Data processing: generic control systems or specific application – Specific application – apparatus or process – Product assembly or manufacturing
Reexamination Certificate
1998-05-06
2001-10-09
Gordon, Paul P. (Department: 2121)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Product assembly or manufacturing
C700S109000, C700S110000, C340S870030, C340S870030
Reexamination Certificate
active
06301514
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method for nonintrusively monitoring one or more physical characteristics associated with a machine. More particularly, the present invention relates to a method for configuring and synchronizing a wireless machine monitoring system for transmitting a wireless signal representing the nonintrusively monitored machine characteristics from at least one sensor to a remote command station.
BACKGROUND
Many manufacturing processes require complex industrial machines utilizing rotating or reciprocating elements. The efficient operation and maintenance of these machines is essential to maximizing production and minimizing downtime. When a rotating machine element acquires a defect, that defect is seldom catastrophic at onset. Instead, the defect is usually of a latent or incipient nature, such as a hairline fracture in the tooth of a gear. Notwithstanding a probable reduction in the efficiency of the machine, if such a fault is not detected, isolated, and repaired, it could grow into a catastrophic failure of the machine with resultant loss of production capacity of the machine and possible injury to personnel. Unfortunately, due to the noise generated by these machines and the acoustic environment in which they normally operate, it is often difficult if not impossible to detect latent or even incipient defects in rotating elements of the machine by visual or aural inspection. Further complicating the detection of such faults is that faulty components may be hidden from view, such as a single gear in an enclosed gearbox.
It is desirable to detect and locate faults while the machine is operating in its normal environment so as not to interfere with the production process. Taking the machine off line to perform preventative maintenance creates an undesirable and inefficient situation, requiring a back-up or redundant machine in order to prevent a shutdown of the production process.
Nonintrusive fault detection may be accomplished by monitoring certain physical characteristics of the machine, such as vibration and temperature levels, using electrical sensors such as accelerometers and temperature sensors. These sensors are typically connected by means of at least one pair of wires per sensor to a monitoring device. The monitoring device processes the sensor signals and produces an output signal which is indicative of the operational health of the machine. Such fault detection devices provide an early indication of machine problems, typically before a catastrophic failure occurs.
One problem associated with wired fault detection systems is the high cost of installation in a typical manufacturing plant. A typical machine may require four to eight vibration sensors mounted at various locations on the machine, and there may be from several dozen to several hundred machines in a typical plant. It is desirable to monitor all of the machines from a central location in the plant, so that manufacturing personnel need not travel to each machine in the plant to assess its health. The installation of wire and conduits to connect each sensor to a central monitoring station could be cost prohibitive.
In addition to installation problems, wired systems are difficult and costly to maintain. Such systems tend to be fragile, primarily due to the wiring. Wires and connectors can easily become contaminated with water or other materials common in dirty industrial environments, resulting in anomalous signals and other failure conditions. Wires are also easily damaged, especially near the connectors, during normal machine maintenance procedures. Such damage is usually manifested as intermittent anomalous signals, which make isolation, diagnosis, and correction of the problem quite difficult.
Wired machine monitoring systems are also inflexible once installed. It is difficult to change the configuration of the system as needs change within the manufacturing plant. If a plant operator decides that more sensors should be added to a machine, or that the location of the machine or sensors should be changed, the cost and difficulties associated with installing additional wiring and conduits must be endured.
Since the major problems associated with wired machine monitoring systems are caused by the presence of the wires, a need exists for a wireless machine monitoring system.
While a number of problems are solved by providing a wireless machine monitoring system, new complexities are introduced as compared to wired systems particularly with regard to the relative positioning and set up of sensors and repeaters. It has been found that the higher the complexity of installation, the greater the chance for error in the installation. Moreover, a high complexity of installation typically results in a large amount of battery life being used during the installation period. Because relatively long battery life is essential for proper operation of the individual components of a wireless system, consuming large amounts of battery life during installation is unacceptable.
Therefore, a need exists for a wireless machine monitoring system that is simple to install and uses very little battery life of the individual components of the wireless machine monitoring system.
SUMMARY
The present invention provides a method for configuring a wireless machine monitoring system that has at least one chain of programmable transceiver devices including a machine monitor, a relay repeater, and an Installation and Configuration Unit (“ICU”). In one embodiment, the method of configuring includes the steps of positioning the ICU in a physical location within wireless communications range of a first transceiver device and receiving data transmitted by the first transceiver device with the ICU. A bit error rate (“BER”) calculation is performed on the data transmitted from the machine monitor to the ICU and a BER is determined. The BER is compared to an acceptable BER to determine whether the BER is acceptable. A second transceiver device is mounted where the ICU is positioned if it is determined that the BER is acceptable.
In a preferred method, the ICU is repositioned if it is determined that the ICU is positioned such that either the BER or the physical location is unacceptable for wireless communications between the machine monitor and the relay repeater.
In another preferred method, a minimum transmit power level for the first transceiver device is determined that results in a BER equal to or less than the acceptable BER for data transmitted from the first transceiver device and received by the second transceiver device. The first transceiver device is configured to communicate at the minimum transmit power level.
In another preferred method, the ICU prompts the repeater to send a transmission strength test signal (which includes different power levels) from the repeater to the machine monitor. This transmission strength test signal is monitored by the machine monitor to determine the BER at different transmit power levels. The ICU also prompts the machine monitor to send a transmission strength test signal to the relay repeater to determine the BER at different transmit power levels. A transmission strength configuration signal is sent from the ICU to the machine monitor and the relay repeater corresponding to the minimum transmit power level for the machine monitor and the relay repeater at the acceptable BER.
The preferred method of the present invention further includes the steps of prompting by the ICU for recordation of the serial numbers of the machine monitor and the relay repeater by an operator of the ICU, prompting by the ICU for the operator to input the logical locations of the machine monitor and the relay repeater within the chain, and prompting by the ICU for recordation of physical locations of the machine monitor and the relay repeater on an industrial setting drawing. The preferred method also includes the step of downloading configuration parameters to the machine monitor and the relay repeater from the ICU. A step is further included of placing the machine monitor in a low p
Canada Ronald G.
Czyzewski Zbigniew
Davidson, Jr. Taylor L.
Pearce James W.
Robinson James C.
CSI Technology, Inc.
Gordon Paul P.
Luedeka Neely & Graham P.C.
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