Programmable Logic Controllers (PLC)

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 877−762−6881.