Rockwell Automation 1771-QC , D17716.5.25 SER/B SERVO POS - Manual (Page 92)

Formatting and Interpreting Data Blocks
Chapter 7
7Ć10
Bit 16 Loss of Feedback
This bit is meaningful only if you enable the loss-of-feedback detection
feature by setting bit 15 of the most significant home position word of the
parameter block.
If loss-of-feedback is enabled, and the servo positioning assembly detects
a loss of feedback, it turns on the loss-of-feedback bit in the status word.
If this bit is on, then the immediate stop bit in the status block is on,
indicating that the 1771-ES expander has executed an immediate stop
after detecting the loss-of-feedback.
Bit 17 Excess Error
If following error equals or exceeds the excess following error value you
enter in the parameter block, the 1771-M3 controller turns on this bit.
Since excess following error turns on immediate stop, the immediate stop
bit in the status block is also on. Additionally, if the 1771-ES expander
applies feedrate reduction to an axis for which excess error is greater than
the 106.25% built-in excess error value, then the feedrate reduction bit
(bit 12) of the first status word for the axis is on. If, however, the excess
error point you enter is less than 106.25%, then the feedrate reduction bit
is not on.
Second Status Word
The second status word (Figure 7.5) identifies the active moveset and
move as well as providing additional status bits.
CAUTION: The function of bits 06, 16, and 17 are different
from the function of the corresponding bits for the series A
servo positioning assembly. If you replace a series A assembly
with a series B assembly without changing your program
accordingly, you may cause unexpected results.