Keithley 2000, User Manual, Page: 136 / 280

*STB? — Status Byte Query
Read status byte register
Description
Use the *STB? query command to acquire the value (in decimal) of the Status Byte Register.
The Status Byte Register is shown in Figure 4-16. The binary equivalent of the decimal value
determines which bits in the register are set.
All bits, except Bit B6, in this register are set by other event registers and queues. Bit 6 sets
when one or more enabled conditions occur.
The *STB? query command does not clear the status byte register. This register can only be
cleared by clearing the related registers and queues. See “status structure” for details.
For example, for an acquired decimal value of 48, the binary equivalent is 00110000. This
binary value indicates that bits 4 and 5 if the Status Byte Register are set.
The bits of the Status Byte Register are described as follows:
• Bit 0, Measurement Status (MSB)-A set bit indicates that a measurement event has oc-
curred. The event can be identified by reading the Measurement Event Status Register
using the :STATus:MEASurement? command (see Section 5 for details).
• Bit 1-Not used.
• Bit 2, Error Available (EAV)-A set bit indicates that an error or status message is present
in the Error Queue. The message can be read using one of the following SCPI com-
mands:
:SYSTem:ERRor?
:STATus:QUEue?
See Section 5 for more information.
• Bit 3, Questionable Summary Bit (QSB)-A set bit indicates that a calibration error has
occurred.
• Bit 4, Message Available (MAV)-A set bit indicates that a message is present in the Out-
put Queue. The message is sent to the computer when the Model 2000 is addressed to
talk.
• Bit 5, Event Summary Bit (ESB)-A set bit indicates that an enabled standard event has
occurred. The event can be identified by reading the Standard Event Status Register us-
ing the *ESE? query command.
• Bit 6, Master Summary Status (MSS)/Request Service (RQS)-A set bit indicates that one
or more enabled Status Byte conditions have occurred. Read the MSS bit by using the
STB? query command, or perform a serial poll to detect the occurrence of a service re-
quest (RQS bit set).
• Bit 7, Operation Summary (OSB)-A set bit indicates that an enabled operation event has
occurred. The event can be identified by reading the Operation Event Status Register us-
ing the :STATus:OPERation? query command (see Section 5 for details).
4-50 Remote Operation