Lake Shore Cryotronics Measure Ready M91 FastHall, Руководство пользователя

Страница: 74 / 195

64 c
HAPTER
4: Computer Interface Operation
MeasureReady™ M91 FastHall™ Measurement Controller
4.3.3 Error Messages As called out in the SCPI-99 specification, the M91 FastHall™ measurement control-
ler implements an error queue that contains coded error and status messages thrown
during operation. SCPI-99 defines error messages with a negative (-) prefix as stan-
dard errors, common to all SCPI compliant instruments. Error messages with a posi-
tive prefix (+) are allocated to instrument manufacturers for instrument specific
messages. Presently, the M91 does not implement any instrument specific messages.
All M91 specific errors and status are captured in the status register system.
Coded error and status messages can be retrieved and cleared over the remote inter-
face using the following commands:
SYSTem:ERRor:ALL?
SYSTem:ERRor:CLEar
SYSTem:ERRor:COUNt?
SYSTem:ERRor[:NEXT]?
The queue is implemented with a “First In, First Out” (FIFO) approach. This means, if
the M91 adds multiple messages to the queue in a given period of time, issuing the
SYSTem:ERRor[:NEXT]?
query will return the message that was added to the
queue first, and, subsequently remove it from the queue. For further details on these
error query commands, see section 4.5.
SCPI-99 categorizes its standard errors into logical groups that match bit definitions
in the standard event status register. When the M91 adds an error message to the
queue, a bit in the standard event status register will be set as well. The error code
range table shown below lists the error code ranges, title, and the corresponding bit
in the standard event status register that gets set when the error or status is added to
the queue.
TABLE 4-3
Error code ranges
Error code range Description Standard event register bit
-100 to -184 Command errors 5
-200 to -294 Execution errors 4
-300 to -365 Device specific errors 3
-400 to -440 Query errors 2
A comprehensive list of standard SCPI error codes descriptions can be found in chap-
ters 21.8.9 through 21.8.16 of the official SCPI-99 standard, located on the IVI foun-
dation website:
http://www.ivifoundation.org/docs/scpi-99.pdf .
The MeasureReady™ M91 FastHall™ measurement controller does not implement every
error code listed in the standard.