ETS-Lindgren HI-4457 User Manual

Archived 4/2/10

HI-4457

Isotropic Magnetic Field Probe

User's Manual

Copyright

Manual #600080 2/00 $12.50

1999 by Holaday Industries, Inc.

©

Revision Record

Archived 4/2/10

Manual #600080

HIn4457 Isotropic Magnetic Field Probe

Revision Description Date

--- Release 3/98
A Changed Specification 1/99
B Changed Charger Specs 8/99
C Changed Area Code 2/00

TABLE OF CONTENTS

Archived 4/2/10

1.0 DESCRIPTION ...................... 1

Introduction ....................... 1

2.0 HInn4457 SPECIFICATIONS ............ 3

3.0 ACCEPTANCE AND CONTROLS ......... 5

Introduction ....................... 5

Unpacking and Acceptance ............ 5

Probe ........................... 5

XMIT/RCV .................... 5

ARM/OFF ..................... 6

CHARGER ...................... 7

Battery .......................... 7

4.0 BATTERY CHARGING ................ 9

Introduction ....................... 9

Charging Procedure .................. 9

Battery Tips ....................... 10

5.0 MAINTENANCE .................... 11

Introduction ....................... 11

Maintenance Recommendations ......... 11

Upgrade Policies .................... 11

Return Procedures ................... 11

Periodic/Preventive Maintenance ......... 13

Parts Information ................... 13

6.0 THEORY OF OPERATION .............. 15

Introduction ....................... 15

System Theory ..................... 15

Probe Operation .................... 17

Probe Power Supply ................. 18

Zeroing .......................... 18

7.0 APPLICATION CONSIDERATIONS ........ 21

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Introduction ....................... 21

Out-of-Band Considerations ............ 21

Resolution Limitations ................ 21

Probe Support Structures .............. 21

APPENDIX A

ERROR CODES ......................... 23

Probe Error Output .................. 23

APPENDIX B

HInn4457 OPERATING PROTOCOLS .......... 25

Introduction ....................... 25

Communication Protocol .............. 25

Information Transfer Protocol ........... 25

Command Structure ................. 25

Commands ........................ 26

Probe Output ...................... 27

Limited Warranty

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Holaday Industries, Inc. warrants each model HIn4457 Isotropic
Magnetic Field Probe to be free from defects in material and
workmanship for a period of one year from the date of shipment
to the purchaser. This warranty extends to the original purchaser
only, and does not apply to the batteries or to any products or
parts subject to misuse, neglect, accident, unauthorized service
or abnormal conditions of operation.

In the event an instrument covered by this warranty fails,
Holaday Industries, Inc. will, without charge, repair and
recalibrate the instrument if returned to their factory within one
year of the original purchase-provided that Holaday Industries'
examination discloses, to its satisfaction, that the product is
defective. Holaday Industries, Inc., may, at its option, replace
the product in lieu of repair. If the defect was caused by misuse,
neglect, accident, unauthorized service or abnormal conditions of
operation, repairs will be billed at a nominal cost. In such cases,
an estimate will be provided before work is started, if requested
by the purchaser.

For warranty service, contact Holaday Industries, Inc. Provide
the serial number of the instrument and complete details
regarding the failure mode. You will then be given either service
information or shipping instructions. Return the instrument to
the factory, transportation prepaid. Repairs will be made at the
factory and the instrument will be returned to you, transportation
prepaid. Holaday Industries, Inc., assumes no responsibility for
loss of, or damage to, products in transit.

Warning!

EXTREME CAUTION IS ADVISED WHEN WORKING IN
ENVIRONMENTS WHERE HIGH-INTENSITY ELECTROMAGNETIC
FIELDS MAY EXIST AND WHERE CONTACT WITH HIGH VOLTAGE
OR HIGH CURRENT CIRCUITS OR APPARATUS IS POSSIBLE.
ACCIDENTAL CONTACT WITH OBJECTS OR CIRCUITS OPERATING
AT HIGH VOLTAGES OR HIGH CURRENTS CAN BE LETHAL!
HOLADAY INDUSTRIES, INC. ASSUMES NO LIABILITY FOR ANY
DAMAGES OR PERSONAL INJURY WHICH MAY RESULT FROM

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1.0 DESCRIPTION

Introduction

The HI-4457 RF Magnetic Field probe is a broadband
isotropic sensor suitable for a wide range of
RF/microwave measurements. The high frequency
response of this probe makes it well suited for near field
measurements in the higher frequency bands approaching
1,000 MHz.

Applications include health and safety monitoring. The HI­4457 probe is optically isolated to minimize field
perturbation during measurements.

The HI-4457 probe assembly consists of a conical casing,
containing the sensor, which is mounted on one end of a
shaft; the other end of the shaft is attached to an
extrusion which houses the electronics (Figure 1n1).
The sensor and electronics housing operate - and are
calibrated - as a unit.

The HI-4457 sensor consists of three mutually orthogonal
(perpendicular) magnetic field sensors. The magnetic
field components in each of these directions are summed
as vectors and the resultant field value (magnitude)
transmitted via the fiber optic cable to the receiver (HI­4416 System Readout or HI-4413P RS-232 Computer
Interface).

The frequency response of the HI-4457 extends from 10
MHz to 1 GHz. The dynamic range of the probe extends
from 0.3 mW/cm2 to 265 mW/cm2.

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Figure 1-1

HI-4457 Probe

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2.0 HInn4457 SPECIFICATIONS

Dynamic Range: 0.03-2.6 A/m (0.02 to 265

mW/cm2)

Ranges: 0.08, .265, 0.838, 2.65

Ampers/meter full scale

User Selectable
Readout Units: A/m, A2/M2, mW/cm

2

Frequency
Response: 10 MHz to 1 GHz +0.5, -2 dB

27 MHz to 500 MHz ±1.0 dB

Linearity: ± 0.5 dB full scale (F.S.): ± 2

least significant bits (LSBs) of A/D
converter

Isotropicity: ± 1 dB

Average Overload: 1 W/cm

Peak Overload: 100 W/cm

2

2

Pulse Energy
Density Overload: 300 W-µsec/cm

2

Electric Field
Rejection: >20 dB

Environmental:

Operating Temp.: 10 °C to 40 °C (50 °F to 104 °F)
Humidity: 5% to 95% relative humidity,

non-condensing

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Fiber Optic Cable
Connectors: Standard FSMA

Battery: 3.6 VDC, 1400 mA-h

rechargeable Nickel-Cadmium
(NiCd)

Battery Charger: 115/230 VAC, approximately 1

hour

Battery Life: 17 Hours continuous (full charge)

Probe Mount: ¼ n 20 UNC tapped hole (internal

thread) in base of probe

Size:
Length (including
electronics housing): 419 mm (16.5 in)
Probe diameter: 76 mm (3.0 in)

Weight: 0.54 Kg (19 oz.)

Optional Equipment: See Table 5n2

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3.0 ACCEPTANCE AND CONTROLS

Introduction

This section contains information on: unpacking and
acceptance of the HIn4457; probe controls; probe
connectors; the battery, and the battery charger.

Unpacking and Acceptance

Step 1. Upon delivery of your order, inspect the

shipping container(s) for evidence of damage.
Record any damage on the delivery receipt
before signing. In case of concealed damage
or loss, retain the packing materials for
inspection by the carrier.

Step 2. Remove the probe from its shipping

containers. Save the boxes and any protective
packing materials for future use.

Step 3. Check all materials against the packing list to

verify that the equipment received matches
that which was ordered. If you find any
discrepancies, note them and call Holaday
Customer Service for further instructions.

Be sure that you are satisfied with the contents of your
order and the condition of your equipment before
installing the probe.

Probe

A switch, two fiber optic connectors and a battery
charger connector are mounted on the HIn4457
electronics housing (Figure 3n1).

XMIT/RCV The fiber optic cable assembly from the

receiver is attached to the probe via two

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connectors. The cables are color-coded-white
for XMIT, yellow for RCV. Identically-colored
dots are located on the electronics housing
adjacent to these connectors. Be sure that
each cable is attached to the proper probe
connector.

Figure 3nn1

Switch and Connectors

When the fiber optic cables are not attached,
always cover the probe connectors with the
protective plastic covers supplied with the
unit, or with similar material. This prevents
dirt or other contaminants from entering the
connector and causing communication
problems.

ARM/OFF The ARM/OFF switch activates and

deactivates the probe. In the ARM position,
the probe is powered by its internal 3.6 VDC
NiCd battery: in the OFF position, the probe is
inactive. To prolong battery life, set the
ARM/OFF switch to OFF at the end of a test
sequence or when the probe is not in use.

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CHARGER A standard fast charger is supplied with the

HIn4457. When charging is complete, the
fast charger acts as a trickle charger. The
battery can be left on this maintenance mode
indefinitely and it’s performance will not
degrade.

Battery

The NiCd battery provides up to 17 hours of probe
operation when fully charged.

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4.0 BATTERY CHARGING

Introduction

Each HIn4457 probe contains a rechargeable nickel­cadmium (NiCd) battery. A fully-charged battery (nominal
output voltage of 3.6 VDC) provides up to 17 hours of
continuous operation.

NOTE

Holaday Industries, Inc., charges the internal NiCd
battery of the HIn4457 at the factory in order to
calibrate the probe prior to shipment. While every
effort is made to ensure that your probe arrives ready
to use, we cannot guarantee that this will be the
case. Always check the condition of the probe's
battery prior to making any measurements. To check
probe battery voltage, refer to the operation of the
BAT keypad in Section 8.0 of the HIn4416 User's
Manual.

Charging Procedure

Step 1. Plug the charger into a suitable AC source.

Step 2. Set the probe switch to OFF. Insert the plug

on the charger cable into the probe's
CHARGER jack.

Step 3. The battery is now charging. This may take

approximately 1 hour, depending on how
deeply the batteries are discharged. When
charging is complete, the charger
automatically goes into a trickle charge and
will continue to do so until the probe is
disconnected.

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Battery Tips

NiCd batteries have several characteristics that can affect
both their performance and operating life. The following
tips advise you how to take advantage of these
characteristics to get the most out of your probe’s
battery.

! Although NiCd batteries are rated for operation in

temperatures from -20 °C to +65 °C (-4 °F to +140
°F), operating the probe in extreme temperatures will
reduce operating time significantly. The optimum
operating temperature range for these batteries is
+20 °C to +30 °C (+68 °F to +86 °F).

! The battery in the HIn4457 probe does not require

periodic "deep discharges" to reverse the capacity­depleting "memory effect" caused by repeated
shallow discharges; however, undercharging can
reduce battery capacity. Therefore, after the charging
procedure is complete, be sure that the battery is fully
charged before resuming field operation.

! If the battery exhibits low terminal voltage during

charging, or if it appears unable to acquire or maintain
an appreciable charge, individual cells in the battery
may be shorted or damaged. If, for any reason, your
battery needs replacement, contact Holaday Customer
Service for assistance.

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5.0 MAINTENANCE

Introduction

This section explains which maintenance tasks can be
performed by the user. It also provides information
regarding replacement and optional parts. If you have
any questions concerning probe maintenance, consult
Holaday Customer Service.

Maintenance Recommendations

Maintenance of the HIn4457 probe is limited to external
components such as cables or connectors.

Any calibration or maintenance task which requires probe
disassembly should be performed at the factory. Check
with Holaday Customer Service (952-934-4920) before
opening the unit to avoid problems with your probe's
warranty.

NOTE

Opening the probe enclosure may void your
warranty. If your system is still under
warranty, contact Holaday Customer Service
before performing any maintenance inside the
probe.

Upgrade Policies

Periodically, probes are upgraded to enhance
functionality. These upgrades are commonly announced
through Holaday Engineering Bulletins.

Return Procedures

To return a probe to Holaday, use the following
procedures:

Step 1. Briefly describe the problem in writing. Give

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details regarding the observed symptom(s), and
whether the problem is constant or intermittent
in nature. If you have talked previously to
Holaday Customer Service about the problem,
provide the date(s), the name of the service
representative you spoke with, and the nature
of the conversation. Include the serial number
of the item being returned.

Step 2. The sensor and electronics housing are

engineered to operate as a unit and MUST be
returned together. Carefully package the probe
assembly in the carrying case. Use the original
boxes and packing materials, if possible. If not,
use the Parts List in Table 5n1 to order new
boxes and foam packing from Holaday
Industries, Inc.

NOTE

If your probe is calibrated in accordance with
MIL-Std-45662A, it is greatly to your benefit
to retain the original shipping box and packing
materials. One of the criteria for certifying a
calibration to MIL standards requires Holaday
Industries to always ship equipment in the
specified packaging. When a MIL Standard
instrument is sent to Holaday in other
packaging, we must replace it with the
specified packaging materials for return
shipment. YOU WILL BE BILLED FOR THE
NEW PACKAGING.

If the probe is under warranty, refer to the Limited
Warranty at the front of this manual for additional
information about your return.

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Periodic/Preventive Maintenance

The HIn4457 probe assembly (sensor and electronics
housing) require an annual calibration check to verify that
they are performing within specifications. This calibration
check may be performed at the factory by Holaday
Service Personnel. Return your probe(s), using the
original packing materials (if possible), to:

Holaday Industries Inc.

Attn. Service Department

14825 Martin Drive

Eden Prairie, MN USA 55344

Parts Information

Use the following tables for ordering replacement (Table
5n1) or optional (Table 5n2) parts for HIn4457 probes.

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Table 5nn1 Replacement Parts List

Part Description (Replacement Parts) Part

Number

Battery Pack, 3.6 VDC, Rechargeable 491038
Standard Fast Charger (115/230

Volt)
Cable, Fiber Optic, Glass, 2 Meter 490994-02
Handle Assembly 491073
HIn4457 User's Manual 600080

Table 5nn2 Optional Parts List

Part Description (Optional Parts) Part Number

Probe Support, HIn4457 490984
Tripod, Dielectric, HIn4457 491000
Fiber Optic / RS232 Interface HIn4413P

491198-36

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6.0 THEORY OF OPERATION

Introduction

This section discusses the theory of operation and the
functions of the HIn4457 Isotropic Magnetic Field Probe.
A high-level block diagram (Figure 6n1) is included to aid
the discussion. The objective is to provide information
that enhances user understanding of the design of this
probe.

System Theory

The HI-4457 Broadband Isotropic Magnetic Field Probe
uses three orthogonal sensing elements. Each of the
elements responds to the magnetic field component
aligned with the particular element. The output of the
three elements are summed as vector quantities and an
output proportional to the resultant field generated.

A microprocessor is contained in the instrumentation
housing located at the base of the probe shaft. The
microprocessor generates an output corrected for
variations in the sensor using lookup tables located in the
processor memory. The resultant value is transmitted in
an ASCII digital format through the optical cable to the
readout. The probe's self-contained power supply
employs a 3.6 VDC NiCd battery which provides up to 17
hours of continuous operation. Refer to Appendix B for
details of the ASCII output formats.

For specialized applications, you may use a computer
with an RS-232 serial port to communicate directly with
the HI-4457 using the optional HI-4413P RS-232
interface.

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Figure 6nn1

Probe Block Diagram

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Probe Operation

Receiver commands to the probe consist of the following:

! Send reading ! Read battery voltage
! Zero ! Set sleep timer
! Switch range ! Read temperature
! Enable axis

The signal flow within the probe is shown in the block
diagram.

To measure field strength, three mutually orthogonal loop
antennas (one per axis) are used to provide an isotropic
response to the ambient field. The signal from each axis
is fed to a Schottky diode detector operating in its
Square-Law region. After filtering, the signals generated
by each axis are added vectorially: the resultant is fed to
the instrumentation amplifier, whose output feeds the
selectable range/offset stage.

NOTE

The HIn4457 does not allow the option of
measuring on an individual axis: all three axes are
active at all times. Consequently, the axis keypads
on the front panel of the HIn4416 System Readout
have no effect when an HIn4457 is connected to
it.

For each of the four ranges, the selectable range and
offset stage provides a coarse analog zero for the
measured signal. The output of the range/offset stage is
fed to the A/D multiplexer, then to the analog-to-digital
(A/D) converter itself.

After acquiring the composite three-axis signal, the
microprocessor commands the A/D multiplexer to read

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the battery voltage and temperature sensing lines.

Data from the A/D converter is fed to the microprocessor,
which transmits it to the receiver.
The EEPROM stores all calibration data for the probe.

Probe Power Supply

The HIn4457 probe is powered by a sealed rechargeable

3.6 VDC NiCd battery, which drives both the analog and

digital power supplies: separate power sources provide
isolation between the analog and digital circuitry. With
the probe switch in the ARM position, battery voltage is
applied to the power switch, which routes this voltage to
the power supply, enabling the microprocessor. The
power switch is controlled by a timer circuit. The timer
monitors the fiber optic connector input line to determine
whether the probe has received a command during a
specified period (several seconds). If no command is
received during this period, the timer signals the power
switch to disable the power supply and the
microprocessor. In essence, the probe goes dormant to
conserve battery power: only the fiber optic input
circuitry remains active in order to detect new
commands. When the next command from the receiver
reaches the probe, power is reapplied automatically and
the processor is reactivated, "waking up" the probe.

NOTE

The probe uses volatile random access
memory (RAM). If, for any reason, power to
the probe is lost, the probe must be re-zeroed.

Zeroing

When the receiver sends a zero command, the probe
must be in a zero field environment. This is because the
zero command causes the multiplexer (via the processor)

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to perform a normal read cycle on the composite axis
signal. This procedure is executed for all ranges. When
the processor receives all the zero-field values, it stores
them in a special register; these values are subtracted
from all subsequent measurements. Therefore, a probe
which is zeroed while it is not in a zero field environment
will give erroneous readings.

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7.0 APPLICATION CONSIDERATIONS

Introduction

The following subsections contain information designed
to help you maximize the effectiveness of the HIn4457.

Out-of-Band Considerations

Although the HIn4457 is nominally rated for operation
from 10 MHz to 1 GHz, it may respond to signals both
above and below these frequencies. Such responses
must be taken into account when performing certain
operations, such as zeroing.

Resolution Limitations

Limitations in probe resolution may result in a non-zero
reading when the receiver is zeroed. If this occurs, it
does not necessarily mean either that there is a problem
with the receiver or that your readings are inaccurate.
Receiver linearity is specified as + 0.5 dB full scale: in
addition, the variance of the A/D converter is + 2 least
significant bits. When using the most sensitive range on
a given probe, these specifications create the possibility
that, under zero field conditions, the receiver may display
a non-zero value.

Probe Support Structures

It is very important to keep conductive objects away from
the HIn4457. Any such objects in the proximity of the
probe may distort the near field and compromise
measurement accuracy. If your application requires
measurements from a fixed position, always mount the
probe on a non-metallic platform, using non-metallic
screws.

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HIn4457 Manual Page — 23

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APPENDIX A

ERROR CODES

Probe Error Output

If an error occurs, the probe will respond with one of the
following strings. These strings begin with a colon and
end with a carriage return.

E01 Communication error (e.g., overflow).

E02 Buffer full error. Too many characters

contained between the Start Character/
Carriage Return sequence.

E03 The received command is not valid.

E04 The received parameter is not valid.

E05 Hardware error (e.g., EEPROM failure).

E06 Parity error.

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APPENDIX B

HInn4457 OPERATING PROTOCOLS

Introduction

The information in this appendix assumes that you have
purchased the optional HIn4413P Fiber Optic / RS232
Interface, and are capable of communicating directly with
the HIn4457 probe via computer. No system readout is
required when using this configuration.

Communication Protocol

Data Type: RS-232 Serial
Data Mode: Asynchronous
Word Length: 7 bit
Parity: Odd
Stop Bits: 1
Data Rate: 9600 baud

Information Transfer Protocol

The HIn4457 operates as a Controller Mode device. This
probe only responds to commands from another device;
it transmits no data without receiving instructions to do
so.

Command Structure

A command to an HIn4457 probe consists of 1) a
command letter, followed by 2) possible parameters, 3)
terminated with a carriage return. When it completes the
command, the probe responds with a string consisting of

1) a start character (":"), 2) the command letter, followed

by 3) data, if required, and terminated with 4) a carriage
return. If the command does not require the probe to
return any data, the probe simply responds with the
command letter and a carriage return. If an error occurs,
the probe responds with an error code, as detailed in

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Appendix A.

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Commands

Command Description

B Read battery voltage.

Cx Set baud rate.

x = 1 sets rate to 2400 baud

x = 2 sets rate to 9600 baud
New baud rate does not take effect until
the next power-up.

Dx Read probe data.

x = 1 enables short form output
x = 2 enables long form output

Lx Load table data. x = ASCII hex data

Rx Set range. x = 1, 2, 3, 4 or N (next

range)

Sx Sleep timer. x = number of seconds to

wait for a command before putting the
probe into the sleep mode.

Tx Read Temperature. x = C or F

Ux Set unit type. x = 1, 2, 3, or N (next unit)

1 = A/m

2 = mW/cm²

3 = [ A/m]²

Vtx Verify table data. t = table (same table as

for the Lx command, above). x = number
of bytes to send in one string.

Z Zero.

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Null Send the ASCII null character. This is a

special command that can be used as the
initial command to the probe after it is
powered up. The probe responds with
“N”.

Probe Output

Command HIn4457 Response

B Bxx.xx, where xx.xx is the battery voltage.

D1 Dxx.xxuuu, the short form output.

xx.xx is the reading. The position of the
decimal point depends upon the range
setting of the probe.

uuu = units
_A_ = A/m, mW2 = mW/cm², _A2 =
[A/m]²
(underscore indicates a space character)

D2 Dxx.xxuuurrrobaaat, the long form output.

xx.xx = the reading, as described for D1.

uuu = units, as describe for D1.

rrr = recorder out value (A 3-digit ASCII
number from 0 to 255).

o = over range indicator ("N" = ok, "O"
= over range).

b = battery status ("N" = safe operating
level, "W" = warning level, "F" = fail

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level).

aaa = axis enable ("E" = enabled).

t = terminating carriage return.

Rx Rx, where x is the range.

x = "" returns the range currently in use
x = 1, 2, 3, 4 enables the selected range
x = N sets the probe to the next (higher)
range.

TF Txxx, where xxx is temperature in °

Fahrenheit.

TC Txxx, where xxx is temperature in °

Centigrade.

Vtx Vxx[xx...], where xx is table data in ASCII

hex.

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- NOTES -

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- NOTES -