User Manual

15-18 Status Structure 2400 Series SourceMeter
®
User’s Manual
which bits are set). The command to select format (FORMat:SREGister) is docu-
mented in Table 15-2.
Queues
The SourceMeter uses two queues, which are first-in, first-out (FIFO) registers:
• Output Queue — Used to hold reading and response messages.
• Error Queue — Used to hold error and status messages. (See
Appendix B.)
The SourceMeter status model (Figure 15-1) shows how the two queues are
structured with the other registers.
Output queue
The output queue holds data that pertains to the normal operation of the instru-
ment. For example, when a query command is sent, the response message is
placed in the Output Queue.
When data is placed in the Output Queue, the Message Available (MAV) bit in the
Status Byte Register sets. A data message is cleared from the Output Queue
when it is read. The Output Queue is considered cleared when it is empty. An
empty Output Queue clears the MAV bit in the Status Byte Register.
A message is read from the Output Queue by addressing the SourceMeter to talk
after the appropriate query is sent.
Table 15-8
Program and read register programming example
Command Description
FORM:SREG BIN
STAT:MEAS:ENAB 512
STAT:MEAS:COND?
STAT:MEAS?
Select binary format to read registers.
Enable BFL (buffer full).
Read Measurement Condition Register.
Read Measurement Event Register.