Simple Solutions That Work! Issue 5

Themajority of plants own RS Logix 500 and has had trained personnel ready to use it. The RS Logix 500 software is used for the SLC 500 PLC hardware as well. We should mention that the SLC 500 family of hardware is slowly but surely being phased out. Only the top of the line SLC 500 products are still being manufactured by AB. Compact and Control Logix PLC’s are programmed with RS Logix 5000 software which is tag based and offers greater flexibility when creating programs, especially with regard to custom data structures. Perhaps the biggest performance difference between the Micro Logix and the Compact/Control Logix platforms is in the area of communication. Native support for Ethernet IPisbuilt intotheCompact/ Control Logix families, enabling communicationwithawider variety of peripheral devices, variable frequency drives or robots for example. Ethernet IP capability will alsomake it easier to communicate with equipment manufactured elsewhere containing Mitsubishi, Omron or Siemens PLC’s. Having Ethernet infrastructure in place now makes it easier to connect sensors and monitor the working condition of the machine. We can compare actual readings with normal operating parameters suchas temperature, RPM, pressure, fluid levels, filter condition, and perhaps avert a breakdown. While this is not a substitute for proper preventativemaintenance, , a piece of machinery that can request assistance by itself can help prevent unplanneddowntime for aworkcell or production line.Weall knowhow much can be lost when production is at a standstill, especially when it could have been prevented at a modest cost. You can also track production quantities and plan for tool sharpening or replenishment of consumables. Having equipment such as Micro Logix controllers that existing system tools and personnel are qualified to support makes a lot of sense for an organization operating in amaintenance budget conscious environment. Thismay be the route to take if the organization hasmade decision that communication between machines is unnecessary and has decided not to connect the machines to a network. This approach can reduce short term costs in order to conserve resources for the future. Be aware that delaying too long has a cost too. Recognizing that eventually all SLC500 and Micro Logix will be phased out, installing a stand- alone machine or two sooner with Compact/Control Logix PLC units may be a good way to get maintenance personnel trained in the more modern product ahead of the time when it will be the only option on a mission-critical production line. This will give maintenance personnel more experience with the platform to keep repairs made and engineering personnel more familiarity to provide better advanced planning for future implementation. Different organizations have different needs, and decisions about if and when to migrate to a different platform are going to be based on those needs. 53 Contact: Tom Daily t_dailey @metalmechanics.com John Kison j_kison @metalmechanics.com