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Application Article
Manufactuer Utilizes Several Entertron Products as Solution
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Controllers used - Elite-2000 and CM-1805-AS
Total Digital Inputs - 32 @ AC
Total Digital Outputs - 32 @ AC
Communication Protocol - ModBus
Operator Interface - Eclipse Vision
Customer Goals - Save Cost; Meet Required OSHA / ANSI requirements
The new press developed by our customer incorporates the Elite 2000 ePLC and Eclipse Vision color touch screen for all its automation needs. The CM-1805-AS module was added to satisfy the OSHA and ANSI requirements for control reliability.
The CM-1805-AS module for clutch/brake control meets or exceeds all OSHA 1910.217 and ANSI B11.1-1988 standards for control reliability. Control reliability standards require that clutch/brake circuits be designed and constructed so that a single failure or fault within the system does not prevent the normal stopping action from being applied to the press when required, or does not create an unintended stroking action, but does prevent initiation of a successive stroke until the failure is corrected.
This module offers safe, repeatable operation by incorporating into its design ANTI-TIE DOWN and ANTI-REPEAT capability, a control component reliability check and a run mode sequential fault feature. The units base design is a solid state complete self-checking dual logic microprocessor base control. The control has two independent CPUs cross checking each function of the controls operation.
The CM-1805-AS comes with an operator message display which will inform the user of any faults, failures, as well as current operating status of the press control system. It will immediately inform the user of such problems as pressure switch faults, failed output relays, or rotary cam mis-adjustments. The system will also pinpoint internal printed circuit board faults for immediate replacement. This module also incorporates redundant safety relays to assure safety if a control output relay should fail. The system utilizes safety relays which have force-guided contacts. This is a configuration where the contacts are not mechanically locked together so that if one set of contacts weld, the other contacts can change state. If one should fail, the control shuts down and the message display will identify which relay has faulted and what state the relay should be in(on/off).
This control offers a MICRO-INCH feature which provides ram movement for a predetermined amount of time.
The module provides positional brake monitoring which is required for all press controls by Federal Regulation. In the event that the control is signaled to stop and does not stop at position, a brake fault is generated. This fault stops all motion functions and informs the operator of the fault condition. In the event that the press control is signaled to start, in any mode of operation, the control monitors the time frame from signal start to physical motion on the cam limit switches. If no motion is detected a mechanical connection could have occurred and the control generates a motion detect fault.
The control offers a BAR MODE OPERATION which will allow the operator the ability to move the ram by way of a physical bar on the flywheel. In this mode all motion functions are deactivated and the clutch/brake valve is energized.
The control has a feature called ENERGY CONSERVATION SHUTDOWN. This was designed into the control as a cost savings option. When the control is idle with the main flywheel started for more than 30 minutes, the control will automatically shut down to conserve on energy consumption. The control informs the operator of the shutdown condition.
This redundant control uses rotary cam switches to monitor the press position. Mechanical cams are used for the critical clutch and brake controls because they are less likely to be affected by electrical noise versus a resolver. The KAMCO K80 style rotating cam limit switches used with this control are the accepted standard for controlling clutch and brake circuits on mechanical press controls. By using multiple cams for each critical event and cross checking the contact operation in the press control, no single component failure can cause inadvertent operation of the press. Typically, the rotary cam switches are mounted on the press in an area that is not easily accessible to unauthorized personnel which lessens the chance of accidentally changing (adjusting) critical control settings. The rotary cam also incorporates a CHAIN BREAK BASE to detect a broken/slack chain or belt. A switch, held active under normal conditions, allows the press to continue its cycle. If the chain loses tension or breaks, the switch changes state and stops the press from cycling.
The Elite-2000 and Eclipse Vision replaced the SLC5/03 and Panel View 550 from Allen Bradley. Our customer received the following benefits from the change:
The press that utilized an Allen Bradley PLC and touch screen offered no safety control as required by OSHA and ANSI. The Entertron solution not only addresses the OSHA and ANSI standards required for press control, but also saves the customer thousands of dollars. To stay with the Allen Bradley controller and add a redundant press control would have added several thousand dollars to the cost of the press. The complete Entertron solution (ePLC, touch screen and CM1805-AS) was $200 less than the Allen Bradley PLC and touch screen alone. In essence, they received the CM1805-AS for nothing.
