OPC UA makes life easier for measurement technicians METAV 2020 showcasing the integration of length measurement technology in digitalised metalworking

The non-pro­pri­etary com­mu­ni­ca­tion stan­dard OPC UA (Open Plat­form Com­mu­ni­ca­tions Uni­fied Archi­tec­ture) is cur­rent­ly expe­ri­enc­ing rapid growth because the open plat­form facil­i­tates the inte­gra­tion of new machines and devices into pro­duc­tion. The VDMA is cur­rent­ly devel­op­ing cor­re­spond­ing domain-spe­cif­ic infor­ma­tion mod­els (“Com­pan­ion Spec­i­fi­ca­tions”) for length mea­sure­ment tech­nol­o­gy. Trade vis­i­tors will be able to receive first-hand infor­ma­tion from renowned mea­sure­ment tech­nol­o­gy man­u­fac­tur­ers at METAV 2020 from 10 to 13 March. 

For many years, length mea­sur­ing tech­nol­o­gy was kept in sep­a­rate air­con­di­tioned mea­sur­ing rooms and was sel­dom linked to oth­er machines or soft­ware prod­ucts of the fac­to­ry via stan­dard­ised net­work­ing. Indus­try 4.0 is chang­ing that. Ear­ly mea­sure­ment with­in the process (inline mea­sure­ment) using por­tal mea­sur­ing devices, and the com­mu­ni­ca­tion of machine tool mea­sure­ment results or cor­rec­tion val­ues can opti­mise process­es and qual­i­ty assur­ance with­in the fac­to­ry, and sig­nif­i­cant­ly increase cus­tomer pro­duc­tiv­i­ty. As Tobias Ischen, Prod­uct Man­ag­er for Automa­tion IT at Carl Zeiss Indus­tri­al Qual­i­ty Solu­tions explains, “At present we gen­er­al­ly set up closed-loop net­work­ing of this kind via file trans­fers and via pro­pri­etary inter­faces and numer­ous clas­sic pro­to­cols at the field and con­trol lev­el.” These solu­tions often only con­tain infor­ma­tion on the “how”, i.e. about the tech­nol­o­gy used to trans­fer the data trans­fer. What remains unclear, how­ev­er, is the “what”, i.e. what the data means: vari­ables with seman­tic descrip­tion. In many cas­es it is also high­ly cost-inten­sive to obtain this valu­able (tech­ni­cal, doc­u­men­ta­tion?) infor­ma­tion. “With net­work­ing based on the Com­pan­ion Spec­i­fi­ca­tions, OPC UA is the most promis­ing solu­tion for reduc­ing the inte­gra­tion effort, at least in new pro­duc­tion facil­i­ties. This will enable us to focus more strong­ly on imple­ment­ing auto­mat­ed mea­sure­ment process­es and val­ue-added metrol­o­gy appli­ca­tions in the future because the tedious work of inter­face pro­gram­ming, includ­ing main­te­nance, is large­ly eliminated.”

METAV exhibitor Carl Zeiss Indus­trielle Messtech­nik from Oberkochen is prin­ci­pal­ly a provider of soft­ware and solu­tions. OPC UA will sim­pli­fy net­work­ing with third-par­ty soft­ware and plat­forms (Man­u­fac­tur­ing Exe­cu­tion Sys­tem, MES, or Cloud) and with shop floor prod­ucts such as pro­gram­ma­ble log­ic con­trollers (PLCs) and periph­er­als such as RFID sys­tems. “It also makes it eas­i­er for us, as an MES provider, to col­lect data from the customer’s machine park for OEE cal­cu­la­tions, for exam­ple,” says Ischen. This makes pro­duc­tion process­es more trans­par­ent and opens up numer­ous oppor­tu­ni­ties for cus­tomers to improve the pro­duc­tiv­i­ty, qual­i­ty and prof­itabil­i­ty of their man­u­fac­tur­ing process­es. OPC UA also brings IT secu­ri­ty to the shop floor.

Reduced costs through standards 

In the con­text of indus­try 4.0, the open inter­face stan­dard OPC UA rep­re­sents a key tech­nol­o­gy for the non-man­u­fac­tur­er-depen­dent exchange of data. By spec­i­fy­ing the trans­mis­sion of tech­ni­cal data and describ­ing the data seman­tics in “infor­ma­tion mod­els” it pro­motes inter­op­er­abil­i­ty and con­se­quent­ly forms the basis for tech­ni­cal com­mu­ni­ca­tion based on Indus­try 4.0 ref­er­ence archi­tec­tures and imple­men­ta­tion rec­om­men­da­tions. “A large num­ber of domain-spe­cif­ic infor­ma­tion mod­els, so-called OPC UA Com­pan­ion Spec­i­fi­ca­tions, are cur­rent­ly being devel­oped on the basis of the OPC UA spec­i­fi­ca­tion,” says Dr. Armin Lech­ler, Deputy Direc­tor of the ISW at the Uni­ver­si­ty of Stuttgart. “These describe the infor­ma­tion required with­in a par­tic­u­lar domain, such as length mea­sure­ment tech­nol­o­gy.” This yields advan­tages for both providers and users. “As with many oth­er aspects, the pur­pose of stan­dar­d­is­ing com­mu­ni­ca­tion inter­faces is to reduce costs. The pro­pri­etary solu­tions used in length mea­sure­ment also result in sig­nif­i­cant amounts of engi­neer­ing and adap­ta­tion work,” says Lech­ler. A stan­dard­ised inter­face per­mits cus­tomer-spe­cif­ic projects to be com­plet­ed more quick­ly. This con­sid­er­ably sim­pli­fies the inter­ac­tion with oth­er machines or high­er-lev­el con­trol and plan­ning sys­tems. “Fur­ther­more, an inter­face is not a unique sell­ing point. All man­u­fac­tur­ers already have this data avail­able in one form or anoth­er – but it is not uni­form,” is how Lech­ler sums up the cur­rent sit­u­a­tion. “I am opti­mistic about future devel­op­ments, giv­en the numer­ous activ­i­ties sur­round­ing the Com­pan­ion stan­dards and the increas­ing spread of OPC UA in gen­er­al. Many projects fail at present due to their imple­men­ta­tion in indus­try, since the use of pro­pri­etary inter­faces makes them uneconomical.”

OPC UA – reduc­ing the num­bers of rejects 

“OPC UA allows us to share our knowl­edge from the mea­sure­ment process with oth­er process par­tic­i­pants. This short­ens response times for devi­a­tions with­in closed loops and saves our cus­tomers a lot of time and mon­ey,” explains Prof. Heiko Wen­zel, CDO of the Wen­zel Group, Wiesthal. “Besides their orig­i­nal appli­ca­tion in the mea­sur­ing room, our coor­di­nate mea­sur­ing machines are now increas­ing­ly being used in pro­duc­tion. We use them to check the parts them­selves, but they also give us a clear insight into pro­duc­tion con­di­tions such as vibra­tion, tem­per­a­ture, etc., which influ­ence our mea­sure­ment results. The col­lec­tion and analy­sis of this data is cur­rent­ly pro­pri­etary and can there­fore only be eval­u­at­ed in its own envi­ron­ment. Here OPC UA facil­i­tates the shar­ing of infor­ma­tion with and from oth­er machines. This pro­vides much faster, more accu­rate feed­back.“ Cus­tomers ben­e­fit from the fact that the results of the analy­sis – aimed at achiev­ing few­er miss­ing parts – can flow direct­ly into com­pre­hen­sive pro­duc­tion mon­i­tor­ing and control.

Wen­zel will once again be show­cas­ing its prod­ucts at the upcom­ing METAV, the 40th anniver­sary of the event. The Qual­i­ty Area will fea­ture the lat­est devel­op­ments in coor­di­nate mea­sur­ing tech­nol­o­gy, com­put­er tomog­ra­phy and opti­cal high-speed scan­ning. The focus will be on inte­gra­tion with­in flex­i­ble man­u­fac­tur­ing process­es and on ensur­ing pro­duc­tion qual­i­ty through prompt process mon­i­tor­ing. “Speed is cur­rent­ly a greater pri­or­i­ty in stan­dard­i­s­a­tion than per­fec­tion. If we are not care­ful, stan­dards will be put for­ward by oth­er indus­tries and regions which we will then have to fol­low,” says Wen­zel. “We can already see that IT and automa­tion com­pa­nies – which have dif­fer­ent focus­es and expec­ta­tions – are look­ing to posi­tion them­selves here. That’s why it’s impor­tant not to pay so much atten­tion to indi­vid­ual inter­ests, but quick­ly to find areas of com­mon ground — how­ev­er small they may be.”
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