CUI AMT203-2300 12 bit absolute encoder Datasheet

date
04/2010
page 1 of 8
PART NUMBER: AMT203
DESCRIPTION:
12 BIT ABSOLUTE ENCODER
This encoder is a 12 bit absolute rotational encoder with SPI serial bus for working as a slave to an external
microprocessor. Incremental A,B and Index signals are provided for high speed operation. The Index is one pulse
per 22.5 degree (16 index per turn).
The encoder contains two channels of a capacitive encoder: a Fine channel and a Coarse channel. The Fine channel
has 16 wavelengths of a periodic capacitive pattern, while the Coarse channel has 5 wavelengths. Each channel has
its own ASIC that interpolates to a resolution of 256 increments per wavelength. A microprocessor on the encoder
PCB is combining the two channels for a position reading that is absolute over a full turn with 12 bit resolution.
ELECTRONIC SPECIFICATIONS
parameter
conditions/description
power supply
min
nom
max
2.7
5
5.5
V
8
10
mA
current consumption
output resolution
1024
incremental output signals
A, B, Z phase
incremental output waveform
square wave
incremental outputs
output voltage - sourcing to +5 V @ -32 mA
output voltage - sinking to ground @ -32 mA
index output
one index pulse per 1/16 turn
SPI output
natural binary
SPI bus
PIC 16F690 (see datasheet)
ppr
3.8
SPI resolution
units
0.55
V
V
12
bit
max
units
MECHANICAL SPECIFICATIONS
parameter
conditions/description
min
nom
output range
SPI speed
mounting hole options
360
deg
8000
RPM
max
units
85
°C
A) 2 each M1.6 holes on 16 mm (0.63”) bolt circle
B) 2 each #4 holes on 19.05 mm (0.75”) bolt circle
C) 2 each M1.6 or M2 holes on 20 mm (0.787”) bolt
circle
D) 3 each M1.6 or M2 holes on 20.9 mm (0.823”)
bolt circle
E) 3 each M1.6 or M2 holes on 22 mm (0.866”) bolt
circle
F) 4 each M1.6 or M2 holes on 25.4 mm (1”) bolt
circle
G) 2 each #4 holes on 15.75 mm (0.62”) x 20.96
(0.825”) hole layout*
H) 2 each #4 holes on 32.43 mm (1.277”) bolt circle*
I) 2 each #4 holes on 46.03 mm (1.812”) bolt circle*
ENVIRONMENTAL SPECIFICATIONS
parameter
conditions/description
min
operating temperature
-25
storage temperature
-40
humidity
vibration
nom
100
85
1.5mm, 3 directions, 2 hours
20050 SW 112th Ave. Tualatin, Oregon 97062
10
phone 503.612.2300
°C
%RH
55
fax 503.612.2380 www.cui.com
Hz
date
04/2010
page 2 of 8
PART NUMBER: AMT203
12 BIT ABSOLUTE ENCODER
DESCRIPTION:
AMT203-V KIT
In order to provide maximum flexibility for our customers, the AMT203 series is provided in kit form standard. This allows the user to
implement the encoder into a range of applications using one sku#, reducing engineering and inventory costs.
SLEEVES
8mm
1/4 inch
(6.35mm)
6mm
5mm
3/16 inch
(4.76mm)
4mm
1/8 inch
(3.175mm)
3mm
2mm
Blue
Snow
Red1
Green1
Yellow1
Gray60
Purple1
Orange
Light Sky Blue
TOOL A
BASE
TOP COVER
TOOL B
SHAFT
ADAPTER
CUSTOM CONFIG KEY
For customers that prefer a specific AMT203 configuration, please reference the custom configuration key below.
AMT203 - XXXX
Sleeve Bore Diameter:
2000 = 2 mm
2300 = 2.3 mm
3000 = 3 mm
3175 = 3.175 mm (1/8”)
4000 = 4 mm
4760 = 4.76 mm (3/16”)
5000 = 5 mm
6000 = 6 mm
6350 = 6.35 mm (1/4”)
8000 = 8 mm
20050 SW 112th Ave. Tualatin, Oregon 97062
phone 503.612.2300
fax 503.612.2380 www.cui.com
date
04/2010
page 3 of 8
PART NUMBER: AMT203
12 BIT ABSOLUTE ENCODER
DESCRIPTION:
Connection to customer electronics
10 lead ribbon cable: Power (2); SPI (4); Quadrature (2); Index (1); Zero set (1)
Output lines can drive 20 mA.
#
color
function
1
black
T bit
2
white
IDX
3
grey
A or Count
4
purple
B or Udn
5
blue
MOSI
6
green
5V
7
yellow
SCK
8
orange
Ground
9
red
MISO
10
brown
CSN
IDX
1
T bit
B or UDN
A or Count
5V
MOSI
Ground
SCK
CSN
MISO
Tyco connector 1658621-1
Encoder Side
Demo Board Side
BROWN
1' 3"
(304.8mm)
BROWN
Round
Dual Shielding Jacket
BLACK
28 AWG
10 conductor
1.27 mm pitch
BLACK
3659-10-1FT-DMBD Demo Board Cable
(Cable available without Demo Board Connector)
20050 SW 112th Ave. Tualatin, Oregon 97062
phone 503.612.2300
fax 503.612.2380 www.cui.com
date
04/2010
page 4 of 8
PART NUMBER: AMT203
DESCRIPTION:
12 BIT ABSOLUTE ENCODER
10.30 0.406
R15.50 0.610
15.34 [0.604]
34.14 1.344
17.30
28.60 1.126
MOUNTING BASE
12.4000 .488
A (3 PLCS)
2.000 0.079
(4 PLCS)
R1.050 0.041
16.003 0.630
1.700 0.067
(2 PLCS)
TOLERANCE:
±0.05mm UNLESS OTHERWISE
SPECIFIED
19.050 0.750
.28 0.011
DETAIL A
SCALE 4 : 1
2.950 0.116
(2 PLCS)
RoHS
21.4500 .844
25.399 1.000
5.30mm
18.60mm
AMT 203 XXYY CUI INC.
US Patent No. 6892690
R1.20mm
SCALE 5:1
20050 SW 112th Ave. Tualatin, Oregon 97062
phone 503.612.2300
fax 503.612.2380 www.cui.com
date
04/2010
page 5 of 8
PART NUMBER: AMT203
DESCRIPTION:
12 BIT ABSOLUTE ENCODER
APPLICATION NOTES
Encoder operational mode
• Initiation mode: At power up the encoder starts by doing:
– Coarse channel measurement
– Fine channel measurement
– Combine fine with coarse for ABS position (natural binary)
The above takes about 1 ms. After this, the encoder switches to continuous operation.
• Tracking mode: Only the Fine channel is active and the MCU internal position register is updated with
data from Fine:
– MCU 12 bit position register is updated from Fine every 125 μs.
– The MCU position register can be lagging up to 120 μs from the real position. This error is
proportional to speed: e<0.75 deg/1k(rpm).
– The MCU is able to follow up to speeds of 8000 RPM and recover to full accuracy when speed
slows down.
– For accurate position update without above time delay, outputs for incremental A quad B or Count
and Up/Dwn from the Fine channel are provided. These outputs are operational up to 8000 RPM
and there is no speed error. There is an acceleration error dependent on an internal filter constant
of about 100 μs.
– When using the incremental output there also is an Index output available, with one index pulse
per 1/16 turn.
• Initiation mode can be repeated at standstill on command from the master MCU in the application.
– Loop time ~1 ms.
Serial Peripheral Interface Commands
The SPI or Serial Peripheral Interface Bus is a standard interface promoted by Motorola and Microchip among
others. It consists of 4 signals:
MOSI: Master Out Slave In
MISO: Master In Slave Out
SCK: Serial Clock
CSB: Chip Select Bar (active low)
SPI BUS
The SPI bus runs full duplex and transfers multiples of 8 bits in a frame. The SPI type is the most common
(CPOL=0, CPHA=0), also known as Microwire. Data is captured on the rising edge of SCK and the output data is
changed after the falling edge of SCK.
MISO
LSB
MSB
SCK
MOSI
LSB
MSB
Setup
CSB
Serial Peripheral Interface Bus (SPI) on AMT1025
20050 SW 112th Ave. Tualatin, Oregon 97062
phone 503.612.2300
fax 503.612.2380 www.cui.com
date
04/2010
page 6 of 8
PART NUMBER: AMT203
DESCRIPTION:
12 BIT ABSOLUTE ENCODER
Figure 7: SPI BUS Timing Diagram
The MSB data out on MISO is valid soon after CSB goes low. The MOSI data is valid soon after the falling edge of
SCK. The Encoder drives data out on MISO as long as CSB is low.
Normally, CSB goes low, then after 8 clocks the command is interpreted. CSB high resets the
clock counter, and terminates any command sequence.
SPI Commands:
The commands are all 8 bits long, the MSB is shifted in first, and is the leftmost bit shown in the documentation.
Encoder Protocol Considerations:
The Encoder is designed to operate with a high speed SPI link, in full duplex mode. This implies the host can issue commands and read data as quickly as necessary but there has to be an acknowledgement from the slave just
before the data is transferred.
Essentially the host issues a command, receives zero or more wait sequences (0xA5 or 1010,0101) then the echo
of the command followed by an optional payload.
So, for example to read the position, the host issues rd_pos (0x10 or 0001,0000), receiving a series of wait
sequences (0xA5) then a reflected rd_pos (0x10), then the MSB data followed by the LSB data.
It is recommended that the host leave a 20 us gap between reads to avoid extending the read time by forcing wait
sequences.
Command 0x00: nop_a5
This command is ignored by the Encoder and simply causes the next data to be read. The encoder responds with
0xA5 if there is nothing else to send.
Command 0x10: rd_pos
This command causes a read of the current position.
The sequence is as follows:
1) issue read command, receive idle character
2) issue NOP, receive idle character 0xA5 or 0x10
3) repeat step 2 if it is 0xA5
4) issue NOP and receive MSB position
5) issue NOP and receive LSB position
Note that it is possible to overlap commands, so instead of NOP is several steps above
the user could start another operation. The read and write FIFOs for the PCI streams are
16 bytes long and it is up to the user to avoid overflow.
20050 SW 112th Ave. Tualatin, Oregon 97062
phone 503.612.2300
fax 503.612.2380 www.cui.com
date
04/2010
page 7 of 8
PART NUMBER: AMT203
12 BIT ABSOLUTE ENCODER
DESCRIPTION:
Comand 0x50: init_cal_md
This command causes the encoder to enter calibration mode. In this mode the coarse and fine devices are
repeatedly read and the position is recalculated. The period for reading these devices is about 500 microseconds
each since the transmitters have to be turned on and off and the devices have to stabilize before reading.
Comand 0x60: norm_md
This command causes the encoder to go back to normal tracking mode.
Command 0x70: set_zero_point
This command sets the current position to zero and saves this setting in the EEPROM. The host should
send nop_a5 repeatedly after sending this command, the response will be 0xa5 while update is
proceeding and eeprom_wr is the response when update is finished.
Comand 0x80,<byte_address>,<data>: eeprom_wr
This command causes the data to be written to the address given in <byte_address>. The address can be 0x00 to
0x7f for 128 bytes of data.
Comand 0x81,<ctl_code>,<data>: ctl_eeprom _wr
This command causes the <data> byte to be written to the offset given in <ctl_code>. Only certain offsets are
valid: 0xFF is the coarse adjust for the absolute position calculation (default 6), 0xFD is the MSB offset for zero
adjustment (default 0), 0xFE is the LSB offset for zero adjustment (default 0).
Comand 0x90,<byte_address>,0x01: eeprom_rd
This command causes the data in eeprom at the given address to be read and put in the output fifo.
The sequence is as follows:
1) issue read command, receive idle character
2) issue NOP, receive idle character or 0x90 (echo of read command)
3) repeat step 2 if it is an idle character
4) issue NOP and receive
20050 SW 112th Ave. Tualatin, Oregon 97062
phone 503.612.2300
fax 503.612.2380 www.cui.com
date
04/2010
page 8 of 8
PART NUMBER: AMT203
DESCRIPTION:
12 BIT ABSOLUTE ENCODER
DATA Sampling:
Position data is read from the AMT devices inside the encoder every 120 μs; it takes approximately 30 μs to
transfer a byte of information so the breakdown is:
1) issue sample command: 30 μs
2) read 2 bytes of data: 60 μs
3) calculate, add zero offset, and save position: 30 μs
The position inside the AMT device is sampled at the end of step 1, and it is 0 to 25 us delayed at that point. So
the data inside the microprocessor is 95 to 120 μs delayed from the actual rotor position.
The SPI interface is capable of 2 MHz operation, and the data read operation consists of a command byte followed
by 3 or 4 byte read operations; this is 12 to 16 μs at the 2 MHz interface speed.
So there is a delay of 95 to 120 μs for the data to be ready, and a delay of 12 or more μs for the user to transfer
data from the encoder interface.
20050 SW 112th Ave. Tualatin, Oregon 97062
phone 503.612.2300
fax 503.612.2380 www.cui.com
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