Query – Measurement Computing TempScan/1100 User Manual
Page 258
A-62 API Command Reference
889897
TempScan / MultiScan User’s Manual
?
- Query
TYPE
System
EXECUTION
Immediate
SYNTAX
?
Query the present configuration or mode of the command preceding the
?
DESCRIPTION
Most commands have a corresponding query command formed by appending the question mark (
?
) command
extension. Stored in the output queue until the PC/IEEE 488 controller retrieves them, query command
responses consist of the present configuration or mode of the previously-executed command. When appropriate,
these query command responses take the form of a command string which, if it were executed, would put the unit
into the configuration it was in when the query was executed.
For example, the Set User Terminator (
V
) command query
V?
gives its response in the following form:
Vval
where
0
<
val
<
255
. This response is in the form of the previous Set User Terminator (
V
) command and, if it is
sent to the unit, it would set the user-defined User Terminator to the same value that it had when the query was
issued.
Query commands are immediate. However, even though query commands generate their responses as soon as
they are interpreted, before any other commands including the Execute (
X
) command, they must still be followed
by this Execute (
X
) command for proper termination. Any number of query commands can be combined into one
command string to create a specialized status command that responds with only the information of interest for a
given application. Query command responses are always fixed-length strings in a pre-defined format.
For more information on command execution, see section Command Interpretation at the beginning of this
chapter, and see command Execute (
X
).
EXAMPLE
PRINT#1, “OUTPUT07; V1X V?X”
‘ Get the response of the current User Terminator
PRINT#1, “ENTER07”
‘ Retrieve response
INPUT A$
PRINT A$
V1
‘ Screen shows the current User Terminator
V1
PRINT#1, “OUTPUT07; V0X V?X”
‘ Change the User Terminator and get response
PRINT#1, “ENTER07”
‘ Retrieve response
INPUT A$
PRINT A$
V0
‘ Screen shows new User Terminator
V0
PRINT#1, “OUTPUT07; V4 V?X”
‘ Change User Terminator and get response, without using
the intermediate Execute (
X
) command
PRINT#1, “ENTER07”
‘ Retrieve response
INPUT A$
PRINT A$
V0
‘ Screen still shows the
V0
because the immediate
command
V?
was executed before the deferred
command
V4
PRINT#1, “OUTPUT07; V?X”
‘ Again get the response of the current User Terminator
PRINT#1, “ENTER07”
‘ Retrieve response
INPUT A$
PRINT A$
V4
‘ Screen shows new User Terminator
V4