Troubleshooting
Appendix C
GPIB-232CT-A for MS-DOS/Windows C- 2
© National Instruments Corp.
Troubleshooting Software Problems
If the following three conditions apply, the GPIB-232CT-A and the
NI -488.2 software are unable to communicate properly.
•
GPIB calls return with the ERR bit set in
ibsta
.
•
The value of
iberr
is EDVR.
•
The value of
ibcntl
is 122541, 188077, or 253613 (
1DEAD
,
2DEAD
,
or
3DEAD
in hexadecimal notation).
The solution depends on the value of
ibcntl
. The following paragraphs
contain troubleshooting tips for each of the
ibcntl
values.
•
If
ibcntl
is
1DEAD
, the software is unable to open and initialize the
serial communications port. You should reconfigure your
GPIB -232CT -A and software to verify that the settings match.
•
If
ibcntl
is
2DEAD
, the software is encountering serial overrun errors
when it attempts to access the GPIB-232CT-A box. Serial overrun
errors occur when the software is not able to service the serial interrupt
receiving a serial byte before the next serial byte arrives. One way to
eliminate this problem is to slow down the baud rate that the
GPIB -232CT-A and NI-488.2 software are using. Another way to
eliminate this problem is to unload any device drivers, TSRs, or
applications that you are using that might disallow interrupts over an
extended period of time.
•
If
ibcntl
is
3DEAD
, there is total miscommunication between the
NI -488.2 software and the GPIB-232CT-A. The only solution is to
power off the box and restart the computer. If the problem persists, try
using a different serial cable.