2.4. Remote control (Matlab, Labview, Scilab or Python)¶

STEMlab board can be controlled remotely over LAN or wireless interface using Matlab, Labview, Scilab or Python via Red Pitaya SCPI (Standard Commands for Programmable Instrumentation) list of commands. SCPI interface/environment is commonly used to control T&M instruments for development, research or test automation purposes. SCPI uses a set of SCPI commands that are recognized by the instruments to enable specific actions to be taken (e.g.: acquiring data from fast analog inputs, generating signals and controlling other periphery of the Red Pitaya STEMlab platform). The SCPI commands are extremely useful when complex signal analysis is required where SW environment such as MATLAB provides powerful data analysis tools and SCPI commands simple access to raw data acquired on STEMlab board.

Features

Quickly write control routines and programs using Matlab, Labview, Scilab or Python
Use powerful data analysis tools of Matlab, Labview, Scilab or Python to analyze raw signals acquired by STEMlab board
Write testing scripts and routines
Incorporate your STEMlab and Labview into testing and production lines
Take quick measurements directly with your PC

2.4.1. Quick start¶

Start SCPI server, this is done simply by clicking the SCPI server icon and starting the SCPI server. When SCPI server is started the IP of your board will be shown. This IP you need to input in to your scripts. Starting SCPI server can be also done manually via Terminal(check bellow).

To run an examples follow instructions bellow:

Go to your STEMlab main page and Select SCPI server.
Start SCPI server by selecting RUN button. Please notice the IP of your STEMlab (192.168.178.100) board as it will be needed to connect to your board.
Follow the instructions bellow sutable to your environment.

Note

It is not possible to run SCPI commands/programs in parallel with web applications.

MATLAB
Python
LabVIEW
SCILAB

2.4.1.1. MATLAB¶

Open MATLAB on your computer
Copy the Code from blink tutorial example to MATLAB workspace
Replace the IP in the example with the IP of your STEMlab board
Hit RUN or F5 on your keyboard to run the code

Check demo video.

More examples about how to control STEMlab from MATLAB can be find here.

2.4.1.2. Python¶

The PyVISA library in combination with the PyVISA-py backend are used. To install them do:

$ sudo pip3 install pyvisa pyvisa-py

Open the blink tutorial and copy the code to your favorite text editor
Save the file as blink.py to your working folder → for example examples_py
Copy and save the redpitaya_scpi.py `` script in to the same folder where you have saved blink.py example (in our case it will be examples_py).

Note

redpitaya_scpi.py script is a standard script needed to establish the connection between your PC and STEMlab board. Without having this script in the same folder as your python script the execution of your script will fail.
Open the Terminal and go to the folder containing your python script (examples_py) and run: python blink.py IP where you give an STEMlab IP as the argument when calling an execution of the blink.py example. Example is given bellow where 192.168.178.108 is the IP of the STEMlab board.
```
cd /home/zumy/Desktop/exmples_py
python blink.py 192.168.178.108
```

More examples about how to control STEMlab from MATLAB can be find here.

2.4.1.3. LabVIEW¶

To set up the LabVIEW driver for Red Pitaya, download the Red_Pitaya_LabVIEW_Driver&Examples.zip file. Unpack it and copy the RedPitaya folder to your LabVIEW installations instr.lib folder e.g. C:/Program Files/National Instruments/LabVIEW 2010/instr.lib. The RedPitaya driver should appear after restarting LabVIEW in Block Diagram -> Instrument I/O -> Instr Drivers -> RedPitaya. Depending on your settings Instrument I/O may be hidden. Please consult LabVIEW Help on how to activate/deactivate those categories. You can access example VIs by going to:

Help -> Find Examples…
click Search tab
Enter RedPitaya in Enter keyword(s) field

More examples about how to control STEMlab from MATLAB can be find here.

2.4.1.4. SCILAB¶

To use the SCPI commands you will need to set up Scilab sockets. The procedure is described below.

Go to Scilab download page and download and Install Scilab for your OS
Go to Scilab socket toolbox page and download the basic socket function for Scilab.
Go to the extracted Scilab folder then to folder named contrib
Copy socket_toolbox zip file to contrib folder
Extract socket_toolbox zip file inside the contrib folder
Delete socket_toolbox zip file because we dont need it any more
Go to socket_toolbox folder
Open loader.sce with your Scilab and press RUN (grey run button on SCILAB editor gui)

These last two steps must be executed each time you start Scilab. To install installing you must have an internet connection. Running the examples is same as on MATALB

Copy the Code from blink tutorial example to MATLAB workspace
Replace the IP in the example with the IP of your STEMlab board
Press RUN to run the code

Different code examples can be found on the Examples page.

Note

Communicating with scpi server and working with web based instruments at the same time can diminish the performance of your Red Pitaya. This is because the same resource is used for both tasks.

More examples about how to control STEMlab from MATLAB can be find here.

2.4.2. Starting SCPI server manually¶

Assuming you have successfully connected to your STEMlab board using these instructions. Remotely connect using Putty on Windows machines or with SSH using Terminal on UNIX (macOSX/Linux) machines.

Connect to your STEMlab board via terminal on a Linux machine and start SCPI server with the following command:

systemctl start redpitaya_scpi &

2.4.3. List of supported SCPI commands¶

Table of correlated SCPI and API commands on Red Pitaya.

SCPI	API	description
`DIG:PIN:DIR <dir>,<gpio>` Examples: `DIG:PIN:DIR OUT,DIO0_N` `DIG:PIN:DIR IN,DIO1_P`	`rp_DpinSetDirection`	Set direction of digital pins to output or input.
`DIG:PIN <pin>,<state>` Examples: `DIG:PIN DIO0_N,1` `DIG:PIN LED2,1`	`rp_DpinSetState`	Set state of digital outputs to 1 (HIGH) or 0 (LOW).
`DIG:PIN? <pin>` > `<state>` Examples: `DIG:PIN? DIO0_N` `DIG:PIN? LED2`	`rp_DpinGetState`	Get state of digital inputs and outputs.

2.4.3.1. LEDs and GPIOs¶

Parameter options:

<dir> = {OUT,IN}
<gpio> = {{DIO0_P...DIO7_P}, {DIO0_N...DIO7_N}}
<led> = {LED0...LED8}
<pin> = {gpio, led}
<state> = {0,1}

2.4.3.2. Analog Inputs and Outputs¶

Parameter options:

<ain> = {AIN0, AIN1, AIN2, AIN3}
<aout> = {AOUT0, AOUT1, AOUT2, AOUT3}
<pin> = {ain, aout}
<value> = {value in Volts}

SCPI	API	description
`ANALOG:PIN <pin>,<value>` Examples: `ANALOG:PIN AOUT2,1.34`	`rp_ApinSetValue`	Set analog voltage on slow analog outputs. Voltage range of slow analog outputs is: 0 - 1.8 V
`ANALOG:PIN? <pin>` > `<value>` Examples: `ANALOG:PIN? AOUT2` > `1.34` `ANALOG:PIN? AIN1` > `1.12`	`rp_ApinGetValue`	Read analog voltage from slow analog inputs. Voltage range of slow analog inputs is: 0 3.3 V

2.4.3.3. Signal Generator¶

Parameter options:

<n> = {1,2} (set channel OUT1 or OUT2)
<state> = {ON,OFF} Default: OFF
<frequency> = {0Hz...62.5e6Hz} Default: 1000
<func> = {SINE, SQUARE, TRIANGLE, SAWU, SAWD, PWM, ARBITRARY} Default: SINE
<amplitude> = {-1V...1V} Default: 1
<offset> = {-1V...1V} Default: 0
<phase> = {-360deg ... 360deg} Default: 0
<dcyc> = {0%...100%} Default: 50
<array> = {value1, ...} max. 16k values, floats in the range -1 to 1
<burst> = {ON,OFF} Default: OFF
<count> = {1...50000, INF} INF = infinity/continuous, Default: 1
<time> = {1us-500s} Value in us.
<trigger> = {EXT_PE, EXT_NE, INT, GATED}
- EXT = External
- INT = Internal
- GATED = gated busts

SCPI	API	description
`OUTPUT<n>:STATE <state>` Examples: `OUTPUT1:STATE ON`	`rp_GenOutEnable` `rp_GenOutDisable`	Disable or enable fast analog outputs.
`SOUR<n>:FREQ:FIX <frequency>` Examples: `SOUR2:FREQ:FIX 100000`	`rp_GenFreq`	Set frequency of fast analog outputs.
`SOUR<n>:FUNC <func>` Examples: `SOUR2:FUNC TRIANGLE`	`rp_GenWaveform`	Set waveform of fast analog outputs.
`SOUR<n>:VOLT <amplitude>` Examples: `SOUR2:VOLT 0.5`	`rp_GenAmp`	Set amplitude voltage of fast analog outputs. Amplitude + offset value must be less than maximum output range ± 1V
`SOUR<n>:VOLT:OFFS <offset>` Examples: `SOUR1:VOLT:OFFS 0.2`	`rp_GenOffset`	Set offset voltage of fast analog outputs. Amplitude + offset value must be less than maximum output range ± 1V
`SOUR<n>:PHAS <phase>` Examples: `SOUR2:PHAS 30`	`rp_GenPhase`	Set phase of fast analog outputs.
`SOUR<n>:DCYC <par>` Examples: `SOUR1:DCYC 20`	`rp_GenDutyCycle`	Set duty cycle of PWM waveform.
`SOUR<n>:TRAC:DATA:DATA <array>` Examples: `SOUR1:TRAC:DATA:DATA` `1,0.5,0.2`	`rp_GenArbWaveform`	Import data for arbitrary waveform generation.
`SOUR<n>:BURS:STAT <burst>` Examples: `SOUR1:BURS:STAT ON` `SOUR1:BURS:STAT OFF`	`rp_GenMode`	Enable or disable burst (pulse) mode. Red Pitaya will generate R number of N periods of signal and then stop. Time between bursts is P.
`SOUR<n>:BURS:NCYC <count>` Examples: `SOUR1:BURS:NCYC 3`	`rp_GenBurstCount`	Set N number of periods in one burst.
`SOUR1:BURS:NOR <count>` Examples: `SOUR1:BURS:NOR 5`	`rp_GenBurstRepetitions`	Set R number of repeated bursts.
`SOUR1:BURS:INT:PER <time>` Examples: `SOUR1:BURS:INT:PER 1000000`	`rp_GenBurstPeriod`	Set P total time of one burst in in micro seconds. This includes the signal and delay.
`SOUR<n>:TRIG:SOUR <trigger>` Examples: `SOUR1:TRIG:SOUR EXT`	`rp_GenTriggerSource`	Set trigger source for selected signal.
`SOUR<n>:TRIG:IMM` Examples: `SOUR1:TRIG:IMM`	`rp_GenTrigger`	Triggers selected source immediately.
`TRIG:IMM`	`rp_GenTrigger`	Triggers both sources immediately.
`GEN:RST`		Reset generator to default settings.

2.4.3.4. Acquire¶

Parameter options:

<n> = {1,2} (set channel IN1 or IN2)

2.4.3.4.1. Control¶

SCPI	API	description
`ACQ:START`	`rp_AcqStart`	Starts acquisition.
`ACQ:STOP`	`rp_AcqStop`	Stops acquisition.
`ACQ:RST`	`rp_AcqReset`	Stops acquisition and sets all parameters to default values.

2.4.3.4.2. Sampling rate & decimation¶

Parameter options:

<decimation> = {1,8,64,1024,8192,65536} Default: 1
<average> = {OFF,ON} Default: ON

SCPI	API	description
`ACQ:DEC <decimation>`	`rp_AcqSetDecimation`	Set decimation factor.
`ACQ:DEC?` > `<decimation>` Example: `ACQ:DEC?` > `1`	`rp_AcqGetDecimation`	Get decimation factor.
`ACQ:AVG <average>`	`rp_AcqSetAveraging`	Enable/disable averaging.
`ACQ:AVG?` > `<average>` Example: `ACQ:AVG?` > `ON`	`rp_AcqGetAveraging`	Get averaging status.

2.4.3.5. Trigger¶

Parameter options:

<source> = {DISABLED, NOW, CH1_PE, CH1_NE, CH2_PE, CH2_NE, EXT_PE, EXT_NE, AWG_PE, AWG_NE} Default: DISABLED
<status> = {WAIT, TD}
<time> = {value in ns}
<counetr> = {value in samples}
<gain> = {LV, HV}
<level> = {value in mV}

SCPI	API	DESCRIPTION
`ACQ:TRIG <source>` Example: `ACQ:TRIG CH1_PE`	`rp_AcqSetTriggerSrc`	Disable triggering, trigger immediately or set trigger source & edge.
`ACQ:TRIG:STAT?` Example: `ACQ:TRIG:STAT?` > `WAIT`	`rp_AcqGetTriggerState`	Get trigger status. If DISABLED -> TD else WAIT.
`ACQ:TRIG:DLY <time>` Example: `ACQ:TRIG:DLY 2314`	`rp_AcqSetTriggerDelay`	Set trigger delay in samples.
`ACQ:TRIG:DLY?` > `<time>` Example: `ACQ:TRIG:DLY?` > `2314`	`rp_AcqGetTriggerDelay`	Get trigger delay in samples.
`ACQ:TRIG:DLY:NS <time>` Example: `ACQ:TRIG:DLY:NS 128`	`rp_AcqSetTriggerDelayNs`	Set trigger delay in ns.
`ACQ:TRIG:DLY:NS?` > `<time>` Example: `ACQ:TRIG:DLY:NS?` > `128ns`	`rp_AcqGetTriggerDelayNs`	Get trigger delay in ns.
`ACQ:SOUR<n>:GAIN <gain>` Example: `ACQ:SOUR1:GAIN LV`	`rp_AcqSetGain`	Set gain settings to HIGH or LOW. This gain is referring to jumper settings on Red Pitaya fast analog inputs.
`ACQ:TRIG:LEV <level>` Example: `ACQ:TRIG:LEV 125 mV`	`rp_AcqSetChannelThreshold`	Set trigger level in mV.
`ACQ:TRIG:LEV?` > `level` Example: `ACQ:TRIG:LEV?` > `123 mV`	`rp_AcqGetChannelThreshold`	Get trigger level in mV.

2.4.3.6. Data pointers¶

Parameter options:

<pos> = {position inside circular buffer}

SCPI	API	DESCRIPTION
`ACQ:WPOS?` > `pos` Example: `ACQ:WPOS?` > `1024`	`rp_AcqGetWritePointer`	Returns current position of write pointer.
`ACQ:TPOS?` > `pos` Example: `ACQ:TPOS?` > `512`	`rp_AcqGetWritePointerAtTrig`	Returns position where trigger event appeared.

2.4.3.7. Data read¶

<units> = {RAW, VOLTS}
<format> = {FLOAT, ASCII} Default FLOAT

SCPI	API	DESCRIPTION
`ACQ:DATA:UNITS <units>` Example: `ACQ:GET:DATA:UNITS RAW`	`rp_AcqScpiDataUnits`	Selects units in which acquired data will be returned.
`ACQ:DATA:FORMAT <format>` Example: `ACQ:GET:DATA:FORMAT ASCII`	`rp_AcqScpiDataFormat`	Selects format acquired data will be returned.
`ACQ:SOUR<n>:DATA:STA:END?` > `<start_pos>,<end_pos>` Example: `ACQ:SOUR1:GET:DATA 10,13` > `{123,231,-231}`	`rp_AcqGetDataPosRaw` `rp_AcqGetDataPosV`	Read samples from start to stop position. `<start_pos> = {0,1,...,16384}` `<stop_pos> = {0,1,...116384}`
`ACQ:SOUR<n>:DATA:STA:N?` `<start_pos>,<m>` > `...` Example: `ACQ:SOUR1:DATA? 10,3` > `{1.2,3.2,-1.2}`	`rp_AcqGetDataRaw` `rp_AcqGetDataV`	Read `m` samples from start position on.
`ACQ:SOUR<n>:DATA?` Example: `ACQ:SOUR2:DATA?` > `{1.2,3.2,...,-1.2}`	`rp_AcqGetOldestDataRaw` `rp_AcqGetOldestDataV`	Read full buf. Size starting from oldest sample in buffer (this is first sample after trigger delay). Trigger delay by default is set to zero (in samples or in seconds). If trigger delay is set to zero it will read full buf. size starting from trigger.
`ACQ:SOUR<n>:DATA:OLD:N?<m>` Example: `ACQ:SOUR2:DATA:OLD? 3` > `{1.2,3.2,-1.2}`	`rp_AcqGetOldestDataRaw` `rp_AcqGetOldestDataV`	Read m samples after trigger delay, starting from oldest sample in buffer (this is first sample after trigger delay). Trigger delay by default is set to zero (in samples or in seconds). If trigger delay is set to zero it will read m samples starting from trigger.
`ACQ:SOUR<n>:DATA:LAT:N?<m>` Example: `ACQ:SOUR1:DATA:LAT? 3` > `{1.2,3.2,-1.2}`	`rp_AcqGetLatestDataRaw` `rp_AcqGetLatestDataV`	Read `m` samples before trigger delay. Trigger delay by default is set to zero (in samples or in seconds). If trigger delay is set to zero it will read m samples before trigger.
`ACQ:BUF:SIZE?` > `<size>` Example: `ACQ:BUF:SIZE?` > `16384`	`rp_AcqGetBufSize`	Returns buffer size.

2.4.4. Examples¶

In the list bellow you will find examples of remote control and C algorithms. This examples are covering all basic STEMlab functionalities such as:

signal generation

signal acquisition

digital I/O control

communication protocols

You can edit and change them according to your needs and develop customized programs and routines.