Status And Error Reporting - Tektronix DC 5010 Anleitung

Operating Instructions-DC 501 0
Remote With Lockout State (RWLS)
The instrument operation is identical to
except that the rtl message is ignored.
REMS operation
Remote State (REMS)
In this state, the instrument executes all instrument com-
mands. Changing a front panel control, except trigger level
controls, generates an rtl and causes the instrument to re-
turn to local (LOCS).
Because the STB conveys limited information about an
event, the events are divided into classes; the Status Byte
-
reports the class. The classes of events are defined as
'
follows:
COMMAND
ERROR
EXECUTION
ERROR
INTERNAL
ERROR
STATUS AND ERROR REPORTING
Through the Service Request function (defined in the
IEEE-488 Standard), the instrument may alert the controller
that it needs service. This service request is also a means of
indicating that an event (a change in status or an error) has
occurred. To service a request the controller performs a
Serial Poll; in response the instrument returns a Status Byte
(STB) which indicates whether it was requesting service or
not. The STB can also provide a limited amount of informa-
tion about the request. The format of the information en-
coded in the STB is given in Table 2-2. When data bit 8 is
set, the STB conveys Device Status information which is
indicated by bits 1 through 4.
Table
2-2
DEFINITION OF STATUS BYTE BITS
If 0, ST6 indicates event class
If
1,
ST6 indicates device status
I
I
I
r
- -
1
if requesting service
I I
I
I
I
I
r
-
-
1
indicates an abnormal event
' 1 1
' I 1
I
:
- -
1 if message processor is busy
I I I I
I l l
'
I I
I
I
DATA BITS
I
I I I l I * I I
DECIMAL
/I
I t
I?
I I
I \
-
SYSTEM
EVENTS
EXECUTION
WARNING
INTERNAL
WARNING
DEVICE
STATUS
lndicates the instrument has received a
command which it cannot understand.
lndicates that the instrument has received
a command that it cannot execute. This is
caused by arguments out of range or
settings that conflict.
lndicates that the instrument has detected
a hardware condition or firmware problem
that prevents operation.
Events that are common to instruments in
a system (e.g., power-on, User Request,
etc.).
The instrument is operating but the user
should be aware of potential problems.
Internal warning indicates that the instru-
ment has detected a problem. The instru-
ment remains operational, but the
problem should be corrected (e.g., out of
calibration).
Device dependent events.
The instrument can provide additional information about
many of the events, particularly the errors reported in the
Status Byte. After determining that the instrument request-
ed service (by examining the STB) the controller may re-
quest the additional information by sending an error query
(ERR?). In response, the instrument returns a code which
defines the event. These codes are described in Table 2-3.
If there is more than one event to be reported, the instru-
ment continues to assert SRQ until it reporits all events.
Each event is automatically cleared when it is reported via
Serial Poll. The Device Clear (DCL) interface rnessage may
be used to clear all events except power-on.
Commands are provided to control the reporting of some
individual events and to disable all service requests. For ex-
ample, the User Request command (USEREQ) provides in-
dividual control over the reporting of the user request event
which occurs when the front panel INST ID button is
pressed. The Requests for Service command (RQS) con-
trols whether the instrument reports any events with SRQ.
- - ,