2 – 18
Remote Operation
2.5.1
Status Byte (SB)
The Status Byte is the top-level summary of the SIM980 status model.
When masked by the Service Request Enable register, a bit set in the
Status Byte causes the
−
STATUS signal to be asserted on the rear-
panel SIM interface connector.
Typically,
−
STATUS remains asserted (low) until a
*STB?
query is
received, at which time
−
STATUS is deasserted (raised)
1
. After clear-
ing the
−
STATUS signal, it will only be re-asserted in response to a
new
status-generating condition.
Weight
Bit
Flag
1
0
OVSB
2
1
undef (0)
4
2
undef (0)
8
3
undef (0)
16
4
IDLE
32
5
ESB
64
6
MSS
128
7
CESB
OVSB : Overload Status Summary Bit. Indicates whether one or more
of the enabled flags in the Overload Status Register has become
true.
IDLE : Indicates that the Input Bu
ff
er is empty and the command
parser is idle. Can be used to help synchronize SIM980 query
responses.
ESB : Event Status Bit. Indicates whether one or more of the enabled
events in the Standard Event Status Register is true.
MSS : Master Summary Status. Indicates whether one or more of
the enabled status messages in the Status Byte register is true.
Note that while
−
STATUS is released by the
*STB?
query, MSS
is only cleared when the underlying enabled bit message(s) are
cleared.
CESB : Communication Error Summary Bit. Indicates whether one or
more of the enabled flags in the Communication Error Status
Register has become true.
Bits in the Status Byte are
not
cleared by the
*STB?
query. These
bits are only cleared by reading the underlying event registers, or by
clearing the corresponding enable registers.
1
but see the
PSTA
command
SIM980
Analog Summing Amplifier