Programmable Logic Controllers (PLC)

Jul 7, 2013

The computer behind the robots performance is the Programmable Logic Controllers (PLCs). PLCS are able to control the robots and help them do their job at very specific times and points in the production process. PLCs help robots accomplish a quality product and keep the production line going.


Pro­gram­ma­ble Log­ic Con­trollers (PLCs) are cen­tral com­put­ers that con­trol where and when indus­tri­al robots per­form their duties. Like a direc­tor con­trol­ling a sym­pho­ny of musi­cians, a PLC con­trols a sym­pho­ny” of spe­cial­ized robots. These robots all do their jobs at the direc­tion and tim­ing of the PLC to work towards a com­mon goal, prod­uct, or com­plet­ed process.

The first PLCs were intro­duced in the late 1960s and were mas­sive, del­i­cate, and com­plex. They had to be care­ful­ly cli­mate con­trolled and shield­ed from the heat, noise, and vibra­tion of a man­u­fac­tur­ing envi­ron­ment. They were very dif­fi­cult to pro­gram. Then, as com­put­ers went through a micro­proces­sor rev­o­lu­tion, so did PLCs. Today’s PLCs are pow­er­ful, resilient machines designed specif­i­cal­ly to oper­ate in a harsh fac­to­ry envi­ron­ment. They have enor­mous­ly flex­i­ble input/​output (I/O) capac­i­ty and fea­ture user-friend­ly man-machine-inter­faces (MMI) or graph­i­cal user inter­faces (GUI). Mod­ern PLCs are also designed with back­up pow­er sup­plies and excep­tion­al­ly sta­ble soft­ware oper­at­ing sys­tems to assure unin­ter­rupt­ed con­trol of all their processes.

The ben­e­fits of a PLC are sig­nif­i­cant. PLCs spe­cial­ize in man­ag­ing com­plex, simul­ta­ne­ous, mul­ti-stage oper­a­tions. For exam­ple, a PLC can man­age mul­ti­ple assem­bly lines all fun­nel­ing parts to pack­ag­ing and pal­letiz­ing robots which must pack­age the right parts in the cor­rect order at a pre­cise time to be shipped out on a spe­cif­ic sched­ule. Then, inef­fi­cien­cies or errors can be detect­ed by the PLC and report­ed to the user, who can repro­gram spe­cif­ic parts or the entire process through a user-friend­ly interface. 

Many busi­ness­es also employ safe­ty PLCs” that remain in stand­by until a non-stan­dard event hap­pens, such as an emer­gency stop of an assem­bly line. A safe­ty PLC would then step in to con­trol the posi­tions, tim­ing, and direc­tion of move­ment of the robots to assure they or any prod­ucts being worked on are not damaged.

Increas­ing num­bers of mod­ern indus­tri­al robots, like the ones from KUKA, Fanuc, and Motoman Robot­ics, have PLC soft­ware and fea­tures built direct­ly into the robot con­troller. This built-in soft­ware has advanced to the point where small groups of robots can act with­out a sep­a­rate, ded­i­cat­ed PLC. For small-scale or sim­ple oper­a­tions, this is often a more cost-effec­tive option than pur­chas­ing a sep­a­rate PLC. This type of cus­tomer could use Motoman Robotics’s user-inter­face, Moto HMITM. It fea­tures a sin­gle-sta­tion solu­tion and user-friend­ly touch-screen graph­ic inter­face to quick­ly and intu­itive­ly mod­i­fy the PLC func­tions of mul­ti­ple mod­ern robots with­out hav­ing to pur­chase anoth­er ded­i­cat­ed PLC. For cus­tomers who need to man­age com­plex oper­a­tions with large num­bers of sim­i­lar units, such as auto man­u­fac­tur­ing, invest­ing in a PLC could be a smart choice, where the cost of pur­chas­ing and pro­gram­ming the PLC can be spread over many units of product. 

Robots​.com is expert­ly trained to help answer the ques­tion of whether a sep­a­rate, ded­i­cat­ed PLC is right for your busi­ness. Once that deci­sion is made, we can help equip you with the best qual­i­ty PLC or indus­tri­al robot that will effi­cient­ly serve your needs.

For more infor­ma­tion, con­tact Robots​.com online or at 8777626881.

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