User`s guide

Chapter 11 167
Working with Automatic Test Systems
Detecting Occurrence of an Error
11. Working with Automatic
Test Systems
The error queue can be used in the following ways:
1. It is used as a branch for error handling. When an error queue is retrieved, it returns 0 as
the error number and “No error” as the error message if no errors detected. This can be
used for detecting of an error and for branching flow of a program. Also this is useful
when you wish to handle a specific error(s). Note that this method will not allow the
user to perform any processing in synchronization with an occurrence of an error.
2. When an error is detected using SRQ, the error queue is used to examine the error.
Refer to the example in Example 11-2.
Sample program
Example 11-2 is a sample program that demonstrates how to use an SRQ to detect
occurrence of an error. You can find the source file of this program, named srq_err.htb, on
the sample program disk.
This program sets SRQs then incidentally send an invalid parameter to generate an error,
which is handled by this program.In the error handling part, this program examines the
error, displays the error number and error message, and display the message indicating the
suspend of the program.
Line 40 Assigns a GPIB address to the I/O pass.
Lines 60 to 70 These lines enables the bit 2, 3 4 and 5 in the standard event status
register, and set the bit 5 to 1 in the service request enable register.
Lines 80 to 100 These lines clear the status byte register, the standard event status
register, and the error queue.
Lines 120 to 130 These lines set the branch target for an SRQ interrupt to enable SRQ
interrupts.
Lines 140 to 260 These lines set the measurement parameters and their data formats for
trace 1 and 2. An invalid parameter is given to the data format setting
for trace 2, causing an error.
Lines 280 to 330 These lines define an error handler that
Lines 290 to 300: These lines retrieve the error number and error
messages for the error from the error queue.
Lines 310 to 330 These lines displays the message indicating
occurrence of the error, the error number, the error message, and
the message showing that the program is suspend.
Line 350 Displays a closing message.Note that this message will not display
unless this program is re-executed after setting a corrected parameter
to the data format setting for trace 2.