Hart Scientific 1502A Manuale utente
a
WARNING
To ensure the safety of operating personnel, and to avoid damage to this equipment:
DO NOT operate this unit without a properly grounded, properly polarized power cord.
DO NOT connect this unit to a non-grounded, non-polarized outlet.
DO USE a ground fault interrupt device.
WARNING
To ensure the safety of personnel, and to avoid damage to this equipment:
DO NOT use this unit in environments other than those listed in the user’s manual.
Follow all safety guidelines listed in the user’s manual.
WARNING
CALIBRATION EQUIPMENT SHOULD ONLY BE USED BY TRAINED PERSONNEL.
Table of Contents
1 Introduction. . . . . . . . . . . . . . . . . . . . . . 1
2 Specifications and Environmental Conditions . . . 3
2.1 Specifications . . . . . . . . . . . . . . . . . . . . . . . 3
2.2 Environmental Conditions . . . . . . . . . . . . . . . . 4
2.3 Warranty . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Safety Guidelines . . . . . . . . . . . . . . . . . . 7
4 Quick Start . . . . . . . . . . . . . . . . . . . . . . 9
4.1 Unpacking . . . . . . . . . . . . . . . . . . . . . . . . 9
4.2 Power . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.3 Connecting the Probe. . . . . . . . . . . . . . . . . . . 9
4.4 DC Power Option . . . . . . . . . . . . . . . . . . . . 10
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 . . . . . . . . . . . . . . . . . . . . . . 20
6.4.5.1 Setting the Characterization Coefficients . . . . . . 21
6.4.5.2 Testing the Coefficients . . . . . . . . . . . . . . . 21
6.5 Filtering . . . . . . . . . . . . . . . . . . . . . . . . . 21
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. . . . . . . . . . . . . . . . . . . . . . 24
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
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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 . . . . . . . . . . . . 29
7.3.2.2 Testing the Characterization . . . . . . . . . . . . . 30
7.3.3 Sample Commands . . . . . . . . . . . . . . . . . . . . . . . 30
7.3.3.1 Setting the Filter . . . . . . . . . . . . . . . . . . . 30
7.3.3.2 Setting the Probe Current . . . . . . . . . . . . . . 30
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 . . . . . . . . . . . . . . . . . . . . . 31
7.3.5.1 Entering the Password . . . . . . . . . . . . . . . . 31
7.3.5.2 Setting the Menu Lockout . . . . . . . . . . . . . . 31
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 . . . . . . . . . . . . 32
8 Calibration Procedure . . . . . . . . . . . . . . . 33
8.1 Accessing the Calibration Parameters . . . . . . . . . 33
8.2 Calibration Procedure . . . . . . . . . . . . . . . . . . 34
9 Maintenance . . . . . . . . . . . . . . . . . . . . 35
10 Troubleshooting . . . . . . . . . . . . . . . . . . 37
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Figures and Tables
Figure 1 Connecting a four-wire probe . . . . . . . . . . . . . . . . 10
Figure 2 12 V DC power source polarity . . . . . . . . . . . . . . . 11
Figure 3 1502A Front Panel . . . . . . . . . . . . . . . . . . . . . 13
Figure 4 1502A Back Panel . . . . . . . . . . . . . . . . . . . . . 14
Figure 5 Parameter Menu Structure . . . . . . . . . . . . . . . . . 16
Table 1 Matching Certificate Values to 1502A ITS-90 Coefficients . 18
Table 2 Setting Coefficients Rtpw, a5, and b5. . . . . . . . . . . . 19
Table 3 Setting Coefficients Rtpw, a8, b8, a4, and b4. . . . . . . . 19
Table 4 Setting Coefficients R(273.16), a6, b6, c6, and d . . . . . . 20
Figure 6 Serial Cable Wiring . . . . . . . . . . . . . . . . . . . . . 23
Table 5 Command List. . . . . . . . . . . . . . . . . . . . . . . . 27
Table 5 Command List Continued . . . . . . . . . . . . . . . . . . 28
1 Introduction
The Hart Model 1502A is a low-cost high-accuracy digital thermometer readout
designed to be used with 25Ωand 100ΩRTDs and SPRTs. Its unique combi-
nation of features makes it suitable for a wide variety of applications from labo-
ratory measurement to industrial processes. Features of the 1502A include:
•Measures 25Ωand 100ΩRTDs 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
•Optional 12 V DC power
•Light weight, small and portable
•Sturdy, reliable construction
1502A Manual Rev. 952801 1
1 Introduction
2 Specifications and Environmental
Conditions
2.1 Specifications
Specifications
Resistance Range 0Ωto 400Ω, auto-ranging
Resistance Accuracy, one
year1
0Ωto 20Ω: 0.0005Ω
20Ωto 400Ω: 0.0025% (25 ppm) of reading
Resistance Accuracy, short
term1, 2
0Ωto 30Ω: 0.0005Ω
30Ωto 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: 0.012°C
300°C: 0.015°C
400°C: 0.018°C
500°C: 0.021°C
600°C: 0.024°C
Temperature Coefficient of
Resistance1
1 ppm/°C
Resistance Resolution 0Ωto 20Ω: 0.0001Ω
20Ωto 400Ω: 0.001Ω
Temperature Resolution 0.001°C
Probe Nominal R(0.01°C): 25Ωto 100Ω
RTD, PRT, or SPRT
Probe Connection 4-wire with shield, 5-pin DIN connector
Maximum acceptable lead re-
sistance
100Ω
Probe Characterizations ITS-90 sub-ranges 4, 6, 7, 8, 9, 10, and 11
IPTS-68: R0,α,δ, a4, and c4
Callendar-Van Dusen: R0,α, δ, and β
Probe Excitation Current 0.5 and 1 mA , reverses every 0.25 seconds
Measurement Period 1 second
Digital Filter Exponential, 0 to 60 seconds time constant (user-selectable)
Communications RS-232 serial standard
IEEE-488 (GPIB) optional, conforms to IEEE-488.1, capability
AH1, SH1, T6, L4, DC1
Display 8-digit, 7-segment, yellow-green LED; 0.5 inch high characters
Clock accuracy, typical 0.01%
Operating Temperature
Range
Full accuracy: 16°C to 30°C
Absolute: 0°C to 55°C
AC power 115 VAC ±10%, 50/60 Hz, 10 VA, nominal
230 VAC ±10%, 50/60 Hz, 10 VA (optional)
Detachable power cord
DC power (optional) 10 to 14 VDC, 1 A maximum
(220 mA typical, normal mode; 120 mA typical, power saver
mode)
Size 5.6 inches (14.3 cm) wide x 7.1 inches (18.1 cm) deep x 2.4
inches (6.1 cm) high
Weight 2.2 lb. (1.0 kg)
1502A Manual Rev. 952801 3
2 Specifications and Environmental Conditions
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 cal-
ibration uncertainties.
3The temperature range may be limited by the sensor.
4Temperature accuracy is for the 1502A only. It does not include probe uncertainty or probe char-
acterization errors.
2.2 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:
•temperature range: Absolute 0–55°C (32–131°F); Recommended
16–30°C (61–86°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
4 Manual Rev. 952801 Hart Scientific
2 Specifications and Environmental Conditions
1502A Manual Rev. 952801 5
2 Specifications and Environmental Conditions
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