Abstract:
A method of identifying a node of an arrangement that includes a plurality of movable parts, the method including moving only one of a plurality of movable parts of an arrangement, detecting the moving of the one of the plurality of movable parts and distinguishing a node associated with the one of the plurality of movable parts based on the detecting.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates to a method of identifying a node of a network system for devices with movable parts. 
     2. Discussion of Related Art 
     It is known to manufacture devices, such as machine tools, that have one or more axes of movement. It is also known to construct an industrial bus network system for such a device where a node is associated with each axis of movement, such as described in U.S. Pat. No. 6,421,628, the entire contents of which are incorporated herein by reference. Each such node needs to be identifiable. Identifying a node allows that node to obtain focused information. In known industrial bus networks such identification of the nodes normally occurs with dip switches or the identification value is hard coded in the software. Each node on the network needs to be set up with a different value. 
     One disadvantage of known industrial bus network systems of machine tools is that the electronic packaging is such the end user of the machine tool does not have access to the electronics and so is unable to adjust the manual setting components, such as switches and jumpers. 
     A second disadvantage of known industrial bus network systems of machine tools is that they often are inflexible in their identification of a node when they use hardware dipswitches. 
     Accordingly, it is an object of the present invention is to improve adjusting of settings of industrial bus network systems. 
     Another object of the present invention is to improve the flexibility in the identification of a node of industrial bus network systems. 
     Other objects of the present invention will become apparent from the following description of the present invention and embodiments thereof. 
     BRIEF SUMMARY OF THE INVENTION 
     One aspect of the present invention regards an arrangement including a plurality of movable parts, wherein each movable part is connected to a corresponding actuator and a measuring device that determines a position of one of the actuators. A master unit coupled to the actuators and to the measuring device, wherein the master unit receives measurement signals from the measuring device and sends control signals to the actuators so as to control movement of the plurality of movable parts, wherein the master unit distinguishes a node associated with the one of the actuators upon detecting movement of the movable part via the measurement signals. 
     A second aspect of the present invention regards a method of identifying a node of an arrangement that includes a plurality of movable parts, the method including moving only one of a plurality of movable parts of a system, detecting the moving of the one of the plurality of movable parts and distinguishing a node associated with the one of the plurality of movable parts based on the detecting. 
     Each aspect of the present invention provides the advantage of improving the adjusting of settings of industrial bus network systems. 
     Each aspect of the present invention provides the advantage of improving the flexibility in the identification of a node of industrial bus network systems. 
     Additional embodiments and advantages of the present invention will become apparent from the following description and the appended claims when considered with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 schematically shows an embodiment of an arrangement of moving parts that employs an identification method in accordance with the present invention; 
     FIG. 2 schematically shows an embodiment of a network system used with the arrangement of moving parts of FIG. 1 that has a node that is identified by an embodiment of an identification method in accordance with the present invention; and 
     FIG. 3 shows a flow chart of an embodiment of an identification method to be used with the network system of FIGS. 1 and 2 in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 schematically shows an arrangement  100  having movable parts  102 ,  104 ,  106 ,  108  and a system for controlling the movement of these movable parts. The arrangement includes a plurality of controllable actuators  110 ,  112 ,  114  and  116  for causing the movement of the movable parts. The actuators may be motors and the movable parts may be rotatable about axes, according to an embodiment of the invention. 
     The movable parts  102 ,  104 ,  106 ,  108  co-operate with measuring devices, i.e. devices for generating a signal indicative of a position or movement, such as optoelectrical positioning measuring devices  118  that include an encoding structure that has an optically readable pattern. The encoding pattern is read by one or more detectors which each deliver an electric signal in relation to the amount of light that is received in the detector, so that movement of the encoding pattern in relation to the detector will be indicated by changes in the electric signal. The encoding pattern includes a periodic pattern, such as a plurality of light and dark fields of mutually the same size, for instance. When the encoding pattern is turned or rotated in the case of a rotary encoder or translated in a measuring direction in the case of a linear encoder, the change between dark and light fields can be detected and a change in angle or linear position thus determined. Some position measurement devices provide a position signal comprising a plurality of pulse signals, where the state of the pulse signals at an instant of time defines the absolute position of the encoding disc in relation to the detector. These position measuring devices are also referred to as absolute encoders. 
     A master unit  120  is coupled to the measuring devices  118  for receiving the measurement signals. The master unit  120  is also coupled to the actuators  110 ,  112 ,  114  and  116  via lines  123  for providing control signals so as to control the movement of the movable parts  102 ,  104 ,  106  and  108  in dependence on the measurement signals. 
     As shown in FIGS. 1 and 2, the master unit  120  is coupled to the measuring devices  118  via a serial data bus  122 . In particular, the master unit  120  includes a microprocessor system  150  that receives the position signals from the measuring devices  118  and controls the actuators  110 ,  112 ,  114  and  116  and the positions of the associated movable parts. The microprocessor system  150  maintains a configuration file with node identification, serial numbers, axis label and other product specific information related to the encoders of the measuring devices  118 . The signals that are received by and sent by the master unit  120  are controlled by a bus controller  124  and bus transceiver  126  whose structure and function are well known in the art. Similarly, the signals sent by the master unit  120  are received by interface units  123 ,  125 ,  127  and  129  of the various movable parts schematically represented by dashed lines in FIG.  2 . Each interface unit is identical in structure and includes a microcontroller system  128  that is used to control its associated actuator. Each interface unit also includes a bus controller  130  and a bus transceiver  132  whose structure and function are well known in the art. The signals received and sent by the movable parts are controlled by the bus controller  130  and bus transceiver  132 . 
     As shown in FIG. 1, the master unit  120  is coupled to a user interface  134  for enabling an operator to manually input set-up information in accordance with the present invention. For this purpose the user interface  134  includes a display  136  and a data input device  138 , such as a mouse or a keyboard. 
     With the above structure of the arrangement  100  in mind, the programming of the moving parts and their associated interface units in accordance with the present invention will be described hereafter with respect to the flow chart of FIG.  3 . In addition, in the example to be discussed hereafter, the node identification values are implemented via user interface  134  that is coupled to a network, such as a CANOpen network, with linear encoders. The network is composed of a number of nodes, wherein a node is a single device that can communicate independently on the network, such as a measuring device, I/O module or a motor. In this example, when the encoders of the measuring devices  118  leave the factory, they will be programmed with a default node identification that is not unique to the particular measuring device. Once a user turns the power on of the arrangement  100  via user interface  134 , the master unit  120  queries the user via user interface  134  whether or not the network is to be reconfigured per step  202 . If the network is to be reconfigured, it is reconfigured via user interface  134  per step  206 . If the network is not to be reconfigured, the master unit  120  checks to see if the desired configuration is saved for the network per step  204  of FIG.  3 . The saved configuration is a list of each encoder&#39;s node identification and serial number. If it is determined that there is a saved configuration, the master unit  120  then verifies the saved configuration by querying each saved node identification for its current serial number and comparing the response to the saved serial number for that node identification. This insures the integrity of the network and that a new node with an existing identification is not placed on the network. If the desired configuration is saved and valid, the master unit  120  implements the saved configuration and the configuration process is discontinued per step  226 . 
     If there is no saved and/or valid configuration per step  204  or there is a need to change the configuration per step  202 , then the master unit  120  will need to cause all nodes on the network to enter a non-configurable state per step  206  and configure each node/encoder and assign node identifications. This is accomplished by having the master unit  120  stop the network and place all nodes of the arrangement  100  into a non-configurable state by means such as the CANOpen Layer Setting Service, per step  206 . At this stage the master unit  120 , prompts the user via the user interface  134  to assign and enter a desired node identification for a particular axis of movement of the arrangement  100  per step  208 . Alternately, the user may let the master unit  120  assign node identifications automatically. 
     After entering the desired node identification, the master unit  120  determines if the entered node identification is valid. If it is not, then the user interface  134  informs the user that the entered node identification is not valid and requests the user to enter a new node identification per step  210 . The validity of a node identification is determined by being a unique integer value within a predetermined range, for example, a valid CANOpen node identification would be an integer value between 1 and 127, such as 29. At this point of the process where the entered node identification has been validated per step  210 , the master unit  120  generates a message at user interface  134  that prompts the user, per step  212 , to move the particular axis associated with the node by either a small distance in the case of a node corresponding to a linear encoder or a small angle in the case of a node corresponding to a rotary encoder. In response to the prompt of step  212 , the user moves the particular axis of a moving part via the user interface  134  per step  214 . 
     The encoder of the measuring device  118  connected to the particular axis associated with steps  212  and  214  recognizes that it has moved by comparing its present count value with its previous count value and determining that there is a difference between the two count values. Upon its recognition that it has moved at least a defined distance, the measuring device  118  associated with the particular axis changes into a configurable state, such as the LSS Configuration Mode. The selected encoder sends a message, such as a CANOpen Transmit Process Data Object (TPDO) message, to the master unit  120  so as to signify that the displaced encoder has changed into a configurable state, such as it has changed to the LSS Configuration Mode, per step  214 . Upon receipt of the message, the master unit  120  determines that the encoder associated with steps  208  and  214  has been placed in a configurable state, such as the LSS Configuration Mode, wherein only one node may be at any particular time. 
     Besides determining that an encoder is in a configurable state, the master unit  120  performs a query of the serial number of the encoder. Upon receipt of the serial number per step  216 , the master unit  120  sends a new node identification to the encoder, such as defined in the CANOpen LSS protocol per step  218 . Upon receipt of its new node identification, the encoder saves the configuration per step  220  and sends a confirmation message to the master unit  120  indicating that the encoder has received the new node identification. 
     With the new node identification in place for the displaced encoder, the master unit  120  resets the microprocessor system and saves the configuration data of the displaced encoder per step  222 , such as the new node identification, the axis label associated with the encoder and the serial number of the encoder. Thus, the above process is able to distinguish one node from other nodes of a network of encoders by displacing an encoder associated with the node to be distinguished 
     After one node is distinguished, the master unit  120  determines if there are other axes or nodes that need to the distinguished in the network per step  224 . If there are, then the process is repeated beginning at step  206 . If there are no further axes or nodes to distinguish, then the process is completed per step  226 . Note that if at the time power is turned off the configuration of the master unit  120  or the encoder saved, then the system will revert to the previously saved configuration for the master unit and encoder upon powering up the system. 
     The foregoing detailed description is merely illustrative of several physical embodiments of the invention. Physical variations of the invention, not fully described in the specification, may be encompassed within the preview of the claims. Accordingly, any narrower description of the elements in the specification should be used for general guidance, rather than to unduly restrict any broader descriptions of the elements in the following claims.