Keithley SourceMeter 2400, User Manual

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15-18 Status Structure 2400 Series SourceMeter
®
User’s Manual
Programming example — program and read register set
The command sequence in Table 15-8 programs and reads the measurement register set.
Registers are read using the binary format (which directly indicates which bits are set).
The command to select format (FORMat:SREGister) is documented 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 instrument. 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.
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