Clear Status Command. Clears the Status Byte, the Data Questionable Event Register, the Standard Event Status Register, the Standard Operation Status Register, the error queue, the OPC pending flag, and any other registers that are summarized in the Status Byte. No Query
Cmd Parameters
NA
Query Parameters
NA
Query Output
NA
Syntax Example
*CLS
*DDT <Arbitrary Block> | <String>
*DDT?
Description
Define Device Trigger. The command enters the 488.2 Define Device Trigger command with an input of arbitrary block or string. The query returns the 488.2 Define Device Trigger command as an arbitrary block output string. Note that the IEEE488.2 Standard specifies the input type to only be <Arbitrary Block>. In addition, VectorStar VNAs will also accept a <String>.
Cmd Parameters
<Arbitrary Block> | <String>
Query Parameters
NA
Query Output
<Arbitrary Block>
Range
NA
Default
NA
Syntax Example
*DDT <String>
*DDT?
*ESE <NRf>
*ESE?
Description
Standard Event Status Enable and Query. The command sets the Standard Event Status Enable Register bits. The binary weighted <NRf> data parameter used with this command must have a value between 0 to 255. The query returns the value of the Standard Event Status Enable Register in <NR1> format. Refer to Status System Reporting.
Cmd Parameters
<NRf>
Query Parameters
NA
Range
0 to 255
Query Output
<NR1>
Syntax Example
*ESE <NRf>
*ESE?
*ESR?
Description
Standard Event Status Register Query. Query only. Returns the value of the Standard Event Status Register in <NR1> format. This command clears the Standard Event Status Register. Refer to Status System Reporting.
Cmd Parameters
NA
Query Parameters
NA
Query Output
<NR1>
Range
NA
Default
NA
Syntax Example
*ESR?
*IDN?
Description
Identification Query. Query only. This query returns an instrument identification string in IEEE-488.2 specified <Arbitrary ASCII> format consisting of four fields separated by commas. The fields are: <Manufacturer>, <Model>, <Serial #>, <Firmware Revision Level> where the actual model number, serial number, and firmware version of the MS4640A Series VNA queried will be passed. The character output is of indeterminate length and must be the last statement issued if multiple commands and/or queries are issued at the same time. See Chapter 2 for definition of <ASCII>.
Cmd Parameters
NA
Query Parameters
NA
Query Output
<Arbitrary ASCII>
Range
NA
Default
NA
Syntax Example
*IDN?
*IST?
Description
Individual Status Query. Output the value of the IST message. This command is not supported by VectorStar VNA hardware.
*OPC
Description
Operation Complete Command. When the *OPC command is encountered, it does nothing. Program flow is allowed to proceed to the next command in the input buffer. No query. Note that *OPC and *OPC? are not a command/query pair although they appear to be.
When the *OPC command is encountered, it immediately sets the Operational Complete bit in the Standard Events Status Register. The *OPC command is a control command for overlapped commands in systems that support command overlapping. The VectorStar does not support overlapped commands, and as a result, no pause function is provided.
Overlapped Command Background
Some non-VectorStar GPIB implementations allow commands to execute simultaneously which is called an Overlapped Command. For example, a calibration step which takes many minutes could be set into operation and then allow other GPIB communication and control commands to proceed while the calibration step continues to take place.
At some point in these non-VectorStar GPIB implementations, the separate Overlapped Operational Streams need to be brought back together and placed under programmatic control in a process called Regaining Synchronization between the controller PC and the instrument. The commands *OPC , *OPC?, and *WAI are designed to regain synchronization control and three different synchronization methods.
IEEE 488.2 Overlapped Command Definitions
The *OPC, *OPC?, and *WAI commands provide coverage for command completion before the next command is parsed and executed and comprise a class of commands termed Overlapped Commands. For instruments that support overlapped commands, each command works differently. Per the IEEE 488.2 specification:
• “IEEE 488.2 defines a distinction between overlapped and sequential commands.
• As defined in IEEE 488.2, a sequential command is one which finishes executing before the next command starts executing. An overlapped command is one which does not finish executing before the next command starts executing.
• These types of commands are described in IEEE 488.2, section 12. Examples are given in IEEE 488.2, Appendix B.
• IEEE 488.2 defines three common commands (*OPC, *OPC?, *WAI) which a device controller can use to synchronize its operation to the execution of overlapped commands.
• Each overlapped command has associated with it a Pending Operation flag.
• The device sets this flag TRUE when it passes the corresponding command from the Execution Control block to the Device Action block.
• The device sets the flag false when the device operation is finished, or has been aborted.”
*OPC Synchronization
The *OPC Operation Complete command is defined in IEEE 488.2-1992, Section 10.18. *OPC works only if one or more preceeding commands are overlapped command. In systems that support overlapped commands, when this command is encountered, it waits until all overlapped commands have completed. Once all prior overlapped commands are complete, it instructs the parser to execute the next following command. A typical use would be to issue a *OPC before issuing a command for a long duration measurement sweep. *OPC causes the instrument to continuously sense the No Operation Pending flag. When the No Operation Pending (NOP) flag becomes TRUE, the OPC event bit in the Standard Event Status Register is set to “1” to indicate that the state of all pending operations have been completed. If this bit had been previously programmed to send a Service Request, then the controller would be aware that all is synchronized.
• For example, OV1 through OV3 are overlapped commands where the command series is OV1, OV2, OV3, *OPC, XXX.
• Commands OV1, OV2, OV3 start running. The NOP is set to FALSE.
• Parser execution stops at *OPC and the parser waits while the NOP is FALSE.
• Commands OV1, OV2, and OV3 continue to run in overlapped mode.
• Commands OV1, OV2, and OV3 are finally complete.
• The NOP flag is set to TRUE and *OPC sets the status bit to 1.
• Parser execution resumes.
• Command XXX starts running.
*OPC? Synchronization
In systems that support overlapped commands, the *OPC? Operation Complete Query command waits until all overlapped commands have been completed. When that synchronizing moment arrives, the ASCII character “1” is placed in the output buffer. This sets the MAV bit in the Status byte to TRUE which indicates there is data in the output buffer. If the controller had been attempting to read data, the moment the “1” appears in the output buffer, it is read by the controller making it aware that all is synchronized. When that synchronizing moment arrives, the next command in the input buffer is executed and the command execution is synchronized.
• For example, OV1 through OV3 are overlapped commands where the command series is OV1, OV2, OV3, *OPC?, XXX.
• Commands OV1, OV2, OV3 start running. The NOP is set to FALSE.
• Parser execution stops at *OPC? and the parser waits while the NOP is FALSE.
• Commands OV1, OV2, and OV3 continue to run in overlapped mode.
• Commands OV1, OV2, and OV3 are finally complete.
• The NOP flag is set to TRUE and *OPC? puts a one (“1”) in the output buffer.
• Parser execution resumes.
• Command XXX starts running.
*WAI Synchronization
In systems that support overlapped commands, the *WAI Wait-to-Continue Command causes the parser to wait until all overlapped commands have been completed. When that synchronizing moment arrives, the next command in the input buffer is executed and command execution is synchronized.
• For example, OV1 through OV3 are overlapped commands where the command series is OV1, OV2, OV3, *WAI, XXX.
• Commands OV1, OV2, OV3 start running. The NOP is set to FALSE.
• Parser execution stops at *WAI and the parser waits while the NOP is FALSE.
• Commands OV1, OV2, and OV3 continue to run in overlapped mode.
• Commands OV1, OV2, and OV3 are finally complete.
• The NOP flag is set to TRUE.
• Parser execution resumes.
• Command XXX starts running.
VectorStar and Overlapped Commands
In VectorStar VNAs, and in Anritsu’s earlier 360 and Lightning VNAs, there are no Overlapped Commands. Everything works synchronously and no command is executed until the command which preceded it has finished. Because of this, the commands *OPC, *OPC? and *WAI work slightly differently than the IEEE 488.2 specification.
Related Commands: *OPC, *OPC?, and *WAI commands.
Cmd Parameters
NA
Query Parameters
NA
Query Output
<NR1>
Range
NA
Default
NA
Syntax Example
*OPC
*OPC?
Description
Operation Complete Query. Query only. Not a command/query pair with *OPC. When the *OPC? command is encountered, it does nothing. Program flow is allowed to proceed to the next command in the input buffer.
Per IEEE 488.2, *OPC? is an Overlapped Command which VectorStar VNAs do not support. When the *OPC? command is encountered, it immediately puts the character “1” (one) in the Output Queue buffer, and parser execution continues. It sets the MAV bit true when all pending operations are complete.
The *OPC, *OPC?, and *WAI Overlapped Commands are related. Because VectorStar does not support overlapped commands, they do not function exactly as specified in IEEE 488.2. See the description of Overlapped Commands in the *OPC command description above.
Related commands: *OPC, *OPC?, and *WAI commands.
Cmd Parameters
NA
Query Parameters
NA
Query Output
<NR1>
Range
NA
Default
NA
Syntax Example
*OPC?
*OPT?
Description
Operation Query. Query only. The query reads out the identification number of an option installed in the MS4640A. See Chapter 2 for definition of <ASCII>.
Cmd Parameters
NA
Query Parameters
NA
Range
NA
Default
NA
Query Output
<Arbitrary ASCII>
Syntax Example
*OPT?
*PRE <NRf>
*PRE?
Description
The command enters the 488.2 Parallel Poll Register Enable mask. The query outputs the 488.2 Parallel Poll Register Enable mask. This command/query is not supported by VectorStar VNA hardware.
*RST
Description
Reset Command. The *RST command performs a device reset of the MS4640A VNA to a pre-defined condition or to a user-defined condition. No query. The user-defined condition of *RST resets all user programmable parameters to those defined by the user in a saved configuration file. The pre-defined condition of the *RST command sets the defaults described below. For additional information on default parameter values, see each SCPI command in this manual.
*RST Does Reset the Following Parameters
Except as explicitly excluded in the next section, the *RST command does the following:
• Sets the device-specific functions to a known state that is independent of the past-use history of the device;
• Device specific commands may be provided to program a different reset state than the original factory-supplied one;
• Sets the macro defined by *DDT to a device-defined state;
• Disables macros;
• Forces the device into the OCIS state (Operation Complete Command Idle State);
• Forces the device into the OQIS state (Operation Complete Query Idle State).
*RST Does Not Reset the Following Parameters
The *RST command does not change the parameters listed below:
• Does not change the state of the IEEE 488.1 interface;
• Does not change the selected IEEE 488.1 address of the device;
• Does not change the GPIB address of the device;
• Does not change the Output Queue;
• Does not change any Event Enable Register settings including the Standard Event Status Enable Register;
• Does not change any Event Register setting including the Standard Event Status Register settings;
• Does not change the power-on-status-clear flag setting;
• Does not change the Service Request Enable Register;
• Does not change the maximum number of instrument points to 25,000 if it is set to 100,000 nor change them to 100,000 if it is set to 25,000.
Cmd Parameters
NA
Query Parameters
NA
Query Output
NA
Range
NA
Default
NA
Syntax Example
*RST
*SRE <NRf>
*SRE?
Description
Service Request Enable. The command sets the Service Request Enable Register bits. A zero value in the command resets the register. The query returns the value of the Service Request Enable Register in <NR1> format. Bit 6 is always zero. The integer data parameter used with this query have a value between 0 to 255.
Cmd Parameters
<NRf>
Query Parameters
NA
Query Output
<NR1>
Range
0 to 255; 0 performs a register reset.
Default
NA
Syntax Example
*SRE <NRf>
*SRE?
*STB?
Description
Read Status Byte Query. Query only. Returns the content of the Status Byte Register (bits 0 through 5 and 7). Bit 6 is the Master Summary Status bit value. This command does not reset the status byte values.
Query Parameters
NA
Query Output
<NR1>
Range
NA
Default
NA
Syntax Example
*STB?
*TRG
Description
Trigger Command. Triggers the instrument if :TRIGger:SOURce command data parameter is set to REMOTE. Performs the same function as the Group Execute Trigger (<GET>) bus command as defined in IEEE 488.2. *TRG or the <GET> can trigger a measurement. No query.
The *TRG and <GET> commands are handled differently by the parser. The *TRG command:
• The *TRG command can be mixed with other GPIB commands in a command string which goes through the parser.
• The *TRG command can only trigger a single measurement event on only one device in the GPIB network.
The <GET> command:
• The <GET> gets turned into the command *TRG and goes through the parser by itself.
• A <GET> can trigger single measurement events on any or all instruments in the GPIB network.
What is measured depends on the setting of the *DDT and :TRIGger[:SEQuence]:EXTernal:TYPe commands.
• If a *DDT command has been issued previously, the *TRG or <GET> will execute what is defined in the *DDT instead.
• If a *DDT has not been issued, the *TRG triggers a measurement based on the :TRIG:EXT:TYP command which can be measurement of a point, a single sweep, a single channel, or all channels.
• If a sweep is selected, on 2-Port VNAs, it can be either a either a forward or reverse sweep. On 4-Port VNAs, the sweep can be between any two ports.
Cmd Parameters
NA
Query Parameters
NA
Query Output
NA
Range
NA
Output
NA
Syntax Example
*TRG
*TST?
Description
Self Test Query. Query only. Performs a self test and outputs the self test status in <NR1> format with the following values:
• 0 indicates that self test passed
• Any number greater than 0 indicates the number of the self test that failed
• 144 indicates that the self test was aborted.
Cmd Parameters
NA
Query Parameters
NA
Query Output
<NR1>
Range
NA
Default
NA
Syntax Example
*TST?
*WAI
Description
Wait-to-Continue Command. When the *WAI command is encountered, it does nothing. Program flow is allowed to proceed to the next command in the input buffer. No query.
The *WAI command is an Overlapped Command that provides coverage for command completion when the device supports overlapped command execution. The VectorStar does not support overlapped commands, and as a result, the *WAI does not function exactly as specified in IEEE 488.2. See the description of Overlapped Commands in the *OPC command description above.