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US Digital

A2T Absolute Optical Inclinometer

Overview

  • 12-bit accuracy and resolution field programmable from 2 to 4096 codes per revolution (3600 factory default)
  • Full 360 degrees range and position update rate is 250 times per second
  • Low power drain of 16 mA max., and 0.6 mA in sleep mode
  • Field programmable parameters such as setting zero position point (free demo software provided)
  • EEPROM stores downloadable parameters
  • 9600 baud default data rate adjustable up to 115K baud
  • 12-bit analog voltage output option (0 to +3.599 volts factory default setting. Field progammable up to 0 to +4.095 volts)
  • Multi-turn mode (note: power must be maintained to prevent reset to zero)
  • -25 to 70 degrees C. operating temperature
  • Simple, low cost

Product Specifications

Typical Settling Time 250mSec
Natural Pendulum Time Period 140mSec
Natural Pendulum Frequency 7.4Hz (preliminary)
Position Error 0.1 max.
Mounting 3" diameter bolt circle or 2-hole on an edge
Weight 9.40oz.

damping-response-table_0.gif

Damping is a balance between response time and ringing. Standard damping will fit most applications. Double damping slows the settling time by several hundred milli-seconds, not by ringing, but by more slowly approaching the final position. Soma applications may require double damping to average out cyclic motion such as found in moving vehicles. Damping options can be specified when ordering.

The analog version of the A2T 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 4.095V which is 1 milli-volt per bit. The value the internal microcontroller sends to the DAC is the same as the digital value that it sends to the host. Since the resolution (which represents the number of CPR) is field programmable, the range of the DAC will also follow that setup. Our default resolution is 3600 CPR, 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 3.599V. If you want the DAC to have the full range to 4.095V, set the single turn resolution to 4096. This is easily done with the available software which runs on a PC.

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

Sealed Housing:
The sealed housing option enables the encoder to be reasonably capable of surviving in liquid environments, but this encoder is NOT water proof.

Notice:
In applications where a failure could result in an unacceptable loss, we recommend that your system be designed to include two redundant inclinometers with the outputs from both continuously compared, making sure they agree. If there is a discrepancy, the system should be designed to automatically shut down as a fail-safe measure to minimize the risk of damage or danger. This product is not certified for applications where a failure could result in a costly, dangerous or life threatening situation.

ParameterMin.Max.Units
Supply Temperature -40 100 C
Operating Temperature -25 70 C
Humidity (non-condensing) 0 95 %
Supply Voltage (PWR) 0 16 Volts
Data H, DataL, Busy+, Busy- -14 14 Volts
Positioning Update Rate - 2 mSec
ParameterMin.Typ.Max.Units
Supply Voltage (PWR) 5.5 - 16 Volts
Supply Current (active) - 14 16 mA
Supply Current (sleep) - - 0.60 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 - 1 LSB
  • Specifications apply over entire operating temperature range.
  • Typical values are specified at Vcc= 12V and 25C
PinDescription
1 Ground
2 Busy+
Analog+
3 Busy-
Analog-
4 Power
5 DataL
6 DataH

Product Description

The A2T is a single axis, digital gravity angle sensor. The A2T serves as a full 360 range absolute tilt sensing programmable level with either digital or analog output. Internally, a rotary bar coded disk is mounted to a weighted gravity driven wheel. A micro-controller strobes an LED to transfer the bar code image onto an optical linear array, then decodes the position every 2 mSec. Magnetic damping provides fast response and settling time while virtually eliminating overshoot and oscillations. An internal EEPROM stores field programmable parameters such as resolution, zero position, direction swap, and mode. This second generation design virtually eliminates the primary accuracy limitation of first generation inclinometers, which is sitation (hysteresis).

The interface of the A2T utilizes our SEI (Serial Encoder Interface) bus (see the SEI page). The SEI bus is a simple, quick, convenient network of devices interfacing to a RS232 serial port. The SEI bus supports from 1 to 15 devices on a single, 6-wire telephone-type cable up to 1000FT long (similar to RS-485).

US Digital offers two SEI interfaces: the AD2B adapter for interface to an RS232 port and the SEI-USB for interface to a USB port. One of these products is required in order to interface the A2T to a PC via our SEI bus. The wall-mount PS-12 power supply furnishes the power for all devices on the SEI bus.

US digital provides software free of charge for all products which require software for operation. The software comes on a CD with each product shipped or can also be down loaded from US Digital's website here. The software can be used as is or it can serve as an example for creating your own custom application. The absolute encoder software utilizes our SEI Explorer software to configure and communicate with the product from a PC platform.

Our absolute encoders may be used in many stand alone applications that do not require a PC interface. For these applications we provide detailed communications protocols for all of our absolute products (see the SEI Absolute Encoder Communications Protocol page).

Product Notes
  • Cables and connectors are not included and must be ordered separately.
  • US Digital warrants its products against defects in materials and workmanship for two years. See complete warranty for details.
Related

Purchasing

Configure and Purchase

1. Interface


2. Damping


3. Housing


Product Part Number
Quantity Price
1 $350.70
10 $313.95
50 $302.40
100 $289.80
Over 100 Call for quote
Quantity
Unit Price

$350.70

Subtotal

$350.70

For your convenience, use the above part number to order via phone 800.736.0194

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