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2600AS-901-01 Rev. B / September 2008
Section 19: Remote Commands
Series 2600A System SourceMeter® Instruments Reference Manual
Status
The following provides a brief overview of the status model. Details on the status model are
provided in
of this manual.
Status register sets
A typical status register set is made up of a condition register, an event register, an event enable
register, a negative transition register, and a positive transition register. A condition register is a
read-only register that constantly updates to reflect the present operating conditions of the
instrument. When an event occurs, and the appropriate NTR or PTR bit is set, the matching event
register bit is set to 1. The bit remains latched to 1 until the register is read or reset. When an event
register bit is set and its corresponding enable bit is set (as programmed by the user), the output
(summary) of the register will set to 1, which in turn sets the condition bit in a higher-level register,
and can ultimately cascade to the summary bit of the Status Byte Register.
Negative and positive transition registers
•
Negative-transition register (NTR):
When a bit in an NTR register is set by the user, the
corresponding bit in the event register will set when the corresponding bit in the condition
register transitions from 1 to 0.
•
Positive-transition register (PTR):
When a bit in a PTR register is set by the user, the
corresponding bit in the event register will set when the corresponding bit in the condition
register transitions from 0 to 1.
Status byte and SRQ
The Status Byte Register receives the summary bits of the five status register sets and two
queues. The register sets and queues monitor the various instrument events. When an enabled
event occurs, it sets a summary bit in the Status Byte Register. When a summary bit of the Status
Byte is set and its corresponding enable bit is set (as programmed by the user), the RQS/MSS bit
will set to indicate that an SRQ has occurred.
SRQs will affect both the GPIB and the VXI-11 connections. On the GPIB, the SRQ line will be
asserted. On a VXI-11 connection, an SRQ event will be generated.
