Instruction manual

Chapter 4 Command Reference
Common Commands
Programming Guide 4-55
4
*STB? (Status Byte Query)
COMMAND *STB?
Queries the Status Byte Register, shown in Figure 4-6.
This register is cleared at power-on.
This query does not directly alter the Status Byte Register (including the
MSS/RQS bit) or anything related to the generation of SRQ.
Figure 4-6. The Status Byte Register
See the section titled “Status Byte Register and Service Request Enable
Register” starting on Page 3-27 for a detailed description of the Status
Byte Register.
QUERY RESPONSE • Numeric data transferred as ASCII bytes in <NR1> format.
• Range is 0 to 255.
• The response value when rounded to an integer value and expressed in
base 2 (binary), represents the bit values of the Status Byte Register.
• The value of unused bits is zero when queried.
• The Master Summary Status, not the RQS message, is reported on
bit 6. Master Summary Status indicates that the Counter has at least
one reason for requesting service. (The Master Summary Status is not
sent in response to a serial poll; the IEEE 488.1 RQS message is sent
instead.) It is the inclusive OR of the bitwise combination (excluding
bit 6) of the Status Byte Register and the Service Request Enable
Register.
3
(
16
)
4
(
32
)
5
(
64
)
6
(
128
)
7
(
8
)
EAV
2
MAV
ESB
RQS/MSS
OSB
QSB
Not
Used
0 to 1
Bits