US Digital

The analog version of the A2K has a 12-bit DAC on the output which feeds to 2 lines that are otherwise used for the BUSY handshaking pair. This DAC has a full range of 0 to 4.095 volts which is 1 milli-volt per bit. The value which the internal microcontroller sends to that DAC is the same as the digital value that it sends to the host. Since the resolution (which represents the number of codes per revolution) is field programmable, the range of the DAC will also follow that setup. Our default resolution is 3600 codes per revolution which yields 1 count per tenth of a degree. This makes the DAC output equal to 1 milli-volt per tenth of a degree or 0 to 3.599 volts. When the DAC needs to have the full range to 4.095 volts, the single turn resolution should be set to 4096. This is easily done with the available software which runs on a PC.  Cable CA-MD6A-SS-MD6-6FT and either the SEI-USB or the AD2B adapter are needed to interface the A2K analog version to a USB port or RS-232 serial COM port.

Please Note: The BUSY handshaking lines are replaced by the analog output option. This means that only one device will be able to be connected to the SEI bus when using the analog output option.

Parameter	Min.	Typ.	Max.	Units
Supply Voltage (PWR)	5.5	-	16	Volts
Supply Current (Active)	-	14	18.5	mA
Supply Current (Sleep)	-	-	1.5	mA
Analog Output Impedance (Anlg+)	950	1000	1050	Ohms
Zero Scale Analog Voltage	0	.0005	.003	Volts
Full Scale Analog Voltage	4.079	4.095	4.111	Volts
Differential Nonlinearity	-1.0	-	1.0	LSB

• Specifications apply over entire operating temperature range.
  
• Typical values are specified at Vcc= 12V and 25C.

 

Parameter	Min.	Max.	Units
Storage Temperature	-40	100	C
Operating Temperature	-25	70	C
Humidity (Non-condensing)	0	95	%
Supply Voltage (PWR)	0	16	Volts
DataH, DataL, Busy+, Busy-	-14	14	Volts
A2 Electrical tracking (Multi-turn Mode)	-	1800	RPM
A2 Electrical Tracking (Single-turn Mode)	-	3600	RPM
A2 Position Update Rate*	-	4	mSec

* The internal microcontroller takes a snapshot of the disk every 4 mSec. and stores the position in memory. It responds immediately to a "report position
request" by sending this value which is always the most current position.

Pin	Description
1	Ground
2	Busy+ Analog+
3	Busy- Analog-
4	Power
5	DataL
6	DataH

Part	Description
Centering Tools
CTOOL-(Shaft Diameter)	This reusable tool provides a simple method for accurately centering the A2K circuit board around the shaft. It is recommended for the following situations: When using mounting screws smaller than 4-40. When the position of the mounting holes is in question. Instructions: When mounting the encoder base, slide the centering tool down the shaft until it slips into the centering hole of the encoder base. Tighten the mounting screws, then remove the centering tool.
Hex Tools
HEXD-050	Hex driver, .050" flat-to-flat for 3-48 set screw.
HEXW-050	Hex wrench, .050" flat-to-flat for 3-48 set screw.
Spacer Tools
SPACER-13
Interfaces
SEI-USB	SEI to USB adapter
AD2B	SEI to RS-232 adapter

Shaft Speed	10,000 rpm max. continuous
Acceleration	10,000 rad/sec²
Weight	2.5 oz.
Moment of Inertia	0.0001 oz in s²
Shaft Length	0.60 to .80" from mounting surface

The A2K can be mounted using the 2 screws on the 1.812" bolt circle.  The is also the M-option 4-hole mounting plate which uses 4 screws on a 3" diameter bolt circle.

All encoder components, spacer tool, centering tool, hex wrench, 2 base mounting screws and 2 cover screws.

H-option

The H-option adds a hole in the housing allowing the shaft to pass through the encoder.

M-option

With the M-option adapter plate the 4 holes in the plate will mount to a 3" diameter bolt circle.

Illustration

 

Mechanical Spec

 

 

1. Base Mounting

Secure base by inserting screws through holes on the 1.812" bolt circle. Holes in base are designed for #4 screws. Use the centering tool to align base with existing shaft.

 

 

 

 

2. Spacer Installation

Place spacer tool on circuit board as shown. Position hub/disk assembly above shaft as shown. Slip over shaft and press down until hub and spacer tool bottom out against base.

 

 

 

3. Tightening Set Screw

Press the hub disk against the spacer tool and tighten the set screw with the hex wrench provided. The set screw should be snug, but do not overtighten. Remove the spacer tool.

 

 

 

 

4. Cover Installation

Important: Cover must be oriented as shown. Because cover plugs into the base, use caution during installation. The posts on the base are two different lengths. Match the cover to mate with the proper post. Connector pins can be damaged if not lined up properly. Secure with two 4-40 X 1" pan head screws provided.