Elec­tri­cal tech­nol­ogy

DEMM Engineering & Manufacturing - - CONTENTS - By Charles Ar­gen­ziano

Data log­gers are tak­ing on a whole new look in today’s mar­ket. Some are the size of match­books, while oth­ers take up huge racks. Many of the old-style units needed to be hard wired and placed near the area where the tests were car­ried out.

Data log­gers of the past were ba­si­cally used to mon­i­tor low volt­age lev­els with very lit­tle iso­la­tion be­tween chan­nels. Re­mem­ber those noisy re­lays you use to hear when they were first in­tro­duced? Now ev­ery­thing is solid state – silent.

Old mod­els were slow in their scan speed, and weren’t the most de­pend­able when do­ing long-term mea­sure­ments. They had no mem­ory, or only a few kilo­bytes, and only the ex­pen­sive units had se­rial out­put to get some raw data out.

With the tech­nol­ogy we have today, new log­gers such as the Hioki LR8410-20, all kinds of dif­fer­ent sig­nals can mon­i­tor things such as cur­rent, tem­per­a­ture, hu­mid­ity, pres­sure, load, flow rates and such.

Sep­a­rate trig­ger points can be set for each chan­nel, en­gi­neer­ing units can be set for in­de­pen­dent chan­nels, alarms, scal­ing func­tions and so on. These new units now have LAN and USB ports built into them, can stream the data di­rectly to SD mem­ory cards or ex­ter­nal hard drives and PCs.

Also, if you wanted to mon­i­tor a large area spread over hun­dreds of me­tres you needed mul­ti­ple units, which was also a prob­lem. How can we ac­com­plish this? How can we mon­i­tor sig­nals such as tem­per­a­ture, hu­mid­ity, sen­sors, up high such as in a ware­house, silo, and at­tic or over long dis­tances? How can we col­lect sig­nals from mul­ti­ple points around a build­ing, while keep­ing the data syn­chro­nised so it can be com­pared on the same time axis?

For ex­am­ple, mon­i­tor­ing mul­ti­ple burn-in racks or ovens, all com­ing into one main log­ging sta­tion can be­come costly. Up un­til now, mul­ti­ple log­gers had to be used, lengthy and costly wire runs had to be made, while try­ing to keep the in­duced noise, de­graded sig­nal due to ca­ble loss to a min­i­mum. This be­comes ex­tremely costly, and most of the time the data from these sig­nals be­comes er­ror-rid­den.

With the in­tro­duc­tion of the new wire­less log­gers that are be­ing in­tro­duced such as the Hioki LR8410-20 log­ger, log­ging multi-point data has never been so easy. Wire­less tech­nol­ogy makes it pos­si­ble to log data in ap­pli­ca­tions where it would have been dif­fi­cult to use a con­ven­tional log­ger, such as high lo­ca­tions where wiring would be dif­fi­cult to in­stall, or in­side se­cured con­trol pan­els.

The sep­a­rate log­ging mod­ules can be placed right next to the sys­tems to be mea­sured re­duc­ing the con­nec­tion com­plex­i­ties. In­di­vid­ual low cost wire­less log­ging sta­tions us­ing Blue­tooth tech­nol­ogy are placed near the de­vices that need to be mon­i­tored.

The data is then sent wire­lessly from the Hioki log­ging mod­ules to the Hioki wire­less log­ging sta­tion in real time mode. The data can then be stored di­rectly to the log­ger’s in­ter­nal mem­ory or saved to its re­mov­able SD card.

Fuel cell testing

Need to mon­i­tor the volt­age, cur­rent, tem­per­a­ture, and hu­mid­ity on mul­ti­ple l high volt­age fuel cell stacks? Us­ing the Hioki IR8410-20 log­ger, hu­mid­ity sen­sor, cur­rent clamps are con­nected to the cell un­der test, the in­puts scaled and en­gi­neer­ing units are en­tered so the log­ger dis­plays the ap­pro­pri­ate read­ings.

Ther­mo­cou­ples are placed on the fuel cell stack to mea­sure the tem­per­a­ture of the cells with the log­ger do­ing the cold junc­tion com­pen­sa­tion.

What is also im­por­tant to re­alise is there is a po­ten­tial of high volt­age on these stacks that does not af­fect the log­gers ac­cu­racy and mea­sure­ments. Also, the need to mon­i­tor mul­ti­ple fuel cell stacks at one time makes this a sim­ple task for the Hioki LR8410-20 by putting LR8500 log­ger mod­ules next to each fuel cell stack and hav­ing the mod­ules com­mu­ni­cate back us­ing its Blue­tooth tech­nol­ogy.

Mon­i­tor­ing ovens

In one case, seven ovens needed to be mon­i­tored, with 12 chan­nels of tem­per­a­ture and hu­mid­ity in each oven. Eight, 12 chan­nel log­gers would need to be in­stalled, and then hard-wired back to a cen­tral PC work­sta­tion.

Chal­lenges in­cluded data not be­ing syn­chro­nised across all ovens, in­di­vid­ual ca­bling needed d to be run to each log­ger (in a not so friendly area), and d the cost of each log­ger with ap­pro­pri­ate in­ter­face was high. Cus­tomer tried to share one log­ger for ev­ery two ovens, but wiring in­di­vid­ual chan­nels be­came a prob­lem with ca­ble run and in­duced noise. Set-up time ap­prox­i­mately 10 days.

Bat­tery dis­charge rate

A cus­tomer needed to mon­i­tor bat­tery dis­charge rate of a wheel­chair, over time, move­ment and load. Us­ing one Hioki data log­ger, the com­pany ran a test on one wheel­chair at a time to get in­for­ma­tion such as DC volt­age, cur­rent, dis­charge rate, ro­ta­tion of wheels, load and run­time.

Mount­ing the older Hioki 8421 se­ries data log­ger the unit was able to cap­ture this in­for­ma­tion store it to a mem­ory card and later loaded onto a PC for eval­u­a­tion.

Us­ing the new Hioki LR8410-20 log­ging sys­tem the man­u­fac­ture mounted the LR8510 log­ger mod­ules with recharge­able bat­tery packs on mul­ti­ple wheel­chairs. These units com­mu­ni­cated back via Blue­tooth to the main LR8410-20 log­ging col­lec­tor with the same data that one unit col­lec­tor only on mul­ti­ple wheel­chairs at the same time.

They ran mul­ti­ple tests at once, sav­ing valu­able time

and al­low­ing them to com­pare dif­fer­ent prod­ucts im­me­di­ately by com­par­ing sig­nals in real time. This saved the valu­able time and money, and al­lowed the firm to show some ma­jor dif­fer­ences be­tween prod­ucts.

Con­clu­sion

New log­gers scan speeds in mil­lisec­ond across mul­ti­ple chan­nels. Plus many of these units have event search func­tions. Log­ger util­ity PC soft­ware is also avail­able to eval­u­ate the data af­ter it has been col­lected, view past data dur­ing record­ing, and out­put this data to a prin­ter to gen­er­ate graphs and re­ports.

Go to demm.co.nz/ en­quiry quote: D140733

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