Synchronization With The Controller - YOKOGAWA WT5000 User Manual

4.5

Synchronization with the Controller

Overlap Commands and Sequential Commands
There are two types of commands: overlap and
sequential. The execution of one overlap command
can start before the execution of the previous overlap
command is completed.
If you specify the voltage range and send the next
program message while you are querying the result,
this instrument 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 is completed. This type of command is
called a sequential command.
Let us assume you send the next program message
when you want 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.
Overlapping refers to the act of executing the next
command before the processing of the current
command is completed, such as in the command
FILE:LOAD:SETup . A command that operates in this
way is called an overlap command.
You can prevent overlapping by using the following
methods.
Synchronizing to 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>
The COMMunicate:OPSE command is used to
select which command to apply *WAI to. Here, it is
applied to the media access command.
*WAI is executed before
:INPut:VOLTage:RANGe:ELEMent1? , so
:INPut:VOLTage:RANGe:ELEMent1? is not
executed until the file loading is completed.
4-8
• Using the COMMunicate:OVERlap command
The COMMunicate:OVERlap command enables (or
disables) overlapping.
Example :COMMunicate:OVERlap #HFFBF;:
FILE:LOAD:SETup "FILE1";:
INPut:VOLTage:RANGe:ELEMent1?
<PMT>
COMMunicate:OVERlap #HFFBF enables
overlapping for commands other than media access.
Because overlapping of file loading is disabled,
FILE:LOAD:SETup operates in the same way as a
sequential command. Thus, :INPut:VOLTage:
RANGe:ELEMent1? is not executed until file loading
is completed.
• Using the *OPC command
The *OPC command sets the OPC bit, which is bit
0 in the standard event register (see page 6-4 for
details), to 1 when the overlapping is completed.
Example :COMMunicate:OPSE #H0040;
*ESE 1;*ESR?;*SRE 32;:FILE:
LOAD:SETup "FILE1";*OPC<PMT>
(Read the response to *ESR? )
(Wait for a service request)
:INPut:VOLTage:RANGe:ELEMent1?
<PMT>
The COMMunicate:OPSE command is used to
select which command to apply *OPC to. Here, it is
applied to the media access command.
*ESE 1 and *SRE 32 indicate that a service
request is only generated when the OPC bit
becomes 1.
*ESR? clears the standard event register.
In the example above, :INPut:VOLTage:RANGe:
ELEMent1? is not executed until a service request
is generated.
• Using the *OPC? query
The *OPC? query generates a response when an
overlapping operation is completed.
Example :COMMunicate:OPSE #H0040;
:FILE:LOAD:SETup "FILE1";
*OPC?<PMT>
(Read the response to *OPC? )
:INPut:VOLTage:RANGe:ELEMent?
<PMT>
IM WT5000-17EN