Rockwell Automation 57C422B 2 Axis Servo Module - Manual (Page 66)

4-38 2-Axis Servo Module M/N 57C422B
position error specified in register 8. Note that this bit can
also be set when the axis is in the velocity mode. See 4.34
for more information about velocity mode.
The output clamped bit indicates that the output reference
generated by the module is greater than or equal to the value
in register 31. It does not turn the control off.
The feedback fault bit is set when the control loop is disabled
due to a severe fault reflected in this same register (note that
bit 7 in this register is not considered a fault bit). The
feedback fault bit is also set if register 65, bit 0 is 0, i.e., the
control loop is not enabled.
The illegal command bit is set in response to an illegal
command. An illegal command is an attempt to issue more
than one command (in registers 66 or 67) at the same time,
or providing illegal parameters for a command, e.g., an
acceleration rate of zero for a move command. This bit is
reset by writing a zero to registers 66 and 67.
The system fault bit is set whenever the processor does a
cold start, a STOP ALL / CLEAR command is issued from
the programming terminal, or a processor module fails. This
bit indicates that the communication between the processor
module and the axis module has been broken. When this
happens, feedback will be disabled, and the drive reference
will be set to zero.
4.39 Registers 74, 75: Current Feedback
Position
Registers 74, 75 contain the current feedback position.
Registers 74, 75 are only updated when the "latch status"
command in register 66 is issued. This ensures that data will
be consistent while the application software interrogates it.
The units are encoder counts.
Figure 4.38 – Current Feedback Position Registers