Installation and Maintenance of PLC

Installation and Maintenance of PLC

  Today’s programmable controller, properly installed, will provide a maximum of productivity with a minimum of maintenance. Cnc machining This section will cover the strength forward but critical areas of installation and maintenance of the programmable controller. It is intended to serve only as an overview on the subject, with the best guide for use being the documentation provided by the programmable controller manufacturer. This section will include rack installation for the CPU and I/O racks involved, line power, grounding, and signal cable consideration. Troubleshooting techniques as well as repair situation will be examined, and finally, training options will be presented.

   Rack Installation

   Depending on the size of the programmable controller being considered, the installation of the racks or chassis can be a simple or very complex task. Since most controllers are of open or particular application area. Many times this is a NEMA 12 type enclosure. Cnc machining It provides an environment in which the controller can operate without exposure to the grime outside the enclosure. Most racks can be mounted in either a panel type mounting arrangement, or a 19 in rack mounting. This is not true of controllers of the very small variety, as they are normally a panel mount only design. Rack mounting is generally used where the equipment is otherwise controlled. This type of installation is common where many instruments are mounted and used along with the programmable controller equipment. In either case, wire conductors must be routed in the rack; this is done with commercially available conduit that provides a means to bring in and out as many as 100 to 200 individual conductors from input and output points to real-world sensors and actuators. It is important that this phase of the design and installation be handled with care as it will dramatically affect the ability to maintain the systems. In addition to allowing any required system maintenance, this early care will make any system additions or modifications much easier.

  Line Power and Grounding     

    Proper power to the programmable controller is critical. Today’s systems are available in a wide variety of electrical configurations. Virtually all are designed for use in single-phase power systems, and most are now beginning to be offered with the optional ability to operate in a DC supply environment. AC designs are offered in either single voltage supplies, Cnc machining such as 115 or 230V AC; while some can be configured as either through a selection made on the power supply. Proper grounding of the power supply connection is required for a safe installation. Some programmable controller designs have individual grounding connections from rack to face- plates and other system components, so care must be taken to follow well electrical practice in system grounding during electrical installation. In certain applications, a 24 or 120 V DC power supply is required. This is common for installations that axe made where no AC power is available, such as remote electrical generation stations. It is also found where AC power is unreliable and where loss of control is considered an unacceptable situation