HEIDENHAIN PWM 20 - Manual (Page 237)

238 HEIDENHAIN ATS Software User's Manual
7.4.3 SSI synchronous serial interface with programming interface (older rotary encoders)
The absolute position value, beginning with the most significant bit, is transferred over the
data lines (DATA) in synchronism with a CLOCK signal from the control. A number of parameters
and functions can be programmed with the enclosed programming software.
In addition to the absolute position values the sinusoidal incremental signals with 1 Vpp level
are output. (Signal description:“Synchronous serial interface; programming via connector” on
page 235.)
The fault detection signal indicates fault conditions such as an interruption in the supply lines,
failure of the light source, etc.
Programmable functions and parameters
The encoders are programmed with HEIDENHAIN software on a personal computer. The
software can also be used to check the parameter settings. Some functions that have no
influence on the interface configuration can also be activated by hardware via the connector.
Interface  Output format of position values in Gray code or pure binary code
 Direction of rotation for increasing position values (also configurable via the connector)
 Data format synchronous-serial right-aligned or 25-bit fir tree format (SSI)
Position values  Singleturn resolution up to 8192 absolute positions per revolution, e.g. for adaptation to any
screw pitch
 Multiturn resolution up to 4096 distinguishable revolutions, e.g. for adaptation to the ball-
screw length
Setting the scaling  Factor for reducing the singleturn resolution
 Unit-distance integral reduction of singleturn or multiturn positions
Offset/preset  Offset and preset values for zeroing and compensation
 Setting the preset value defined by software through the connector
For further information refer to http://www.heidenhain.de on the Internet.
Note
With the ATS software you can check programmed SSI encoders, however you cannot
program them or alter the programming.