Keithley 2635 Reference Manual

2600S-901-01 Rev. C / January 2008 Return to Section Topics D-27
Series 2600 System SourceMeter® Instruments Reference Manual Appendix D: Status Model
Register programming example
The command sequence below programs the instrument to generate an SRQ and set the system
summary bit in all TSP-Link nodes when the current limit on Channel A is exceeded.
status.reset() - Clear all registers.
status.measurement.current_limit.enable =
status.measurement.current_limit.SMUA
- Enable current limit bit in
current limit register.
status.measurement.enable =
status.measurement.ILMT
- Enable status measure
current limit bit.
status.system_enable = status.MSB - Set system summary;
enable MSB.
status.request_enable = status.MSB - Enable status SRQ MSB.
Queues
The SourceMeter uses two queues, which are first-in, first-out (FIFO) queues:
• Output Queue — Used to hold response messages.
• Error Queue — Used to hold error and status messages (see Table B-2 in Appendix B).
The SourceMeter status model (Figure D-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 print 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 response 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.
print(status.measurement buffer_available.event)
To set register bits:
status.measurement.reading_overflow.* = status.measurement.reading_overflow.SMUA B1
status.measurement.reading_overflow.* = status.measurement.reading_overflow.SMUB B2
To read registers:
print(status.measurement.reading_overflow.*)
print(status.measurement.reading_overflow.condition)
print(status.measurement.reading_overflow.event)
1. * = '.ntr', '.ptr' and '.enable'; smuX = smua or smub.
Table D-9 (continued)
Operation event commands
Command
1
Bit

Keithley 2635 Specifications

General

Brand	Keithley
Model	2635
Category	Measuring Instruments
Language	English