MSP430I2040: Can't understand the byte vector from serial communication section

Nathan Azevedo

Part Number: MSP430I2040

I am trying to send serial commands to EVM by protocol RS232 USB.

The software i'am using is Docklight. The sequence i'am sending is {0xFE, 0xFE, 0xFE, 0xFE, 0x68, 0x99, 0x99, 0x99, 0x99, 0x99, 0x99, 0x68, 0x23, 0x02, 0x61, 0x00, 0xEC, 0x16} the EVM is supposed to return power factor in 0.001 and i am receiving :

I can't understand what mean the information after 0x80 in the vector received the question is how can i understand this information ?

And what are the other sequences that provide me Voltage, Current, Power in mW ?

over 5 years ago

0 James Evans over 5 years ago

TI__Mastermind 49692 points

Hello Nathan,

Section 7.3.7 in the Single Phase and DC Embedded Metering Power Using MSP430I2040 app note should help you understand the information.

Regards,

James

0 Nathan Azevedo over 5 years ago in reply to James Evans

Intellectual 270 points

I already read it but i can't understand what i need to change in this sequence in blue that i posted before to call Voltage.

0 James Evans over 5 years ago in reply to Nathan Azevedo

TI__Mastermind 49692 points

This command reads the latest measurements from the EVM. It sends all the readings at once. You'll need to modify the application code to support different commands to send just voltage, power factor, etc. or keep the existing commands and parse the results on the host.

Regards,

James

0 Nathan Azevedo over 5 years ago in reply to James Evans

Intellectual 270 points

But all the readings about power factor or all the readings avaiable ?

0 James Evans over 5 years ago in reply to Nathan Azevedo

TI__Mastermind 49692 points

Power factor is just one of the readings per phase. The packet shown in red in your first post contains all the readings for that phase. The table in your other post explains what data is located where in that packet.

For example, notice how the offset starts at 0 at 0x60. At an offset of 2 (2 bytes to the right of 0x60), this would be the start of the 32-bit (4 8-bit bytes) value for VRMS. Here, you have 0x2F, 0xCB, 0x01, 0x00. The LSB is sent first and the MSB is sent last. Thus, VRMS equals 0x0001CB2F. Converting that from hex to decimal results in a value of 117,551 mV (units shown in the packet table above) which equals 117.551V.

Make sense? You can apply this for all the other readings in this packet.

Regards,

James

0 Nathan Azevedo over 5 years ago in reply to James Evans

Intellectual 270 points

Thank you !! Understood

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MSP430I2040: Can't understand the byte vector from serial communication section