Stanford Research Systems DS345, Manual

Page: 62 / 139

Programming Commands
3-12
STATUS BYTE DEFINITIONS
Status Reporting
The DS345 reports on its status by means of three status bytes: the serial poll byte, the standard status byte,
and the DDS status byte.
On power on the DS345 may either clear all of its status enable registers or maintain them in the state they
were in on power down. The action taken is set by the *PSC command and allows things such as SRQ on
power up .
Serial Poll Status Byte:
bit name usage
0 Sweep Done set when no sweeps are in progress
1 Mod Enable set when modulation is enabled
2 User SRQ set if the user sends a SRQ from the front panel
3 DDS An unmasked bit in the DDS status register has been set.
4 MAV The gpib output queue is non-empty
5 ESB An unmasked bit in the standard status byte has been set.
6 RQS/MSS SRQ (Service Request)bit.
7 No Command There are no unexecuted commands in the input queue
The DDS and ESB bits are set whenever any unmasked bit (bit with the corresponding bit in the byte enable
register set) in their respective status registers is set. They are not cleared until the condition which set the bit
is cleared. Thus, these bits give a constant summary of the enabled status bits. A service request will be
generated whenever an unmasked bit in the serial poll register is set. Note that service requests are only pro-
duced when the bit is first set and thus any condition will only produce one service request. Accordingly, if a
service request is desired every time an event occurs the status bit must be cleared between events.
Standard Event Status Byte:
bit name usage
0 unused
1 unused
2 Query Error Set on output queue overflow
3 unused