3. Programming Guide

3.1 Introduction

This programming guide provides details on remotely controlling each channel of the Source Measure Unit (SMU). Control is based on a subset of the SCPI (Standard Commands for Programmable Instruments) command set but does not strictly conform to the standard. All supported common commands must be entered in uppercase. All other supported commands are in abbreviated form and must be entered in lowercase. All messages sent and received between the control computer and SMU are ASCII strings terminated with a carriage return character (\r).

Each channel has its own command buffer that can queue up a maximum of four commands for execution, including the one currently being executed. It is highly recommended that the programmer implement command flow control in their application to avoid filling the commands buffer and generating errors. The recommended approach is to wait for query commands to return a response before issuing the next commands. Write-only commands, such as setting parameter values, do not return a response. For write-only commands is is recommended that they be followed immediately by an error query (syst:err:all?) to determine that the write has been processed, and to validate that it was successful. After receiving the error response, it is safe to issue further commands.

3.2 Common commands

*IDN?

Description

The *IDN? command queries the instrument identification string. This provides information about the manufacturer, model, serial number, firmware version, channel serial number, and channel firmware version for the queried channel on the SMU.

Syntax

*IDN?

Response Format

Returns a comma-separated string containing the following information:

Manufacturer Name
Model Number
Serial Number
Firmware Version
Channel Serial Number
Channel Firmware Version

Examples

Retrieve the instrument identification string:

*IDN?

Example Response:

Manufacturer, Model, SerialNumber, FirmwareVersion, ChannelSerialNumber, ChannelFirmwareVersion

Notes

The response format and values depend on the specific instrument model and firmware version.
This command is commonly used to verify communication with the instrument.

*RST

Description

The *RST command hard resets an SMU channel to its default factory settings by resetting the channel microcontroller. This command restores measurement, sourcing, and protection settings for a channel to their default values.

Syntax

*RST

Effects

Clears all user-configured settings.
Resets measurement functions, sourcing settings, and protection limits.
Does not affect network communication settings.

Examples

Reset the instrument to factory defaults:
```
*RST
```

Notes

Use this command with caution, as all settings will be lost.
The command takes ~5s to return the channel to a usable state.
A soft reset to default settings is almost always preferable. See syst:pres instead.

*STB?

Description

The *STB? command queries the status byte register of the SMU channel. The status byte contains information about the current state of the instrument, including errors, state, and event flags.

Syntax

*STB?

Response Format

Returns an integer value representing the status byte. The meaning of each bit in the status byte is given in Table 3.2.1:

Table 3.2.1. Status Register Bits
Bit	Name	Description
0	Watchdog reset flag	The channel microcontroller has been reset by a watchdog timeout.
1	Compliance flag	The channel is currently in compliance.
2	Output enabled flag	The channel output is currently enabled.
3	Output mode flag	The current channel output mode. If set, sourcing current and measuring voltage. If not set, sourcing voltage and measuring current.
4	Command error bit 0	Bit 0 for error type of the most recent command.
5	Command error bit 1	Bit 1 for error type of the most recent command.
6	Reserved for future use.
7	Reserved for future use.

The meaning of each combination of command error bit values in the status byte is given in Table 3.2.2:

Table 3.2.2. Command error bits
Bit 0	Bit 1	Description
0	0	No error
1	0	Invalid command
0	1	Invalid CRC
1	1	Response overflow

Examples

Retrieve the current status byte:
```
*STB?
```
Example Response:
```
14
```
14 is represented in binary as 00001110 meaning there has been no watchdog timer reset, the channel is in compliance, the output is enabled, the channel is sourcing current and measuring voltage, and there was no command error.

Notes

The returned value is a decimal representation of the binary status byte.
If multiple bits are set, their values are summed in the response.
This command is useful for detecting errors and monitoring instrument state.

3.3 Command reference

outp

Description

The outp command controls the output state of an SMU channel. This command enables or disables the output, allowing or preventing voltage or current sourcing.

Syntax

outp <state>

Parameters

<state>: Specifies whether the output is enabled or disabled.
- 0 - Output Off
- 1 - Output On

Default Value

The default output state is Off (0).

Query Form

To retrieve the current output state, use:

outp?

This command returns 0 if the output is off, or 1 if the output is on.

Examples

Enable the output:
```
outp 1
```
Disable the output:
```
outp 0
```
Retrieve the current output state:
```
outp?
```
Example Response:
```
1
```

Notes

Changing the output state takes effect immediately.
If the output is enabled, ensure that appropriate voltage or current limits are set to avoid unintended behavior.
The output state persists until modified or the instrument is reset.

read?

Description

The read? command triggers and returns the measurement value(s) from an SMU channel based on its current configuration.

Syntax

read?

Response Format

Returns a comma-separated list of measurement data. Each data point is a sub-list of three floating-point numbers and an integer representing the measured voltage in volts, measured current in amps, timestamp in ms since the channel was last powered on, and status byte, respectively. If the source is configured in sweep mode, the return value is a concatenated comma-separated list of all measurement points maintaining the aforementioned sub-list order. To understand the meanings of the bits in the status byte see *STB?.

Examples

Retrieve the current measured value:

read?

Example Response:

0.0,0.0,123.456,14,1.0,0.05,143.456,14,2.0,0.1,163.456,14

This response contains measurement data from a sweep of three points as detailed in Table 3.3.1:

Table 3.3.1. Example measurement data
Measurement Point	Voltage (V)	Current (A)	Timestamp (ms)	Status byte
0	0.0	0.0	123.456	14
1	1.0	0.05	143.456	14
2	2.0	0.1	163.456	14

Notes

Ensure the measurement configuration is correctly set before using this command.
If the instrument is in remote sensing mode, the voltage measurement reflects the value across the sense terminals rather than the force terminals.

sens:curr:nplc

Description

The sens:curr:nplc command sets the integration time for both current and voltage measurements in terms of number of power line cycles (NPLC) for an SMU channel. A higher NPLC value increases measurement accuracy by reducing noise but also increases measurement time.

The equivalent integration time, $t_{int}$ , can be calculated as $t_{int}=NPLC/PLF$ where $PLF$ is the power line frequency, e.g. 50Hz (see syst:lfr).

Syntax

sens:curr:nplc <value>

Parameters

<value>: The number of power line cycles for current and voltage measurement, specified as a floating-point number.

Default Value

The default NPLC value is 1.000.

Range

Minimum: 0.01 NPLC
Maximum: 10.0 NPLC

Query Form

To retrieve the current NPLC setting for current and voltage measurements, use:

sens:curr:nplc?

This command returns the NPLC setting in floating-point format.

Examples

Set the NPLC value to 5.0:
```
sens:curr:nplc 5.0
```
Retrieve the current NPLC value:
```
sens:curr:nplc?
```
Example Response:
```
5.000
```

Notes

The setting is applied to both current and voltage measurements. sens:volt:nplc is an identical command.
Increasing NPLC improves accuracy but slows down measurements.
Lower values allow faster readings but may introduce more noise.
The command takes effect immediately upon execution.
The setting persists until modified or the instrument is reset.

sens:curr:prot

Description

The sens:curr:prot command sets the current protection (compliance) limit for an SMU channel. This limit defines the maximum allowable current before the instrument enters a protection state to prevent damage or unintended operation. This limit applies when sourcing voltage. The limit is bipolar meaning that is applies to the absolute value of current.

Syntax

sens:curr:prot <value>

Parameters

<value>: The current protection limit, specified in amperes (A).

Default Value

The default current protection limit is 0.200 A.

Range

Minimum: 0.0005 A
Maximum: 0.2000 A

Query Form

To retrieve the current protection limit, use:

sens:curr:prot?

This command returns the current protection limit setting in floating-point format with units of amperes (A).

Examples

Set the current protection limit to 0.2 A:
```
sens:curr:prot 0.2
```
Retrieve the current protection limit:
```
sens:curr:prot?
```
Example Response:
```
0.200
```

Notes

If a value outside the allowed range is provided, the SMU will generate an error.
The command takes effect immediately upon execution.
Protection settings persist until modified or the instrument is reset.

sens:volt:nplc

Description

The sens:volt:nplc command sets the integration time for both current and voltage measurements in terms of number of power line cycles (NPLC) for an SMU channel. A higher NPLC value increases measurement accuracy by reducing noise but also increases measurement time.

The equivalent integration time, $t_{int}$ , can be calculated as $t_{int}=NPLC/PLF$ where $PLF$ is the power line frequency, e.g. 50Hz (see syst:lfr).

Syntax

sens:volt:nplc <value>

Parameters

<value>: The number of power line cycles for current and voltage measurement, specified as a floating-point number.

Default Value

The default NPLC value is 1.000.

Range

Minimum: 0.01 NPLC
Maximum: 10.0 NPLC

Query Form

To retrieve the current NPLC setting for current and voltage measurements, use:

sens:volt:nplc?

This command returns the NPLC setting in floating-point format.

Examples

Set the NPLC value to 5.0:
```
sens:volt:nplc 5.0
```
Retrieve the current NPLC value:
```
sens:volt:nplc?
```
Example Response:
```
5.000
```

Notes

The setting is applied to both current and voltage measurements. sens:curr:nplc is an identical command.
Increasing NPLC improves accuracy but slows down measurements.
Lower values allow faster readings but may introduce more noise.
The command takes effect immediately upon execution.
The setting persists until modified or the instrument is reset.

sens:volt:prot

Description

The sens:volt:prot command sets the voltage protection limit for an SMU channel. This limit defines the maximum allowable voltage before the instrument enters a protection state to prevent damage or unintended operation. This limit applies when sourcing current. The limit is bipolar meaning that is applies to the absolute value of voltage.

Syntax

sens:volt:prot <value>

Parameters

<value>: The voltage protection limit, specified in volts (V).

Default Value

The default voltage protection limit is 5.000 V.

Range

Minimum: 0.0125 V
Maximum: 5.000 V

Query Form

To retrieve the current voltage protection limit, use:

sens:volt:prot?

This command returns the voltage protection limit setting in floating-point format with units of volts (V).

Examples

Set the voltage protection limit to 20 V:
```
sens:volt:prot 1.0
```
Retrieve the voltage protection limit:
```
sens:volt:prot?
```
Example Response:
```
1.000
```

Notes

If a value outside the allowed range is provided, the SMU will generate an error.
The command takes effect immediately upon execution.
Protection settings persist until modified or the instrument is reset.

sour:curr

Description

The sour:curr command sets the output current of an SMU channel when operating in current source mode.

Syntax

sour:curr <value>

Parameters

<value>: Specifies the output current, in amperes (A).

Default Value

The default output current is 0.000 A.

Range

Minimum: -0.200 A
Maximum: 0.200 A

Query Form

To retrieve the current output current setting, use:

sour:curr?

This command returns the current setting in floating-point format with units of amperes (A).

Examples

Set the output current to 0.1 A:
```
sour:curr 0.1
```
Retrieve the current output current setting:
```
sour:curr?
```
Example Response:
```
0.1
```

Notes

The SMU must be in current source mode (sour:func curr) for this command to take effect when the output is enabled.
Ensure that appropriate voltage compliance (sens:volt:prot) is set to protect the device under test (DUT).
The current setting takes effect immediately upon execution.
The setting persists until modified or the instrument is reset.

sour:curr:mode

Description

The sour:curr:mode command sets the current sourcing mode for an SMU channel. This determines whether the current output operates in a fixed mode or as part of a sweep operation.

Syntax

sour:curr:mode <mode>

Parameters

<mode>: Specifies the current sourcing mode.
- fix - Fixed current mode
- swe - Current sweep mode

Default Value

The default current sourcing mode is Fixed (fix).

Query Form

To retrieve the current sourcing mode, use:

sour:curr:mode?

This command returns the current mode as either "fix" or "swe".

Examples

Set the current source to fixed mode:
```
sour:curr:mode fix
```
Set the current source to sweep mode:
```
sour:curr:mode swe
```
Retrieve the current source mode:
```
sour:curr:mode?
```
Example Response:
```
fix
```

Notes

Fixed mode (fix) maintains a constant current output.
Sweep mode (swe) varies current over a defined range for characterisation applications.
If switching from sweep mode to fixed mode, ensure that the current is set to an appropriate level.
The command takes effect immediately upon execution.
The setting persists until modified or the instrument is reset.

sour:curr:start

Description

The sour:curr:start command sets the starting current value for a current sweep operation. This defines the initial current level when performing a programmed current sweep.

Syntax

sour:curr:start <value>

Parameters

<value>: Specifies the starting current, in amperes (A).

Default Value

The default starting current is 0.000 A.

Range

Minimum: -0.200 A
Maximum: 0.200 A

Query Form

To retrieve the current starting current setting, use:

sour:curr:start?

This command returns the starting current setting in floating-point format with units of amperes (A).

Examples

Set the starting current to 0.0 A:
```
sour:curr:start 0.0
```
Retrieve the current starting current setting:
```
sour:curr:start?
```
Example Response:
```
0.0
```

Notes

This command is only used in current sweep mode (sour:curr:mode swe).
The starting current should be set before defining the stop current.
The setting persists until modified or the instrument is reset.

sour:curr:stop

Description

The sour:curr:stop command sets the stopping current value for a current sweep operation. This defines the final current level when performing a programmed current sweep.

Syntax

sour:curr:stop <value>

Parameters

<value>: Specifies the stopping current, in amperes (A).

Default Value

The default stopping current is 0.000 A.

Range

Minimum: -0.200 A
Maximum: 0.200 A

Query Form

To retrieve the current stopping current setting, use:

sour:curr:stop?

This command returns the stopping current setting in floating-point format with units of amperes (A).

Examples

Set the stopping current to 0.1 A:
```
sour:curr:stop 0.1
```
Retrieve the current stopping current setting:
```
sour:curr:stop?
```
Example Response:
```
0.100
```

Notes

This command is only used in current sweep mode (sour:curr:mode swe).
The stopping current should be set after defining the starting current.
The setting persists until modified or the instrument is reset.

sour:del:auto

Description

The sour:del:auto command enables or disables the automatic source delay mode. When enabled for an SMU channel, it uses a source delay of 1 ms.

Syntax

sour:del:auto <state>

Parameters

<state>: Specifies whether automatic source delay is enabled or disabled.
- 0 - Automatic source delay off (manual mode)
- 1 - Automatic source delay on

Default Value

The default state is Enabled (1).

Query Form

To retrieve the current automatic source delay setting, use:

sour:del:auto?

This command returns 0 if auto delay is disabled, or 1 if auto delay is enabled.

Examples

Enable automatic source delay:
```
sour:del:auto 1
```
Disable automatic source delay:
```
sour:del:auto 0
```
Retrieve the current automatic delay setting:
```
sour:del:auto?
```
Example Response:
```
0
```

Notes

The command takes effect immediately upon execution.
The setting persists until modified or the instrument is reset.

sour:del

Description

The sour:del command sets the source delay time for an SMU channel. This delay determines the time interval between setting the source value and taking a measurement, allowing stabilisation of the sourced voltage or current before measurement.

Syntax

sour:del <value>

Parameters

<value>: The delay time, specified in seconds (s).

Default Value

The default source delay is 0.000 s (no delay).

Range

Minimum: 0.000 s
Maximum: 9999.999 s

Query Form

To retrieve the current source delay setting, use:

sour:del?

This command returns the source delay setting in floating-point format with units of seconds (s).

Examples

Set the source delay to 0.1 seconds:
```
sour:del 0.1
```
Retrieve the current source delay:
```
sour:del?
```
Example Response:
```
0.1
```

Notes

A longer delay can improve measurement accuracy by allowing transients to settle.
Setting the delay to 0.000 minimises latency but may introduce instability in some setups.
The command takes effect immediately upon execution.
The setting persists until modified or the instrument is reset.

sour:func

Description

The sour:func command sets the sourcing function of an SMU channel. This determines whether the instrument operates as a voltage source or a current source.

Syntax

sour:func <function>

Parameters

<function>: Specifies the sourcing function.
- volt - Voltage source mode
- curr - Current source mode

Default Value

The default sourcing function is Voltage (volt).

Query Form

To retrieve the currently set sourcing function, use:

sour:func?

This command returns the current sourcing mode as either "volt" or "curr".

Examples

Set the instrument to voltage source mode:
```
sour:func volt
```
Set the instrument to current source mode:
```
sour:func curr
```
Retrieve the currently set sourcing function:
```
sour:func?
```
Example Response:
```
curr
```

Notes

Changing the sourcing function may require reconfiguring output settings (e.g., voltage or current limits).
Ensure the selected mode is compatible with your test setup to prevent unintended behavior.
The command takes effect immediately upon execution.
The setting persists until modified or the instrument is reset.

sour:swe:poin

Description

The sour:swe:poin command sets the number of points in a sweep operation. This defines how many discrete steps the source will take from the start to stop value.

Syntax

sour:swe:poin <value>

Parameters

<value>: Specifies the number of points in the sweep, as an integer.

Default Value

The default number of sweep points is 1.

Range

Minimum: 1 points
Maximum: 117 points

Query Form

To retrieve the current number of sweep points, use:

sour:swe:poin?

This command returns the number of points as an integer.

Examples

Set the sweep to use 50 points:
```
sour:swe:poin 50
```
Retrieve the current number of sweep points:
```
sour:swe:poin?
```
Example Response:
```
50
```

Notes

The total sweep time is affected by the number of points, the delay, and NPLC settings.
A larger number of points provides finer resolution but increases total sweep time.
The setting persists until modified or the instrument is reset.

sour:swe:spac

Description

The sour:swe:spac command sets the spacing type for a sweep operation. This determines whether the sweep steps are linearly or logarithmically spaced.

Syntax

sour:swe:spac <type>

Parameters

<type>: Specifies the sweep spacing type.
- lin - Linear sweep spacing
- log - Logarithmic sweep spacing

Default Value

The default sweep spacing is Linear (lin).

Query Form

To retrieve the current sweep spacing type, use:

sour:swe:spac?

This command returns the current spacing type as either "lin" or "log".

Examples

Set the sweep spacing to logarithmic:
```
sour:swe:spac log
```
Set the sweep spacing to linear:
```
sour:swe:spac lin
```
Retrieve the current sweep spacing setting:
```
sour:swe:spac?
```
Example Response:
```
lin
```

Notes

Linear spacing (lin) steps through values with equal increments.
Logarithmic spacing (log) steps through values with a logarithmic spacing.
The setting persists until modified or the instrument is reset.

sour:volt

Description

The sour:volt command sets the output voltage of an SMU channel when operating in voltage source mode.

Syntax

sour:volt <value>

Parameters

<value>: Specifies the output voltage, in volts (V).

Default Value

The default output voltage is 0.000 V.

Range

Minimum: -5.0 V
Maximum: 5.0 V

Query Form

To retrieve the current output voltage setting, use:

sour:volt?

This command returns the voltage setting in floating-point format with units of volts (V).

Examples

Set the output voltage to 5.0 V:
```
sour:volt 5.0
```
Retrieve the current output voltage setting:
```
sour:volt?
```
Example Response:
```
5.000
```

Notes

The SMU must be in voltage source mode (sour:func volt) for this command to take effect.
Ensure that appropriate current compliance (sens:curr:prot) is set to protect the device under test (DUT).
The voltage setting takes effect immediately upon execution.
The setting persists until modified or the instrument is reset.

sour:volt:mode

Description

The sour:volt:mode command sets the voltage sourcing mode for an SMU channel. This determines whether the voltage output operates in a fixed mode or as part of a sweep operation.

Syntax

sour:volt:mode <mode>

Parameters

<mode>: Specifies the voltage sourcing mode.
- fix - Fixed voltage mode
- swe - Voltage sweep mode

Default Value

The default voltage sourcing mode is Fixed (fix).

Query Form

To retrieve the current voltage sourcing mode, use:

sour:volt:mode?

This command returns the current mode as either "fix" or "swe".

Examples

Set the voltage source to fixed mode:
```
sour:volt:mode fix
```
Set the voltage source to sweep mode:
```
sour:volt:mode swe
```
Retrieve the current voltage source mode:
```
sour:volt:mode?
```
Example Response:
```
fix
```

Notes

Fixed mode (fix) maintains a constant voltage output.
Sweep mode (swe) varies voltage over a defined range for characterisation applications.
If switching from sweep mode to fixed mode, ensure that the voltage is set to an appropriate level.
The command takes effect immediately upon execution.
The setting persists until modified or the instrument is reset.

sour:volt:start

Description

The sour:volt:start command sets the starting voltage value for a voltage sweep operation. This defines the initial voltage level when performing a programmed voltage sweep.

Syntax

sour:volt:start <value>

Parameters

<value>: Specifies the starting voltage, in volts (V).

Default Value

The default starting voltage is 0.000 V.

Range

Minimum: -5.0 V
Maximum: 5.0 V

Query Form

To retrieve the current starting voltage setting, use:

sour:volt:start?

This command returns the starting voltage setting in floating-point format with units of volts (V).

Examples

Set the starting voltage to -2.5 V:
```
sour:volt:start -2.5
```
Retrieve the current starting voltage setting:
```
sour:volt:start?
```
Example Response:
```
-2.500
```

Notes

This command is only used in voltage sweep mode (sour:volt:mode swe).
The starting voltage should be set before defining the stop voltage.
The setting persists until modified or the instrument is reset.

sour:volt:stop

Description

The sour:volt:stop command sets the stopping voltage value for a voltage sweep operation. This defines the final voltage level when performing a programmed voltage sweep.

Syntax

sour:volt:stop <value>

Parameters

<value>: Specifies the stopping voltage, in volts (V).

Default Value

The default stopping voltage is 0.000 V.

Range

Minimum: -5.0 V
Maximum: 5.0 V

Query Form

To retrieve the current stopping voltage setting, use:

sour:volt:stop?

This command returns the stopping voltage setting in floating-point format with units of volts (V).

Examples

Set the stopping voltage to 2.5 V:
```
sour:volt:stop 2.5
```
Retrieve the current stopping voltage setting:
```
sour:volt:stop?
```
Example Response:
```
2.500
```

Notes

This command is only used in voltage sweep mode (sour:volt:mode swe).
The stopping voltage should be set after defining the starting voltage.
The setting persists until modified or the instrument is reset.

syst:err:all?

Description

The syst:err:all? command retrieves up to 10 system error messages from an SMU channel. This provides information on any errors that have occurred, allowing for troubleshooting and debugging. Once this command has been issued, the channel error buffer is cleared. Possible error messages and their meanings are given in Table 3.3.2.

Table 3.3.2. Error messages
Message	Description
"+000, No Error"	The previous command was valid.
"-100, Command error"	The previous command was malformed or not supported.
"-154, String too long"	The response string for the last command exceeds the valid length of the response buffer.
"-220, Parameter error"	The parameter for the previous message was malformed or out of range.
"-363, Input buffer overrun"	The command string is too long for the SMU channel command buffer.
"+950, Command queue overflow"	The command buffer is full because the instrument is still processing previous commands.

Syntax

syst:err:all?

Response Format

Returns a comma-separated list of error codes and corresponding messages.

Examples

Retrieve all system error messages:
```
syst:err:all?
```
Example Response:
```
+000, No Error
```

Notes

If multiple errors exist, they are all returned, emptying the error queue.
A response of +000, No Error indicates that there are no active errors in the system.
Errors remain in the queue until read or the instrument is reset.

syst:lfr

Description

The syst:lfr command sets the power line frequency for noise filtering in measurements. This setting is used internally by an SMU channel to determine integration time from NPLC.

Syntax

syst:lfr <value>

Parameters

<value>: Specifies the AC line frequency in hertz (Hz).
- 50 - 50 Hz power line frequency
- 60 - 60 Hz power line frequency

Default Value

The default line frequency is 50 Hz.

Query Form

To retrieve the current line frequency setting, use:

syst:lfr?

This command returns the frequency in hertz as an integer (50 or 60).

Examples

Set the line frequency to 50 Hz:
```
syst:lfr 50
```
Retrieve the current line frequency setting:
```
syst:lfr?
```
Example Response:
```
50
```

Notes

The selected frequency should match the local power grid to optimise noise rejection.
Changing the line frequency setting affects integration time for measurements.
The setting persists until modified or the instrument is reset.

syst:pres

Description

The syst:pres command restores an SMU channel to its factory preset state. This resets all user-configurable settings to their default values while maintaining communication settings.

Syntax

syst:pres

Effects

Clears all user-defined configurations.
Resets measurement, sourcing, and protection settings.
Does not affect communication settings.

Examples

Restore factory preset settings:
```
syst:pres
```

Notes

Use this command with caution, as all configuration settings will be lost.
This is a soft reset of parameter values that doesn't fully reset the SMU channel microcontroller.
This soft reset to default settings is almost always preferable over *RST.
The command takes effect immediately upon execution.

syst:rsen

Description

The syst:rsen command enables or disables remote sensing mode for voltage measurements. Remote sensing helps compensate for voltage drops across test leads by using a separate sense connection.

Syntax

syst:rsen <state>

Parameters

<state>: Specifies whether remote sensing is enabled or disabled.
- 0 - Remote sensing off (2-wire mode)
- 1 - Remote sensing on (4-wire mode)

Default Value

The default setting is Remote sensing off (1).

Query Form

To retrieve the current remote sensing state, use:

syst:rsen?

This command returns 0 if remote sensing is disabled, or 1 if it is enabled.

Examples

Enable remote sensing (4-wire mode):
```
syst:rsen 1
```
Disable remote sensing (2-wire mode):
```
syst:rsen 0
```
Retrieve the current remote sensing setting:
```
syst:rsen?
```
Example Response:
```
0
```

Notes

Remote sensing (1) improves accuracy by eliminating lead resistance effects.
Local sensing (0) uses standard 2-wire connections without additional compensation.
Ensure that appropriate sense leads are connected when enabling remote sensing.
The setting persists until modified or the instrument is reset.