User`s manual

DS2100 User’s Manual SECTION 7: CANOPEN DRIVE PROFILE: DS402
PAGE 7-52 C27750-001
STATUS WORD
1. The status word is implemented as specified in the DS402 standard, with the following mode specific bits
Figure 7.27 Interpolated Position Mode Status Word
2. The “target reached bit” indicates that the target position has been reached (within position window). If the
Halt bit is set, it will indicate if the drive has stopped or not. See Section 7.20 Position Control Function
3. The “IP Mode active” bit indicates whether the mode is active or not.
GENERAL ISSUES
1. The Sub-Mode Select parameter has not been implemented since only linear interpolation is supported.
2. The interpolation time period is scaled internally to the number of position loops periods within this period,
and is limited to 1...255. This limits the largest interpolation time period to 255 mSecs. This reduces the
range that is specified in DS402, that in theory could go from 1x10
-128
…255x10
63
Seconds
3. In the case of the Ring Buffer no synchronisation occurs, instead the read pointer constantly cycles through
the data. In the case of the FIFO, the Synchronisation event (i.e. every X Syncs), causes the drive to read
all the data in its buffer. When the end of the data is reached it waits for the next synchronisation trigger.
4. Default Actual Buffer Size is set to Max Buffer Size, although standard says it should be 0.
5. Units of time period, if in data record, are determined using the interpolation time period index.
6. The default value of time period of 1mSec, matches the position loop rate, which means that in effect no
interpolation is done, and the buffer contains set points applied to the position loop every position loop
period.
7. In the case of buffer organisation = FIFO, the queue size is actually one less than the actual buffer size. In
this case there will always be one buffer entry which cannot be accessed, since buffer is considered empty
if read pointer = write pointer. The buffer is considered full, if incrementing write pointer, would make
both pointers equal.
8. Since scaling/limiting is done when data is written into the buffer,
• If the user changes the scaling related parameters such as position factor, position dimension etc… it
will have no effect until new data is written into the buffer.
• If the home position is changed, the data in the buffer will be relative to the home position, when the
records were written, not any new home position.
• If no data has been written to the buffer it contains all zeros. To prevent the drive moving to zero,
the position loop reference is set to the current position when the user sets the mode of operation.