Browse Prior Art Database

WIRELESS MULTI LINK ACCESS TO A DRIVE

IP.com Disclosure Number: IPCOM000248412D
Publication Date: 2016-Nov-25
Document File: 2 page(s) / 168K

Publishing Venue

The IP.com Prior Art Database

Related People

Mikko Kohvakka: AUTHOR [+3]

Abstract

The disclosure is related to an environment, where multiple electric drives are connected together by "daisy chains" and have wireless links. The wireless link is typically implemented by a radio interface embedded inside the drive or the control panel or may be installed as an optional module. This radio interface connected to the drive network is called a wireless gateway. This disclosure presents a solution for improving the wireless link reliability. The wireless gateways are connected together by a wired network and thus communication through any of the wireless gateways can reach any of the drives in the drive network. In the solution the signal strength of the available wireless gateways within the range is tracked, e.g. by the mobile station, and the wireless gateway with the best signal strength is selected for the communication.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 52% of the total text.

Page 01 of 2

Page 1 of 2

WIRELESS MULTI LINK ACCESS TO A DRIVE

The disclosure is related to an environment, where multiple drives are connected together by "daisy chains". Examples of drives generally include various electric drives such as AC or DC motor drives. This kind of drive network makes it possible to communicate with any drive within the network from any point of the network. The communication can comprise reading and/or setting parameter values, reading fault logs, controlling the drive by setting a speed reference and/or start/stop commands etc., for example.

The network connections are typically wired connections, e.g. RS-485 or Ethernet connections. Wired connections are preferred in an industrial environment due to their high reliability and predictable performance. Also, stationary installations do not require the mobility provided by wireless technologies.

However, there is an emerging need for wireless mobile user interfaces for drives. The wireless link is typically implemented by a radio interface embedded inside the drive or the control panel or may be installed as an optional module. This radio interface connected to the drive network is called a wireless gateway. Wireless mobile user interface may be a mobile phone, a tablet PC, a portable PC or a similar device or unit, for example. Typical wireless technologies include Bluetooth, Wifi and proprietary protocols using simple radio transceivers operating in globally available industrial, scientific and medical (ISM) frequency bands.

A problem with the wireless user interfaces is the reliability of the wireless link which may be much lower than in wired networks. Also local disturbances and mobility of a mobile user may cause fading and temporary loss of connectivity, for example. When the user moves too far from the wireless gateway, a new wireless gateway is discovered and connected, which typically causes multiple-seconds break in the wireless communication. In some, especially demanding, applications, these problems may prevent the use of the wireless technology.

This innovation presents a solution for improving the wireless link reliability. The wireless gateways are connected together by a wired network and thus communication through any of the wireless gateways can reach any of the drives in the drive network. In the solution the signal strength of the available wireless gateways within the range is tracked, e.g. by the mobile station, and the wireless gateway with the best signal strength is selected for the communication. The signal strength tracking may be performed continuously which makes it possible to change the wireless gateway on demand in a controlled way, when the signal strength degrades and/or a wireless gateway with a better signal strength arrives within the radio range. This may be caused by local disturbances or mobility of the mobile station, for example. Another option for further improving the reliability and performance of the wireless communic...