Instrument Control module

May 16, 2017

This post demonstrates how to get data from a measuring instrument in Scilab and display it using Equalis software. The pre-requirements are given below for this demo.




  • NI-VISA Software[1]

  • Scilab[2]

  • Equalis Instrument Control Module[3]

  • Rigol DS4024 Digital Oscilloscope[4]

  • Microchip MPLAB X[5]

  • Microchip MCLV Board and the associated BLDC Motor[6]

  • Microchip ICD 3 In-Circuit Debugger/Programmer[7]


At this point, please have a look at the blog post Embedded Coder Module [8], because we will use the system described in it as signal sources


Equalis Instrument Control Module[3] VISA[9] functions are given below which will be used in this demo


  • VISA_open(visa_id , resource_descriptor)

This function opens a VISA session

  • VISA_write(visa_id, text_message)

This function sends a text_message to the instrument connected with the visa_id

  • data = VISA_read(visa_id, buffer_size)

The function reads the data from an instrument after a command is sent to the instrument with VISA_write()


SCPI[10] commands of Rigol DS4024 Digital Oscilloscope[4] are given below which will be used in this demo


  • *IDN?

Return instrument id


Return average value of signal on selected channel

  • :MEASure:PERiod? CHAN

Return period of signal on selected channel

  • :WAV:MODE Mode

Select waveform reading mode

  • :WAVeform:FORMat Format

Select waveform return format


Select source channel to read waveform