Technical data

Agilent B1500A/B1505A Programming Guide, Edition 11 1-57
Programming Basics
Status Byte
The status byte register can be read with either a serial poll or the *STB? query
command. Serial poll is a low-level GPIB command that can be executed by the
SPOLL command in HP BASIC, for example Status=SPOLL(@B1500).
In general, use serial polling (not *STB?) inside interrupt service routines. Use
*STB? in other cases (not in interrupt service routine) when you want to know the
value of the Status Byte.
NOTE If Bit 3 and Bit 5 are masked, they are not set to “0” by a serial poll. Also, if these
bits are masked, set to “1”, and then unmasked, a serial poll does not set them to “0”.
After a masked bit is set to “1”, removing the mask does not set Bit 6 to “1”. That is,
the B1500 does not send an SRQ to the controller. Therefore, if you remove a mask
from a bit, it is usually best to do it at the beginning of the program.
4 16 Set ready
If the B1500 receives a GPIB command or a trigger signal,
this bit is set to “0”. It is set to “1” when its operation is
completed. This bit is also set to “0” when the self-test or
calibration is started by front panel operation, and set to
“1” when it is completed.
532Error
Indicates whether any error has occurred. If an error
occurred, this bit is set to “1”. It is set to “0” when the
B1500 receives a serial poll, *RST, ERR?, ERRX?, CA,
*TST?, *CAL?, DIAG? or device clear command.
6 64 RQS (You cannot mask this bit.)
Indicates whether an SRQ (Service Request) has occurred.
This bit is set to “1” whenever any other unmasked bit is
set to “1”. This causes the B1500 to send an SRQ to the
controller. It is set to “0” when the B1500 receives a serial
poll, *RST, or device clear command.
7 128 Not applicable. This bit is always set to “0”.
Bit
Decimal
Value
Description