User`s manual

Visual BASIC and
Visual C/C++ Program
Versions
The Visual BASIC example program, ERRORCHK.FRM, is in directory
“ VBPROG” and the Visual C example program, ERRORCHK.C, is in
directory “VCPROG” on the CD that came with your Agilent E1445A.
The Status Byte
Status Group
The registers in the Status Byte Status Group enable conditions monitored
by the other status groups to generate a service request.
The Status Byte
Register
The Status Byte Register contains the summary bits of the Questionable
Signal Status Group (QUES), the Operation Status Group (OPER), and the
Standard Event Status Group (ESB). The register also contains the message
available bit (MAV) and the service request bit (RQS).
76543210
OPER RQS ESB MAV QUES unused
– Questionable Signal Summary Bit (QUES): Bit 3 is set (1) when a
condition monitored by the Questionable Signal Status Group is
present, when the appropriate bit is latched into the group’s Event
Register, and when the bit is unmasked by the group’s Enable Register.
– Message Available Bit (MAV): Bit 4 is set (1) when data, such as a
query response, is in the AFG’s output queue.
– Standard Event Summary Bit (ESB): Bit 5 is set (1) when a
condition monitored by the Standard Event Status Group is present
and the appropriate bit is set in the group’s Event Register, and when
the bit is unmasked by the group’s Enable Register.
– Service Request Bit (RQS): Bit 6 is set (1) when any other bit in
the Status Byte Register is set.
– Operation Status Summary Bit (OPER): Bit 7 is set (1) when a
condition monitored by the Operation Status Group is present, when
the appropriate bit is latched into the group’s Event Register, and
when the bit is unmasked by the group’s Enable Register.
Reading the Status Byte Register
The Status Byte Register can be read with either of the following commands:
*STB?
SPOLL
Both commands return the decimal weighted sum of all set bits in the register.
The difference between the commands is that
*STB? does not clear bit 6 (RQS
service request). The serial poll (SPOLL) does clear bit 6. All bits in the Status
Byte Register with the exception of MAV are cleared with the command:
*CLS (*CLS also aborts the current waveform)
MAV is cleared when data is read from the output queue.
442 AFG Status Chapter 9