User manual

2400 Series SourceMeter
®
User’s Manual Status Structure 15-19
Error queue
The Error Queue holds error and status messages. When an error or status event
occurs, a message that defines the error/status is placed in the Error Queue.
When a message is placed in the Error Queue, the Error Available (EAV) bit in the
Status Byte Register is set. An error/status message is cleared from the Error
Queue when it is read. The Error Queue is considered cleared when it is empty.
An empty Error Queue clears the EAV bit in the Status Byte Register.
The Error Queue holds up to 10 error/status messages. The commands to read
the Error Queue are listed in Table 15-9. When you read a single message in the
Error Queue, the “oldest” message is read and then removed from the queue. If
the queue becomes full, the message “350, ‘Queue Overflow’” will occupy the last
memory location. On power-up, the Error Queue is empty. When empty, the mes-
sage “0, No Error” is placed in the queue.
Messages in the Error Queue are preceded by a code number. Negative (-) num-
bers are used for SCPI-defined messages, and positive (+) numbers are used for
Keithley-defined messages. The messages are listed in Appendix B. As shown in
Table 15-7, there are commands to read the entire message (code and message)
or the code only.
On power-up, all error messages are enabled and will go into the Error Queue as
they occur. Status messages are not enabled and will not go into the queue. As
listed in Table 15-9, there are commands to enable and/or disable messages. For
these commands, the <list> parameter is used to specify which messages to
enable or disable. The messages are specified by their codes. The following
examples show various forms for using the <list> parameter.
<list> = (-110) Single message
= (-110:-222) Range of messages (-110 through -222)
= (-110:-222, -220) Range entry and single entry (separated by a comma)
When you enable messages, messages not specified in the list are disabled.
When you disable messages, each listed message is removed from the enabled
list.
NOTE To prevent all messages from entering the Error Queue, send the enable
command along with the null list parameter as follows:
STATus:QUEue:ENABle ().