Preliminary
Magnetic Products
THREE-AXIS STRAPDOWN MAGNETOMETER
HMR2300r
FEATURES
APPLICATIONS
• Strapdown Magnetometer Replaces Bulky Fluxvalves
• Navigation Systems—Avionics and Marine
• Microprocessor Based Smart Sensor
• Fluxvalve Replacement
• Range of ±2 Gauss—<70 µGauss Resolution
• Can be Slaved to AHRS System
• Readings can Achieve Heading Resolution of 0.02°
• GPS Backup Systems
• Rate Selectable—10 to 154 Samples/Sec.
• Remote Vehicle Monitoring
• Small Size: 2.83 in.—Fits in ML-1 Style Enclosure
• Unpiloted Air Vehicles (UAVs)
• Repeatable and Reliable—MTBF >50,000 hours
• Navigation/Attitude for Satellites
GENERAL DESCRIPTION
Honeywell’s three-axis strapdown magnetometer detects
the strength and direction of the earth’s magnetic field and
communicates the x, y, and z component directly via serial
bus. The HMR2300r is compliant with applicable MIL-STD810E requirements for military and commercial flight systems (see Table 6). It was designed to be a replacement for
bulky fluxvalve magnetic sensors commonly used in aviation systems.
The HMR2300r strapdown magnetometer provides an
excellent replacement of conventional fluxvalve sensors,
commonly used in aviation systems today. The HMR2300r
offers higher reliability (MTBF >50,000 hours) that reduces
maintenance and repair cost. Since the design is strapdown,
as opposed to a gimballed fluxvalve, it has no moving parts
to damage or wear out during severe flight conditions. Low
cost, high sensitivity, fast response, small size, and reliability are advantages over mechanical or other magnetometer alternatives. With an extremely low magnetic field
sensitivity and a user configurable command set, these
sensors solve a variety of problems in custom applications.
A unique switching technique is applied to the solid-state
magnetic sensors to eliminate the effects of past magnetic
history. This technique cancels out the bridge offset as well
as any offset introduced by the electronics. The data is
serially output at either 9,600 or 19,200 baud, using the RS422 or RS-485 standard. The RS-485 standard allows
connection of up to 32 devices on a single wire pair up to
4,000 feet in length. An HMR address can be stored in the
on-board EEPROM to assign one of thirty-two unique ID
codes to allow direct line access. An internal microcontroller handles the magnetic sensing, digital filtering, and all
output communications eliminating the need for external
trims and adjustments. Standard RS-422 or RS-485 drivers provide compliant electrical signalling.
A command set is provided (see Table 4) to configure the
data sample rate, output format, averaging and zero offset.
An on-board EEPROM stores any configuration changes
for next time power-up. In addition, the user has 55 bytes
of EEPROM locations available for data storage. Other
commands perform utility functions like baud rate, device
ID and serial number. Also included in the HMR magnetometer is a digital filter with 50/60 Hz rejection to reduce
ambient magnetic interference.
Solid State Electronics Center • 12001 State Highway 55, Plymouth, MN 55441 • (800) 323-8295 • http://www.ssec.honeywell.com
HMR2300r
1 Gauss (G) = 1 Oersted (in air), 1G = 79.58 A/m
1G = 10E-4 Tesla, 1G = 10E5 gamma
ppm - parts per million
OPERATING SPECIFICATIONS—Table 1
Characteristic
Conditions
Min
Supply Voltage
Pin 9 referenced to pin 5
6.5
Supply Current
Vsupply=15V (with 120 Ω termination)
Operating Temperature
Ambient
Storage Temperature
Field Range
Max
Unit
15
Volts
55
mA
-40
85
°C
Ambient, unbiased
-55
125
°C
Full scale (FS)—total applied field
-2
+2
Gauss
0.1
1
0.5
2
%FS
Best fit straight line
Linearity Error
Typ
45
±1 Gauss
Hysteresis Error
3 sweeps across ±2 Gauss @ 25 ° C
0.01
0.02
%FS
Repeatability Error
3 sweeps across ±2 Gauss @ 25 ° C
0.05
0.10
%FS
Gain Error
Applied field for zero reading
0.05
0.10
%FS
Offset Error
Applied field for zero reading
0.01
0.03
%FS
RSS of all errors
0.12
1
0.52
2
%FS
Accuracy
±1 Gauss
Resolution
Applied field to change output
Axis Alignment
Variation to 90 degrees
Noise level
67
µGauss
±1
±2
degree
Output variation in fixed field
0.07
±0.13
mGauss
Temperature Effects
Coefficient of gain
Coefficient of offset (with S/R=ON)
-0.06
±0.01
%/° C
Power Supply Effect
From 6 to 15V with 1 Gauss applied
150
ppm/V
Vibration (operating)
5 to 10Hz for 2 hrs.
10Hz to 2KHz for 30 min.
10
2.0
mm
g force
Max. Exposed Field
No perming effect on zero reading
10
Gauss
Weight
Board only
40
grams
Max
Unit
TIMING SPECIFICATIONS—Table 2
Characteristic
Conditions
TRESP
Timing Diagrams (Figs. 1,2)
*dd command (dd=Device ID)
*ddP
*ddRST
*ddC
*99 command (exceptions below)
*ddQ
*99Q
TDELAY
Timing Diagram (Fig. 2)
*99 comand (dd=Device ID)
TBYTE
TSTARTUP
Timing Diagrams (Fig. 1)
Min
Typ
1.9
2.2
2.2
6
40
2 + (dd x 40)
2 + (dd x 80)
2 + (dd x 120)
3.2
3.2
6.5
msec
60
2 + Typ
2 + Typ
2 + Typ
2+ (dd x 40)
2 + Typ msec
9600
19200
Power Applied to start of Start-Up message
2
1.04
0.52
28
80
msec
140
msec
HMR2300r
RS-485 and RS-422 COMMUNICATIONS—Figure 1
Start
LSB
MSB
Timing is not to scale
Stop
4V
Hi
...
2V
1V
4V
Lo
...
2V
1V
<cr> of Command
TBYTE
HMR2300r Response
TRESP
AAA
AAA AAA
GLOBAL ADDRESS (*99) DELAY—Figure 2
TRESP
Command
Bytes
(*01P<cr>)
Timing is not to scale
HMR ID=01
Response
(XXYYZZVC<cr>)
TDELAY (ID=02)
AAA
AAA
AAA
AAA
AAA AAA AAA AAA
TDELAY (ID=01)
TRESP
Command
Bytes
(*99P<cr>)
Sample
HMR ID=01
Response
(XXYYZZVC<cr>)
HMR ID=00
Response
(XXYYZZVC<cr>)
HMR ID=02
Response
(XXYYZZVC<cr>)
(sps)
9600
19200
9600
19200
(Hz)
(Hz)
Continuous
Reading Period
(msec)
10
yes
yes
yes
yes
17
50/60
101
20
17
50/60
51
25
21
63/75
41.5
30
26
75/90
35
40
34
100/120
24
50
42
125/150
19.6
51
150/180
16.1
85
250/300
9.8
104
308/369
8.1
131
385/462
6.5
ASCII
Rate
60
100
123
Binary
DATA
INVALID
154
f3dB
Notch
Parameter Selections verses Output Sample Rate—Table 3
3
HMR2300r
COMMAND INPUTS—Table 4
A simple command set is used to communicate with the HMR. These commands can be typed in through a standard
keyboard while running any communications software such as HyperTerminal® in Windows®.
(1)
Response
(2)
Bytes(3) Description
Command
Inputs
Format
*ddWE *ddA
*ddWE *ddB
ASCII_ON ←
BINARY_ON ←
9
10
Output
*ddC
{x, y, z reading}
{x, y, z stream}
{stream stops}
9 or 28
...
0
P=Polled - Output a single sample.
C=Continuous - Output readings at sample rate. (default)
Escape key - Stop continuous readings.
3
Set sample rate to nnn where: nnn= 10, 20, 25, 30, 40,
50, 60, 100, 123, or 154 samples/sec (default 30 sps)
Sample Rate
*ddWE *ddR=nnn OK ←
Set/Reset Mode
*ddWE *ddTN
*ddWE *ddTF
*ddWE *ddT
S/R_ON ←
S/R_OFF ←
{Toggle}
7
8
7 or 8
ASCII - Output readings in BCD ASCII format.
Binary - Output signed 16 bit binary format. (default)
S/R mode: TN -> ON=automatic S/R pulses (default)
TF -> OFF=manual S/R pulses
SET ←
RST ←
{Toggle}
4
4
4
Toggle alternates between SET and RESET pulse.
ID=_n n ←
OK ←
7
3
Read device ID (default ID=00)
Set device ID where nn=00 to 98
Set baud rate to 9600 bps.
Baud Rate
OK ←
BAUD=_9600 ←
OK ←
BAUD=_19,200 ←
14
*99WE *99!BR=S
*99WE *99!BR=F
16
Set baud rate to 19,200 bps. (default)
(8 bits, no parity, 1 stop bit)
Zero Reading
*ddWE *ddZN
*ddWE *ddZF
*ddWE *ddZR
ZERO_ON ←
ZERO_OFF ←
{Toggle}
8
9
8 or 9
Zero Reading will store and use current reading as a
negative offset so that the output reads zero field
*ddZR toggles command. (default=OFF)
Average
Readings
*ddWE *ddVN
*ddWE *ddVF
*ddWE *ddV
AVG_ON ←
AVG_OFF ←
{Toggle}
7
8
7 or 8
The average reading for the current sample X(N) is:
Xavg = X(N)/2 + X(N-1)/4 + X(N-2)/8 + X(N-3)/16 + ...
*ddV toggles command. (default=OFF)
Re-enter
Response
*ddWE *ddY
*ddWE *ddN
OK ←
OK ←
Set/Reset Pulse
*dd]
Device ID
*ddWE *ddID=nn
Query Setup
3
3
{see Description}
62-72
16
Default Settings
*ddWE *ddD
OK ←
BAUD=_19,200 ←
Restore Settings
*ddWE *ddRST
OK ←
BAUD=_9600 or
BAUD=_19,200
14
16
] character - single S/R: ]S -> SET=set pulse
Turn the "Re-enter" error response ON (*ddY) or OFF
(*ddN). OFF is recommended for RS-485 (default=ON)
Read setup parameters. default: binary, Continuous,
S/R ON, ZERO OFF, AVG OFF, R ON, ID=00, 30 sps
Change all command parameter settings to factory
default values.
Change all command parameter settings to the last
user stored values in the EEPROM.
Serial Number
*dd#
SER#_nnnn ←
22
Output the HMR2300r serial number.
Software Version
*ddF
S/W_vers:_ nnnn ←
27
Output the HMR2300r software version number.
Hardware Version
*ddH
H/W_vers:_ nnnn ←
19
Output the HMR2300r hardware version number.
OK ←
3
Activate a write enable. This is required before
commands like Set Device ID, Baud Rate, and others
shown in table.
Store Parameters *ddWE *ddSP
DONE ←
OK ←
8
This writes all parameter settings to EEPROM. These
values will be automatically restored upon power-up.
Too Many
Characters
Re-enter ←
9
A command was not entered properly or 10 characters
were typed after an asterisk (*) and before a <cr>.
WE_OFF ←
7
This error response indicates that this instruction
requires a write enable command immediately before it.
Write Enable
*ddWE
Wrong Entry
Missing WE Entry Write Enable Off
(1) All inputs must be followed by a <cr> carriage return, or Enter, key. Either upper or lower case letters may be used. The device ID (dd) is a
decimal number between 00 and 99. Device ID=99 is a global address for all units.
(2) The “←”symbol is a carriage return (hex 0D). The “_” symbol is a space (hex 20). The output response will be delayed from the end of the
carriage return of the input string by 2 msec (typ.), unless the command was sent as a global device ID=99 (see TDELAY).
4
HMR2300r
DATA FORMATS
The HMR2300 transmits each x, y, and z axis as a 16-bit
value. The output data format can either be 16-bit signed
binary (sign + 15-bits) or binary coded decimal (BCD) ASCII
characters. The command *ddA will select the ASCII format
and *ddB will select the binary format.
The Validity byte indicates that the onboard microprocessor has properly executed code routines for the selected
mode of operation. The various user selectable modes are
shown in the table below with the corresponding validity
byte and associated ASCII character.
The order of output for the binary format is: Xhi, Xlo, Yhi,
Ylo, Zhi, Zlo. The binary format is more efficient for a computer to interpret since only 9 bytes are transmitted. The
BCD ASCII format is easiest for user interpretation but requires 28 bytes per reading. There are limitations on the
sample rate based on the format and baud rate selected
(see Table 3). Examples of both binary and BCD ASCII outputs are shown below for field values between ±2 Gauss.
Field
BCD ASCII
(Gauss)
+2.0
+1.5
+1.0
+0.5
0.0
-0.5
-1.0
-1.5
-2.0
Value
30,000
22,500
15,000
7,500
00
- 7,500
-15,000
-22,500
-30,000
Zero
Readings
off
off
off
off
on
on
on
on
Binary Value (Hex)
High Byte
75
57
3A
1D
00
E2
C3
A8
8A
Low Byte
30
E4
98
4C
00
B4
74
1C
D0
(1)
XH
|
XL
|
YH
|
|
XH =
XL =
YH =
YL =
ZH =
ZL =
Validity =
Checksum=
<cr> =
ZH
|
ZL
|
Validity
|
Checksum
|
Validity
Character byte
O
4F
S (1)
53
O
4F
V
56
P
50
T
54
P
50
W
57
28 bytes
SN | X1 | X2 | CM | X3 | X4 | X5 | SP | SP | SN | Y1 | Y2 | CM | Y3 | Y4 |
Y5 | SP | SP | SN | Z1 | Z2 | CM | Z3 | Z4 | Z5 | SP | SP | <cr>
The ASCII characters will be readable on a monitor as
signed decimal numbers. This format is best when the user
is interpreting the readings.
9 bytes
YL
Auto
Set/Reset
off
on
off
on
off
on
off
on
Default mode. This mode can be reset using the
*99we, *99rst command sequence.
ASCII Format:
Output Readings—Table 5
Binary Format:
Average
Readings
off
off
on
on
off
off
on
on
<cr> = carriage return (Enter Key), Hex code = 0D
SP = space, Hex code = 20
SN (sign) = - if negative, Hex code = 2D
SP if positive, Hex code = 20
CM (comma) = , if leading digits are not zero, Hex code = 2C
SP if leading digits are zero, Hex code = 20
X1, X2, X3, X4, X5 = Decimal equivalent ASCII digit
X1, X2, X3 = SP if leading digits are zero, Hex code = 20
<cr>
signed high byte, x axis
low byte, x axis
signed high byte, y axis
low byte, y axis
signed high byte, z axis
low byte, z axis
Validity byte is described below
Checksum is the ones complement of
the sum of the first seven bytes
carriage return (Enter Key), Hex code = 0D
RS-232 to RS-485
B&B Electronics
#485PTBR
Output data format is in counts (sign + 15 bit magnitude)
Scale factor is 1 gauss = 15,000 counts
Output measurement range = ± 30,000 counts
RS-232
TD
RD
GD
The binary characters will be unrecognizable on a monitor
and will appear as strange symbols. This format is best
when a computer is interpreting the readings.
Checksum = ones complement of the sum
(XH + XL + YH + YL + ZH + ZL + Validity)
2RD
3TD
7GD
120VAC
TD(A)
TD(B)
RD(A)
RD(B)
SG
+12VDC
TERM.
HMR2300r
RS-422
Rx-lo
Rx-hi
Tx-lo
Tx-hi
Gnd
Pwr
1
8
3
2
5
9
J1 Pin
connector
+12VDC
INTERFACE CONVERTER TO RS-232—FIGURE 3
5
HMR2300r
DATA COMMUNICATIONS
the escape code immediately after it, then a systematic
stop reading will occur. If an operator is trying to stop
readings using the keyboard, then several (if not many)
escape key entries must be given, since the RS-485 lines
share the same wires for transmit and receive. If an escape
key is entered during the time data is sent from the
HMR2300r, then the two will produce an erroneous
character that will not stop the data stream. The data stream
stop only when the escape key is pressed during the time
the HMR2300r is not transmitting.
The RS-422 signals are balanced differential signals that
can send and receive simultaneously (full-duplex). The RS485 signals are also balanced differential levels but the
transmit and receive signals share the same two wires.
This means that only one end of the transmission line can
transmit data at a time and the other end must be in a
receive mode (half-duplex).
The RS-422 and RS-485 lines must be terminated at both
ends with a 120 ohm resistor to reduce transmission errors.
There are termination resistors built into the HMR2300r as
shown in Figures 4 and 5.
Computer
The signals being transmitted are not dependent on the
absolute voltage level on either Lo or Hi but rather a
difference voltage. That is, when a logic one is being
transmitted, the Tx line will drive about 1.5 volts higher than
the Rx line. For a logic zero, the Lo line will drive about 1.5
volts lower than the Hi line. This allows signals to be
transmitted in a high noise environment, or over very long
distances, where line loss may otherwise be a problem—
typically 4,000 feet. These signals are also slew-rate limited
for error-free transmission. The receiver has a common
mode input range of -7 to +12 volts. The signal connections
are shown in Figure 6.
HMR
Rx-lo
Z
D
Z
Rx-hi
R
Tx-lo
Z
R
Z
Tx-hi
D
Z=120Ω
RS-422 Balanced (full-duplex)—Figure 4
Computer
Lo (A)
HMR
Lo
D
R
Z
Note: When the HMR2300r is in a continuous read mode
on the RS-485 bus, it may be necessary to enter several
escape keys to stop the readings. If the computer taking
the readings can detect a carriage return code and send
Z
R
D
Hi (B)
Hi
Z=120Ω
RS-485 Balanced (half-duplex)—Figure 5
PINOUT DIAGRAMS—FIGURE 6
J1 Pins
+6.5 to +15VDC power - 9
connected to P1 pin 6 - 7
+6.5 to +15VDC return - 5
Tx-lo (RS-422) or Lo (RS-485) - 3
Rx-lo (RS-422) - 1
J1 Pin#
1
2
3
4
5
6
7
8
9
10
P1 Sockets
10 - nc
10 - for manufacturers use only
for manufacturers use only - 9
8 - Rx-hi (RS-422)
8 - for manufacturers use only
nc - 7
6 - connected to P1 pin 2
6 - connected to J1 pin 7
+6.5 to +15VDC power - 5
4 - Chassis ground
4 - Chassis ground
+6.5 to +15VDC return - 3
2 - Tx-hi (RS-422) or Hi (RS-485)
2 - connected to J1 pin 6
nc - 1
Pin Assignment
Rx-lo (RS-422)
Tx-hi (RS-422) or Hi(B) (RS-485)
Tx-lo (RS-422) or Lo(A) (RS-485)
Chassis ground
+6.5 to +15VDC return
connected to P1 pin 2
connected to P1 pin 6
Rx-hi (RS-422)
+6.5 to +15VDC power
(no connect)
P1 Pin#
1
2
3
4
5
6
7
8
9
10
6
Pin Assignment
(no connect)
connected to J1 pin 6
+6.5 to +15VDC return
Chassis ground
+6.5 to +15VDC power
connected to J1 pin 7
(no connect)
for manufacturers use only
for manufacturers use only
for manufacturers use only
HMR2300r
BOARD DIMENSIONS—FIGURE 7
All Dimensions in inches
J1
TOP-SIDE OF CIRCUIT BOARD ASSEMBLY
AAA
A
AAA
A
AAA
A
AAA
A
AAA
A
AAA
A
AAA
A
AAA
A
AAA
A
AAA
A
P1
+Y
+X
(FWD)
J1
SAMTEC TSW-105-06-T-D
10-PIN HEADER
P1
SAMTEC SSQ-105-01-S-D
10-SOCKET HEADER
+Z axis
(Down)
.39 MAX
COMPONENT
HEIGHT
.12 MAX
.060
BACK-SIDE OF CIRCUIT BOARD ASSEMBLY
7
COMPONENT
HEIGHT
HMR2300r
QUALITY AND ENVIRONMENTAL CONDITIONS—TABLE 6
Parameter
Method and Test Levels
Printed Circuit Board
Conforms to IPC-6011 and IPC-6012, Class 3, using FR-4 laminates and prepreg per IPC-4101/21.
Assembly and Workmanship
Conforms to J-STD-001, Class 3, and IPC-A-610, Class 3, respectively.
Electrostatic Sensitive Devices
The HMR2300r shall be treated as an Electrostatic Sensitive Device (ESD) and precautionary
handling and marking shall apply.
Mean Time Between Failure (MTBF) The MTBF of the HMR2300r is 25,000 hours minimum under the environmental conditions specified.
Altitude
The HMR2300r is capable of withstanding altitudes per MIL-STD-810E, Method 520.1, Procedure III.
Fungus
The HMR2300r is constructed with non-nutrient materials and will withstand, in both operation and
storage conditions, exposure to fungus growth per MIL-STD-810E, Method 508.4
Shock
The HMR2300r will perform as specified following exposure to shock IAW MIL-STD-810E, Method
513.4, Table 516.4, Procedure I, V, and VI. Functional shock (20g, 11ms, 3 shocks in both directions of
3 axes) and crash hazard shock (40g, 11ms, 2 shocks in both directions of 3 axes.
Vibration
The HMR2300r will perform as specified during exposure to random vibration per MIL-STD-810E
Method 514.4, Category 10, Figure 514.4, random vibration, 4 Hz - 2000 Hz (0.04g^2/Hz to 0.0015
g^2/Hz), 3 hr./axis operating.
Salt Fog*
The HMR2300r, when clear coated, will operate as specified after 48 hrs. exposure to a salt
atmosphere environment per MIL-STD-810E, Method 509.3, Procedure I *User must provide
polyurethane clear coat to board.
Explosive Atmosphere
The HMR2300r will not ignite an explosive atmosphere when tested IAW MIL-STD-810E, Method
511.3, Procedure I.
Humidity
Method 507.3, Procedure III.
Temperature
10 cycles at -54° C to +71 degC operating (approx. 4 hours/cycle including stabilization time).
EMI
The HMR2300r will meet the requirements of MIL-STD-461C, Notice 2, and MIL-STD-462, Notice 5.
APPLICATIONS PRECAUTIONS
the earth’s magnetic field are quite dramatic between
North America, South America and the Equator region.
Several precautions should be observed when using magnetometers in general:
•
The presence of ferrous materials—such as nickel, iron,
steel, cobalt—near the magnetometer will create disturbances in the earth’s magnetic field that will distort x,
y and z field measurements.
•
The presence of the earth’s magnetic field must be taken
into account when measuring other x, y and z, fields.
•
The variance of the earth’s magnetic field must be accounted for in different parts of the world. Differences in
•
Perming effects on the HMR board need to be taken
into account. If the HMR board is exposed to fields
greater than 10 Gauss (or 10 Oersted), then the board
must be degaussed. The result of perming is a high zero
field output code that may exceed specification limits.
Degaussing devices are readily available from local electronics outlets and are inexpensive. If the HMR board is
not degaussed, zero field offset values may result.
ORDERING INFORMATION
HMR2300r-422
HMR2300r-485
RS-422 Communication Standard
RS-485 Communication Standard
Customer Service Representative
1-800-238-1502 fax: (612) 954-2257
E-Mail: [email protected]
Honeywell reserves the right to make changes to any products or technology herein to improve reliability, function or design. Honeywell does not assume any liability
arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of others.
900232 Rev. B
1/99