---
title: "readAttributeRmsVoltageSwellPeriod(withAttributeCache:endpoint:queue:completionHandler:)"
framework: matter
role: symbol
role_heading: Type Method
path: "matter/mtrbaseclusterelectricalmeasurement/readattributermsvoltageswellperiod(withattributecache:endpoint:queue:completionhandler:)"
---

# readAttributeRmsVoltageSwellPeriod(withAttributeCache:endpoint:queue:completionHandler:)

## Declaration

```swift
class func readAttributeRmsVoltageSwellPeriod(withAttributeCache attributeCacheContainer: MTRAttributeCacheContainer, endpoint: NSNumber, queue: dispatch_queue_t, completionHandler: @escaping @Sendable (NSNumber?, (any Error)?) -> Void)
```

```swift
class func readAttributeRmsVoltageSwellPeriod(withAttributeCache attributeCacheContainer: MTRAttributeCacheContainer, endpoint: NSNumber, queue: dispatch_queue_t) async throws -> NSNumber
```