Omega Products HHMA2 Installation Manual

HHMA2

DC / TRUE RMS AC

NON-CONTACT MILLIAMMETER

Instruction Manual

Manual UN-01-249
Item 359934
April, 1999
Rev. -­OMEGA Engineering Inc.
All rights reserved.

This symbol appears on the instrument and probe. It

refers the operator to additional information

contained in this instruction manual, also identified

by the same symbol.

NOTICE:

See Pages 3-1 and 3-2

for SAFETY

instructions prior to first use !

Table of Contents

SECTION-1 INTRODUCTION

DESCRIPTION....................................................... 1-1

APPLICATIONS..................................................... 1-2

SECTION-2 SPECIFICATIONS

SPECIFICATIONS................................................. 2-1

SECTION-3 OPERATING INSTRUCTIONS

OPERATOR SAFETY....................................................... 3-1

OPERATING FEATURES................................................. 3-3

MEASUREMENT PROCEDURES..................................... 3-7

Instrument Preparation............................... 3-7

DC Current Measurements......................... 3-8

Low Frequency AC Current

Measurements........................................ 3-10

High Frequency AC Current

Measurements........................................ 3-11

Measurement Hints.................................... 3-11

GENERAL MAINTENANCE............................................... 3-13

SECTION-4 WARRANTY

i

List of Tables

Table 2-1 HHMA2 Specifications........................ 2-1

List of Illustrations

Figure 3-1 Conductor Voltage Limit Warning ........ 3-1

Figure 3-2 Bare Conductor Warning...................... 3-2

Figure 3-3 Auxiliary Power Connection Warnings.. 3-2

Figure 3-4 Product Features.................................. 3-3

Figure 3-5 Battery Installation and AC Adapter

Connection........................................

Figure 3-6 Probe Connection................................. 3-8

Figure 3-7 DC Zeroing Process.............................. 3-9

3-7

ii

Section 1

Introduction

DESCRIPTION

The HHMA2 is a battery-powered, clamp-on instrument that
measures dc and ac current as low as 1 mA and as high as 2000
mA, at frequencies up to 100 kHz. The HHMA2 consists of a
palm-sized meter and a detachable probe. The probe clamps
around the conductor to be measured. There is no need to
disconnect the conductor or to make physical contact with the
circuit being measured. The current-carrying conductor is
surrounded by a magnetic field that is proportional to the amount
of current that is flowing through it. The probe senses the
magnetic field and provides a signal to the meter. The meter
then translates this signal into a milliamp current value.

The probe features a unique aperture mechanism that retracts
easily and closes smoothly. The probe can accommodate
conductors up to 5.3 mm (0.21 in) in diameter.

The meter operates on two standard 9-volt alkaline batteries, or it
can be operated with an ac adapter. Two ranges can be selected
(199.9 mA or 1999 mA full scale) in addition to three modes of
measurement: dc, low-frequency ac or high-frequency ac. The
meter contains a 3 ½ digit display that provides dc and true rms
ac readings. In addition, an analog output provides a 1 mV / mA
voltage signal proportional to the current being measured. This
output can be connected to a voltmeter, oscilloscope or recorder.

The meter, probe and accessories are protected between uses
by a sturdy carrying case.

1-1

INTRODUCTION

APPLICATIONS

• Diagnosis and general maintenance of 4 - 20 mA process

control loops.

Troubleshooting of low-to-medium current devices in

•

automobiles, such as lamps, relays, motors and
communications lines.

Detection of leakage current in battery-operated devices.

•

Monitoring charge current in battery charging systems.

•

Testing of low level signal lines in electronic equipment.

•

Monitoring serial communications bit streams (RS-232).

•

1-2

Section 2

Specifications

ELECTRICAL

Range / Resolution: (displayed reading)

LOW (200 mA): 0.1 to 199.9 mA dc or rms ac
HIGH (2000 mA): 1 to 1999 mA dc or ac peak

Accuracy: (% of reading, ± 3 counts for the displayed reading or

± 0.15% of range for the analog output.
Meter zeroed prior to measurement in DC or
AC-LOW mode.)

dc: 1%
ac low: 2%
ac high (200 Hz - 400 Hz): 4%
ac high (400 Hz - 40 kHz): 2%
ac high (40 kHz - 100 kHz): 3%

Repeatability: 0.5% of reading, ± 3 counts for the

displayed reading or ± 0.15% of
range for the analog output.

Output noise: less than 100 µV rms

2-1

Table 2-1 HHMA2 Specifications

2-2

Frequency Range: (displayed reading)

dc: 0 Hz

ac low: 10 Hz to 200 Hz
ac high: 200 Hz to 100 kHz

Frequency Range: (analog output)

dc: 0 Hz to 200 Hz

ac low: 0 Hz to 200 Hz
ac high: 200 Hz to 100 kHz

Frequency response: (-3 dB point)

ac low: 400 Hz
ac high: 250 kHz

Rise Time:

ac low: 750 µs.
ac high: 1 µs.

Analog output scaling: 1 mV / mA

Analog output load: 10 kΩ min., 100 pF max.

Current • Frequency Limit: 80 A • kHz maximum

Probe Inductance: less than 1 µH

2-3