Synchronized wireless networked system

• US 8,229,486 B2
• Filed: 12/15/2008
• Issued: 07/24/2012
• Est. Priority Date: 12/28/2007
• Status: Expired due to Fees

• Current Assignee: ABB Limited
• Original Assignee: ABB Limited
• Inventors: Hellstrom, Ake
• Primary Examiner(s): YOUNG, BRIAN K
• Application Number:
  US12/335,130
• Publication Number:
  US 20090168749A1
• Time in Patent Office: 1,317 Days
• Field of Search: 455/39, 455/500, 455/502, 162/232
• US Class Current: 455/500
• CPC Class Codes: G05B 19/042 using digital processors G05B19/05 takes precedence
• CPC Class Codes: G05B 2219/25042 Clock derived from power supply

Abstract

A sheet making system that has two or more separated nodes one of which may be a scanner sensing head and the other of which may be a scanner end column. Each node has a wireless system and receives power from a common AC source. Each node receives events data associated with the wireless system. Each wireless system has a circuit that obtains from the common AC power source an associated events data acquisition clock that is the same for all of the wireless systems to time synchronize to each other the associated events data signals at each of the two or more nodes. A central computer may be connected to the two or more nodes. The communication between the computer and each of the two or more nodes can be wireless or by a LAN or other mechanisms.

Claims

1. A method for time synchronizing signals in a sheet making system that has two or more nodes separated from each other that each receive signals having data therein about sheet making events associated with each of said two or more nodes, said method comprising:

providing at each of said two or more nodes a wireless system for acquiring at each of said nodes said signals having said associated sheet making events data, each of said wireless systems having a distinct processing device; and

comparing at each of said two or more nodes the timing of associated sheet making events data signals to the timing of the AC voltage waveform on a power line connected to power each of said two or more wireless sheet making events data acquiring systems to thereby time synchronize said associated sheet making events data signals at each of said two or more nodes to each other.

2. The method of claim 1 further comprising determining at each of said two or more nodes the timing of said AC voltage waveform on said power line.

3. A method for time synchronizing signals in a sheet making system that has two or more nodes separated from each other that each receive signals having data therein about sheet making events associated with each of said two or more nodes, said method comprising:

providing at each of said two or more nodes a wireless system for acquiring at each of said nodes said signals having said associated sheet making events data, each of said wireless systems having a distinct processing device and a data acquisition clock; and

using an AC power signal on a power line connected to power each of said two or more wireless sheet making events data acquiring systems as a source of a common clock for all of said two or more wireless sheet making events data acquiring systems data acquisition clocks to time synchronize said associated sheet making events data signals at each of said two or more nodes to each other.

4. The method of claim 3 further comprising comparing at each of said two or more nodes the timing of said associated sheet making events data signals to the timing of said AC power signal to thereby derive from said AC power signal said common clock.

5. The method claim 3 further comprising coarsely synchronizing within one cycle of said AC power signal said two or more wireless sheet making events data acquiring systems data acquisition clocks at startup of said system having two or more nodes separated from each other.

6. A sheet making system comprising:

two or more nodes separated from each other;

each of said two or more nodes comprising a wireless system for acquiring at each of said nodes signals having associated events data, each of said wireless systems receiving signals having data therein about events associated with a respective one of each of said two or more wireless systems and connected to receive AC power from a common source of AC power; and

each of said two or more wireless systems comprising;

a circuit that obtains from said common source of AC power an associated events data acquisition clock that is the same for all of said wireless systems at said two or more nodes to thereby time synchronize said associated events data signals at each of said two or more nodes to each other; and

a distinct processing device.

7. The sheet making system of claim 6 further comprising a computing device in communication with each of said two or more wireless systems.

8. The sheet making system of claim 7 wherein said computing device causes when said sheet making system is started up each of said two or more wireless systems to coarsely synchronize within one cycle of said AC power signal said two or more sheet making events data acquiring systems data acquisition clocks.

9. The sheet making system of claim 7 wherein said computing device causes at predetermined intervals of time when said sheet making system is operational each of said two or more wireless systems to coarsely synchronize within one cycle of said AC power signal said two or more sheet making events data acquiring systems data acquisition clocks.

10. The sheet making system of claim 7 wherein communication between said computing device and each of said two or more wireless systems is either wireless or by a cable connected between said computing device and each of said two or more wireless systems.

11. The sheet making system of claim 6 further comprising a scanner across a moving sheet made by said system, said scanner comprising one or more sensor heads movably mounted on said scanner, said moving sheet between said one or more sensor heads, said scanner causing said one or more sensors to traverse back and forth across said moving sheet to thereby provide signals that can be used to generate a profile of said moving sheet.

12. The sheet making system of claim 11 wherein said scanner comprises an end column and one of said two or more nodes is associated with said sensor heads and another of said or more nodes is associated with scanner end column.