Stb? - Status Byte Query - Keithley 2002 User Manual

IEEE-488 Reference
3.10.12
Description
Program fragment
3-38
*STB? — status byte query
The *STB? query command is used to acquire the value (in decimal) of the Status Byte Register.
The Status Byte Register is shown in Figure 3-17. The binary equivalent of the decimal value
determines which bits in the register are set.
All bits, except Bit 6, 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. Register and queue structure are explained
in paragraph 3.7.
For example, for an acquired decimal value of 48, the binary equivalent is 00110000. This
binary value indicates that Bits 4 and 5 of the Status Byte Register are set.
The bits of the Status Byte Register are described as follows:
Bit 0, Measurement Status (MSB) — Set bit indicates that a measurement event has occurred.
The event can be identified by reading the Measurement Event Status Register using the
:STATus:MEASurement? command (see paragraph 3.20 for details).
Bit 1 — Not used.
Bit 2, Error Available (EAV) — 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 commands:
:SYSTem:ERRor?
:STATus:QUEue?
See paragraphs 3.21 and 3.20 for details.
Bit 3, Questionable Summary Bit (QSB) — Set bit indicates that a calibration error has
occurred.
Bit 4, Message Available (MAV) — Set bit indicates that a message is present in the Output
Queue. The message is sent to the computer when the Model 2002 is addressed to talk.
Bit 5, Event Summary Bit (ESB) — Set bit indicates that an enabled standard event has
occurred. The event can be identified by reading the Standard Event Status Register using the
*ESE? query command (see paragraph 3.10.2).
Bit 6, Master Summary Status (MSS) / Request Service (RQS) — Set bit indicates that one
or more enabled Status Byte conditions have occurred. The MSS bit can be read using the STB?
query command, or the occurrence of a service request (RQS bit set) can be detected by per-
forming a Serial Poll.
Bit 7, Operation Summary Bit (OSB) — Set bit indicates that an enabled operation event has
occurred. The event can be identified by reading the Operation Event Status Register using the
:STATus:OPERation? query command (see paragraph 3.20 for details).
PRINT #1, "output 16; *stb?"
PRINT #1, "enter 16"
Read the Status Byte Register
' Query Status Byte Register
' Send response message to 2002