Synchronization With The Controller - YOKOGAWA DL350 User Manual

3.5

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 V/div and send the next program
message to query the result, the instrument always
returns the most recent setting (5 V in this case).
:CHANnel1:VDIV 5V;VDIV?<PMT>
This is because the next command is forced to wait
until the processing of CHANnel1:VDIV 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 V/div value
of the result.
:FILE:LOAD:SETup:EXECute "CASE1";:
CHANnel1:VDIV?
In this case, CHANnel1:VDIV? is executed before the
loading of the file is completed, and the V/div value 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:EXECute "CASE1" . 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 a *WAI command
A *WAI command holds the subsequent commands
until the overlap command is completed.
Example :COMMunicate:OPSE #H0040;:
FILE:LOAD:SETup:
EXECute "CASE1";*WAI;:
CHANnel1:VDIV?<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 CHANnel1:VDIV? , so
CHANnel1:VDIV? is not executed until the file
loading is completed.
3-8
• Using the COMMunicate:OVERlap command
The COMMunicate:OVERlap command enables (or
disables) overlapping.
Example :COMMunicate:OVERlap #HFFBF;:
FILE:LOAD:SETup:
EXECute "CASE1";:CHANnel1:
VDIV?<PMT>
COMMunicate:OVERlap #HFFBF enables
overlapping for commands other than media access.
Because overlapping of file loading is disabled,
FILE:LOAD:SETup:EXECute "CASE1" operates
in the same way as a sequential command. Thus,
CHANnel1:VDIV? 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 5-4), to 1
when the overlapping is completed.
Example :COMMunicate:OPSE #H0040;*ESE 1;
*ESR?;*SRE 32;:FILE:LOAD:SETup:
EXECute "CASE1";*OPC<PMT>
(Read the response to *ESR? )
(Wait for a service request)
:CHANnel1:VDIV?<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 is 1.
*ESR? clears the standard event register.
In the example above, CHANnel1:VDIV? is not
executed until a service request is generated.
IM DL350-17EN