---
title: "readAttributeRmsVoltageSagPeriodPhaseB(completionHandler:)"
framework: matter
role: symbol
role_heading: Instance Method
path: "matter/mtrbaseclusterelectricalmeasurement/readattributermsvoltagesagperiodphaseb(completionhandler:)"
---

# readAttributeRmsVoltageSagPeriodPhaseB(completionHandler:)

## Declaration

```swift
func readAttributeRmsVoltageSagPeriodPhaseB(completionHandler: @escaping @Sendable (NSNumber?, (any Error)?) -> Void)
```

```swift
func readAttributeRmsVoltageSagPeriodPhaseB() async throws -> NSNumber
```