Tektronix FCA3000 Series, Programmer'S Manual

Page: 138 / 191

Status and Events
Table 3-1: SESR bit functions
Bit Function
7 (MSB) PON Power On. Shows that the instrument was powered on. On
completion, the diagnostic self tests also set this bit.
6 URQ User Request. Shows that an application event has
occurred. *See note.
5 CME Command Error. Shows that an error occurred while the
instrument was parsing a command or query.
4 EXE Execution Error. Shows that an error occurred while
executing a command or query.
3 DDE Device Error. Shows that a device error occurred.
2 QYE Query Error. Either an attempt was made to read the Output
Queue when no data was present or pending, or that data in
the Output Queue was lost.
1 RQC Request Control. This is not used.
0 (LSB) OPC Operation Complete. Shows that the operation is complete.
This bit is set when all pending operations complete
following an *OPC command.
The Status Byte Register (SBR).
Records whether output is available in the
Output Queue, whether the instrument requests service, and whether the SESR
has recorded any events.
Use a Serial Poll or the *STB? query to read the contents of the SBR. The bits in
the SBR are set and cleared depending on the contents of the SESR, the Event
Status Enable Register (ESER), and the Output Queue. When you use a Serial
Poll to obtain the SBR, bit 6 is the RQS bit. When you use the *STB? query to
read the SBR, bit 6 is the MSS bit. Reading the SBR does not clear the bits.
Figure 3-2: The Status Byte Register (SBR)
Table 3-2: SBR bit functions
Bit Function
7 (MSB) OPR Operation status.
6
(serial poll)
RQS Request Service. Obtained from a serial poll. Shows that
the instrument requests service from the GPIB controller.
6
(*STB? query) MSS Master Status Summary. Obtained from *STB? query.
Summarizes the ESB and MAV bits in the SBR.
5 ESB Event Status Bit. Shows that status is enabled and present
in the SESR.
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