6482-901-01 Rev. A / August 2012
Return to
13-17
Model 6482 Dual-Channel Picoammeter / Voltage Source Reference Manual
Section 13: Status Structure
Output queue
The output queue holds data that pertains to the normal operation of the instrument. For example,
when a query command is sent, the response message is placed in the output queue.
When data is placed in the output queue, the Message Available (MAV) bit in the status byte
register sets. A data message is cleared from the output queue when it is read. The output queue
is considered cleared when it is empty. An empty output queue clears the MAV bit in the status
byte register.
A message is read from the output queue by addressing the Model 6482 to talk after the
appropriate query is sent.
Error queue
The error queue holds error and status messages. As programming errors and status messages
occur, a message that defines the error or 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 or 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 and status messages. The commands to read the error
queue are listed in
. 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 error code 350,
“Queue Overflow,” will occupy the last memory location. On power-up, the error queue is empty.
When empty, the message “0, No Error” is placed in the queue.
Messages in the error queue are preceded by a code number. Negative (-) numbers are used for
SCPI-defined messages, and positive (+) numbers are used for Keithley-defined messages. The
messages are listed in
. As shown in
, 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
, there are
commands to enable and 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 specific 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 with
the null list parameter as follows: STATus:QUEue:ENABle ().
Summary of Contents for 6482
Page 3: ......
