SARAD GmbH Tel.: 0351 / Wiesbadener Straße 10 FAX: 0351 / Dresden Internet:

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1 SARAD GmbH Tel.: 0351 / Wiesbadener Straße 10 FAX: 0351 / Dresden supprt@sarad.de GERMANY Internet: APPLICATION NOTE AN-001_EN The Installatin f autnmus instrumentatin sites Versin June 2007 This paper demnstrates the installatin f autnmus instrumentatin sites linked t a cntrl centre by remte cntrl. Based n the usage f cmmercial available mdems, cmplex sampling netwrks can be established. The several ffered transmissin standards allwing a perfect adptin t the varius lcal infrastructures. The installatin steps are quite simple, even a nn skilled persn can d it. Only a lw number f additinal cmpnents is required All slutins shwn within this paper are available n the market r can be purchased directly frm SARAD During the planning perid f an instrumentatin site, tw imprtant aspects have t be cnsidered beside the selectin f the mnitr: 1. Which cmmunicatin channels are available n site? 2. Hw can the system supplied with electricity? The system cncepts described in the fllwing text ffering a suitable slutin fr the mst applicatins and lcal cnditins. Furthermre, an efficient shielding with respect t the climatic situatin as well as prtectin against unauthrised access an vandalism have t be established. Thse items depending strngly n the particular cnditins n site, therefre n general cncept can be ffered. Which mnitr is the best chice? Remte cntrl via mdem is supprted by the instrument types -Scut, -Scut PLUS, RTM1688-2, RTM1688 Ge Statin and RTM2200. The basic mdel f the Scut des nt allw an external pwer cnnectin. Therefre, the autnmus peratin is limited t several weeks by the internal batteries. A mdem cnnectin can still make sense if actual readings are always requested during the limited measurement perid. The -Scut PLUS, the RTM and the RTM2200 are the perfect chice fr urban envirnments. The internal batteries serve as an energy buffer in case f temprary pwer interruptins. The mdels RTM r RTM1688 Ge Statin are recmmended if n develped infrastructure is available at the place f installatin. The internal 12V battery can be easily replaced by a cmmercial available slar r wind pwer system.

2 AN-001 Installatin f Autnmus Instrumentatin Sites 2 Which is the best cmmunicatin cncept? PCwitht Visin sftware Internal Analgues -Kabel 9-pl. Buchse/Stecker -Kabel 9-pl. Buchse/Stecker netwrk Analgues Analgues TAE-cable TAEscket -Antenna -Antenna TAEScket Public telephneliner exchangeline Installatin n site In the mst urban regins a telephne line is available. The usage f an analgus mdem is recmmended in this case. If there is n telephne line, the digital cellular phne netwrk () has t be used. mdems are ffered by a large number f manufacturers. Similar t a mbile phne, a SIM card is required. The s-called data channel has t be activated fr the SIM card by the prvider. This is generally pssible fr each card but can invlve additinal csts fr the clearing f the service. The data channel includes a separate call number beside the vice dial in. It is recmmended t use special data transfer nly cards resulting in lwer initial and peratinal csts. Telephne charges have nt t be paid fr the mdems n the instrument site because they are always listen t a call f the cntrl centre. If the installatin site is ut f the ftprint (e.g. in hllws), a satellite mdem is the ptin. Because the charges fr satellite cmmunicatin are very high, an additinal terrestrial line (cable r wireless) between mdem and mnitr culd be installed. This slutin is als preferred if the place f installatin is in undergrund mines, caves etc. where a telephne line is nt available. A big number f cnverters fr this purpse (e.g. RS485/RS232 r wireless UART) are cmmercially available. RS232 maximum cabel length 1000m RS485 RS485 RS232 wireless UART wireless UART r Analues if a public telephne line is available netwrk -Antenna AN-001_AutnmusStatins_EN_

3 AN-001 Installatin f Autnmus Instrumentatin Sites 3 Installatin f the cntrl centre The cmmunicatin between the cntrl centre and the single mnitrs is realised by the Visin sftware running n a PC. A mdem has t be cnnected t a free COM prt f the cmputer. If is n COM prt available, an USB/Serial adapter can be used. Als fr the cntrl centre it culd be the less expensive slutin t chse a mdem instead f an analgus ne. Especially the charges fr t cnnectins are nt as high as fr line t cnnectins. Use als a data transfer nly SIM card and chse the best ffer with respect t yur transfer vlume. Smetimes it is better t pay per data vlume, smetimes per cnnectin time. Keep in mind that the mdem at the PC in the cntrl centre cvers all the csts fr the calls t the instrumentatin sites. Visin will detect a cnnected mdem autmatically. Additinal Windws drivers are nt required. Selectin f the s Generally, each mdem which can be cntrlled by AT cmmands via a serial interface is suitable. External mdems fr the several transmissin standards (analgue, ISDN,, GPRS) are ffered by SARAD. Als already existing mdems r internal devices (e.g. the Agere sft mdem in ntebks) can be used. If pssible, mdems f the same type shuld be used fr bth, instrumentatin site and cntrl centre. This ensures a simple handling and ptimised transfer rates. If the mdems has been purchased frm SARAD, all necessary accessries like cables, antennas and AC/DC adapters are included in delivery. Otherwise thse parts have t be rdered separately frm the manufacturer r supplier f the equipment. The nly thing yu have t buy frm SARAD is the cnnectin cable between the mdem and the mnitr. This custmised cable has additinal slder bridges and a special cnnectr. AN-001_AutnmusStatins_EN_

4 AN-001 Installatin f Autnmus Instrumentatin Sites 4 Hw t supply the system n site with electricity? N prblems are expected if the mains supply is available n site. Bth, mdem and radn mnitr can be perated a infinite perid using simple AC/DC wall adapters. The internal battery f the instruments ensures the cntinuus pwer supply during temprary pwer interruptins. If the interruptin ccur frequently, a buffer supply fr the mdem shuld be taken in accunt. If the mains pwer is nt available, an autnmus pwer supply has t be designed. One can distinguish between a true autnmy and the autnmy fr a given time span (limited autnmy). Limited autnmy The pwer is supplied by a battery which can nt be recharged during the whle peratin perid. This requests an as lw as pssible cntinuus pwer cnsumptin f the system. The wattage f a mdem is generally much higher than the ne f the mnitr. Therefre it is a prper slutin t switch n the mdem peridically nly fr a shrt time. Within this time slt, the mdem can be accessed by the cntrl centre. The figure beside shws a typical cnfiguratin. Dimensining steps: 12V Akku Zeitschaltuhr Determinatin f the pwer cnsumptin f the mnitr, the mdem and the clck timer Definitin f the time schedule (time and duratin f desired mdem access) Calculatin f the ttal energy request Dimensining f the battery with respect t the required perid f autnmy Example: A RTM set t cntinuus sampling mde shall be used in cmbinatin with a Falcm Tang-55 mdem and the clck timer mdel GEV The daily pwer up perid f the mdem shall be 1 hur. The autnmus peratin has t be ensured fr at least 3 mnth. pwer cnsumptin RTM pwer cnsumptin mdem pwer cnsumptin clck timer = 15 ma = 32 ma (lgged in) = 1 ma Because the mdem is switched n nly 1 hur per day, the average current cnsumptin is: 32 ma * 1 hur / 24 hurs = 1,33 ma The ttal cntinuus pwer cnsumptin is calculated by the sum f the single currents (RTM1688-2, clck timer, mdem average current): Ttal current = 15 ma + 1 ma + 1,33 ma = 17,33 ma Nw it is pssible t determine the required battery capacity: AN-001_AutnmusStatins_EN_

5 AN-001 Installatin f Autnmus Instrumentatin Sites 5 3 (mnth) * 30 (days) * 24 hurs * 17,33 ma = 37,43 mah = 37,43 Ah The self discharge prcess as well as capacity lss at lw temperatures have t be taken in accunt fr the battery selectin. A safety factr f 2 is a gd number. The usage f a battery with 12V/80Ah (e.g. Slar-Dryfit S12/85Ah manufactured by Snnenschein) is recmmended. True autnmy True autnmy is given if the used battery is recharged during system peratin by renewable energy surces. The figure shws a typical system set-up. It makes als sense t insert a clck timer t reduce the required pwer utput f the slar panel r wind generatr. The slar panel is the preferred slutin because the expected prblems during the peratin even under extreme climatic cnditins are much smaller. Take in cnsideratin that the average pwer generatin f a slar panel is nly in the rder f 5% t 30% f the stated peak pwer depending n the place f installatin. The battery capacity has t be large enugh t ensure the pwer supply ver lnger cludy perids. It is recmmended t purchase a turn key system as used fr yachts cntaining all necessary equipment. All cmpnents are well balanced and manufactured t withstand extreme envirnmental cnditins. The panel has t be installed at a place where it is expsed t the sun as lng as pssible ver the daytime. The panel rientatin shall be exactly suthwards/nrthwards (in nrthern/suthern hemisphere). The munting angle has t be adjusted that the wave angle is 90 in case f the lwest altitude f the sun (winter time). This smthes the seasnal variatins f the radiatin availability and avids snw depsits n the surface f the panel. Example: Slar Panel Charger 12V Battery Wind Generatr mdem Clck Timer A RTM1688 Ge Statin tgether with the mdem mdel Falcm Tang-55 are used. The mdem shall be lgged in permanently. T ensure a stable pwer supply, a slar pwer system is used. The average efficiency f the slar panel at the installatin site is nly 5% during the winter time. The 12V battery has t ensure the pwer supply fr at least fur weeks. pwer cnsumptin RTM1688 Ge Statin pwer cnsumptin resulting ttal pwer cnsumptin = 5 ma = 32 ma (lgged in) = 37 ma Using a nminal battery vltage f 12V, an average wattage f apprximately 450 mw (12 V * 37 ma) is necessary. The assumed panel efficiency f 5% leads t the required peak pwer f the slar panel: 450 mw * 100% / 5% = 9000 mw = 9 W AN-001_AutnmusStatins_EN_

6 AN-001 Installatin f Autnmus Instrumentatin Sites 6 T cmpensate the energy lst f the charge regulatr etc. a safety factr f 2 shuld be applied additinally. A slar panel with 20 W peak pwer is a gd selectin. Finally, the battery capacity has t be calculated by the current cnsumptin and the perid with n recharge: 4 (weeks) * 7 (days) * 24 hurs * 37 ma = mah = ca. 25 Ah Because the battery is permanently recharged, the self discharging prcess is negligible. This results in a smaller safety factr. A slar battery 12V/35Ah (e.g. Slar-Dryfit S12/35Ah manufactured by Snnenschein) is suggested. This specificatin sheet is fr infrmatin purpses nly and is subject t change withut ntice. SARAD GmbH makes n warranties, expressed r implied, in this prduct summary. SARAD GmbH. All rights reserved. AN-001_AutnmusStatins_EN_