to move between digits. The selected digit will flash. Use the U and D buttons to increase or decrease the digit.

When the sample period is set as desired press Enter.

The sample period can also be set using the “SA” communications command. The period can be specified in seconds, in minutes and seconds, or in hours, minutes, and seconds. For example, SA=15<EOS> causes the 1502A to trans mit measurements at 15-second intervals. SA=10:00<EOS> causes the 1502A to transmit a measurement every ten minutes. SA=2:00:00<EOS> causes the 1502A to transmit a measurement every two hours. (<EOS> represents the ter mination character which is either a linefeed or carriage return).

7.1.3 Time Stamp and System Clock

The 1502A has a built-in system clock that counts hours, minutes, and seconds while the power is on. The clock can be used to time stamp measurement data read from the communications interfaces. When the power is switched on the clock is set to 00:00:00. You can set the clock to show the actual time-of-day. This can be done within the Comm menu. Press the Menu button (“SEt?”appears) and then the Comm menu button. The display will briefly show “CLOC” then the current clock time in hours, minutes, and seconds. The time is represented in 24-hour format with 00 hours meaning 12:00 a.m. and 23 hours

meaning 11:00 p.m. Use the L and R buttons to move between digits. The selected digit will flash. Use the U and D buttons to change the digit. Once

the digits are correct, press Enter to accept the new time. If you decide not to change the time press the Exit button instead.

The clock can also be set using the “CL” communications command: CL=hh:mm:ss <EOS>.

The time stamp allows you to record the time-of-day with measurements that are printed or transmitted to a computer. The given time is the value of the sys tem clock at the time of transmission. An example of time-stamped readings is shown below.

t: 31.787 F 14:04:40

t: 31.788 F 14:04:50

t: 31.792 F 14:05:00

t: 31.793 F 14:05:10

The time stamp control is also accessed in the Comm menu. Press the Menu button (“SEt?” appears) and then the Comm menu button. Press Exit to skip

to the time stamp parameter. The display will briefly show “ti Sta” then the time stamp state which is either ON or OFF. Use the U and D buttons to

change the state and press Enter. ON enables transmission of the time stamp and OFF disables it.

The time stamp can also be set using the “ST” communications command. The command ST=ON<EOS> enables the time stamp and ST=OF<EOS> disables it.

The clock and time stamp parameters affect the time stamp of data read through both the RS-232 and IEEE-488 interfaces.

7.1.4 Duplex Mode and Linefeed

7 Digital Communications Interface

GPIB Interface

Commands sent to the 1502A through the RS-232 interface are normally ech oed back to the remote device. To disable this feature set the duplex option to half instead of full. The duplex parameter is found in the Comm menu after the sample period parameter. The display will briefly indicate “dUPL”andthen

display the current duplex setting. Use the U and D buttons to set duplex to “HaLF”or“FULL”thenpressEnter.

Duplex can also be set using the “DU” communications command. The command DU=H<EOS> sets duplex to half and DU=F<EOS> sets duplex to full.

Transmissions from the 1502A through the RS-232 interface are normally followed by a linefeed character (ASCII decimal 10). The linefeed character can be disabled by setting the linefeed “LF” parameter to “OFF”. The linefeed parameter is found in the Comm menu after the duplex parameter. The display will briefly indicate “LF” and then display the current linefeed setting. Use the

U and D buttons to set linefeed “On”or“OFF”thenpressEnter.

The linefeed can also be set using the “LF” communications command. The command LF=OF<EOS> disables the linefeed character and LF=ON<EOS> enables it.

7.2 GPIB Interface

The 1502A is available with an optional IEEE-488 (GPIB) port. The IEEE-488 interface is useful when one computer needs to control and collect data from many instruments simultaneously. The IEEE-488 connector is located on the back panel of the 1502A above the RS-232 connector. To eliminate noise, the GPIB cable should be shielded.

The 1502A is equipped with basic communication capabilities as specified in IEEE-488.1. The particular capabilities of the IEEE-488 interface are AH1, SH1, T6, L4, DC1 (TE0, LE0, SR0, RL0, PP0, DT0). Refer to “IEEE Std

488.1-1987". The 1502A can talk and listen and accepts the DCL and SDC clear commands. The 1502A does not respond to trigger (GET), serial poll, parallel poll, or remote/local commands and is not capable of talk-only mode.

1502A Thermometer Readout

User’s Guide

7.2.1 Setting the Address

The IEEE-488 bus requires that each device has a unique address. The default address of the 1502A is 22 but can be changed if necessary. The IEEE-488 ad dress of the 1502A is set within the Comm menu after the serial linefeed pa rameter. (This menu option will not appear if the IEEE-488 interface is not installed). Press the Menu button (“SEt?” appears) then press the Comm but ton. The display will briefly indicate “SErIAL”, then “bAUd” and then display the current baud rate. Press Enter several times until “IEEE”appears.Thedis play will briefly indicate “AddreSS” and then display the current IEEE-488

address. Use the U and D buttons to change the number then press Enter.

7.2.2 Setting the Termination Character

The 1502A will normally terminate transmissions from the IEEE-488 port with a linefeed (newline) character. Some systems may require a terminating car riage return instead. The termination character can be changed if necessary. The termination character is set within the Comm menu after the IEEE-488 address parameter. (This menu option will not appear if the IEEE-488 interface is not installed). The display will briefly indicate “EOS” (end of string) and then dis-

play the current setting. Use the U and D buttons to change the termination character then press Enter.

7.2.3 Time Stamp

Measurement data read from the GPIB interface can be stamped with the time-of-day. For instructions on setting the time stamp and system clock see Section 7.1.3 above.

7.3 Remote Commands

ASCII commands are used to instruct the 1502A to perform certain actions. Ta

ble 6 provides a complete list of commands. These commands can be used with

either the RS-232 or IEEE-488 interface. All commands sent to the 1502A must be terminated with a carriage return or linefeed. Either upper or lower case letters are accepted. Commands used to set a parameter are issued with the command header, an “=“ character, and the parameter value. For example, U=C<EOS> sets the units to Celsius. (The symbol <EOS> represents the termi nation character.) Commands used to request data are issued with only the command header. For example, T<EOS> causes the 1502A to return the most recent measurement. Basic operations using commands are explained in the fol lowing sub-sections.

7.3.1 Measurement Commands

The following commands relate to reading measurement data.

7 Digital Communications Interface

Tabl e 6 Command List

Command Description

Measurement Commands

T read measurement (includes label, unit, and time)

F[ETCH?] read measurement value (SCPI compatible)

SA[=[[[hh:]mm:]ss] read [or set] serial sample period

U=C|F|K|O select units

ST[=ON/OF] read [or set] the time stamp

CL[=hh:mm:ss] read [or set] the system clock

Probe Characterization Commands

PR[=90|68|R|S] read [or select] the characterization type

R0[=<value>] read [or set] R0 or R(0.01°C) depending on the selected characterization

AL[=<value>]

DE[=<value>]

BE[=<value>]

read [or set]

red [or set]

A4[=<value>] read [or set]

B4[=<value>] read [or set]

C4[=<value>] read [or set]

[=<value>] read [or set]

D6[=<value>] read [or set]

for the Callendar-Van Dusen or IPTS-68 characterization

for the Callendar-Van Dusen characterization

for the ITS-90 or IPTS-68 characterization

for the ITS-90 characterization

for the IPTS-68 characterization

a6,a7,a8,a9,a

b6,b7,b8,orb

for the ITS-90 characterization

,or

for the ITS-90 characterization

SC[=68/90] read [or set] IPTS-68 scale conversion

CO=<value> test resistance to temperature conversion

Sample Parameter Commands

FI[=<value>] read [or set] filter time constant

CU[=<value>] read [or set] probe current

PS[=<value.] read [or set] the power saver period

Communication parameter commands

DU[=F/H] read [or set] serial sample duplex mode

LF[=ON/OF] read [or set] serial linefeed

Remote Commands

1502A Thermometer Readout

User’s Guide

Command List Continued

Command Description

Calibration Commands

*PA=<password> disable password lockout of calibration commands

*LO=[=CA|AL] read [or set] menu lockout

*C0[=<value>]

*C1[=<value>]

*C4[=<value>]

*SN[=<value>] read [or set] the instrument serial number

Miscellaneous Commands

*VER read model number and firmware version number

*IDN? read manufacturer, model number, serial number, and firmware version number (SCPI

H read a list of commands

read [or set] the 0

read [or set] the 100

read [or set] the 400

compatible)

calibration parameter

7.3.1.1 Reading Temperature

The most recent temperature measurement can be read using the following command:

T<EOS> reads the most recent measurement

The syntax of the response is as follows:

t:_nnnn.nnn_u

t:_nnnn.nnn_u_hh:mm:ss

The _’s represent space characters. The n’s represent the digits of the measure ment value. If fewer digits are needed the leading positions are filled with space characters. The u represents the unit which is either ‘C’, ‘F’, ‘K’, or ‘O’ (for ohms). The time stamp appears if this option is enabled (see Section 7.3.1.4 be low). The time appears in 24-hour format with two digits each for hours, min utes, and seconds.

The following SCPI compatible command can also be used to return the most recent measurement but without the label and unit.

FETC?<EOS> or

FETCH?<EOS> returns the value of the most recent measurement

7 Digital Communications Interface

7.3.1.2 Automatically Transmitting Measurements

By setting the sample period, the 1502A can be programmed to automatically transmit measurements from the RS-232 port at specified intervals. The sample period can be set remotely using the commands:

SA=[[hh:]mm:]ss<EOS> sets the sample period

SA=0<EOS> disables automatic transmission of measurements

The value of the sample period can be from 0 seconds to 24 hours. It is not nec essary to give hours or minutes for values in seconds. A value of 0 disables au tomatic transmission of measurements. Following are some example commands.

SA=10<EOS> sets the sample period to 10 seconds

SA=5:00<EOS> sets the sample period to 5 minutes

SA=1:00:00<EOS> sets the sample period to 1 hour

7.3.1.3 Selecting the Unit of Measurement

The selected unit is used in displaying measurements on the front panel and in reading measurements from the communications interfaces. The following commands can be used to select the unit of measurement:

U=C<EOS> selects Celsius

U=F<EOS> selects Fahrenheit

U=K<EOS> selects Kelvin

U=O<EOS> selects ohms

Remote Commands

7.3.1.4 Enabling the Time Stamp

Enabling the time stamp causes the time of the system clock to be transmitted along with measurement data. The time stamp can be enabled or disabled using the following commands:

ST=ON<EOS> enables the time stamp

ST=OFF<EOS> disables the time stamp

7.3.1.5 Setting the Clock

The system clock is set in 24-hour format using the command:

CL=hh:mm:ss<EOS>

For example:

CL=14:24:00 sets the time to 2:24 pm.

7.3.2 Probe Characterization Commands

The following commands relate to reading measurement data.

1502A Thermometer Readout

User’s Guide

7.3.2.1 Selecting the Characterization

The following commands can be used to select the probe characterization and coefficients:

P=90<EOS> selects the ITS-90 characterization

P=68<EOS> selects the IPTS-68 characterization

P=R<EOS> or P=S<EOS> selects the standard Callendar-Van Dusen characterization

R0=<value><EOS> sets R terization

AL=<value><EOS> sets α for the Callendar-Van Dusen or IPTS-68 char acterization

DE=<value><EOS> sets δ for the Callendar-Van Dusen or IPTS-68 char acterization

BE=<value><EOS> sets β for the Callendar-Van Dusen characterization

A4=<value><EOS> sets a

B4=<value><EOS> sets b

C4=<value><EOS> sets c

An=<value><EOS> sets a ization. n is a number from 6 to 11.

Bn=<value><EOS> sets b is a number from 6 to 9.

Cn=<value><EOS> sets c

D6=<value><EOS> sets d

SC=69<EOS> or SC=90<EOS> sets the temperature scale for the IPTS-68 characterization

or R(0.01C) depending on the selected charac

for the ITS-90 or IPTS-68 characterization

for the ITS-90 characterization

for the IPTS-68 characterization

, a7, a8, a9, a10, or a11for the ITS-90 character-

, b7, b8, or b9for the ITS-90 characterization. n

, or c7for the ITS-90 characterization. n is 6 or

for the ITS-90 characterization

7.3.2.2 Testing the Characterization

The following command can be used to test the probe characterization:

CO=<value><EOS> returns a temperature calculated from resistance

The 1502A will respond with a temperature value computed from the given re sistance value. The temperature is given in the currently selected unit. As an ex ample, if the Callendar-Van Dusen characterization is selected with IEC-751 coefficients and the selected unit is Celsius, sending this command with a resis tance value of 138.5 will return a temperature value of 100.0°C.

7.3.3 Sample Commands

The following commands ralate to the measurement process.

7.3.3.1 Setting the Filter

The filter helps to reduce variations in the measurements. The filter can be set remotely using the command:

FI=<value><EOS> sets the filter time constant

FI=0<EOS> disables the filter

The value is the filter time constant in seconds. It must be between 0 and 60 in clusive. A value of 0 disables the filter.

7.3.3.2 Setting the Probe Current

The probe excitation current can be set remotely using the commands:

CU=1<EOS> sets the current to 1 mA

CU=.5<EOS> sets the current to 0.5 mA

7.3.3.3 Setting the Power Saver

Activating the power saver can conserve power. The power saver causes the display to blank if no front panel buttons are pressed for a given number of minutes. The power saver can be set using the commands:

PS=<value><EOS> sets the power saver time in minutes

PS=0<EOS> or PS=OF<EOS> disables the power saver

The value is the power saver time-out period in minutes. It must be between 0 and 60 inclusive. It is automatically rounded to a multiple of five minutes. A value of 0 or OFF disables the power saver.

7 Digital Communications Interface

Remote Commands

7.3.4 Communication Commands

The following commands relate to external communications.

7.3.4.1 Setting the Duplex Mode

When the RS-232 duplex mode is set to FULL all commands received by the 1502A from the RS-232 port are echoed back. Setting the mode to HALF dis ables the echo. The duplex mode can be set remotely using the commands:

DU=F<EOS> sets duplex to full

DU=H<EOS> sets duplex to half

7.3.4.2 Setting the Linefeed Option

When the RS-232 linefeed option is enabled any data transmitted from the RS-232 port is terminated with a carriage return and a linefeed. Disabling the linefeed sets the termination to carriage return only. The linefeed option can be set remotely using the commands:

LF=ON<EOS> enables linefeed

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User’s Guide

LF=OF<EOS> disables linefeed

7.3.5 Calibration Commands

The following commands are used in calibrating the instrument.

7.3.5.1 Entering the Password

In order to set the calibration parameters the password must be issued first. The following command enables access to the calibration parameters:

*PA=2051<EOS> enables the calibration commands

Calibration parameters can be locked out again by sending *PA=0 or by cycling the power.

7.3.5.2 Setting the Menu Lockout

The following commands can be used to select the menu lockout options:

*LO=CA<EOS> locks out only the calibration menu

*LO=AL<EOS> locks out all menus

7.3.5.3 Setting the Calibration Coefficients

The instrument calibration coefficients are used to maintain the resistance measurement accuracy of the 1502A. These coefficients must not be changed except by a qualified technician during the calibration of the 1502A. The following commands can be used to set the instrument calibration coefficients:

*C0=<value><EOS> sets the calibration parameter CAL0

*C1=<value> <EOS> sets the calibration parameter CAL100

*C4=<value><EOS> sets the calibration parameter CAL400

7.3.5.4 Setting the Serial Number

The following command is used to set the serial number of the 1502A:

*SN=<value><EOS> sets the instrument’s serial number

7.3.6 Other Commands

Remaining commands are described below.

7.3.6.1 Instrument Identification

The following command returns the model number and firmware version number:

*VER<EOS> returns the model and firmware version numbers

The syntax of the response is as follows:

ver.mmmmm,v.vv

The m’s represent digits of the model number. The v’s represent the digits of the firmware version number. As an example, if the version number was 1.10 the response would be “ver.1502A,1.10".

The following IEEE-488.2 and SCPI compatible command can be used to read the manufacturer, model number, serial number, and firmware version number.

*IDN?<EOS> returns identification data for the instrument

The syntax of the response is as follows:

HART,1502A,<serial number>,v.vv

The v’s represent the digits of the firmware version number. As an example, if the serial number was 6A1202 and the version number was 1.10 the response would be “HART,1502A,6A1202,1.10".

7.3.6.2 Reading a List of Commands

The following command returns a list of commands:

H<EOS>

HELP<EOS> returns a list of commands

7 Digital Communications Interface

Remote Commands

Accessing the Calibration Parameters

8 Calibration Procedure

The 1502A uses a three-point calibration scheme with a quadratic polynomial correction function to maintain the accuracy of its resistance measurement. The

three calibration points are at 0Ω, 100Ω, and 400Ω. Three calibration pa

rameters determine the correction function: CAL0, CAL100, and CAL400. The CAL0 parameter sets the correction at 0Ω resistance (but does not affect the correction at 100Ω). The CAL100 parameter sets the correction at 100Ω resistance (but does not affect the correction at 0Ω). The CAL400 parameter sets the correction at 400Ω resistance (but does not affect the correction at 0 and 100Ω). Adjusting the calibration param eters directly affects the measurement at the specific resistances. For example, increasing the CAL100 parameter by 0.005 increases the measured value at 100Ω by 0.005Ω.

8.1 Accessing the Calibration Parameters

The calibration parameters are accessed in the Cal menu. The calibration parameters are protected by requiring the correct password to access them. Press

the Menu button, “SEt?” appears. Press the Ω/Exit button and hold it down for one second, “CAL” appears briefly. The display will show “PA= 0000”and allow you to change the number to the correct password. You must enter the

password (“2051”). Use the L and R buttons to move between the password digits and the U and D buttons to increase or decrease the value of a digit. Press Enter when all the digits are correct. If the password is entered correctly

the first parameter in the calibration menu will appear.

The first parameter in the Cal menu is the lockout control parameter, indicated on the display as “LOCOUt”. This parameter has two options, “CAL” and “ALL”. “CAL” (default) locks out the calibration menu only. “ALL” locks out

all menus and access to any menu requires the correct password. Use the L and R buttons to select the lockout option and press Enter to continue. The

instrument calibration parameters follow.

The calibration parameters appear with the name shown briefly then the value. You can change the sign and digits of each parameter. Use the L and R but tons to move between digits and the U and D buttons to increase or decrease the value of the digit. Press Enter to save the new value.

The last parameter in the Cal menu is the factory reset function. This can be used to clear the internal memory and reset all parameters to the defalut values. This is intended to be used only at the factory.

The calibration parameters can also be set using remote commands through the RS-232 or IEEE-488 interface. The *PA=<password><EOS> command must be used first, using the correct password (“2051”), to enable access to the cali bration parameters. Lockout protection is automatically set by cycling the

1502A Thermometer Readout

User’s Guide

power. The *C0=<value><EOS>, *C1=<value> <EOS>, and *C4=<value><EOS> commands can be used to set the values of the CAL0, CAL100, and CAL400 parameters respectively.

8.2 Calibration Procedure

Calibration requires four-wire 100Ω and 400Ω resistors of 6.25 ppm uncer

tainty and a 0Ω resistor (or short). For verification, 25Ω and 200Ω resistors of 10 ppm accuracy are also required. The resistors are connected to the input the same way probes are. The calibration procedure is as follows:

Connect a 0Ω resistor to the input and measure its resistance. Note the average error in the measurement. Adjust the CAL0 parameter by sub

tracting the measured error. For example, if the input is exactly 0.0000Ω and readout shows –0.0011Ω, the CAL0 parameter should be adjusted

by adding 0.0011 to it.

Connect a 100Ω resistor to the input and measure its resistance. Note the average error in the measurement. Adjust the CAL100 parameter by subtracting the measured error. For example, if the input is exactly

100.000Ω and the readout shows 100.029Ω, the CAL100 parameter should be adjusted by subtracting 0.029 from it.

Connect a 400Ω resistor to the input and measure its resistance. Note the average error in the measurement. Adjust the CAL400 parameter by subtracting the measured error. For example, if the input is exactly

400.000Ω and the readout shows 399.991Ω, the CAL400 parameter should be adjusted by adding 0.009 to it.

Verify the accuracy at 0Ω, 25Ω , 100Ω, 200Ω, and 400Ω. The accuracy should be within the short-term accuracy limits given in the specifications.

9 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 environments.

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 or the plastic of the outside shell.

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 an Authorized Service Center for more information.

• Before using any cleaning or decontamination method except those rec-

ommended by Hart, users should check with an Authorized Service Center to be sure that the proposed method will not damage the equipment.

• If the instrument is used in a manner not in accordance with the equip-

ment design, the operation of the thermometer may be impaired or safety hazards may arise.

9 Maintenance

10 Troubleshooting

In case you run into difficulty while operating the 1502A, this section provides some suggestions that may help you solve the problem. Below are several situa tions that may arise followed by possible causes of the problem and suggested actions you might take.

Incorrect Temperature Reading

While attempting to measure temperature the display shows an incorrect value.

If the temperature readings seem to be incorrect you should first check to see if the resistance is being measured correctly. Select ohms to display resistance. If the resistance is incorrect refer to the next subsection for troubleshooting incor rect resistance readings. If the resistance is being measured correctly but the displayed temperature value is incorrect consider the following possibilities.

One or more coefficients are incorrect. This is a common mistake.

•

While entering coefficients it is easy to miss a digit or sign. Check all the values carefully comparing them with the values on the calibration certificate for the probe.

• The selected conversion type is incorrect. Check to make sure the cor-

rect conversion type (ITS-90, RTD, or IPTS-68) is selected.

• The measurement is out of range. The 1502A may not be able to calcu-

late temperature accurately if the resistance is outside the valid range. The measured resistance may be too low or too high if the actual temperature is too low or too high or if there is a problem with the sensor (see below).

10 Troubleshooting

Incorrect Resistance Reading

While attempting to measure resistance the display shows an incorrect value. Consider the following possibilities.

•

Poor or incorrect connection of the probe. A common mistake is to connect the wires of the probe to the wrong terminals. Check the wiring carefully (see Figure 1 on page 12).

•

Open, shorted, or damaged sensor or lead wires. Check the resistance across the sensor using a hand-held DMM. Also check the resistance be tween common pairs of leads. Check to make sure there is no conductiv ity between any of the leads and the probe sheath. Use a good-quality sensor to avoid errors caused by drift, hysteresis, or insulation leakage.

•

Electrical interference. Intense radio-frequency radiation near the 1502A or the probe can induce noise into the measurement circuits resulting in erratic readings. The 1502A is intended to operate in a laboratory environ ment with limited radio-frequency noise. If interference seems to be a problem you might try eliminating the source of interference or moving the 1502A to a different location. A well-grounded, shielded cable should be used for the probe leads.

1502A Thermometer Readout

User’s Guide

Stem conduction error. The problem may be that the actual temperature

•

of the sensor is not what you expect. This is often the result of stem con duction where heat flowing through the stem of the probe to ambient af fects the temperature of the probe. It is very important that immersion probes be inserted to an adequately depth into the material being mea sured. Measuring temperature using a surface sensor can be especially difficult as the sensor is directly exposed to ambient.

Error Message at Power Up

The 1502A reports an error during the power up self-test.

On power up the 1502A performs a self-test of several of its key components. A failure of a component will cause an error message to be displayed such as “Err 4”. The possible error messages and their meanings are as follows:

Err 1Static RAM failure.

Err 2Nonvolatile RAM failure.

Err 3Internal data structure error.

Err 4ADC initialization failure.

Err 5ADC operation error.

Generally, each of these conditions require a qualified factory technician to replace a faulty component. Contact the factory for assistance. One possible exception might be if a large static discharge nearby disturbs the circuits. Cycling the power off and back on again may allow the 1502A to resume normal operation. Another might be if the AC source voltage is incorrect, e.g. using 115 V when the 1502A is configured for 230 V. Check the source voltage and the 1502A’s configuration and make sure they agree.

10.1 CE Comments

10.1.1 EMC Directive

Fluke Corporation, Hart Scientific Division’s equipment has been tested to meet the European Electromagnetic Compatibility Directive (EMC Directive, 89/336/EEC). The Declaration of Conformity for your instrument lists the spe cific standards to which the unit was tested.

The instrument was designed specifically as a test and measuring device. Com pliance to the EMC directive is through IEC 61326-1 Electrical equipment for

measurement, control and laboratory use – EMC requirements (1998).

As noted in the IEC 61326-1, the instrument can have varying configurations. The instrument was tested in a typical configuration with shielded, grounded probe and RS-232 cables. Emissions may, in non-typical applications, exceed the levels required by the standard. It is not practical to test all configurations, as the manufacturer has no control over the probes the user may connect to the instrument.

10.1.1.1 Immunity Testing

The instrument was tested to the requirements for industrial locations. This al lows the instrument to be used in all types of locations from the laboratory to the factory floor. Criterion C was used for Electrostatic Discharge (ESD, IEC 61000-4-2) and Electric Fast Transit (EFT, Burst, IEC 61000-4-4). If the instru ment is subjected to EFT conditions at 2kV, the instrument may require the user to cycle the power to return to normal operation.

10.1.1.2 Emission Testing

The instrument fulfills the limit requirements for Class A equipment but does not fulfill the limit requirements for Class B equipment. The instrument was not designed to be used in domestic establishments.

10.1.2 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 the IEC 1010-2-010 (EN 61010-2-010) standards.

10 Troubleshooting

CE Comments

Fluke 1502A User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Table of Contents

Figures

Tables