Hart Scientific 1502A Thermometer Readout User’s Guide Rev.
Limited Warranty & Limitation of Liability Each product from Fluke Corporation, Hart Scientific Division ("Hart") is warranted to be free from defects 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 repairs, and services are warranted for 90 days.
Table of Contents 1 Before You Start . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 1.2 Symbols Used . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.2.1 1.2.2 1.3 Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Cautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Authorized Service Centers. . . . . . . . . . . . . . . . . . . . . .
7 Digital Communications Interface . . . . . . . . . . . . . . . 23 7.1 Serial Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 7.1.1 7.1.2 7.1.3 7.1.4 7.2 Setting the Baud Rate . . . . . . . . . . . . Automatic Transmission of Measurements . Time Stamp and System Clock . . . . . . . Duplex Mode and Linefeed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Connecting a four-wire probe 1502A Front Panel . . . . . . 1502A Back Panel . . . . . . Parameter Menu Structure . . Serial Cable Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tables Table1 Table 2 Table 3 Table 4 Table 5 Table 6 Table 6 iv International Electrical Symbols . . . . . . . . . . . . . . . . . . . . . 1 Matching Certificate Values to 1502A ITS-90 Coefficients . . . . . . . 18 Setting Coefficients Rtpw, a8, b8, a4, and b4 . . . . . . . . . . . . . . 19 Setting Coefficients Rtpw, a5, and b5 . . . . . . . . . . . . . . . . . . 19 Setting Coefficients R(273.16), a6, b6, c6, and d . . . . . . . . . . . . 20 Command List . . . . . . . . . . . . . . . . . . . . . . . . .
1 Before You Start Symbols Used 1 1.1 Before You Start Symbols Used Table 1 lists the symbols that may be used on the instrument or in this manual Table1 International Electrical Symbols and the meaning of each symbol.
1502A Thermometer Readout User’s Guide Symbol Description On Canadian Standards Association OVERVOLTAGE (Installation) CATEGORY II, Pollution Degree 2 per IEC1010-1 refers 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.
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.
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.
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.
2 Introduction 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 features makes it suitable for a wide variety of applications from laboratory measurement 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.
3 Specifications and Environmental Conditions Specifications 3 3.1 Specifications and Environmental Conditions Specifications Resistance Range 0Ω to 400Ω, auto-ranging Resistance Accuracy, one year1 0Ω to 20Ω: 0.0005Ω 20Ω to 400Ω: 0.0025% (25 ppm) of reading Resistance Accuracy, short term1, 2 0Ω to 30Ω: 0.0005Ω 30Ω to 400Ω: 0.0015% (15 ppm) of reading Temperature Range3 –200°C to 962°C (–328°F to 1764°F) Temperature Accuracy1, 3, 4 –100°C: 0.004°C 0°C: 0.006°C 100°C: 0.009°C 200°C: 0.
1502A Thermometer Readout User’s Guide Weight 2.2 lb. (1.0 kg) Safety OVERVOLTAGE (Installation) CATEGORY II, Pollution Degree 2 per IEC 1010-1 1Accuracy specifications apply within the recommended operating temperature range. Accuracy limits are increased by a factor of the temperature coefficient outside this range. 2Short-term accuracy includes nonlinearity and noise uncertainties. It does not include drift or calibration uncertainties. 3The temperature range may be limited by the sensor.
4 Quick Start Unpacking 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.
1502A Thermometer Readout User’s Guide to pins 4 and 5. (Pins 1 and 5 source current and pins 2 and 4 sense the potential.) If a shield wire is present it should be connected to pin 3. Probe Connector 1 5 2 3 4 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.
5 Parts and Controls Front Panel Buttons 5 5.1 Parts and Controls Front Panel Buttons See Figure 2. The front panel buttons are used to select units of measurement, access operating 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.
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 computer 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.
6 General Operation Selecting Units 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.
1502A Thermometer Readout User’s Guide Menu Probe Sample Comm (Cal) Set probe type Set filter Set clock Enter password Pr= t90 FI= 4 11.23.30 PA= 0000 Set coefficients Set current Set time stamp Set menu lockout Cur= 1.0 ts= OFF LO=CaL Set power saver Set baud rate Set CAL0 PS= OFF 2400 b -0.0006 Test conversion Set sample period Set CAL 100 100.0000 00.00.01 +0.0128 Set duplex Set CAL 400 duP=FULL -0.
6 General Operation Selecting the Probe Characterization when all the digits are correct. If the password is entered correctly the first parameter in the menu will appear. 6.4 Selecting the Probe Characterization Before the 1502A can measure temperature accurately it must know how to calculate temperature from the resistance of the sensor. You must select a conversion type and enter the proper characterization coefficients. There are several temperature conversion algorithms available.
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 number as follows: E -04 Increase or decrease the exponent using the U and D buttons.
6 General Operation Selecting the Probe Characterization 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. Table 3 Setting Coefficients Rtpw, a8, b8, a4, and b4 1502A Coefficient Certificate Value R0.
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 values from the certificate as follows: Table 5 Setting Coefficients R(273.16), a6, b6, c6, and d 1502A Coefficient 6.4.4 Certificate Value R0.01 R(273.16K) A a6 B b6 C c6 D d A4 0.0 b4 0.
6 General Operation Selecting the Probe Characterization 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 coefficients are R0 (“r0”), α (“ALPHA”), δ (“dELtA”), a4 (“A4”), and c4 (“C4”). You can also select the temperature scale (“SCALE”) as IPTS-68 (“68”) or ITS-90 (“90”).
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 resolution.
7 Digital Communications Interface Serial Interface 7 Digital Communications Interface Remote communications allows an external device, such as a computer, to communicate 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 given in Section 7.3. 7.1 Serial Interface The 1502A is equipped with an RS-232 serial port.
1502A Thermometer Readout User’s Guide 7.1.2 Automatic Transmission of Measurements The 1502A can be programmed to automatically send measurements to a remote 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 parameter. The display will briefly indicate “SA PEr” and then display the current sample period. The sample period is specified in hours, minutes, and seconds.
7 Digital Communications Interface GPIB Interface 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 enables the time stamp and ST=OF disables it.
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 address of the 1502A is set within the Comm menu after the serial linefeed parameter. (This menu option will not appear if the IEEE-488 interface is not installed). Press the Menu button (“SEt?” appears) then press the Comm button.
7 Digital Communications Interface Remote Commands Table 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[=] read [or set]
1502A Thermometer Readout User’s Guide Command List Continued Command Description Calibration Commands *PA= disable password lockout of calibration commands *LO=[=CA|AL] read [or set] menu lockout *C0[=] read [or set] the 0Ω calibration parameter *C1[=] read [or set] the 100Ω calibration parameter *C4[=] read [or set] the 400Ω calibration parameter *SN[=] read [or set] the instrument serial number Miscellaneous Commands *VER read model number and firmwa
7 Digital Communications Interface Remote Commands 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 sets the sample period SA=0 disables automatic transmission of measurements The value of the sample period can be from 0 seconds to 24 hours.
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 selects the ITS-90 characterization P=68 selects the IPTS-68 characterization P=R or P=S selects the standard Callendar-Van Dusen characterization R0= sets R0 or R(0.
7 Digital Communications Interface Remote Commands 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= sets the filter time constant FI=0 disables the filter The value is the filter time constant in seconds. It must be between 0 and 60 inclusive. A value of 0 disables the filter. 7.3.3.
1502A Thermometer Readout User’s Guide LF=OF 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 enables the calibration commands Calibration parameters can be locked out again by sending *PA=0 or by cycling the power. 7.3.5.
7 Digital Communications Interface Remote Commands 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.
8 Calibration Procedure 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 parameters 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).
1502A Thermometer Readout User’s Guide power. The *C0=, *C1= , and *C4= 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 uncertainty 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.
9 Maintenance 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.
10 Troubleshooting 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 situations 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.
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 conduction where heat flowing through the stem of the probe to ambient affects the temperature of the probe. It is very important that immersion probes be inserted to an adequately depth into the material being measured.
10 Troubleshooting CE Comments 10.1.1.1 Immunity Testing The instrument was tested to the requirements for industrial locations. This allows 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 instrument is subjected to EFT conditions at 2kV, the instrument may require the user to cycle the power to return to normal operation. 10.1.
