1
2
3
4
5
6
7
App
Index
7-9
IM WT3001E-17EN
Status Reports
7.5 Output Queue and Error Queue
Output Queue
The output queue is provided to store response messages to queries. For example, if
you send the
WAVeform:SEND?
command, which requests the output of acquired data,
the data is stored in the output queue until it is read. As shown below, data are stored in
order and read from the oldest ones first. The output queue is emptied in the following
cases (in addition to when read-out is performed).
• When a new message is received from the controller.
• When a deadlock occurs (see page 5-2).
• When a device clear command (
DCL
or
SDC
) is received.
• When the instrument is power cycled.
The output queue cannot be emptied using the
*CLS
command. To see whether the
output queue is empty or not, check bit 4 (MAV) of the status byte.
D1
D2
D1
D2
D1
Error Queue
The error queue stores the error No. and message when an error occurs. For example, if
the controller sends an incorrect program message, the error number and message “
113,
"Undefined header"
” are stored in the error queue when the error is displayed. The
contents of the error queue can be read using the
STATus:ERRor?
query. As with the
output queue, the messages are read from the oldest ones first. When the error queue
overflows, the last message is replaced by the message “
350, "Queue overflow"
.”
The error queue is emptied in the following cases (in addition to when read-out is
performed).
• When a
*CLS
command is received
• When the instrument is power cycled.
To see whether the error queue is empty or not, check bit 2 (EAV) of the status byte.