Interpolator (Block = 2); Position (Block = 3); Output Control (Block = 4) - Renishaw RPI30 User Manual

2.4 Interpolator (Block = 2)

2.4.1 Magnitude (Sub = 0)
Read only register containing the 12-bit magnitude of the input signal. To
convert to signal strength (100% = 1V p-p) divide by 20.47.
Bit 23 - 12
Function Zeros
Magnitude register definition.
2.4.2 Angle (Sub = 1, 2)
Read only registers containing the 12-bit angle in latched (1) and
unlatched (2) state. To convert to degrees multiply by 360/4096.
Bit 23 - 12
Function Zeros
Angle register definition.
Reading the magnitude register (0) captures the current angle into the
latched angle register (1). This allows the simultaneous reading of the
magnitude and angle.
2.4.3 Angle offset (Sub = 3)
Read only register containing the angle offset stored when the position
is zeroed. It can be reset to zero by the reset angle offset command.
Bit 23 - 12
Function Zeros
Angle offset register definition.
11 - 0
Magnitude – unsigned integer
11 - 0
Angle – unsigned integer
11 - 0
Angle offset – unsigned integer
SPI programming guide

2.5 Position (Block = 3)

2.5.1 Position (Sub = 0, 1)
Read only registers containing the full internal 44-bit position sign
extended to 48-bits in two registers, it isn't affected by the RPI30
emulation resolution setting. The high bytes register (1) is latched on
reading the low bytes register (0), therefore to read the position read
the low bytes first followed by the high bytes and concatenate the two.
Scale factor is lissajous wavelength / 4096, which for a nominal 158nm
lissajous is 38.574pm / LSB.
Bit
Definition Least significant 24 bits of position – signed integer
Low bytes (Sub = 0) register definition.
Bit 23 - 20
Definition Sign extended
High bytes (Sub = 1) register definition.

2.6 Output control (Block = 4)

The output control registers provide the functionality of the switches on
the RPI20, setting the address, direction and resolution of the parallel
bus. Register bits set to 0 are equivalent to the RPI20 configuration
switch being off, and 1 as the switch being on.
2.6.1 2.6.1 Parallel Bus Address (Sub = 1)
Read / write register containing the RPI30 address. It is loaded on
power up from the EEPROM. In order to change the value, the Enable
bus settings change command must be sent. Once the address
23 - 0
19-0
Most significant 20 bits of position
– signed integer
25