Control Techniques Nidec SI-EtherCAT User Manual page 101

The implementation of cyclic sync position mode will provide linear interpolation, which will always
cause a delay of one operating mode cycle. The time specified must always be an integer multiple
of the control loop cycle time; this will be checked. Every interpolator time period, a value will be
read from the target position object, and the interpolator will generate a new position command to
the control loops, every control loop cycle (between the current and new position).
7.7.2 0x6086 Motion Profile Type
This object is used to configure the type of motion to perform in motion profile modes.
Table 7-76 Motion Profile Type
0x6086 Motion Profile Type
Access: RW
Default: 0
PDO Mappable: No
Motion Profiles: CSP, PP
Motion profile to perform (values less than zero are manufacture specific)
-1 = Linear interpolation followed by linear extrapolation on data loss (CSP only see notes)
Description: 0 = Linear interpolation terminated on data loss
3 = Jerk limited (PP only)
Others - treat same as value 0
In Cyclic Synchronous Position mode, the AMC always needs to be supplied with updated values
every 250 µs, since PDOs may not always be exchanged at 250 µs, interpolation is used by the
EtherCAT module to provide linear values calculated from the previous and currently supplied
target value. The EtherCAT module can also use extrapolation, this is used when a target value
hasn't been supplied in the defined cyclic period caused by a PDO loss. In this case, linear
extrapolation of the target value is performed from the last two valid target values until a valid target
value is supplied. Extrapolation is currently only supported for Cyclic Synchronous Position mode.
SI-EtherCAT User Guide
Range: -32768 to
Size: 2 bytes
32767
Type: Signed integer / INT
Update rate: Read when state changes to Switch On
Unit: N/A
101