# Helpful Hints

Here is some useful information to know when using the 89600 VSA SCPI interface.

- Performance Considerations
- VSA SCPI with X-Series Signal Analyzers
- More information from related .NET commands
- Enumeration names specified with quotes
- Channelized commands (CHAN[1:N], LIST)
- Min/Max and value limiting
- Type information

## Performance Considerations

See the Performance Considerations topic for some tips on how to maximize measurement speed.

## VSA SCPI with X-Series Signal Analyzers

In order to use the VSA SCPI interface when running the VSA software on an X-Series Signal Analyzer, the default port in the VSA SCPI Configuration tool should be changed to something other than 5025 (e.g. 5026) to avoid a conflict with the X-Series Signal Analyzer's default socket port. The client software intending to connect with the VSA SCPI interface would use the following connection string "TCPIP0::instrument_hostname_or_ip_address::5026::SOCKET".

## More information from related .NET commands

SCPI commands are usually directly related to a property or method on the .NET interface that the SCPI interface is built on top of. To learn more about a particular SCPI command, refer to the .NET Equivalent link in a SCPI command topic.

## Enumeration names specified with quotes ("")

There are many SCPI commands that accept parameters which correspond to .NET enumerations. Most of the .NET enumeration member names are not compliant with SCPI enumeration naming rules because the .NET enumerations do not have both a short and long form (no short form, because the first few characters are not unique among other enum members).

For this reason, most .NET enum members that are used as arguments for SCPI commands are specified as string values and must be surrounded in double quotes.

Double-quotes are only required around the enum name when the names in the list of possible enums are also surrounded by double-quotes.

For example, the argument for [:SENSe]:LTE:ADVanced:SYMBol:TIME:ADJust:MODE can be one of several possible .NET enum member names, but the enum member name is specified as a string since the short form does not exist for the enum members starting with "Window" (short form would be the same):

> LTE:ADV:SYMB:TIME:ADJ:MODE "MaxOfWindowStartAndWindowEnd"

> LTE:ADV:SYMB:TIME:ADJ:MODE "MinOfWindowStartAndWindowEnd"

> LTE:ADV:SYMB:TIME:ADJ:MODE "WindowStart"

> LTE:ADV:SYMB:TIME:ADJ:MODE "WindowEnd"

> LTE:ADV:SYMB:TIME:ADJ:MODE "WindowCenter"

> LTE:ADV:SYMB:TIME:ADJ:MODE "PercentFftSize"

However, some enum names do have a short form. For these enums, the enum value must be specified without double-quotes. For example, to change the input source for VSA application between recording and hardware the :INPut:DATA command takes a single enum argument as shown:

> INPut:DATA REC

> INPut:DATA HW

## Channelized commands (CHAN[1:N], LIST)

Some commands which can be used to set the value for multiple items have three forms for convenience. The three forms are in the following format:

- `COMMAND` -- sets a parameter for all channels
- `COMMAND:CHAN` or `COMMAND:CHAN[1:N]` - sets a parameter for a particular channel
- `COMMAND:LIST` -- used to specify the values for multiple channels as a comma-separated list of values.

As an example, here are some ways you can set the Range for input channels:

> // sets the range for all logical input channels to 10.0 Vpk

> INPut:ANALog:RANGe 10.0

> // both commands set the range for channel 1 to 10.0 Vpk

> INPut:ANALog:RANGe:CHAN 10.0

> INPut:ANALog:RANGe:CHAN1 10.0

> // sets the range for logical input channels 1-4 to 5.0 Vpk

> INPut:ANALog:RANGe:LIST 5.0,5.0,5.0,5.0

## Min/Max and value limiting

Minimum and Maximum value information is not provided for 89600 VSA SCPI commands because, unlike other devices controlled by SCPI, the 89600 VSA is not tied to a specific hardware platform. The current Min/Max values for 89600 VSA SCPI commands depend on the currently selected hardware as well as the current measurement setup.

The behavior of the SCPI interface is such that when you set a parameter to a value that is outside the range of currently allowable values, the parameter will be set to the closest allowable value.

To verify that a parameter has the value you specified, read the parameter with the corresponding SCPI query after setting the parameter and compare with the expected value.

## Type information

The possible types for SCPI command arguments or for SCPI query return values are as follows:

- Boolean -- denoted by a 0 (false) or a 1 (true)
- Real number -- single-precision (32-bit) or double-precision (64-bit) floating point number, expressed using ASCII characters.
- Integer number -- 32-bit binary integer number, expressed using ASCII characters.

- String -- IEEE 488.2 String response type; surrounded by double-quotes ("").

  Note: used for enums without a SCPI short form.

- Character data -- IEEE 488.2 Character data response type; no double-quotes; allowed characters are alphanumeric and the underscore (_).

  Note: used for enums with a SCPI short form.

- Arbitrary ASCII -- IEEE 488.2 Arbitrary ASCII response type; list of 8-bit values, interpreted as 7-bit ASCII with the MSB bit set to 0.

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