Models 707B and 708B Switching Matrix Reference Manual
Section 7: Command reference
707B-901-01 Rev. A / August 2010
7-3
Logical instruments
You would normally refer to all instrumentation in one enclosure or node as a single instrument. In the
context of TSP and instrument control libraries, it is useful to think of each individual subdivision in an
enclosure, such as a card slot or the channels, as a standalone instrument. To avoid confusion, all
subdivisions of the instrumentation in an enclosure are referred to as "logical instruments."
Each logical instrument is given a unique identifier in a system. These identifiers are used as part of
all ICL commands that control a given logical instrument. The logical instruments are:
•
beeper
•
bit
•
channel
•
digio
•
display
•
eventlog
•
errorqueue
•
format
•
gpib
•
lan
•
scan
•
slot
•
status
•
timer
•
trigger
•
tsplink
NOTE
Do not create variable names that are the same as names of logical instruments. Doing so will result
in the loss of use of the logical instrument and its associated ICLs. For example, if you send the
command
digio = 5
, you cannot access the
digio.*
ICL commands until you cycle the power to
the instrument.
Time and date values
Time and date values are represented as the number of seconds since some base. Representing
time as a number of seconds is referred to as “standard time format.” There are three time bases:
•
UTC 12:00 am Jan 1, 1970.
Some examples of UTC time are reading buffer base timestamps,
adjustment dates, and the value returned by
os.time()
.
•
Instrument on.
References time to when the instrument was turned on. The value returned by
os.clock()
is referenced to the turn-on time.
•
Event.
Time referenced to an event, such as the first reading stored in a reading buffer.