GPIB IEEE Std. 488.2 Error Handling – Query Error Register
The IEEE 488.2
the instrument is addressed to talk and the response formatter is inactive and the input queue is
empty then the
Standard Event Status Register, a value of 3 to be placed in the Query Error Register and the parser
to be reset. See the Status Reporting section for further information.
The IEEE 488.2
send a response message and a
the input queue contains more than one END message then the instrument has been
and an error is generated. This will cause the Query Error bit to be set in the Standard Event Status
Register, a value of 1 to be placed in the Query Error Register and the response formatter to be
reset thus clearing the output queue. The parser will then start parsing the next
from the input queue. See the Status Reporting section for further information.
UNIT>
The IEEE 488.2
response message and the input queue becomes full then the instrument enters the
and an error is generated. This will cause the Query Error bit to be set in the Standard Event Status
Register, a value of 2 to be placed in the Query Error Register and the response formatter to be
reset thus clearing the output queue. The parser will then start parsing the next
from the input queue. See the Status Reporting section for further information.
UNIT>
GPIB Parallel Poll
Complete parallel poll capabilities are offered on this instrument. The Parallel Poll Enable Register
is set to specify which bits in the Status Byte Register are to be used to form the
The Parallel Poll Enable Register is set by the *PRE <nrf> command and read by the *PRE?
command. The value in the Parallel Poll Enable Register is ANDed with the Status Byte Register; if
the result is zero then the value of
The instrument must also be configured so that the value of
during a parallel poll operation. The instrument is configured by the controller sending a Parallel Poll
Configure command (PPC) followed by a Parallel Poll Enable command (PPE). The bits in the PPE
command are shown below:
Example.
To return the RQS bit (bit 6 of the Status Byte Register) as a 1 when true and a 0 when false in
bit position 1 in response to a parallel poll operation send the following commands
The parallel poll response from the instrument will then be 00H if RQS is 0 and 01H if RQS
is 1.
During parallel poll response the DIO interface lines are resistively terminated (passive termination).
This allows multiple devices to share the same response bit position in either wired-AND or wired-
OR configuration, see IEEE 488.1 for more information.
error (addressed to talk with nothing to say) is handled as follows. If
UNTERMINATED
error is generated. This will cause the Query Error bit to be set in the
UNTERMINATED
error is handled as follows. If the response formatter is waiting to
INTERRUPTED
<PROGRAM MESSAGE TERMINATOR>
error is handled as follows. If the response formatter is waiting to send a
DEADLOCK
bit 7 =
X
don't care
bit 6 =
1
bit 5 =
1
Parallel poll enable
bit 4 =
0
bit 3 =
Sense
sense of the response bit; 0 = low, 1 = high
bit 2 =
?
bit 1 =
?
bit position of the response
bit 0 =
?
*PRE 64
<pmt>,
is 0 otherwise the value of
ist
then PPC followed by 69H (PPE)
has been read by the parser or
<PROGRAM MESSAGE
<PROGRAM MESSAGE
ist
is 1.
ist
can be returned to the controller
ist
INTERRUPTED
state
DEADLOCK
local message
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