Automation of fish farming systems

The topic of auto­ma­ti­on is beco­m­ing more and more important, espe­cial­ly in today’s world. Espe­cial­ly in indus­try, whe­re high pro­duc­ti­vi­ty is always the goal and pro­ces­ses are incre­a­singly digi­ta­li­zed (Indus­try 4.0), many dif­fe­rent app­li­ca­ti­ons of auto­ma­ti­on can be found. Howe­ver, the begin­nings of elec­tro­tech­ni­cal auto­ma­ti­on date back several deca­des. A major step was the deve­lo­p­ment of the so-cal­led pro­gramm­a­ble logic con­trol­ler, or PLC, in the 1970s. Sin­ce then, this tech­no­lo­gy has been con­ti­nuous­ly deve­lo­ped to take over more and more tasks. Nowa­days, the plan­ning and imple­men­ta­ti­on of elec­tro­tech­ni­cal plants is vir­tual­ly impos­si­ble without such a PLC.

The programmable logic controller (PLC)

A pro­gramm­a­ble logic con­trol­ler is basi­cal­ly the brain of a tech­ni­cal sys­tem. Its task is to ensu­re the opti­mal func­tion of the respec­ti­ve plant. Decisi­ve for its use are dura­bi­li­ty and relia­bi­li­ty under dif­fi­cult con­di­ti­ons. This means that the PLC is not affec­ted by dust, cor­ro­si­on or heat and the plant can the­re­fo­re ope­ra­te without con­stant supervision.

The app­li­ca­ti­on pos­si­bi­li­ties of a PLC are very wide. The desi­red func­tions, which the PLC is to imple­ment, are pro­gram­med accord­in­gly and loa­ded into the memo­ry. During ope­ra­ti­on, input signals are acqui­red and pro­ces­sed accord­ing to the pro­gramming, and then out­put signals are issued to con­trol other com­pon­ents. In addi­ti­on to simp­le app­li­ca­ti­ons, high­ly com­plex tasks can also be imple­men­ted, making it high­ly ver­sa­ti­le. Des­pi­te this, pro­ces­sing times are only in the mil­li­se­cond ran­ge, which allows a fast reac­tion to occur­ring events.

In addi­ti­on to con­trol­ling nor­mal ope­ra­ti­on, the PLC is also used for gene­ral moni­to­ring and detec­ting errors. If a fault should occur, it is detec­ted direct­ly and repor­ted to the user via various warning sys­tems and with detail­ed infor­ma­ti­on, so that quick action or coun­ter­mea­su­res can be taken. Such messages are out­put in the so-cal­led HMI, the „Human Machi­ne Inter­face“. This is a dis­play that is con­nec­ted to the PLC. In addi­ti­on to the dis­play of messages, it can also be used to con­trol indi­vi­du­al parts of the plant and to moni­tor various parameters.

Automation of recirculation systems

Pro­gramm­a­ble logic con­trol­lers are also incre­a­singly being used in recir­cu­la­ti­on sys­tems. In clo­sed recir­cu­la­ti­on sys­tems, many dif­fe­rent para­me­ters have to be con­trol­led to ensu­re good water qua­li­ty. This is essen­ti­al for the well-being and health of the ani­mals and thus for suc­cess­ful pro­duc­tion. The fol­lowing sen­sors are used to mea­su­re para­me­ters in aquacultures:

The sen­sors regu­lar­ly record mea­su­red values and for­ward them to the PLC. The sys­tem then reacts auto­ma­ti­cal­ly to fluc­tua­tions and crea­tes pro­gres­si­on cur­ves that can be view­ed by the sys­tem ope­ra­tor. The fol­lowing sen­sors are instal­led to mea­su­re para­me­ters in aquaculture:

    • tem­pe­ra­tu­re
    • fil­ling level
    • ORP / redox
    • PSU / salinity
    • pH
    • oxy­gen satu­ra­ti­on (O2)
    • flow rate
    • car­bon dioxi­de (CO2)

In addi­ti­on to set­ting the para­me­ters, the PLC is also respon­si­ble for con­trol­ling all actua­tors and sub­sys­tems. The fol­lowing com­pon­ents can be con­nec­ted to the automation:

    • pumps
    • com­pres­sor
    • val­ves
    • drum fil­ter
    • deni­tri­fi­ca­ti­on
    • ozone gene­ra­tor
    • sedi­men­ta­ti­on
    • auto­ma­tic feeder
    • oxy­gen production
    • light
    • ven­ti­la­ti­on

Sta­te of the art aquacul­tu­re faci­li­ties are often equip­ped with soft­ware solu­ti­ons for sub­sec­tions or indi­vi­du­al units (e.g. only for the drum fil­ter), but do not have auto­ma­ti­on of the com­ple­te pro­cess. The­re­fo­re, the data con­sis­ten­cy of cou­pled pro­ces­ses is not given, and the workload is dif­fi­cult to generalize.

The fully automated SEAWATER Cube

For the SEAWATER Cube we have deve­lo­ped our own auto­ma­ti­on solu­ti­on accord­ing to modern stan­dards. This is based on Sie­mens tech­no­lo­gy and has more than 30 func­tions (e.g. fee­ding, rinsing, aera­ti­on) and thus con­trols about 20 sub­sys­tems, resul­ting in full auto­ma­ti­on of the ent­i­re pro­cess. The fish know­ledge that is necessa­ry for a smooth plant ope­ra­ti­on is stored in our con­trol sys­tem. Thus, the ope­ra­tor does not necessa­ri­ly have to be a bio­lo­gist or fish far­mer to con­trol the rea­ring pro­cess. The plant knows all important direc­tio­n­al limits and warning values and is able to react inde­pendent­ly to chan­ging con­di­ti­ons. In case of pro­blems, the sys­tem calls the ope­ra­tor and the con­trol sys­tem can also be acces­sed from out­side via remo­te main­ten­an­ce. The full auto­ma­ti­on also results in a plan­n­ab­le workload in plant ope­ra­ti­on of 1h per day on average. A cloud con­nec­tion enab­les exter­nal access to all data of rele­vant pro­cess variables.

The panel as it is dis­play­ed in the SEAWATER Cube. Here you can see the over­view page on which all rele­vant com­pon­ents are lis­ted. The­re are dif­fe­rent ways to get to sub­me­nus and to see and con­trol more details.

A con­trol menu can be seen in this view, here on the drum fil­ter as an examp­le. The „Ope­ra­ting mode“ fiel­ds can be used to switch par­ti­al func­tions from auto­ma­tic to manu­al mode.

In sum­ma­ry, the SEAWATER Cube uses modern auto­ma­ti­on tech­no­lo­gy through the use of a pro­gramm­a­ble logic con­trol­ler to ensu­re opti­mal plant ope­ra­ti­on with a mana­ge­ab­le workload. The sta­te of the art in fish far­ming is thus rai­sed to a new level.

Newsletter abonnieren

Du möchtest regelmäßige Updates zu SEAWATER Cubes erhalten? In unserem monatlichen Newsletter informieren wir zu aktuellen Themen und Entwicklungen rund um unser Unternehmen. Außerdem warten spannende Fachbeiträge zum Thema Aquakultur sowie exklusive Informationen zu Veranstaltungen auf Dich.

Vielen Dank! Du hast Dich erfolgreich für unseren Newsletter angemeldet.