Keysight P9241, Руководство программиста SCPI

Страница: 55 / 1344

Getting Started
3
Keysight P9241/42/43A Oscilloscopes SCPI Programmer's Guide 55
The "8" states the number of digits that follow, and "00001000" states the number
of bytes to be transmitted.
The VISA COM library's ReadIEEEBlock and WriteIEEEBlock methods understand
the definite-length block syntax, so you can simply use variables that contain the
data:
' Read oscilloscope setup using ":SYSTem:SETup?" query.
myScope.WriteString ":SYSTem:SETup?"
Dim varQueryResult As Variant
varQueryResult = myScope.ReadIEEEBlock(BinaryType_UI1)
' Write learn string back to oscilloscope using ":SYSTem:SETup" command:
myScope.WriteIEEEBlock ":SYSTem:SETup ", varQueryResult
Sending Multiple Queries and Reading Results
You can send multiple queries to the instrument within a single command string,
but you must also read them back as a single query result. This can be
accomplished by reading them back into a single string variable, multiple string
variables, or multiple numeric variables.
For example, to read the :TIMebase:RANGe?;DELay? query result into a single
string variable, you could use the commands:
myScope.WriteString ":TIMebase:RANGe?;DELay?"
Dim strQueryResult As String
strQueryResult = myScope.ReadString
MsgBox "Timebase range; delay:" + strQueryResult
When you read the result of multiple queries into a single string variable, each
response is separated by a semicolon. For example, the output of the previous
example would be:
Timebase range; delay: <range_value>;<delay_value>
To read the :TIMebase:RANGe?;DELay? query result into multiple string variables,
you could use the ReadList method to read the query results into a string array
variable using the commands:
myScope.WriteString ":TIMebase:RANGe?;DELay?"
Dim strResults() As String
strResults() = myScope.ReadList(ASCIIType_BSTR)
MsgBox "Timebase range: " + strResults(0) + ", delay: " + strResults(1)
Figure 1 Definite-length block response data
#800001000<1000 bytes of data><terminator>
Actual Data
Number of Bytes
to be Transmitted
Number of Digits
That Follow