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 [email protected]
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 monoc rome COG (c ip 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 24 calculated by MicroLink
STORAGE MEMORY
Samples 21.504 (8 monitoring sequences) / 432 (snaps ot)
INTERFACES
ptical interfaces Serial, full duplex
Probe input Plug-and-play auto detection, connector LEMO™
GPS
Receiver
Sensitivity
-
163dBm, 48 c annels, L1 C/A code, update
rate 4Hz
Time to first position (TTFF) typical < 60 seconds
GENERAL SPECIFICATIONS
Recommended calibration interval 24 mont s
Battery
Alkaline
or rec argeable
NiMH,
4 x AA size (Mignon), 2800
mA
Battery operation time > 72 ore (backlig t and GPS off)
Charging time 4 ours
Battery level indication 100%, 66%, 33%, < 10%
perative 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 (wit out probe)
Weight Approx 400 g (including batteries wit out probe)
Accessories (included)
Rec argeable batteries, AC c arger, 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 mont s 24 mont s 24 mont s 24 mont s 24 mont s
perative 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 cm
2
) 30B 33B (100cm
2
)
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 mont s 24 mont s 24 mont s 24 mont s
perative 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 mont s 24 mont s 24 mont s
perative 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.

NHT310 4. Unit description
12
10
POWER key
ON / OFF: Switching the device on / off.
11
GPS key
ON / OFF: enables / disables the GPS receiver.
12 Blue LED indicating battery recharge.
13
RESET key
AVG: reset of time average value.
If pressed for
more than 10 seconds performs a reset of the
instrument, reinitializing all parame
ters and
deleting all stored data.
MAX: reset of the MAX measured value.
14
ALARM key
ON / OFF: enables / disables the acoustic alarm
of
exposure threshold exceeded.
15
FILTER key
ON / OFF: Enables / disables a
filter for low
frequency probes.
With the magneto-
static probes 10H or 33H, if the 3
axis display mode (X,Y,Z) is activated, the field
direction, positive or negative are also displayed.
16 ¼-
inch threaded hole for tripods or brackets
mounts
Tab. 4.1 – Front panel and keyboard legend

NHT310 4. Unit description
13
4.2 Connectors and interfaces legend
The tables below refer to connectors and interfaces available on the back and
at the top of the base unit.
Fig. 4.2 – Rear View
Item
Name Function
1 FIBER Fiber optic cable interface for connection to a
remote PC/Tablet
Tab. 4.2 – Rear interfaces
1

NHT310 4. Unit description
14
Fig. 4.3 – Top view
Item
Name Function
1 BARREL JACK Battery charge input
2 LEMO Probes Input connector
3 GPS GPS Antenna
Tab. 4.3 – Top interfaces
1 3
2
2

5 PREPARATION FOR USE
5.1 Unpacking
As soon as the instrument arrives at its destination, please carefully check the
packages to verify possible damages caused by shipment. If any damage is
found, inform Microrad immediately. It is recommended to keep the original
packages for a future return shipment due to, for instance, repairing or
resetting.
5.2 Storage
After the material contained in the packages has been inspected and it has
been verified for damages, it should be stored in its original packing until the
time of use. The storage deposit must be well protected and free from
humidity. If the instrument should be kept in storage for a long time, it is
advisable to insert hygroscopic substances (such as silicon gel salts) in the
package.
5.3 Connecting the probes
The probe is equipped with a LEMO “Push/Pull” connector. To connect it to the
NHT310 unit, push the probe plug straight down into the probe socket until it
clicks into place (the red mark on the probe plug must point towards the red
mark on the unit socket).
To disconnect the probe, slide the sleeve on the probe plug upwards and pull
the probe upwards to remove it.
PROBE PLUG
Fig. 5.1
WA
RNING: TO REMOVE DO NOT TURN THE PROBE !
SLIDE THE SLEEVE ON THE PROBE PLUG UPWARDS AND PULL THE PROBE
UPWARDS TO REMOVE IT.

NHT310 5. Preparation for use
16
5.4 Power supply
NHT310 operates both with NiMh rechargeable batteries (supplied) and with
alkaline dry batteries (4 x AA stylus). The battery charger delivered with the
instrument can be used to charge the rechargeable batteries supplied.
During the battery recharge cycle, the instrument can not be used for
measurements.
The batteries are usually delivered pre-charged, but they need a complete
charge before the first use. The full recharging time, very close to 100%, is
about 4 hours.
WARNING
Never connect the battery charger if dry batteries are installed!
This procedure can cause significant damage to the instrument!
Failure to do so will cause the warranty being declined!
During normal operation, the battery charge status is always displayed at the
top right of the screen.
Fig. 5.2
During the batteries charging cycle, the blue LED lights up.
Fig. 5.3