Output Queue And Error Queue - YOKOGAWA TA720 User Manual

5.5 Output Queue and Error Queue

Overview of the Output Queue
The output queue is provided to store response
messages to queries. For example, when the
MEMory:SEND? query is sent to request output of the
acquired waveform, the response data will be stored in
the output queue until it is read out.
The example below shows that data is stored record
by record in the output queue, and is read out oldest
item 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 3-2).
• 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.
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Overview of the 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 "113" and the message "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.
If an overflow occurs in the error queue, the final
message will be replaced by 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.
IM 704510-17E
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5.5 Output Queue and Error Queue
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