Rockwell Automation 1771-QC , D17716.5.25 SER/B SERVO POS - Manual (Page 158)

Formatting and Interpreting Data Blocks
Chapter 7
7Ć76
During tach calibration, bit 15 of the most significant home position word
in the parameter block (loss-of-feedback detection enable) must also be
on.
This bit is ignored when the servo positioning assembly is in auto mode.
Bit 17 Get New Preset Value
When you turn on bit 17, the 1771-M3 controller requests a
command-block transfer to include the position preset for the axis. The
servo positioning assembly uses the position preset value when you issue
a preset command for the axis.
The command-taken bit of the status block is on as long as the
get-new-preset-value bit is on (unless the preset data results in a
programming error).
When bit 17 is off, the position preset words are not transferred to the
1771-M3 controller during command block transfer.
Note that the preset command causes the 1771-M3 controller to use the
position preset value that was transferred to the 1771-M3 controller
during execution of the most recently issued get-new-preset-value
command.
Position Preset Words
Two words of the command block are used to specify a new position
preset value for the axis (Figure 7.45). These two words are requested by
the 1771-M3 controller when the get-new-preset-value bit is on.
Note that bit 17 of the most significant position preset word specifies the
sign of the preset value (0=+, 1=-).
Preset values are in BCD format. The maximum value is 999.9999 in. or
19999.999 mm.