ENGLISH User manual Copyright HT ITALIA 2017 Release EN 2.
HT79 Table of contents: 1. PRECAUTIONS AND SAFETY MEASURES ............................................................... 2 1.1. 1.2. 1.3. 1.4. 2. GENERAL DESCRIPTION ........................................................................................... 4 2.1. 2.2. 3. Measuring average values and TRMS values.................................................................. 4 Definition of true root mean square value and crest factor................................................
HT79 1. PRECAUTIONS AND SAFETY MEASURES The instrument has been designed in compliance with directive IEC/EN61010-1 relevant to electronic measuring instruments. For your safety and in order to prevent damaging the instrument, please carefully follow the procedures described in this manual and read all notes preceded by symbol with the utmost attention.
HT79 1.2. DURING USE Please carefully read the following recommendations and instructions: CAUTION Failure to comply with the caution notes and/or instructions may damage the instrument and/or its components or be a source of danger for the operator. Before switching on the clamp, remove the conductor from the clamp jaw. When the instrument is connected to the circuit being tested, do not touch any unused terminal.
HT79 2. GENERAL DESCRIPTION The instrument carries out the following measurements: DC and AC TRMS voltage up to 300V DC current from 0.1mA up to 10A AC TRMS current from 0.1mA up to 20A AC and DC leakage current Resistance and continuity test with buzzer Each of these functions may be selected through a 6-position rotary switch, including the OFF position and a key for enabling the HOLD function. The instrument also has a “MAX/MIN, “ZERO” and “ ” key. For their use, please refer to § 4.2.
HT79 3. PREPARATION FOR USE 3.1. INITIAL CHECKS Before shipping, the instrument has been checked from an electric as well as mechanical point of view. All possible precautions have been taken so that the instrument is delivered undamaged. However, we recommend generally checking the instrument in order to detect possible damage suffered during transport. In case anomalies are found, immediately contact the forwarding agent.
HT79 4. NOMENCLATURE 4.1. DESCRIPTION OF THE INSTRUMENT CAPTION: 1. Openable flexible jaws 2. Hand protection 3. Key 4. Jaw trigger 5. Rotary selector switch 6. ZERO key 7. MIN/MAX key 8. HOLD key 9. LCD display 10. Input terminal COM 11. Input terminal V 12. Battery cover fastening screw 13. Battery compartment cover Fig. 1: Description of the instrument 4.1.1.
HT79 4.2. DESCRIPTION OF THE SYMBOLS SHOWN ON THE DISPLAY CAPTION: 1. Auto Power OFF symbol 2. AC quantities symbol 3. DC quantities symbol 4. Active HOLD function 5. Active ZERO function 6. Resistance measuring unit 7. Active continuity test 8. Voltage measuring unit 9. Current measuring unit 10. Active MAX function 11. Active MIN function 12. Low battery symbol 13. Polarity indication Fig. 3: Display description 4.3. DESCRIPTION OF FUNCTION KEYS 4.3.1.
HT79 5. OPERATING INSTRUCTIONS 5.1. DC VOLTAGE MEASUREMENT CAUTION The maximum input DC voltage is 300V. Do not measure voltages exceeding the limits given in this manual. Exceeding these limits could result in electrical shocks to the user and damage to the instrument. Fig. 4: Use of the instrument for DC voltage measurement 1. Select the position. 2. Insert the red cable into input terminal V and the black cable into input terminal COM. 3.
HT79 5.2. AC VOLTAGE MEASUREMENT CAUTION The maximum input AC voltage is 300Vrms. Do not measure voltages exceeding the limits given in this manual. Exceeding these limits could result in electrical shocks to the user and damage to the instrument. Fig. 5: Use of the instrument for AC voltage measurement 1. Select the position. 2. Insert the red cable into input terminal V and the black cable into input terminal COM. 3. Position the test leads in the desired spots of the circuit to be measured (see Fig.
HT79 5.3. RESISTANCE MEASUREMENT CAUTION Before attempting any resistance measurement, remove power from the circuit under test and discharge all capacitors, if present. Fig. 6: Use of the instrument for Resistance measurement 1. Select the position. 2. Insert the red cable into input terminal V and the black cable into input terminal COM. 3. Position the test leads in the desired spots of the circuit to be measured (see Fig. 6). The display shows the value of resistance. 4. Symbol “OL.
HT79 5.4. CONTINUITY TEST CAUTION Before attempting any resistance measurement, remove power from the circuit under test and discharge all capacitors, if present. Fig. 7: Use of the instrument for Continuity test 1. Select the position. 2. Press the MIN/MAX key until the symbol “ ” is displayed. 3. Insert the red cable into input terminal V and the black cable into input terminal COM and carry out the continuity test on the object to be tested (see Fig. 7).
HT79 5.5. DC CURRENT MEASUREMENT CAUTION Before attempting any measurement disconnect all the test leads from the circuit under test and from the meter's input terminals. Fig. 8: Use of the instrument for DC current measurement 1. Select the position. 2. Press the ZERO key to zero residual magnetization current. 3. Insert the cable in the middle of the clamp jaws (see Fig. 8), in order to obtain accurate measures (see Fig. 2). The display shows the value of DC current. 4.
HT79 5.6. AC CURRENT MEASUREMENT CAUTION Before attempting any measurement disconnect all the test leads from the circuit under test and from the meter's input terminals. Fig. 9: Use of the instrument for AC current measurement 1. Select the position. 2. Insert the cable in the middle of the clamp jaws (see Fig. 9), in order to obtain accurate measures (see Fig. 2). The display shows the value of AC current. 3. Symbol “OL.” appearing on the display indicates the overload condition of the instrument. 4.
HT79 5.7. AC/DC LEAKAGE CURRENT MEASUREMENT CAUTION Insert the cable(s) in the middle of the clamp jaws, in order to obtain accurate measures (see § 4.1.1). Fig. 10: Use of the instrument for AC or DC leakage current measurement Measuring with direct method on earth leads 1. Select position (AC current) or (DC current) 2. To measure DC current, press the ZERO key to zero residual magnetization current. 3. Open the clamp jaws and connect the instrument as shown in Fig.
HT79 6. MAINTENANCE 6.1. GENERAL INFORMATION 1. While using and storing the instrument, carefully observe the recommendations listed in this manual in order to prevent possible damage or danger during use. 2. Do not use the instrument in environments with high humidity levels or high temperatures. Do not expose to direct sunlight. 3. Always switch off the instrument after use.
HT79 7. TECHNICAL SPECIFICATIONS 7.1. TECHNICAL CHARACTERISTICS Accuracy indicated as [%reading + (number of digits*resolution)] at 23°C±5°C, <80%RH DC Voltage (Autorange) Range Resolution Accuracy Input impedance Protection against overcharge 50.00V 300.0V 0.01V 0.1V (1.0%rdg + 2digits) 1M 300VDC/ACrms AC TRMS Voltage (Autorange) Range Resolution Accuracy Bandwidth Protection against overcharge 50.00V 300.0V 0.01V 0.1V (1.
HT79 7.1.3. General characteristics Mechanical characteristics Dimensions (L x W x H): Weight (batteries included): Clamp jaw opening: Max. cable diameter: Mechanical protection: 206 x 76 x 34mm (8 x 3 x 1in) 262g (9ounces) 23mm (1in) 23mm (1in) IP20 Power supply Battery type: Low battery indication: Battery duration (without backlight): 2x1.5V batteries type AAA IEC LR03 symbol “ ” on the display ca. 15 hours (DC current) ca. 60 hours (AC current and voltage) ca.
HT79 8. ASSISTANCE 8.1. WARRANTY CONDITIONS This instrument is warranted against any material or manufacturing defect, in compliance with the general sales conditions. During the warranty period, defective parts may be replaced. However, the manufacturer reserves the right to repair or replace the product. The manufacturer declines any responsibility for injury to people or damage to property.
