Model 2651A High Power System SourceMeter® Instrument Reference Manual
Section 7: Command reference
2651A-901-01 Rev. A / March 2011
7-251
The individual bits of this register have the following meanings:
Bit Value
Description
B0
status.MEASUREMENT_SUMMARY_BIT
status.MSB
Set summary bit indicates that an enabled measurement
event has occurred.
Bit B0 decimal value: 1
B1
status.SYSTEM_SUMMARY_BIT
status.SSB
Set summary bit indicates that an enabled system event
has occurred.
Bit B1 decimal value: 2
B2
status.ERROR_AVAILABLE
status.EAV
Set summary bit indicates that an error or status
message is present in the Error Queue.
Bit B2 decimal value: 4
B3
status.QUESTIONABLE_SUMMARY_BIT
status.QSB
Set summary bit indicates that an enabled questionable
event has occurred.
Bit B3 decimal value: 8
B4
status.MESSAGE_AVAILABLE
status.MAV
Set summary bit indicates that a response message is
present in the Output Queue.
Bit B4 decimal value: 16
B5
status.EVENT_SUMMARY_BIT
status.ESB
Set summary bit indicates that an enabled standard
event has occurred.
Bit B5 decimal value: 32
B6
status.MASTER_SUMMARY_STATUS
status.MSS
Request Service (RQS)/Master Summary Status (MSS)
- Depending on how it is used, Bit B6 of the status byte
register is either the Request for Service (RQS) bit or the
Master Summary Status (MSS) bit:
- When using the GPIB or VXI-11 serial poll sequence of
the 2651A to obtain the status byte (serial poll byte), B6
is the RQS bit. Set bit indicates that the Request Service
(RQS) bit of the status byte (serial poll byte) is set and a
serial poll (SRQ) has occurred.
- When using the
status.condition
register
command or the *STB? common command to read the
status byte, B6 is the MSS bit. Set bit indicates that an
enabled summary bit of the status byte register is set.
Bit B6 decimal value: 64
B7
status.OPERATION_SUMMARY_BIT
status.OSB
Set summary bit indicates that an enabled operation
event has occurred.
Bit B7 decimal value: 128
In addition to the above constants, when more than one bit of the register is set,
statusByte
will equal the sum
of their decimal weights. For example, if 129 is returned, bits B0 and B7 are set (1 + 128).
Bit
B7 B6 B5 B4 B3 B2 B1 B0
Binary
value
0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1
Decimal
128 64 32 16 8 4 2 1
Weights (2
7
) (2
6
) (2
5
) (2
4
) (2
3
) (2
2
) (2
1
) (2
0
)
Example
statusByte = status.condition
print(statusByte)
Returns
statusByte
.
Sample output:
1.02
Converting this output (129) to its binary equivalent
yields: 1000 0001
Therefore, this output indicates that the set bits of
the status byte condition register are presently B0
(MSS) and B7 (OSB).
