Status and Events
3–2 TDS Family Oscilloscope Programmer Manual
PON URQ CME EXE DDE QYE RQC OPC
76543210
Figure 3–1: The Standard Event Status Register (SESR)
Table 3–1: SESR Bit Functions
Bit Function
7 (MSB) PON (Power On). Shows that the digitizing oscilloscope was powered on. The
completion of the diagnostic tests also sets this bit.
6URQ (User Request). Shows that an Application menu button was pressed.
5CME (Command Error). Shows that an error occurred while the digitizing
oscilloscope was parsing a command or query. Command error messages are
listed in Table 3–4 on page 3–12.
4EXE (Execution Error). Shows that an error occurred while the digitizing
oscilloscope was executing a command or query. Execution error messages are
listed in Table 3–5 on page 3–14.
3DDE (Device Error). Shows that a device error occurred. Device error
messages are listed in Table 3–6 on page 3–17.
2QYE (Query Error). Shows that 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.
1RQC (Request Control). Not used.
0 (LSB) OPC (Operation Complete). Shows that the operation is complete. This bit is
set when all pending operations complete following an  command.
The Status Byte Register (SBR) — shown in Figure 3–2, records whether output
is available in the Output Queue, whether the digitizing oscilloscope 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
obtain the SBR, bit 6 is the MSS bit. Reading the SBR does not clear the bits.
—
RQS
ESB MAV — — — —
MSS
7
6
543210
6
Figure 3–2: The Status Byte Register (SBR)