SD Series Ultra-slim user-friendly devices for protecting electronic equipment and systems against surges on signal and I/O cabling RRaannggee ooff AATTEEXX CCeerrttiiffiieedd iinnttrriinnssiiccaallllyy ssaaffee ssuurrggee pprrootteeccttoorrss UUllttrraa--sslliimm ssppaaccee--ssaavviinngg ddeessiiggnn eeaassyy iinnssttaallllaattiioonn MMuullttiissttaaggee hhyybbrriidd pprrootteeccttiioonn cciirrccuuiittrryy 1100kkAA mmaaxxiimmuumm ssuurrggee ccuurrrreenntt RRaannggee ooff vvoollttaaggee rraattiinnggss ---- ttoo ssuuiitt aallll pprroocceessss II//OO aapppplliiccaattiioonnss HHiigghh bbaannddwwiiddtthh,, llooww rreessiissttaannccee,, RRTTDD,, PPSSTTNN aanndd 33--wwiirree ttrraannssmmiitttteerr vveerrssiioonnss aavvaaiillaabbllee TThhee SSDD SSeerriieess is a range of surge removal of the surge protection device. TTeelleepphhoonnee nneettwwoorrkkss can be protected by protection devices combining unparalleled This facility is provided by the SD07, SD16, the SDPSTN. packing densities, application versatility, SD32 and SD55 units. In addition, a third OOnnee ssiimmppllee mmaannuuaall ooppeerraattiioonn clamps proven reliable hybrid circuitry, simple connection on the field and safe side of modules securely onto DIN rail, which installation and optional loop disconnect the protector is provided in order to automatically provides the essential high- facilities features which make the series terminate screens safely. integrity earth connection. the ultimate surge protection solution for FFoorr tthhrreeee wwiirree aapppplliiccaattiioonnss the specially process equipment, I/O systems and TToopp--hhaatt ((TT--sseeccttiioonn)) DDIINN rraaiill is generally designed SDRTD (Resistance communications networks. suitable for mounting SD modules Temperature Detector) and the SD32T3, although for adverse environments, a TThhee eexxcceeppttiioonnaallllyy hhiigghh ppaacckkiinngg ddeennssiittiieess (for separately powered 4-20mA loops) specially-plated version is available from are the consequence of an ultra slim provide full 3-wire protection in a single MTL Surge Technologies. A footprint for individual modules which can compact unit. The recommended choice comprehensive range of mounting and thus double-up as feedback terminals. for the protection of 3-wire pressure earthing accessories can also be Each module provides full hybrid surge transducers on low power circuits is the supplied, see page 7 for further protection for 2 and 3 wire loop SD07R3. details. protection. FFoorr hhiigghheerr bbaannddwwiiddtthh aapppplliiccaattiioonnss,, the MMoodduulleess wwiitthh aa ccoommpprreehheennssiivvee rraannggee ooff SDR series has been developed to meet vvoollttaaggee rraattiinnggss cover all process related the demands of todays highest speed signals such as RTDs, THCs, 4 to 20mA communication systems. loops, telemetry outstations, shut-down 112200VV aanndd 224400VV AACC vveerrssiioonnss systems and fire and gas detectors. are available for I/O and OOppttiioonnaall lloooopp ddiissccoonnnneecctt,, is a feature power supplies up to which allows commissioning and three Amps of load maintenance to be carried out without current. Data & Signal ProtectionGGuuiiddee ttoo aapppplliiccaattiioonnss aanndd sseelleeccttiioonn The SD Series of SPDs includes models for almost all possible applications operating at voltages up to 250V ac. The optional fuse/disconnect package provides both fused protection against fault currents and a convenient method of isolating field cir- cuitry from protected circuitry without needing additional disconnect terminals. The standard fuse (which is replaceable) is rated 250mA with 50mA fuses also being available by special request. Where only the disconnect feature is required, solid links can be used. As an example, this feature is of particular value in applications in which an SPD is used with a bulk power supply feeding multi- ple loops. The individual module fuse prevents a fault or follow on current on one loop disrupting the power supply to the others. Also, loops can be removed from the circuit for maintenance reasons or added without needing additional disconnect terminals. The following guide to selection suggests the most suitable SDs for a number of specific applications. For technical information, see the detailed specifications on the back page of this publication (some field circuit protection is shown for completeness). FFIIEELLDD CCIIRRCCUUIITT PPRROOTTEECCTTEEDD CCIIRRCCUUIITT AAnnaalloogguuee iinnppuuttss ((hhiigghh--lleevveell)) 22--wwiirree ttrraannssmmiitttteerrss,, 44--2200mmAA,, ccoonnvveennttiioonnaall aanndd ssmmaarrtt The SPDs recommended for use with conventional and smart 4-20mA transmitters (fed by a well- regulated supply) are the SD32 and SD55, the choice depending upon the maximum working voltage of the system (32V and 55V respec- tively). The diagram illustrates a prime exam- ple of an application for which the fuse/dis- connect facility is particularly useful, however, both models are available in X versions with- 22--wwiirree ttrraannssmmiitttteerrss out the optional fuse/disconnect feature. AAnnaalloogguuee iinnppuuttss ((llooww--lleevveell)) RRTTDDss These applications are best served using the SDRTD. For optimum accuracy, the energising current should be chosen to ensure the voltage across the RTD does not exceed 1V over the full measurement range. When using a PT100 device, we recommend an energising current of 1mA. 33 wwiirree RRTTDDss PPhhoottoocceellllss,, TTHHCCss,, mmVV ssoouurrcceess aanndd ttuurrbbiinnee fflloowwmmeetteerrss The SD07 or SD16 (depending upon the operational voltage) are the favoured choices for this application. SD07X and SD16X are also suitable. pphhoottoocceellllss,, TTHHCCss,, mmVV ssoouurrcceess aanndd ttuurrbbiinnee fflloowwmmeetteerrss 2