Rockwell Automation GMLC Reference Manual - Manual (Page 711)

Publication GMLC-5.2 - November 1999
674 Using AxisLink
If a virtual axis connection could not be established by a Virtual Axis
Control block (the axis, motion controller, or ALEC could not be found),
the link is said to have failed. When an attempted connection fails,
AxisLink_failed = 1, Axis_fault = 6, Axis_status = 13, and
Global_fault = 9. In addition, the AxisLink LED on the front panel
flashes green. The typical causes of an AxisLink failure are:
• The controller address specified in the Virtual Axis Control block
does not match any of the modules (motion controllers or ALECs) on
the link.
• The module containing the physical axis to which the virtual axis is
linked has failed, has disabled AxisLink, or has not finished powering
up.
• The physical axis on the controller specified in the Virtual Axis
Control block does not exist (axes 2 and 3 on a two-axis controller,
for instance) or is disabled in the Axis Use definition in that
controller.
• The AxisLink cable is broken or disconnected.
After identifying and correcting the cause of the problem, clear the virtual
axis fault with a Reset AxisLink Fault block or by setting the
AxisLink_timeout or AxisLink_failed variable for the virtual axis to 0
using an Equation block. Then re-enable the virtual axis using a Virtual
Axis Control block.
AxisLink General Faults
When an AxisLink general fault (an AxisLink fault not directly associated
with a virtual axis) occurs, the Global_fault variable has a value of 8, and
the message “AxisLink General Fault” appears in the global fault field in
the Terminal window (and in the Runtime Display, if enabled). An
AxisLink general fault (Global_fault = 8) is second in priority only to an
AxisLink virtual axis fault.
An AxisLink general fault is caused by:
• By an AxisLink timeout while attempting to access another motion
controller’s AxisLink outputs or data.