Microrad NHT-310 User Manual

NHT-310

User Manual

II

Release 2.5 June 2017

Design development and manufacturing

MICRORAD

P.zza delle Azalee 13/14
05019 Orvieto (TR) – ITALIA
Tel [phone]
Fax [phone]
email [e-mail]
web www.microrad.it

III

INDEX

1 GENERAL INFORMATION .............................................................................................. 1

1.1 Application .................................................................................................................... 1

1.2 About the instrument ..................................................................................................... 1

1.3 Operating modes ........................................................................................................... 1

1.3.1 Single EMF measurement .................................................................................... 1

1.3.2 Long-term Monitoring ........................................................................................... 2

1.3.3 NHT310 remote control through MicroLink software ............................................ 2

1.3.4 Downloading data to PC ....................................................................................... 2

1.4 Measurement probes .................................................................................................... 3

1.5 GPS module and temperature sensor ........................................................................... 3

1.6 Equipment configuration ................................................................................................ 4

1.7 NHT310 technical specifications .................................................................................... 5

1.7.1 NHT310 base unit ................................................................................................. 5

1.7.2 Measurement probes ............................................................................................ 6

1.8 Standard compliance ..................................................................................................... 7

2 SAFETY INSTRUCTIONS ............................................................................................... 8

2.1 Foreword ....................................................................................................................... 8

2.2 Correct use ................................................................................................................... 8

3 CERTIFICATION AND WARRANTY ................................................................................ 9

3.1 Certification ................................................................................................................... 9

3.2 Warranty ....................................................................................................................... 9

3.3 Limitation of warranty .................................................................................................... 9

4 UNIT DESCRIPTION ..................................................................................................... 10

4.1 Front panel legend ...................................................................................................... 10

4.2 Connectors and interfaces legend ............................................................................... 13

5 PREPARATION FOR USE ............................................................................................. 15

5.1 Unpacking ................................................................................................................... 15

5.2 Storage ....................................................................................................................... 15

5.3 Connecting the probes ................................................................................................ 15

5.4 Power supply ............................................................................................................... 16

5.4.1 Battery autonomy ............................................................................................... 17

5.4.2 Battery replacement ........................................................................................... 17

6 OPERATION .................................................................................................................. 18

6.1 Base unit switching on ................................................................................................. 18

6.2 Main measuring display screen ................................................................................... 20

6.3 Recording measured value .......................................................................................... 23

6.3.1 Single storing ...................................................................................................... 23

6.3.2 Monitoring........................................................................................................... 24

6.4 Measurement download and display ........................................................................... 25

6.5 Spatial Average Mode ................................................................................................. 25

6.6 Alert levels .................................................................................................................. 26

6.7 Factory reset ............................................................................................................... 27

IV

7 MICROLINK SOFTWARE .............................................................................................. 28

7.1 Description .................................................................................................................. 28

7.2 Software installation .................................................................................................... 28

7.3 Software main screen .................................................................................................. 28

7.4 Functions .................................................................................................................... 29

7.5 NHT310 parameters setting (Settings) ........................................................................ 30

7.6 Download data from NHT310 (Download) ................................................................... 32

7.6.1 SnapShots panel ................................................................................................ 33

7.6.2 Monitoring panel ................................................................................................. 34

7.6.3 Monitoring data graphic format ........................................................................... 36

7.7 Microsoft Excel™ data export ...................................................................................... 38

7.8 NHT310 remote control ............................................................................................... 39

7.9 GPS and Google Maps ............................................................................................... 39

7.10 NHT310 firmware update ......................................................................................... 41

APPENDIX A COMMUNICATION PROTOCOL ................................................................ 42

1 GENERAL INFORMATION

1.1 Application

Human exposure to electromagnetic fields (not ionizing radiation) is nowadays
a very critical subject with which almost all countries must deal. Technical and
normative bodies work alongside government institutions to enact new
guidelines and decrees regarding maximum permitted exposure levels for
populations and workers.

The measurement equipment for this type of analysis must suit the technical
requirements from the guidelines and must provide the user with qualified
physical parameters for compliance with legally required thresholds.

1.2 About the instrument

NHT310 is the new Microrad solution for the measurement of electromagnetic
fields. Besides being handy and compact, the instrument operates in the
widest frequency band possible for a handheld instrument.

It is user-friendly and provides extremely reliable measurements; it also
provides the operator with local temperature and GPS coordinates of the site
being measured for inclusion in a final report.

1.3 Operating modes

1.3.1 Single EMF measurement

The main application of NHT310 is to perform wideband electromagnetic field
measurements allowing the user to make evaluations in relation to established
protective safeguards. The system uses a variety of probes to measure
specific physical parameters (magnetic induction, magnetic field and electric
field) according to the frequency band of interest.

On the instrument LCD display, are always displayed:

 Instantaneous isotropic value ISO of measured field.
 Time average isotropic value (AVG) of measured field.
 Spatial average value SPT of measured field.
 Maximum isotropic value MAX of measured field.
 Alarm threshold ALM.
 Geographic coordinates GPS.
 Ambient temperature.
 Date and time.

The instrument can be used in direct operating mode via the front keyboard
panel and the measurements can be viewed on the LCD display. The user can
store single measurement data by pressing the [STORE SINGLE] command.
Each measured value is stored in a specific memory portion for single

NHT310 1. General information

2

measurements (for a total of 432 measurements) along with the information
regarding date and time, GPS coordinates, and ambient temperature.

1.3.2 Long-term Monitoring

NHT310 can perform up to 8 data acquisition sequences for long-term
monitoring of broadband electromagnetic fields. This mode is particularly
useful for low frequency magnetic induction measurements, since it is possible
to follow the possible fluctuation of field values depending on the daily
variation of the current flow in the electric lines or in the transformation cabins
(field source).

The user can initiate the acquisition sequence by simply pressing the [SHIFT]
key and then the [STORE MONIT] key.

Each monitoring can extend to full memory space (over 21’500 acquisitions) or
until the user wishes to interrupt the process by pressing any key on the
instrument.

1.3.3 NHT310 remote control through MicroLink software

This operation mode is recommended in order to avoid where possible the
influence of the user's presence on the environment being measured (mainly
for low and high frequency electric field analysis) or when there is a
requirement to install the measurement system in a screened and controlled
space (anechoic chamber for EMC testing). In such a situation it is strongly
recommended that a wooden tripod with variable height (optional) is used.

NHT310 can be remotely managed through a fiber optic connection to an
external PC. This operation is possible with the MicroLink software. MicroLink
allows the total remote control of the NHT310 unit by displaying on PC screen
the same keys of the instrument keyboard, making the system easy to use.

The software displays the measured data in real time and simultaneously
displays the amplitude / time graph of the field being analyzed.

In remote mode, it is possible to store single data or to start and stop
monitoring sequences.

1.3.4 Downloading data to PC

All measured values, recorded both as single acquisition or continuous
monitoring, can be downloaded to an external PC through the fiber optic cable
using MicroLink software.

Once the values have been transferred, they can be viewed and analyzed
within the MicroLink software and saved on a hard disk or other mass storage
units for later reference.

The software allows the numeric and tabular display of the field values as well
as the display of amplitude / time diagram with zoom function in the time
window of interest.

NHT310 1. General information

3

Data export in tabular format (Excel compatible) and graphics, jpeg or bitmap
format, is also possible.

Using MicroLink software, the user can send configuration data to the device
in order to set the threshold for a high field acoustic alarm, set the sampling
interval between an acquisition and the next in long-term monitoring, set the
time interval to calculate the moving average with high frequency probes
(default value is 6 minutes as per international regulations), set the date and
time.

MicroLink is also able to calculate the 24-hour moving average on monitoring
sequences that exceed that duration.

1.4 Measurement probes

Various measurement probes are available for use in conjunction with NHT310
for both magnetic and electric field measurements, with frequency bands
ranging from dc up to 40 GHz.

The NHT310 automatically recognizes each probe when it is inserted.
A detailed list of available probes is given in section 1.7.2.

1.5 GPS module and temperature sensor

NHT310 integrates a GPS module to acquire geographic coordinates as
reference to the area in which the measurements were carried out.

In case of outdoor activities, it is always recommended to add the GPS data
related to the measurement site in order to mention them in the final report.
GPS associates not only geographic information but also the exact time (UTC
time).

No other external device is required to perform these operations as the
NHT310 performs the measurement and automatically provides field values
together with GPS coordinates of the site. The MicroLink software can directly
show them on Google Maps™.

In addition NHT310 integrates a temperature sensor acquiring the
temperature value during measurement activity.

Since the sensor is integrated into the front of the instrument, it is necessary to
consider that, as the meter shell is a good thermal conductor, the
measurement may be influenced by the operator's hand temperature. In order
to have exact temperature values, the instrument must be used with a tripod
support.

NHT310 1. General information

4

1.6 Equipment configuration

The basic unit NHT310 is delivered in the standard configuration including:

 NHT310 basic unit for measuring, storing and display field data
 Fiber optic cable (10 meters length)
 Fiber-USB adapter to link fiber optic to PC
 USB A/B adapter cable
 Battery charger
 Rechargeable batteries
 Sturdy carrying case with IP67 protection class
 MicroLink software and user manual (available on www.microrad.it)
 ISO 9001:2008 calibration certificates

In order to work correctly, the NHT310 meter must be connected to a
measurement probe from those available for this model.

NHT310 1. General information

5

1.7 NHT310 technical specifications

1.7.1 NHT310 base unit

PROBE TYPE

Frequency range From DC to 18GHz using several B, E, H probes

DISPLAY

Type Transflective LCD monochrome COG (chip on glass)

Size 7 cm , 128x64 dots

Backlight Electroluminescent screen 10s/continuous selectable

MEASUREMENT FUNCTIONS

Measurement units mW/cm², W/m², V/m, A/m, Tesla

Display range

from 0.0001 to

999999 (

depending on

probe

and

measurement unit)

Result type (isotropic, RSS)

I

nstantaneous (ACT), Maximum

(MAX),

Average (AVG),

Median

Time average 6min std, from 4s to 30 min (step 2s ), software selectable

Moving average 24h calculated by MicroLink

STORAGE MEMORY

Samples 21.504 (8 monitoring sequences) / 432 (snapshot)

INTERFACES

Optical interfaces Serial, full duplex

Probe input Plug-and-play auto detection, connector LEMO™

GPS

Receiver

Sensitivity

-

163dBm, 48 channels, L1 C/A code, update

rate 4Hz

Time to first position (TTFF) typical < 60 seconds

GENERAL SPECIFICATIONS

Recommended calibration interval 24 months

Battery

Alkaline

or rechargeable

NiMH, 4 x AA size (Mignon), 2800

mAh

Battery operation time > 72 ore (backlight and GPS off)

Charging time 4 hours

Battery level indication 100%, 66%, 33%, < 10%

Operative Temperature range -10 °C to +50 °C

Storage Temperature range -20 °C to +70°C

Humidity 5 to 95%, non-condensing

Size (h x w x d) 160 x 98 x 30 mm (without probe)

Weight Approx 400 g (including batteries without probe)

Accessories (included)

Rechargeable batteries, AC charger, fiber optic cable

(10mt), USB-Optical Converter, User manual, MicroLink
software, probes calibration certificate

Note: technical specifications are subject to change without any prior notice.

NHT310 1. General information

6

1.7.2 Measurement probes

Radio-frequency probes

P/N Probe 01E 02E 02H 03E 04E

Frequency range 100 kHz - 6.5 GHz 400 kHz - 30 MHz 300 kHz - 30MHz 100k Hz - 18GHz 3 MHz - 40GHz

Frequency Response Flat Flat Flat Flat Flat

Measurement range 0.2 - 350 V/m 2 - 800 V/m 0.016 - 16 A/m 0.8 - 340 V/m 0.5 - 350 V/m

Directivity Isotropic Isotropic Isotropic Isotropic Isotropic

Calibration interval 24 months 24 months 24 months 24 months 24 months

Operative temperature 0°C - 50°C 0°C - 50°C 0°C - 50°C 0°C - 50°C 0°C - 50°C

Low-frequency probes

P/N Probe 11E e 33E 10B 20B (100 cm2) 30B 33B (100cm2)

Frequency range 5Hz - 400 kHz 5 Hz - 400 kHz 5 Hz - 20 kHz 5 Hz - 400 kHz

Frequency Response Flat Flat Flat Flat

Measurement range 20 V/m - 20KV/m 0.1 µT - 1 mT 0.3 µT - 16 mT 0.3 µT - 16 mT

Directivity Isotropic Isotropic Isotropic Isotropic

Calibration interval 24 months 24 months 24 months 24 months

Operative temperature 0°C - 50°C 0°C - 50°C 0°C - 50°C 0°C - 50°C

Static probes

P/N Probe 10H e 33H 20H 30H

Frequency range DC DC - 1 kHz DC - 1 kHz

Frequency Response n/a Flat Flat

Measurement range 150 nT – 2.5 mT 1 mT – 5 T 200 µT - 600 mT

Directivity Isotropic Isotropic Isotropic

Calibration interval 24 months 24 months 24 months

Operative temperature 0°C - 50°C 0°C - 50°C 0°C - 50°C

Note: technical specifications are subject to change without any prior notice.

NHT310 1. General information

7

1.8 Standard compliance

ESD e EMC

Electrical equipment for measurement, control and

laboratory use. EMC requirements: radiating emission,

radiating immunity in radio frequency, electrostatic

discharge.

CEI EN 61326

SAFETY

Safety requirements for electrical equipment for

measurement, control and laboratory use – General

requirements.

CEI EN 61010

CE MARK

European Union

OK

Country of origin

ITALY

2 SAFETY INSTRUCTIONS

2.1 Foreword

The following general safety precautions must be observed during all phases
of operation, service, and repair of this instrument. Failure to comply with
these precautions or with specific WARNINGS elsewhere in this manual may
impair the protection provided by the equipment. Such non compliance would
also violate safety standards of design, manufacture, and intended use of the
instrument.

2.2 Correct use

• Keep away from live circuits
Operators must not remove instrument covers. Component replacement and

internal adjustments must be made by qualified maintenance personnel. Do
not replace components with the power cable connected. Under certain
conditions, dangerous voltages may exist even with the power cable removed.
To avoid injuries, always disconnect power and discharge circuits before
touching them.

• DO NOT substitute parts or modify instrument
To avoid the danger of introducing additional hazards, do not install substitute

parts or perform unauthorized modifications to the instrument. Return the
instrument to Microrad Service Center for service and repair to ensure that
safety features are maintained in operational condition.

3 CERTIFICATION AND WARRANTY

3.1 Certification

Microrad certifies that this product met its published specifications at the time
of shipment from the factory. Microrad also certifies that each probe for the
NHT310 instrument has been calibrated according to DIN EN ISO 9001: 2008.
On request, SIT certification is available, covering magnetic and electric field
strength and high frequency electromagnetic power density, and OKD
certification for magnetic induction intensity and low frequency electric field.

3.2 Warranty

This Microrad product is warranted against defects in material and
workmanship for a period of 24 months. Accessories are warranted for a
period of 6 months. During the warranty period, Microrad will, at its option,
either repair or replace products that prove to be defective.

For warranty service or repair, this product must be returned to Microrad.
Microrad warrants that its software and firmware, designated by Microrad for

use with an instrument, will execute its programming instruction when properly
installed on that instrument.

3.3 Limitation of warranty

The foregoing warranty shall not apply to defects resulting from: improper use
or inadequate maintenance by User, User-supplied software or interfacing,
unauthorized modification or misuse, operation outside the environmental
specifications for the product, or improper site preparation or maintenance.

4 UNIT DESCRIPTION

4.1 Front panel legend

The following table refers to Figure 4.1 which shows the keyboard and the
main parts on the NHT310 base unit front panel.

Some keys have a second function, indicated in blue, which can be enabled
by pushing the middle button SHIFT in advance.

Fig. 4.1 – Front view

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

NHT310 4. Unit description

11

Item

Name Function

1

GPS Antenna

2

Probes Input connector

3

Battery charge input

4

Backlit display

5

Temperature sensor

6

MODE key
UNIT: changes the field measurement unit.

Pressing the button for 10 seconds

it is possible to

change the temperature unit from °C to °F and vice

versa.

AXES: visualizza i singoli assi X, Y, Z.

7

STORE key

SINGL: storing a single measuring value. If

pressed for more than 2 seconds, initiates a
countdown sequence before starting the store. If
pressed for more than 4 seconds enables/disables
the spatial average mode.

MONIT: start a monitoring sequence.

8

LIGHT key

TEMP: Temporary backlight of 10 s.

CONT: Continuous backlight.

9

SHIFT key

SHIFT: Enables all blue defined functions.