Abstract:
A method for manufacturing a programmable logic controller (PLC) module includes mounting at least one valve inside the PLC module and positioning at least one outlet line in flow communication with the valve.

Description:
BACKGROUND OF INVENTION  
         [0001]    This invention relates generally to a programmable logic controller (PLC) and, more particularly, to modules for PLCs.  
           [0002]    High purity gases are frequently utilized in manufacturing. Many gases, such as, for example, Nitrogen, Oxygen, and Argon are provided in bulk, and utilized in manufacturing processes. The processes are sometimes controlled by a PLC. Typically, the PLC includes a conventional electronic output module electronically connected to a conventional external valve assembly. However, a PLC in combination with an external valve assembly constitutes an enlarged system that occupies valuable space which otherwise can be used for other purposes.  
         SUMMARY OF INVENTION  
         [0003]    In one embodiment of the invention, a method for manufacturing a programmable logic controller (PLC) module includes mounting at least one valve inside the PLC module and positioning at least one outlet line in flow communication with the valve.  
           [0004]    In another embodiment of the invention, a module for use with a programmable logic controller (PLC) including a base plate bus connector is provided. The module includes a module bus connector configured to operationally couple with the PLC. The module further includes a valve assembly connected to the module bus connector and controlled by the PLC.  
           [0005]    In yet another embodiment of the invention, a module for use with a programmable logic controller (PLC) including a base plate bus connector includes a module bus connector configured to operationally couple with the PLC via the base plate bus connector. The module further includes a valve assembly connected to the module bus connector and controlled by the PLC. The valve assembly includes at least one valve, at least one inlet line in flow communication with the valve, at least one pneumatic line in flow communication with the valve, and at least one solenoid connected to the valve and controlled by the PLC. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0006]    [0006]FIG. 1 is a perspective view of two conventional PLC controlled valve systems.  
         [0007]    [0007]FIG. 2 is a perspective view of one embodiment of a PLC controlled valve system including at least one valve module.  
         [0008]    [0008]FIG. 3 is a cut away view of the PLC controlled valve system shown in FIG. 2. 
     
    
     DETAILED DESCRIPTION  
       [0009]    [0009]FIG. 1 is a perspective view of two conventional PLC controlled valve systems  10  including a hard wired valve system  12  and a network based valve system  14 . Hard wired valve system  12  includes a mechanical valve unit  16  coupled to an input/output (I/O) module  18  of a programmable logic controller (PLC)  20 . Valve unit  16  includes at least one inlet line (not shown), a manifold (not shown), and a plurality of outlet lines  22 . The inlet line is in flow communication with the manifold and pressurizes the manifold. A solenoid-actuated valve (not shown) controls each outlet line  22  from the manifold. A direct current (DC) wiring harness  24  extends from I/O module  18 .  
         [0010]    Harness  24  includes a plurality of electrical wires (not shown) wherein each wire is connected to one of the solenoid-actuated valves. PLC  20  controls valve unit  16  by directing I/O module  18  to energize or de-energize the wires.  
         [0011]    Network based valve system  14  include at least one intelligent valve unit  26  connected via a communications cable  28  to a communication module  30  of PLC  20 .  
         [0012]    Each valve unit  26  is electrically connected to a power source (not shown) and includes an inlet line (not shown), a manifold (not shown), and a plurality of outlet lines  32 . The inlet line is in flow communication with the manifold and a solenoid-actuated valve (not shown) controls each outlet line  32  from the manifold. Each valve unit  26  further includes a network connection  34  for communication with communication module  30 . Accordingly, PLC  20  controls the solenoid-actuated valves by directing communication module  30  to open and close the valves though the use of command signals sent from communication module  30  to network connections  34 . However, both systems  12  and  14  occupy more space than PLC  20  due to the overhead of the separate valve units  16  and  26 . Furthermore, valve unit  26  has the additional overhead of network connection  34 .  
         [0013]    [0013]FIG. 2 is a perspective view of one embodiment of a PLC controlled valve system  40  including at least one valve module  42  operationally coupled to a PLC  44 . At least one pneumatic line  46  extends from module  42 . Accordingly, PLC controlled valve system  40  occupies less space than hard wired system  12  and networked system  14  (shown in FIG. 1).  
         [0014]    [0014]FIG. 3 is a cut away view of PLC controlled valve system  40  (shown in FIG. 2) including a base plate  48 . A central processing unit (CPU)  52  is mounted to base plate  48 . CPU  52  includes a programmable memory (not shown) for storing instructions to implement specific functions such as logic, sequence, timing, counting, and arithmetic to control machines and processes. Base plate  48  supplies inputs and outputs to CPU  52 . PLC  44  can be a master PLC or a slave PLC. Base plate  48  includes a plurality of base plate bus connectors  54  for mounting various modules such as known I/O modules. In an exemplary embodiment, PLC  44  is a series 90-30 controller commercially available from the GE Fanuc Automation Corporation, Charlottesville, Va. A valve module  56  is mounted to one base plate bus connector  54 . Valve module  56  includes a valve assembly  57  including a valve manifold  58  and an inlet line  60  extending to valve manifold  58 .  
         [0015]    Inlet line  60  is in flow communication with manifold  58 . At least one valve  62  is in flow communication with manifold  58 . In an exemplary embodiment, valves  62  are solenoid-actuated valves and are connected to at least one solenoid  64 . At least one outlet line  66  is in flow communication with valves  62 . In one embodiment, outlet lines  60  are pneumatic lines  46  (shown in FIG. 2). In another embodiment, outlet lines  60  are hydraulic lines. Valve module  56  further includes a module bus connector  68  for connecting module  56  to base plate  48 . In an exemplary embodiment, module bus connector  68  is sized to mate with base plate bus connector  54 , wherein module bus connector  68  and base plate bus connector  54  each include a plurality of electrical contacts (not shown) such that module bus connector  68  operationally couples to base plate bus connector  54  for communication between module  56  and PLC  44 .  
         [0016]    In an exemplary embodiment, a pendant control  70  extends from module  56 . Pendant control  70  includes at least one selection device  72  to manually control at least one valve  62 . Selection device  72  has an on position  74  and an off position  76 . In one embodiment, selection device  72  is a toggle switch. In another embodiment, selection device  72  is a turn knob. In a further embodiment, selection device  72  is a push button. When PLC  44  is functioning, a user selects on position  74  to force valve  62  open overriding an off control signal generated by CPU  52 . However, a selection of off position  76  will not force valve  62  closed if module  56  is receiving an on control signal from CPU  52 . Accordingly, pendant control  70  acts as a partial manual override for controlling valves  62  when PLC  44  is functioning. Additionally, when PLC  44  is not functioning, pendent  70  control can be used to open and close valves  62 . In other words, pendant control  70  controls valve  62 , independently of PLC  44  when PLC  44  is not functioning.  
         [0017]    During operation, a gas is in flow communication with inlet line  60  and pressurizes manifold  58 . Outlet lines  66  are connected to various devices and PLC  44  controls delivery of the gas to the devices by controlling solenoids  64 . Each solenoid  64  has a normal position (non-actuated) and a thrown position (actuated), wherein when an electromagnet (not shown) of solenoid  64  is energized, solenoid  64  is in the thrown position. Each valve  62  has an open position and a closed position, wherein the gas can flow through valve  62  when valve  62  is in the open position, and the gas can not flow through valve  62  when valve  62  is in the closed position. In an exemplary embodiment, when solenoid  64  is in the normal position, valve  62  is closed, and when solenoid  64  is in the thrown position, valve  62  is open. A user observes the process utilizing the gas and utilizes selection device  72  to open valves  62  when desired. In an exemplary embodiment, pendant control  70  includes a plurality of selection devices  72  that allows the user to selectively close a particular valve  62 . In an exemplary embodiment, module  56  includes a plurality of indicator lights  78  corresponding to valves  62 . Each light  78  is on when the corresponding valve  62  is open, and each light  78  is off when the corresponding valve is closed. Accordingly, the user receives a visual signal of each valve&#39;s  62  state. In one embodiment, module  56  includes at least one DC output (not shown) and an associated indicator light (not shown) is energized when the output is energized.  
         [0018]    Valve module  56  is cost effective and facilitates reducing an amount of space occupied by a PLC based valve system. Accordingly, a PLC valve system utilizing a valve module such as module  56  occupies less space than system  12  and system  14  (shown in FIG. 1).  
         [0019]    While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.