Stb?  Status Byte Query - Keithley 7001 Instruction Manual

IEEE-488 Reference
*STB?  status byte query
5.10.14
Purpose
Format
Description
5-58
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To read the contents of the Status Byte Register.
*STB?
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 5-16. The binary equivalent of the decimal value
determines which bits in the register are set. The set bits in this register define the operating sta-
tus of the Model 7001.
When the *STB? query command is sent, the decimal value is placed in the Output Queue.
When the Model 7001 is addressed to talk, the value is sent from the Output Queue to the com-
puter.
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 5.6.
For example, for an acquired decimal value of 48, the binary equivalent is 00110000. This bi-
nary 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 — Not used.
Bit 1 — Not used.
Bit 2, Error Available (EAV)  Set bit indicates that an error message is present in the Error
Queue. The error message can be read using one of the following SCPI commands:
:SYSTem:ERRor?
:STATus:QUEue?
See paragraphs 5.17 and 5.16 for details.
Bit 3,Questionable Summary Bit (QSB)  Always zero (Questionable events not used by
Model 7001).
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 7001 is addressed to talk.