Emerson SM-ETHERCAT 0471-0128-02 - Manual (Page 40)

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SM-EtherCAT User Guide
www.controltechniques.com Issue Number: 2
7.4.2 0x60C1 Interpolation_data_record
This object is used to specify the target position. Linear interpolation is used to generate
position demand values every 250µs. The position is specified in user-defined position
units. The value is written into sub-index 1.
Table 7.33 0x60C1 Interpolation_data_record
7.4.3 0x60C2 Interpolation_time_period
The implementation of interpolated position mode allows synchronous operation only,
where a fixed, common interpolation interval is defined. The time specified must always
be an integer multiple of the control loop cycle time. The time period index has a
minimum value of -6 (i.e. the smallest time unit will be microseconds), see Table 7.35 for
more information.
0x60C1 Interpolation_data_record
Sub-index 0
Access: RO Range: N/A Size: Unsigned 8 Unit: N/A
Default: 1
Description: This object is used to specify the target position.
Sub-index 1
Access: RW Range: 0 to 0xFFFFFFFF Size: Unsigned 32 Unit: N/A
Default: N/A
Description: The set-point
Table 7.34 Interpolation_time_period
0x60C2 Interpolation_time_period
Sub-index 0
Access: RO Range: N/A Size: Unsigned 8 Unit: N/A
Default: 2
Description: The number of last sub-indexes in this object.
Sub-index 1
Access: RW Range: 0 to 255 Size: Unsigned 8 Unit: (sub-index 2)
Default: 250 (units are dependant on the value in sub-index 2)
Description: The number of time units between interpolator re-starts. A time unit is defined by sub-index
2. The interpolator time period value is checked to ensure that it is valid. Valid values are
250µs, 500µs or any multiple of 1ms. An attempt to write other values results in an SDO
Abort code.
Sub-index 2
Access: RW Range: -6 to 0 Size: Signed 8 Unit: N/A
Default: -6 (a time unit of 1 µs )
Description: This specifies the time unit for the interpolation time period. Sub-index 2 specifies the unit
exponent. The time unit, therefore, is 10(sub-index 2). The range of values allows for the
shortest time unit to be 1µs, and the longest to be 1s.
Table 7.35 Interpolation time period units
Value in 0x60C2, sub-index 2 Description
0 1 second
-1 0.1 of a second
-2 0.01 of a second
-3 0.001 of a second
-4 0.0001 of a second
-5 0.00001 of a second
-6 0.000001 of a second