National Instruments NI-488.2 - Manual (Page 111)

Appendix C Error Codes and Solutions
NI-488.2 User Manual C-10 ni.com
ELCK (21)
ELCK indicates that the requested operation could not be performed
because of an existing lock by another process accessing the same interface.
ELCK is also returned when a process attempts to unlock an interface for
which it currently has no lock.
Solutions
Call
iblck
to lock the interface. If
iblck
continues to return ELCK,
lengthen the
LockWaitTime
and wait for the other process to relinquish its
interface lock.
Ensure that you have successfully locked the interface prior to unlocking it.
EARM (22)
EARM indicates that ibnotify ’s asynchronous event notification
mechanism failed to rearm itself. This generally occurs when an ibnotify
Callback has attempted to rearm itself by returning an illegal value or
when a fatal driver error (EDVR) has occurred.
Solutions
Ensure that the value being returned by your Callback function is a valid
ibnotify mask value.
Return a zero value from your Callback function to unregister the
asynchronous event notification mechanism. Then call
ibnotify to
re-enable notification.
EHDL (23)
EHDL results when an invalid handle is passed to a function call.
The following are some examples:
• A valid board handle is passed in as a handle parameter to a
device-level NI-488 function or a valid device handle is passed
in as a handle parameter to a board-level NI-488 function.
• An invalid board or device unit descriptor is passed as input to any
NI-488.2 function.