ANGLE MEASUREMENT & CONTROL
| SENSORS M Inc. |
|
|||||
|
MEMS
Angular
Rate
Sensors
FPGA Real
Time Processing
|
An Accurate, Reliable & Low Cost Angle Sensing/Control Solution |
|
ANGLE MEASUREMENT & CONTROL |
| Models F20(16 Bit Raw Gyro Data) and F15 (12 Bit Raw Gyro Data) |
|
Angle |
+1023
to
-1024 |
Degrees
max. |
|
Angle
Rate
|
F20 ± 300°/sec F15 ± 250°/sec |
|
|
LCD
Display |
±999
|
Degrees |
|
Angle
Accuracy |
<±1°
Typical
Add: 0.005°/sec for F20 0.02°/sec for F15 0-60 seconds |
Degrees
Time from Set_Bias |
| Raw
Bias |
F20
±0.6°/sec.
F15 ±400 lsb |
|
|
IR
Detector
-
Reference
Position |
980 |
nm |
|
SPI
Bus
-
Data
Rate |
256
|
Hz |
|
Data Out
|
Angle, Angle Rate, Difference Angle & Status Word | 16 Bit signed 2's complement |
|
Data In
|
Commanded-To/Reference
Angle
+1023
to
-1024 Control Word |
16 Bit signed 2's complement |
|
Logic
Controls
|
||
|
Bias Compensation
|
Sample Period 2 Seconds | (5V CMOS) |
|
Reset Display
|
Resets LCD Display to "000" Degrees | (5V CMOS) |
|
Reset
|
Resets
Processor
and
Gyro |
(5V CMOS) |
|
Event Capture Start
/
Stop
|
Starts
Angle
Accumulation
Holds
Last
Value
on
Stop |
(5V CMOS) |
|
Power |
5
±
0.25
V
DC
-
85
ma
F20,
5 ± 0.25 V DC - 45 ma |
|
| Operaturing
Temperature
Range |
-
40°c
to +85°c¹ |
Units can be ordered without LCD |
| Storage
Temperature |
-55°c
to
+125°c¹ |
¹ LCD Limited to 0°c to +50°c |
| Notes |
| 1 |
Bias-
Compensation
|
All
angle
rate MEMS gyros have a bias that is variable over time and
temperature. The Bias Compensation command initiates a 2
second sampling and averages the bias signal under a zero
motion condition. This
bias sample is subtracted from the raw gyro
signals in the angle integrator. Typical compensated bias
performance is
0.005°/sec for Model F20. Model F15 bais
compensation is within 0.02°/sec
for up to 60 seconds. Recommended operation, if
possible, is to initiate a Bias Compensate command just prior to
an angular measurement. Bias Compensation/Removal
is active "High"
Typical raw Bias and
Bias Compensated data charts more |
|
| 2 |
Reset Display | This command resets the LCD and Angle Integrator to "000" degrees. Reset Display is active "High" | |
| 3 |
Reset |
Reset
clears
all
functions
to
the
power
up
condition.
Reset
is
active
"High" |
|
| 4 |
Event
Capture
Start
/Stop
|
Event
Capture
Start/Stop
starts
the
angle
accumulator
and
stops
the
accumulation.
It
is
active
"Low"
can
be
left
in
the
"Low
"
state
for
continuous
operation Event Capture Start/Stop holds the last Angle value when it is set to a '1' and can be employed when stepping to an angle and holding that position for a period of time. In this state the Angle accumulator is held constant and Gyro bias does not accumulate avoiding an error in Angle value when making the next angular move. |
|
| 5 |
IR
Detection
|
A
940
nm
IR
Detector
is
located
on
the
assembly
and
can
be
used
to
indicate
that
the
assembly
is
aligned
with
a
reference
or
home
position.
IR
Detection
(
Zero
Reference)
outputs
a
'1'
in
the
Status
word
.
The
IR
Detector
is
a
Lite-On_inc.
LTR-301
device
and a complementary IR source
is a Lite-On_inc. LTE-4206' The Zero Reference position has
a
green LED to indicate alignment with the reference source.
Data_Out(MOSI) Bit 55 is the Zero Reference with a '1' indicating
detection of an IR Emitter. Zero Reference when gated with
the Home Command" resets the angle accumulator to 0°
as
as the assembly physically passes by
the Zero Reference point. This has the effect of removing
short term accumulated bias as the assembly passes Zero Reference. |
| Timing |
 |
| Data is available when SEL is "low" MOSI is data out MISO is data in to unit |
| MOSI
Data Out |
Bit 0 - 15 | Raw Angle Rate | MSB Bit 0 | LSB
Bit
15
|
Bit
0
is
Sign
Bit 2' Complement |
|
| Bit 16 - 31 |
Angle
|
MSB Bit 16 | LSB Bit 31 | |||
| Bit 32 - 47 | Difference Angle | MSB Bit 32 | LSB Bit 47 | |||
| Bit
48
-
55 |
Status |
Reserved |
Bits
48-54 |
|||
| Zero
Reference |
Bit 55 '1' = @ ZeroReference Position |
|||||
| MISO
Data IN |
Bit
8
-
23 Bits 0-7 |
Commanded-to
Angle
Rate Command Word² |
MSB Bit 8 | LSB Bit 23 |
|
|
| Clock |
Hz |
Pulsewidth
|
1
=
4.09 |
0
=
4.09 |
Microseconds |
| SEL |
1 |
7 | EVENT
START_STOP |
| MISO
DATA
IN |
2 |
8 |
RESET_ALL |
| SPI
CLOCK |
3 |
9 |
RESET_DISPLAY |
|
MOSI-DATA
OUT |
4 |
10 |
SET_BIAS |
| RESERVED |
5 |
11 |
RESERVED |
| +5VDC |
6 |
12 |
GROUND
Note:
Pins
7-10
should
be
grounded
if
unused |
| 12 PIN I/O
HEADER "0.1" |
| ²
Command
Word |
BIT |
0 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
| BIT
0 |
RESERVED |
||
| BIT
1 |
RESERVED |
||
| BIT
2 |
|||
| BIT3 |
Reset_Display |
||
| BIT
4 |
Set_Bias |
||
| BIT
5 |
Event
Start_Stop |
||
| BIT6 |
Reset_All |
||
| BIT
7 |
Enable
Zero
Reference
Bias |