Applied Physics Systems 544 User manual

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281 East Java Drive Sunnyvale, CA. 94089 USA • 650.965.0500 • Fax: [phone] • [email protected]
Model 544
MSP430 CPU Version
Miniature Angular Orientation Sensor
User Manual

Model 544 User Manual
................www.appliedphysics.com
Copyright
Copyright 2007 - 2017 Applied Physics Systems Incorporated.
All Rights Reserved.
The contents of this manual may not be reprinted in part or whole without permission.
The contents of this manual are subject to change without notice.
Trademarks
All other brands or products mentioned are trademarks or registered trademarks of their
respective holders and should be treated as such.
Contact Information
Applied Physics Systems
Corporate Headquarters
281 East Java Drive
Sunnyvale, California 94089
USA
Phone: [phone]
Fax: [phone]
Email: [email protected]
Web: www.appliedphysics.com
Technical Support Hours:
Monday - Friday
9:00 AM - 5:00 PM
Pacific Standard Time
Document Number
250-1256-03-1117
Revision History
Revision Description Date
1 Initial draft of this manual. March 2007
2Renamed Binary Constant to Byte Constant. February 2017
Renamed Floating Constant to Float Constant.
Updated Table 1 - Model 544 System Specifications.
Updated Table 6 - Baud Rate Settings.
Added Figure 1 - Model 544 Mechanical Diagram.
Added Figure 2 - Model 544 Coordinate System and Orientation Angles.
Updated Section 6.5 - Enabling the Echoing of Incoming Commands.
Updated Table 7 - Autosend Modes.
Updated Table 8 - Averaging Output Data.
Updated Section 6.10 - Single Packet Binary Communication Modes.
Updated Table 9 - Binary Data Packets.

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Updated Section 6.12 - Comparison of ASCII and Standard Binary Data
Structures.
Removed Section 6.13 Changing the 544 Coordinate System (Optional).
Updated Figure 6 - Corrected ASCII Mode.
Updated Figure 8 - Model 544 Inclination versus Azimuth Error.
3Removed the following sections:
..7 - Calculating the Orientation Sensor Angles
..7.1 - Sensor Based Coordinate System
..7.2 - Definition of Orientation Angles
..7.3 - Definitions
..7.4 - Calculating Roll and Magnetic Roll
..7.5 - Calculating Inclination
..7.6 - Magnetic Heading (Azimuth)
November 2017
Added 3.1 - Coordinate System.
Added a warning about changing float constants in
6.1 - Model 544 Internal Byte and Float Constants.
Removed Table 5. Float Constants.
Revision Description Date

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Contents
Chapters
Chapter 1 - Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
Chapter 2 - System Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Chapter 3 - Mechanical Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
3.1 - Coordinate System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Chapter 4 - Electrical Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Chapter 5 - Setting up the System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Chapter 6 - Computer Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
...... 6.1 - Model 544 Internal Byte and Float Constants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
...... 6.2 - ASCII Communication Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
...... 6.3 - Changing Data Output Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
...... 6.4 - Changing the Baud Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
...... 6.5 - Enabling the Echoing of Incoming Commands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
...... 6.6 - Entering a Serial Number into the Power Up Sign On Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
...... 6.7 - Disabling the Power Up Sign On Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
...... 6.8 - Configuring for Autosend . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
...... 6.9 - Averaging and Filtering Output Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
...... 6.10 - Single Packet Binary Communication Modes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
...... 6.11 - Autosend Binary Communication Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
...... 6.12 - Comparison of ASCII and Standard Binary Data Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Chapter 7 - Windows Software for the Model 544 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Appendix
Appendix A - Azimuth Accuracy Estimates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
...... A.1 - Orientation Sensor Azimuth Accuracy as a Function of the Earth’s Magnetic Field Dip Angle . . . . . . . .25
...... A.2 - Orientation Sensor Azimuth Accuracy as a Function of the Inclination . . . . . . . . . . . . . . . . . . . . . . . . . .26
Figures
Figure 1 - Model 544 Mechanical Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Figure 2 - Model 544 Coordinate System and Orientation Angles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Figure 3 - Sensor Interface Software Main Display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Figure 4 - Sensor Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Figure 5 - Monitor Sensor Display Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Figure 6 - Corrected ASCII Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Figure 7 - Corrected HEX Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Figure 8 - Model 544 Inclination versus Azimuth Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

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Tables
Table 1 - Model 544 System Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Table 2 - Model 544 Electrical Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Table 3 - RS-232 Interface Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Table 4 - Model 544 Byte Constants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Table 5 - Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Table 6 - Baud Rate Settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Table 7 - Autosend Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Table 8 - Averaging Output Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Table 9 - Binary Data Packets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Table 10 - Dip Angle versus Azimuth Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25

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1 - Introduction
This manual describes the Model 544 Miniature Orientation Sensor. This system is designed to
enable high accuracy measurement of the inclination, roll (toolface) and azimuth orientation
angles of the system to which it is mounted. A common application of the 544 is to measure the
orientation of borehole logging and directional drilling systems.
The 544 sensor contains both a 3-axis fluxgate magnetometer and a 3-axis accelerometer. The
combination of these two sensor systems enables the inclination, roll and azimuth angles of the
544 reference frame to be determined. Inclination and roll angles are determined from the
accelerometer subsystem, which measures the pull of gravity. After inclination and roll are known,
the magnetometer subsystem is used to determine the system azimuth angle. Knowledge of the
inclination and roll angles enable determination of the horizontal components of the earth's local
magnetic field; this information defines the azimuth angle.
The 544 system contains a microprocessor and 8 channels of 16-bit analog to digital conversion.
Six channels are assigned to the magnetometer and accelerometer outputs. One channel
provides temperature data from an internal thermometer and one channel is configured to
measure the system input voltage.
The 544 system communicates over one of two serial bidirectional interfaces that can be selected
for either TTL or RS-232 voltage levels. An ASCII character command language has been
created to facilitate communication with the 544. For example, if the ASCII string “0SD”<CR> is
sent to the unit, the 544 interprets this as a "send data" command and responds by sending over
the serial interface an ASCII string representing the value of all magnetometer, accelerometer
and temperature outputs. The leading zero in this sequence denotes the system serial number.
The 544 can also be configured to send angle data (roll, pitch and azimuth) instead of the
accelerometer and magnetometer sensor data.
An autosend data mode is included in the 544 firmware. When this mode is active, data is
repeatedly sent after power is applied to the system.
The 544 accelerometers are calibrated by placing the system in a precision rotation fixture and
systematically changing the system orientation in the earth's gravitational field. The 544 system
magnetometers are calibrated by placing the system in a precision 3-axis Helmholtz coil system,
which enables the application of known magnetic fields to the system. Both the rotation fixture
and Helmholtz coil mounting fixture have alignment pins and reference surfaces, which mate to
the 544 reference surface.
When the system is calibrated over a temperature range, data is read from the system at
temperature intervals between the minimum and maximum temperature specification. For
example, for calibration over the interval of 0°C - 75°C, data is read at 25°C temperature intervals
between 0°C and 75°C. The data taken at each temperature includes scale, offset and sensor
alignment data. The recorded data is then used to create a look up table for scale offset and
alignment corrections. This table is then downloaded into the 544 internal EEROM memory,
where it can be accessed by the system internal microprocessor. Corrections to the read sensor
data can then be made by the internal microprocessor system before data is transmitted.

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2 - System Specifications
The system specifications for the 544 are shown in Ta ble 1 .
Specifications are subject to change without notice.
Table 1. Model 544 System Specifications
Specification Value Notes
Angular Accuracy
Azimuth ±1.2° Inclination 90°
Inclination ±0.4° Inclination 90°
Roll ±0.4° Inclination 90°
Power
Voltage +4.9 to +12 VDC
Current 55 mA
Operating Temperature 0°C - 70°C Optional range of 0°C to 125°C available
Vibration 10 g RMS, random 20 - 250Hz
Shock 750 g 1ms half-sine
Size 0.75" x 0.80" x 4.6"
Mass 50 grams
Digital Outputs
Logic Level TTL or RS-232 User selectable
Baud rate 300 – 9600, 19200, 38400
baud User selectable
Protocol ASCII text or binary User selectable
Leads 27" flying leads Color coded
Data output speed in autosend mode: Data rates listed are for a filter setting of 30 Hz.
ASCII angle mode 6 Samples/second
ASCII sensor mode 9 Samples/second
Binary sensor mode 18 Samples/second

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3 - Mechanical Features
An outline drawing of the 544 system is shown in Figure 1. The system dimensions are 0.75" x
0.80" x 4.60" (1.90 cm x 2.03 cm x 11.68 cm). The system is normally mounted by using four 2-56
x 0.250 long screws to secure the 544 reference surface to a flat mating surface. Two 0.062"
diameter x 0.125" long pins protruding from the external mating surface can be used to orient the
544 on the external mounting surface. The orientation of the X, Y and Z-axes and the
approximate location of the magnetometer and accelerometer sensors are also shown in Figure
1. The output polarity sense of the axes is such that a field pointing in the direction of the arrows
shown in Figure 1 will produce a positive output voltage. For example, if the X magnetometer is
oriented so the X-axis arrow points north, then the X-axis magnetometer output will record a
positive value. If the X-axis accelerometer arrow is pointed down, the X-axis accelerometer
output will be positive. The orientation of the axes is silk-screened onto the 544 case.
Figure 1. Model 544 Mechanical Diagram

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Chapter 3 - Mechanical Features
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3.1 - Coordinate System
The coordinate system and orientation angles for the 544 are shown in Figure 2.
Figure 2. Model 544 Coordinate System and Orientation Angles

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4 - Electrical Interface
The 544 electrical interface is shown in Table 2. The serial communications interface to the 544 is
provided by the serial in and serial out lines shown in the table. Two serial interfaces are
provided. The RS-232 interface can be connected directly to an external computer COM port.
The TTL serial interface is used for communication between the 544 and other system
electronics. The serial interfaces are normally set to operate at 9600 baud using 8 bits with one
stop bit and no parity. The user, however, can change the baud rate by setting bits in the system
EEROM. See Chapter 7 - Windows Software for the Model 544.
Table 2. Model 544 Electrical Interface
Wire Color Function
Red +4.9 to +12 VDC Unregulated
Black Ground
Orange RS-232 Serial In
Yellow RS-232 Serial Out
White / Orange TTL Serial In
White / Yellow TTL Serial Out

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5 - Setting up the System
To operate the 544, power must be applied to it and an interface with an external computer must
be set up. Input power should be applied to the red (+4.95 to +12 VDC) and the black (ground)
wires of the system. To set up a computer interface with the system, select the output protocol of
the 544. This can be either TTL or RS-232. The TTL protocol is usually used in
microprocessor-to-microprocessor communications. Since PC serial COM ports use RS-232
protocol, they can be directly connected to a 544 using this protocol. PC’s use either a 25-pin or a
9-pin D connector on their serial ports. This connector is always a bulkhead male connector on
the PC chassis. The serial-in, serial-out and ground connections for these connectors are shown
in Table 3. The 544 serial output line is connected to the computer serial in line and the 544 serial
input line is connected to the computer serial out line.
An easy way to communicate with the 544 using the ASCII protocol is to run a terminal program
on the PC. The Windows Hyperterminal program is one choice for this. Other suitable terminal
programs are ProComm and ASCII Pro. These programs turn the computer into a dumb terminal.
In this mode, whatever you type on the keyboard goes out the selected serial port (for example,
COM 1) and whatever comes in the serial port is displayed on the computer video display.
If the program HyperTerminal is used, the proper COM port (for example COM 1, COM 2, …)
must be selected. In addition, a baud rate of 9600 with one stop bit and no parity must be
selected.
Set the port up for direct connect and select “none” for handshaking.
After setting up communications with an external computer, the 544 will respond with the
following startup message when power is turned on:
APS: S/Nxxxxxxxxxx
Ver: 4.3 Bow Dip•C
In the above messages, the x’s represent the unit serial number.
A second method of communicating with the 544 is to use the Sensor Interface software
described in Chapter 7 - Windows Software for the Model 544.
Table 3. RS-232 Interface Connections
Function 544 Wire 25-Pin D 9-Pin D
544 Serial In Orange 2 3
544 Serial Out Yellow 3 2
Ground Black 5 5

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Chapter 5 - Setting up the System
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6 - Computer Interface
6.1 - Model 544 Internal Byte and Float Constants
The operating characteristics of the 544 are controlled by the value of internal byte constants.
The most important constants are listed in Table 4.
To change the internal system byte constants, a write enable command must first be issued.
This is:
0l <CR>
Where 0 is zero, l is the letter L (lower case or capital) and <CR> is a carriage return.
When this command is sent to the 544, it will respond with the reply
enabled!
To write byte constant 02=03, the command
0WC02b03 <CR>
is issued. After receiving this and acting upon it, the 544 will respond with the reply
done
Table 4. Model 544 Byte Constants
Byte Constant Function
00 Enables echoing when 00 is non zero
01 Enables autosend upon power up when 01 = 5A
02
Enables sensor A/D count output when 02 = 0
Enables calibrated sensor output (in Gauss and gees) when 02 = 2
Enables angle output (roll, pitch, azimuth) when 02 = 3
Enables alternate labels Roll: Pitch: Az:) when 02 = 4
05 Controls sending of power up sign on message
(default=0, message enabled)
08 Sets power on mode
(for example 08 = 10 enables ASCII autosend upon power up)
09 Baud rate lock (must be 09 = 5A if a baud rate other than 9600 is used)
10 Sets baud rate
23 Sets up averaging of the output
35 Sets delay between transmissions in autosend mode

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The reading of internal constants can be accomplished by issuing the command
0SC02b <CR>
(0Send Constant 02 byte). When this command is sent, the 544 will respond by sending the
value of constant 02. Wildcards are also recognized. The command OSC*b will cause the 544 to
send the value of all internal byte constants.
In addition to internal byte constants, the 544 also has a number of float constants. These are
used to store the calibration data in the 544 EEROM. These constants can be read by using the
commands
DO NOT alter float constants or you will invalidate the system calibration.
Float constants are meant for use by Applied Physics Systems personnel only.
The 544 sensor is temperature compensated to ensure that the accuracy of the sensor is
maintained over its intended temperature range. The temperature calibration data is stored in the
system EEROM memory.
This data can be accessed by using the following commands:
0SC*f <CR> for all constants
0SC06F <CR> for constant 06
0st*b <CR> Send temperature calibration table in binary format
0st*i <CR> Send temperature calibration table in integer format
0st*f <CR> Send temperature calibration table in float format

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6.2 - ASCII Communication Mode
Communication is initiated when the external computer issues a command such as ASCII
characters 0SD. The characters 0SD stand for 0(zero) Send Data. When this command is
issued, the 544 will respond with a formatted output similar to the following:
When internal byte constant 02=02, the 544 is in sensor output mode and the above numbers
represent the magnetometer X, Y and Z sensor outputs in Gauss and the accelerometer outputs
in gees. When byte constant 02=03, the 544 is in angle mode and The 544 responses to a send
data command with the following format,
When byte constant 02=04, the 544 is in angle mode and the 544 responses to a send data
command with the following format:
where ROLL is gravity roll (toolface), PITCH is inclination, HEAD is Azimuth, MAGROLL is
magnetic roll, MAG is the total magnetic field, GRAV is the total gravity field, and DA is the
magnetic field dip angle.
MX:+0.20346 AX:-0.07852
MY:+0.23165.AY:+0.72136
MZ:+0.29525 AZ:+0.70226
T: +28.148
MX: +35.17825 AX: +198.24032
MY: +90.14559 AY: +0.43326
MZ: +26.76792 AZ: +1.00101
T: +28.026 DA: 55.893
ROLL: +35.17825.MAGROLL: +198.24032
PITCH: +90.14559 MAG: +0.43326
HEAD: +26.76792 GRAV: +1.00101
TEMP: +28.026 DA: 55.893

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6.3 - Changing Data Output Mode
The 544 can be configured to output in raw ADC counts, sensor values or angles. Data output
format is determined by the value of byte constant 02 as follows:
6.4 - Changing the Baud Rate
The communications baud rate can be changed by using the following sequence:
1. Set byte constant 10 according to Table 6 below.
2. Set byte constant 09 to 0x5a.
3. Cycle power off and on.
The following commands illustrate setting the baud rate to 2400.
0l <CR>
0wc10b32 <CR>
0l <CR>
0wc09b5a <CR>
When byte constant 09 is set to any value other than 0x5a, the system baud rate is 9600.
Table 5. Operating Modes
Byte 02 Value Output Data Format
0x00 Raw A/D counts (uncalibrated)
0x02 Calibrated sensor outputs (accelerometers and magnetometers)
0x03 Angular outputs (roll, Inc, azimuth)
0x04 Angular outputs with alternate labels
Table 6. Baud Rate Settings
Baud Rate Byte 10 Value
300 0x35
1200 0x33
2400 0x32
4800 0x31
9600 (default) 0x30 (default)
19200 0x05
38400 0x06