5-8
IM WT3001E-17EN
5.5 Synchronization with the Controller
Overlap Commands and Sequential Commands
There are two types of commands, overlap commands
and sequential commands. In the case of overlap
commands, the execution of the next command may
start before the execution of the previous command is
completed.
For example, if the next program message is
transmitted when specifying the voltage range and
querying the result, the response always returns the
most recent setting (100 V in this case).
:INPut:VOLTage:RANGe;ELEMent1 100V;
ELEMent?<PMT>
This is because the next command is
forced to wait until the processing of
“
INPut:VOLTage:RANge:ELEMent1
” itself is
completed. This type of command is called a sequential
command.
On the contrary, let us assume that you send the next
program message when you wish to load a file and
query the voltage range of the result.
:FILE:LOAD:SETup “FILE1”;:INPut:VOLTage:
RANGe:ELEMent1?
In this case, “
:INPut:VOLTage:RANGe:ELEMent1?
”
is executed before the loading of the file is completed,
and the voltage range that is returned is the value
before the file is loaded.
The act of executing the next command before
the processing of itself is completed such as with
“
FILE:LOAD:SETup
” is called an overlap operation. A
command that operates in this way is called an overlap
command.
In such case, the overlap operation can be prevented
by using the methods below.
Synchronizing with Overlap Commands
Using the *WAI Command
The
*WAI
command holds the subsequent commands
until the overlap command is completed.
Example
:COMMunicate:OPSE
#H0040;:FILE:LOAD:SETup
“FILE1”;*WAI;:INPut:VOLTage:
RANGe:ELEMent1?<PMT>
“
COMMunicate:OPSE
” is a command used
to select the “
*WAI
” target. Here, media
access is specified.
Because “
*WAI
” is executed immediately
before
“
:INPut:VOLTage:RANGe:ELEMent1?
,”
“
:INPut:VOLTage:RANGE:ELEMent1?
”
is not executed until the loading of the file is
completed.
Using the COMMunicate:OVERlap command
The
COMMunicate:OVERlap
command enables (or
disables) overlap operation.
Example
:COMMunicate:OVERlap
#HFFBF;:FILE:
LOAD:SETup
“FILE1”;:INPut:VOLTage:
RANGe:ELEMent1?<PMT>
“
COMMunicate:OVERlap #HFFBF
”
enables overlap operation on commands
other than media access.
Because the overlap operation of file loading
is disabled, “
FILE:LOAD:SETup
” operates
in the same way as a sequential command.
Therefore, “
:INPut:VOLTage:RANGe:ELE
Ment1?
” is not executed until the loading of
the file is completed.