line to line measurement

Hello Ikon,

Thanks for your post. Looking at Microchip's MCP39F521, I see that it's a single-phase power monitoring device. Line-to-line voltages are typically measured in poly-phase configurations. For single-phase configurations, line voltage is measured with respect to neutral. However, split-phase (single-phase, three-wire) configurations (such as US residential utility service) may not have access to the neutral connection, so they reference the other "line" voltage as the reference (or ground) instead. Is this what you're referring to?

Depending on your application and configuration, I would recommend three options: MSP430F6779A (three-phase configuration with LCD support), MSP430F6736A (single-phase configuration with LCD support), and MSP430i2041 (single-phase, split-phase, or two-phase configurations w/o LCD). Conveniently, all these devices are supported by our Energy Measurement Design Center (EMDC). It allows users to quickly and easily evaluate and design power and energy monitoring applications using our MSP430 devices.

EMDC doesn't support line-to-line measurements in poly-phase configurations, but it does support split-phase configurations where the voltage is measured between two line voltages (120V @ 0 degrees  phase, 120V @ 180 degrees phase) as well as the typical configurations where the voltage is measured with respect to neutral.

Although this may not be applicable to your application, I found an interesting app note by National Instruments discussing how line-to-line voltages can be calculated using the line-to-neutral voltages (some things are assumed though). It may be interesting to you.

Calculating Line-to-Line Voltages from Line-to-Neutral Measurements

Please let me know if you have any questions.

Regards,

James