1.1. SCPI Command Set
Standard Commands for Programmable Instrumentation (SCPI) support is provided for all MagnaDC power supply products. These commands provide programming compatibility with other instruments. SCPI commands are ASCII textual strings, which are sent to the instrument over the physical layer, providing support over all communication interfaces. Utilizing these SCPI commands provides the simplest form of programming a MagnaDC power supply product, as they are driver and programming environment independent. Further information about the SCPI standard and conventions are in the section: SCPI Introduction. The full list of linked commands are in section: SCPI Command Reference List.
1.1.1. SCPI Introduction
1.1.1.1. Command Structure
There are two types of SCPI messages: program and response.
A program message consists of one or more properly formatted SCPI commands sent from the controller to the MagnaDC power supply. The message, which may be sent at any time, requests the MagnaDC power supply to perform some action.
A response message consists of data in a specific SCPI format sent from the MagnaDC power supply to the controller. The MagnaDC power supply sends the message only when requested from a program message query.
1.1.1.2. Data Types
The following datatypes, referenced in the SCPI command descriptions, describe the responses from query SCPI commands:
- <NR1>
Digits with an implied decimal point assumed at the right of the least-significant digit. Example: 273
- <NR2>
Digits with an explicit decimal point. Example: .0273
- <NR3>
Digits with an explicit decimal point and an exponent. Example: 2.73E+2
The following data types, referenced in the SCPI command descriptions, describe the parameters from program SCPI commands:
- <Nrf>
Extended format that includes <NR1>, <NR2>, and <NR3>. Examples: 273, 273., 2.73E2
- <Nrf+>
Expanded decimal format that includes <NRf> and MIN MAX. MIN and MAX are the minimum and maximum limit values that are implicit in the range specification for the parameter. Examples: 273, 273., 2.73E2, MAX
- <Bool>
Boolean Data. Example: 0 | 1 or ON | OFF
1.1.1.3. Termination
A new line <NL> character must be sent to the MagnaDC power supply to terminate a SCPI command string. The IEEE-488 EOI (End-Or-Identify) message is interpreted as a <NL> character and can be used to terminate a command string in place of an <NL>. A carriage return followed by a new line <CR><NL> is also accepted. Command string termination will always reset the current SCPI command path to the root level.
1.1.1.4. Syntax Conventions
- Square brackets []
Used to enclose a parameter that is optional when programming the command; that is, the instrument shall process the command to have the same effect whether the option node is omitted by the programmer or not.
- Angle brackets <>
Used to enclose mandatory parameters or to indicate a returned parameter. For example, in the CURRent <value> command syntax, the <value> parameter is enclosed in triangle brackets. The brackets are not sent with the command string. You must specify a value for the parameter, for example:
CURRent 125- Vertical bar |
Used to separate multiple parameter choices for the command string, for example:
[SOURce:]CURRent 0through MAX | MINimum | MAXimum
1.1.2. SCPI EEPROM Write Behavior
The power supply saves key configuration and set point values, such as voltage and current set points, to its internal non-volatile EEPROM memory. This feature ensures that your essential settings are maintained when the unit is powered cycled.
To maximize the lifespan of the hardware, Firmware Version 9.1 and later includes a protective EEPROM feature. In its default factory configuration, the power supply will only perform an EEPROM write operation if a new command value is different from the value already stored in EEPROM. For example, sending CURRent 1.5 when the stored current value is already 1.5 will not trigger an EEPROM write. For most applications, this behavior is sufficient to protect the EEPROM from unnecessary wear.
Certain applications, such as automated test sequences involving rapid “microstepping” of voltage or current, can still generate a high volume of unique commands in a short period. This can lead to an excessive number of write cycles that may reduce the EEPROM’s operational life.
For these specific scenarios, we strongly recommend using the SYSTem:EepromLoCK command to temporarily disable all EEPROM writes while the high‑rate of commands is active.
1.1.3. SCPI Command Reference List
The subsystems provide more details on all the supported commands. The following table provides a summary of the available SCPI commands:
SCPI Command |
Description |
|---|---|
MEASure Subsystem |
|
Measures and returns the average voltage at the sense location |
|
Measures and returns the average current at the sense location |
|
OUTPut Subsystem |
|
Provides the output state of the product |
|
Enables or disables ARM functionality for auto-sequencing |
|
Enables the power processing circuitry in the product to begin producing output |
|
Disables the power processing circuitry in the product to stop producing output |
|
Reset soft faults |
|
SOURce Subsystem |
|
Sets the voltage set-point |
|
Sets the over voltage trip (OVT) set-point |
|
Sets the current set-point |
|
Sets the over current trip (OCT) set-point |
|
Sets the time period for present auto-sequencing memory step |
|
Selects a memory location for auto-sequencing |
|
CONFigure Subsystem |
|
Configures the ability start, stop, arm, and clear via the front panel |
|
Configures the ability start, stop, arm, and clear via digital inputs and computer command |
|
Configures the sense location and automated compensation values |
|
Configures the product’s interlock functionality |
|
Configures from which interface the product receives its set points |
|
SYSTem Subsystem |
|
Returns hardware revision and firmware version |
|
Returns error type and message |
|
Configures the EEPROM writing behavior |
|
Returns MAC address |
|
Returns Ethernet module serial number |
|
Returns firmware version of the Ethernet module |
|
Set the static IP address |
|
Set the Gateway IP address |
|
Set the subnet IP Mask address |
|
Set the socket number |
|
Return hostname |
|
Set DHCP operation mode |
|
Returns firmware version of GPIB module |
|
Returns address of GPIB module |
|
STATus Subsystem |
|
Clear all status registers |
|
Configure Event Status Enable Register |
|
Read Event Status Register |
|
Product identification |
|
Operation Complete Bit |
|
Returns the value of the Operation Status register |
|
Returns the value of the Questionable Status register |
|
Reset to factory default states |
|
Service Request Enable Register |
|
Status Byte |
|
CALibration Subsystem |
|
Updates the product identification string |
|
Initiates the calibration sequence |
|
Sets the value for the specified calibration potentiometer |
|
Sets the voltage scale factor |
|
Sets the current scale factor |
|
Sets the full scale external programming inputs |
|
Resets the calibration potentiometers to factory defaults |
|
Terminates the calibration subsystem |
|
MODulation Subsystem |
|
Selects the modulation type and table |
|
Programs the user defined modulation table |
|
Saves the active modulation table to non-volatile memory |
|
Loads the cached modulation table into the active table |
|
TRIGger Subsystem |
|
Controls remote triggering of the power supply |
|
Enables the trigger system |
|
Cancels any trigger actions presently in process |