This board features a power-on self-test that will do an accuracy check of each channel and report the results in the BIT Status register when complete. After power-on, the Power-on BIT Complete register should be checked to ensure that POST/PBIT/SBIT test is complete before reading the BIT Latched Status.

The background Built-In-Test or Continuous BIT (CBIT) (“D2”) runs in the background where each channel is checked to a test accuracy of 0.2% FS. The testing is totally transparent to the user, requires no external programming, and has no effect on the operation of the module or card.

The technique used by the continuous background BIT (CBIT) test consists of an “add-2, subtract-1” counting scheme. The BIT counter is incremented by 2 when a BIT-fault is detected and decremented by 1 when there is no BIT fault detected and the BIT counter is greater than 0. When the BIT counter exceeds the (programmed) Background BIT Threshold value, the specific channel’s fault bit in the BIT status register will be set. Note, the interval at which BIT is performed is dependent and differs between module types. Rather than specifying the BIT Threshold as a “count”, the BIT Threshold is specified as a time in milliseconds. The module will convert the time specified to the BIT Threshold “count” based on the BIT interval for that module. The “add-2, subtract-1” counting scheme effectively filters momentary or intermittent anomalies by allowing them to “come and go“ before a BIT fault status or indication is flagged (e.g. BIT faults would register when sustained; i.e. at a ten second interval, not a 10-millisecond interval). This prevents spurious faults from registering valid such as those caused by EMI and/or dirty power causing false BIT faults. Putting more “weight” on errors (“add-2”) and less “weight” on subsequent passing results (subtract-1) will result in a BIT failure indication even if a channel “oscillates” between a pass and a fail state.

The DS and DR modules supports an off-line Initiated Built-In Test (IBIT) (“D3”).

IBIT test starts an initiated BIT test that utilizes an internal stimulus to generate and test the full-scale positional range to a default test accuracy of 0.1% full scale range. IBIT test cycle is completed within 30 seconds and the result can be read from the BIT status registers when IBIT bit changes from 1 to 0.

Function: Turns on the selected channel and initiates output.

Type: unsigned binary word (32-bit)

Data Range: 0x0000 0000 - 0x0000 0007 (for supporting up to 3 channels)

Read/Write: R/W

Initialized Value: 0x0000 0000

Operational Settings: To turn on the selected channel, set the bit to 1.

Function: Sets synchro or resolver angle data in each channel for single-speed or multi-speed applications.

Type: unsigned binary word (32-bit)

Range: 0 to 359.9999 degrees

Read/Write: R/W

Initialized Value: 0°

Operational Settings: For single-speed applications (Ratio=1), write a 32-bit integer to the corresponding channel D/S Data Register.

          WORD = Angle / (360/ 2^32)

LSB is 360/2³² or approximately 0.00000008382 degrees. The upper 24 bits define the angle, while the lower 8 bits are at zero.

The module can automatically simulate two-speed applications (applies only to multiple channel modules. By entering a ratio in the DS Ratio Mode Ch ½ register, the fine channel (channel 2) will automatically output an angle proportional to the programmed coarse channel (channel 1) angle, multiplied by the ratio programmed.

Function: Sets signal voltage “VL-L” to a corresponding register.

Type: unsigned binary word (32-bit)

Range: 2-28 or 28-90 VL-L depending on model

Read/Write: R/W

Initialized Value: 26 VL-L for low voltage modules and 90 VL-L for high voltage modules.

Operational Settings: The output voltage is set with a resolution of 10 mV_RMS. The setting is in integer decimal format.

For example, if channel 1 Signal (VL-L) voltage is to be 11.8 V_RMS, the set word to the corresponding register would be 1180.

Function: Sets reference voltage “V_REF” to a corresponding register.

Type: unsigned binary word (32-bit)

Range: 26 V_REF for low voltage module or 115 V_REF for high voltage module

Read/Write: R/W

Initialized Value: 2 or 28 VL-L depending on model

Operational Settings: The input voltage is set with a resolution of 10 mV_RMS. The setting is in integer decimal format.

For example, if channel 1 expected input REF voltage is 26.0 V_RMS, the set word to the corresponding register would be 2600.

Function: Enables setting the phase (in degrees) of each channel to an offset of the Reference.

Type: unsigned binary word (32-bit)

Range: ± 90°

Read/Write: R/W

Initialized Value: 0°

Operational Settings: The phase offset has 24-bit resolution put into the MSBs of the 32-bit word.

Word = Phase / (360/2^32%).

Function: Enables selection of either ratiometric (ratio) or absolute (fixed) mode output voltages.

Type: unsigned binary word (32-bit)

Range: NA

Read/Write: R/W

Initialized Value: 0 = Ratiometric

Operational Settings: Ratiometric Mode, when selected, will cause the output signal voltage of the channel to vary with the input Reference Voltage. Fixed Mode, when selected, will cause the output signal voltage of the channel NOT to vary with the input Reference Voltage. Set corresponding channel bit to 0 for Ratiometric Mode. Set corresponding channel bit to 1 for Fixed Mode.

Function: Sets channel for continuous or start/stop rotation.

Type: unsigned binary word (32-bit)

Range: NA

Read/Write: R/W

Initialized Value: NA

Operational Settings: For continuous rotation, set the corresponding channel bit to 0. For rotation to cease at a designated stop angle, set the bit to 1. For 2-speed applications, only the odd (coarse) channel needs to be programmed (Ch1).

Function: Stops rotation on selected channel when desired stop angle is reached.

Type: unsigned binary word (32-bit)

Range: 0 to 359.9999 degrees

Read/Write: R/W

Initialized Value: 0

Operational Settings: Word = Angle /(360/2³²)

Function: Sets rotation rate for selected channel.

Type: signed binary word (32-bit)

Range: +/-9.999 dps

Read/Write: R/W

Initialized Value: 0

Operational Settings: Write a 2’s complement number representing the desired rotation rate. LSB = 0.015°/sec.

For example, 12 RPS = (12 x 360°/0.015° = 288000 = 46500h), -12 RPS = (-12 x 360°/0.015° = -288000 = FFFB9B00h)

Function: Set this register after Rotation Rate register has been set. Will start rotating in continuous or start/stop rotation mode.

Type: unsigned binary word (32-bit)

Range: NA

Read/Write: R/W

Initialized Value: 0

Operational Settings: To start rotation for the corresponding channel, write a 1 to the corresponding channel.

Function: Stops a channel from rotating when a 1 is written to the corresponding bit location.

Type: unsigned binary word (32-bit)

Range: NA

Read/Write: R/W

Initialized Value: 0

Operational Settings: To stop rotation for the corresponding channel, write a 1 to the corresponding channel.

Function: Sets the ratio from the coarse channel (channel 1) to the fine channel (channel 2).

Type: unsigned binary word (32-bit)

Range: 1 to 255

Read/Write: R/W

Initialized Value: 1

Operational Settings: Set desired ratio between coarse (channel 1) and fine (channel 2) channels to be used as a two-speed channel.

Example 1: In single speed mode, set this register to 1. This will allow channel 2 to be controlled by its own set angle register.

Example 2: For a 36:1 ratio, set this register to 36. Now, the set angle for channel 2 will be equal to the set angle of channel 1, multiplied by 36.

Function: Measures the output angle.

Type: unsigned binary word (32-bit)

Range: 0-359.9999

Read/Write: R

Initialized Value: 0

Operational Settings: Measured angle in degrees = value * (360/2³²).

Function: Reads CW and CCW velocity of each channel in degrees per second (dps).

Type: unsigned binary word (32-bit)

Range: ±10,000 dps

Read/Write: R

Initialized Value: 0

Operational Settings: Velocity registers of each channel are read as a two’s complement word, with 0x7FFFh FFFF being maximum CW rotation, and 0x8000 0000 being maximum CCW rotation. LSB = 0.015°/sec.

To convert a velocity word to dps: Velocity in dps = value * 0.015 (0.015 degree/second resolution)

Function: Reads each channel’s input reference frequency.

Type: unsigned binary word (32-bit)

Range: Depends on model

Read/Write: R

Initialized Value: 0 Hz

Operational Settings: The input reference frequency is reported to a resolution of 1 Hz. The output is in integer decimal format. For example, if channel 1 input excitation is 400 Hz, the output measurement word from the corresponding register would be 400.

Function: Reads each channel’s output signal voltage V_L-L.

Type: 32-bit unsigned integer

Range: unsigned binary word (32-bit)

Read/Write: R

Initialized Value: 0 VLL

Operational Settings: The output voltage is reported to a resolution of 10 mV_RMS. The output is in integer decimal format. For example, if channel 1 output signal voltage is 11.8 V_RMS, the output measurement word from the corresponding register would be 1180.

Function: Reads each channel’s input signal reference voltage (V_REF).

Type: 32-bit unsigned integer

Range: unsigned binary word (32-bit)

Read/Write: R

Initialized Value: 0 V_REF on power up

Operational Settings: The input voltage is reported to a resolution of 10 mV_RMS. The output is in integer decimal format. For example, if channel 1 input VREF voltage is 26.0 V_RMS, the output measurement word from the corresponding register would be 2600.

Function: Displays the measured current on the channel’s output.

Type: unsigned binary word (32-bit)

Range: NA

Read/Write: R

Initialized Value: 0

Operational Settings: Measures current in milliamps.

Function: Programmable status threshold to indicate when the measured VLL falls below this value.

Type: unsigned binary word (32-bit)

Range: 0 to 90 VL-L

Read/Write: R/W Initialized Value: 80% of default DS output voltage.

Operational Settings: The signal loss detection circuitry can be tailored to report a signal loss (at Signal Loss Status register) at a user defined threshold. This threshold can be set to a resolution of 10 mVL-L. Program the threshold by writing the value of the voltage threshold in integer decimal format. For example, if Channel 1 signal loss voltage threshold is to be 7 VL-L, the programmed word to the corresponding register would be 700 (2BCh).

Function: Programmable status threshold to indicate when the measured VREF falls below this value.

Type: unsigned binary word (32-bit)

Range: 0 to 115 Vrms

Read/Write: R/W

Initialized Value: 80% of the default expected reference

Operational Settings: The reference loss detection circuitry can be tailored to report a reference loss at a user defined threshold. This threshold can be set to a resolution of 10 mVrms. Program the threshold by writing the value of the voltage threshold in integer decimal format. For example, if channel 1 input reference loss voltage threshold is to be 20 V_RMS, the programmed word to the corresponding register would be 2000 (7D0h).

This module features a power-on self-test that will perform an accuracy check on each channel. In addition, two different tests, one on-line (CBIT) and one off-line (IBIT), can be selected. External reference voltage is not required for any of these tests.

Function: Set bit in this register to enable associated Built-In Self-Test IBIT and CBIT.

Type: unsigned binary word (32-bit)

Data Range: 0x0000 to 0x000D

Read/Write: R/W

Initialized Value: 0x4 (CBIT Test Enabled)

Operational Settings: BIT tests include an on-line (CBIT) test and an off-line (IBIT) test. Failures in the BIT tests are reflected in the BIT Status registers for the corresponding channels that fail. In addition, an interrupt (if enabled in the BIT Interrupt Enable register) can be triggered when the BIT testing detects a failure.

Function: Allows user to verify if the CBIT test is running.

Type: unsigned binary word (32-bit)

Data Range: 0x0000 0000 to 0xFFFF FFFF

Read/Write: R/W

Initialized Value: 0

Operational Settings: User can write any value to this register. If CBIT test is running, after a minimum of 10ms the value read back will be 0x0000 0055, otherwise the value read back will be the value written.

Function: Determines whether to update the status for the channels. The feature can be used to “mask' status bits of unused channels in status registers that are bitmapped by channel

Type: unsigned binary word (32-bit)

Data Range: 0x0000 0000 - 0x0000 FFFF

Read/Write: R/W

Initialized Value: 0x0000 FFFF

Operational Settings: When the bit corresponding to a given channel in the Channel Status Enabled register is not enabled (0), the statuses will be masked and report “0” or “no failure”. This applies to all statuses that are bitmapped by channel (BIT Status, Signal Loss Status, Reference Loss Status, Phase Lock Status, DS Rotation Status and Overcurrent Status). When the bit corresponding to a given channel is enabled (1), it will allow the statuses for that channel to be updated.

There are four registers associated with the BIT Status: Dynamic, Latched, Interrupt Enable, and Set Edge/Level Interrupt.

Function: Sets the corresponding bit associated with the channel’s BIT error.

Type: unsigned binary word (32-bit)

Data Range: 0x0000 0000 to 0x0000 0007

Read/Write: R (Dynamic), R/W (Latched, Interrupt Enable, Edge/Level Interrupt)

Initialized Value: 0

There are four registers associated with the Signal Loss Status: Dynamic, Latched, Interrupt Enable, and Set Edge/Level Interrupt.

Function: Sets the corresponding bit associated with the channel’s Signal Loss error.

Type: unsigned binary word (32-bit)

Data Range: 0x0000 0000 to 0x0000 0007

Read/Write: R (Dynamic), R/W (Latched, Interrupt Enable, Edge/Level Interrupt)

Initialized Value: 0

There are four registers associated with the Reference Loss Status: Dynamic, Latched, Interrupt Enable, and Set Edge/Level Interrupt.

Function: Sets the corresponding bit associated with the channel’s Reference Fault Low error.

Type: unsigned binary word (32-bit)

Data Range: 0x0000 0000 to 0x0000 0007

Read/Write: R (Dynamic), R/W (Latched, Interrupt Enable, Edge/Level Interrupt)

Initialized Value: 0

There are four registers associated with the Phase Lock Status: Dynamic, Latched, Interrupt Enable, and Set Edge/Level Interrupt.

Function: Sets the corresponding bit associated with the channel’s Phase Lock error.

Type: unsigned binary word (32-bit)

Data Range: 0x0000 0000 to 0x0000 0007

Read/Write: R (Dynamic), R/W (Latched, Interrupt Enable, Edge/Level Interrupt)

Initialized Value: 0

There are four registers associated with the DS Rotation Status: Dynamic, Latched, Interrupt Enable, and Set Edge/Level Interrupt.

Function: Sets the corresponding bit associated with the channel’s DS Rotation error.

Type: unsigned binary word (32-bit)

Data Range: 0x0000 0000 to 0x0000 0007

Read/Write: R (Dynamic), R/W (Latched, Interrupt Enable, Edge/Level Interrupt)

Initialized Value: 0

There are four registers associated with the Overcurrent Status: Dynamic, Latched, Interrupt Enable, and Set Edge/Level Interrupt.

Function: Sets the corresponding bit associated with the channel’s Overcurrent error.

Type: unsigned binary word (32-bit)

Data Range: 0x0000 0000 to 0x0000 0007

Read/Write: R (Dynamic), R/W (Latched, Interrupt Enable, Edge/Level Interrupt)

Initialized Value: 0

Function: Set an identifier for the interrupt.

Type: unsigned binary word (32-bit)

Data Range: 0x0000 0000 to 0xFFFF FFFF

Read/Write: R/W

Initialized Value: 0

Operational Settings: When an interrupt occurs, this value is reported as part of the interrupt mechanism.

Function: Sets where to direct the interrupt.

Type: unsigned binary word (32-bit)

Data Range: See table Read/Write: R/W

Initialized Value: 0

Operational Settings: When an interrupt occurs, the interrupt is sent as specified: