EVM of MSP430F677x three-phase meter

Tamir Friedrich

Hi,

Can I get a connection diagram for operating the above three-phase meter as a single-phase one?

The relevant documentation is slat144 for three phases, and slyt428 for the single-phase one. I did not find any confirmation on the possibility of doing so, although it seems like a desirable feature during testing.

Thanks a lot, Tamir

over 8 years ago

0 James Evans over 8 years ago

TI__Mastermind 49692 points

Hi Tamir,

Take a look at Figure 2 (also shown below) in the Implementation of a Single-Phase Electronic Watt-Hour Meter Using the MSP430F6736(A) app note. It shows a 1-phase 2-wire star configuration using the MSP430F67xx. It looks very similar to what you've found in slyt428.

In the Implementation of a Three-Phase Electronic Watt-Hour Meter Using the MSP430F677x(A) app note, Figure 2 shows a 3-phase 4-wire star configuration instead.

Regards,

James

MSP Customer Applications

0 Steve Underwood over 8 years ago

TI__Intellectual 2595 points

The EVM will work if you just connect one of the three phases. This is a requirement in most utility metering applications. A meter needs to work if one or two of the phases are down.

0 Tamir Friedrich over 8 years ago in reply to James Evans

Prodigy 30 points

Thank you James for your answer.

The diagrams are a bit unclear in the sense that the physical connections of the EVM are not clearly marked.

My understanding from reviewing the diagrams is as follows, I would appreciate if you can comment on it:

For connecting a single phase source and load to a three-phase MSP430F67xx eval board

There are 4 lines involved: UL, UN, LL, LN (corresponding to Utility Line, Utility Neutral, Load Line, and Load Neutral).

Connect UN to VN (on EVM).

Connect UL to V+ (voltage measurement)

Connect UL to IA+.

Connect LL to IA- (current measurement)

Thanks,

Tamir

0 Steve Underwood over 8 years ago in reply to Tamir Friedrich

TI__Intellectual 2595 points

I assume you found this connection information in www.ti.com/.../slaa577g.pdf . You may notice that the VA+, VB+ and VC+ terminals are jumper connections. If the jumpers are positioned to the right, the voltage connections are separated from the current circuits. This is useful when operating the meter on many test sets, which feed current and voltage separately to the meter. However, if you want the meter to measure in a normal power circuit you need to ensure these jumpers are positioned to the left, where they connect to the current circuit. If you want to use phase A for your single phase measurements you would connect your power feed to IA+ and VN, and your load to IA- and Vn.

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EVM of MSP430F677x three-phase meter