Serial Devices Reach Longer Distances with Optical Fiber

Transcription

1 Serial Devices Reach Lnger Distances with Optical Fiber Antaira s STF-401C, STF-501C, STF-502C Series By: Brian Rth, Antaira s Prduct Marketing Engineer Octber 31, 2013

2 Serial Devices Reach Lnger Distances with Optical Fiber Tday, serial devices cntinue t be used arund the wrld as an essential cmpnent f many ITS (Intelligent Transprtatin Systems) applicatins, such as, weigh statins, tll plazas, and intersectin traffic mnitring. As a matter f fact, the serial RS-232/422/485 technlgy is still a ppular slutin fr device manufacturers t build in their current r future prduct design(s) as a cmmunicatin prt(s) slutin. Serial is stable, there is n risk f data crrsin, and it is easy t setup, deply and maintain all while being ecnmically friendly. The reliability and benefits prvided by serial allw its cntinued usage in weigh scales, ticket machines, turnstiles, messaging signs and traffic signal cntrllers. Additinal benefits can be incrprated int the system when expanding r retrfitting sectins, while maintaining the value and reliability f the same equipment. Industrial serial t fiber cnverters are able t prvide additinal redundant ring reliability t serial devices within a netwrk; while at the same time the cnverters are als able t significantly increase cmmunicatin distance between field site serial devices and the traffic management center (TMC). The flexibility f a serial interface can be used t cnnect up t 32 ndes in a single half-duplex line when using a 2-wire RS485 bus. Since the RS-485 bus allws users t have a data transmissin distance f up t 1.2KM, it is suitable fr many industrial autmatin applicatins. In traditinal slutins fr serial device netwrking, users can chse RS-485 repeaters t extend the 1.2KM transmissin distance limitatin, r increase the number f required serial devices cnnected t the system. In sme cases, serial repeaters can als be used t cmbine several RS-485 netwrks int a mre cmplex netwrk. The drawback f using the serial repeater is that each extensin will still have the 1.2KM transmissin distance limitatin and the serial signals wuld have a chance t be crrupted by the effects f electrmagnetic interference. In rder t vercme these issues, Antaira s industrial serial-t-fiber media cnverters prvide slutins at half r full duplex ver fiber at a thrughput rate up t 1024Kbps. The fiber lines are inherently resistant t EMI/RFI and transient surges, in rder t prevent electrical r radi interference. Plus these slutins allw a data signal transmissin distance extensin f up t 30 kilmeters. Antaira s industrial STF-401C, STF-501C, and STF-502C (Serial-t- Fiber) media cnverter series are designed t extend the data transmissin distance by ptical fiber media, and prvide built-in high grade data secure prtectin in ESD and EMI. Antaira s STF-401C, STF-501C, and STF-502C series are available with either multi-mde r single-mde fiber and SC r ST type cnnectrs. This flexibility allws users t setup their serial fiber netwrk int different tplgies: - Pint-t-pint cnnectin mde - Single ring cnnectin mde in half duplex - Self-healing dual ring redundant cnnectin mde in full duplex Fig. 1 - Antaira Industrial Serial-t Fiber Media Cnverter series WP-P_STF Phne: sales@antaira.cm Page 1

3 The Antaira STF-401C, STF-501C, and STF-502C series are designed with a user friendly cncept. Users are nly required t perfrm a simple hardware cnfiguratin in rder t cnnect their devices t their netwrks r systems. The nly task a user must perfrm is simply cnfiguring each STF unit fr a particular serial interface. In additin, users can easily adjust the built-in terminatin resistrs by switching the external dip switches, r the rtary switch t prtect the cnverter frm unexpected surges in the serial signals. Fig 2: DIP Switch & Rtary Switch Thery f Operatin Antaira s STF series uses cntrl lgic t cnnect an RS-485/422 interface, tw RS wire interfaces and tw ptical fiber channels. The units are intercnnected by the fiber channels and can frm pint-tpint, cascaded (linear) r ring tplgies. The peratin uses a master/slave hierarchy where nly ne master unit exists and all ther units are slaves in the applicatin. In an 'idle' cnditin, all interfaces are in a listening state. When any unit's receive interface receives a data transmissin, it will bradcast and transmit the data ut acrss all units transmit interfaces. The STF unit perates cmpletely at the physical layer, transparent t cmmunicatin prtcls. These cmmunicatin prtcls are required t handle bi-directinal data flw cntrl and device addressing. Operatin Mde Tw Unit Pint-t-Pint Cnnectin Mde This peratin mde is used t extend the transmissin distance f a serial cnnectin. In this example, tw STF-401C serial-t-fiber cnverters can be used t cnnect a cmputer t a serial device that is lcated at a remte site up t 30 km frm the cmputer (if single-mde fiber is used)as shwn in Figure 3. Tw Unit Pint-t-Pint Cnnectin Mde Multi Serial Lines in a Netwrk The pint-t-pint cnnectin mde can als be used t cmbine several RS-485 lines int ne serial netwrk as seen in Figure 4. The nly WP-P_STF Phne: sales@antaira.cm Page 2

4 drawback is that a pair f STF-401C units is required fr each serial device. Tw Unit Pint-t-Pint Cnnectin Mde with Fiber Prtectin Sme pint-t-pint applicatins require tw duplex fiber cnnectins t ensure that the serial signals are prtected in extremely harsh envirnments (Figure 5). Antaira s STF-502C series is a dual fiber prt versin. Users can set ne STF-502C unit as a 'master', and the ther unit as a 'slave'. The RS-485 and RS-232 are electrically islated. A receive signal can nly be cnnected t either the RS-485 (terminal blck) r t the RS-232 DB9 (nt bth at the same time). That received signal will be transmitted simultaneusly n every transmit cnnectin, bth RS-485 and RS-232. Master Slave Three r Mre Units One Way Daisy Chain Slutin There are quite a few applicatins that require data transmissin t nly ccur ne-way, and the manner f these types f applicatins requires data that can be transmitted frm a remte admin center (cntrl rm) t all remte field site devices. Sme examples f message display bards in public venues include: rail statins, bus terminals, and warning messages alng freeways. In this applicatin, administratrs can use Antaira s STF-501C single fiber prt units fr a ne-way daisy chain setup netwrk t cntinuusly update any text infrmatin frm the remte center t multiple statins (Figure 6). WP-P_STF Phne: sales@antaira.cm Page 3

5 Three r Mre Units- Daisy Chain Slutin In sme applicatins with three r mre units in different lcatins, a daisy chain slutin with duplex fiber prtectin is required (Figure 7). The RS-485 and RS-232 are electrically islated. A receive signal can nly be cnnected t either the RS-485 (terminal blck) r t the RS-232 DB9 (nt bth at the same time). Fig. 7 Single Ring Cnnectin Mde with Half Duplex In single fiber ring tplgy, the fiber transmit (Tx) f ne device cnnects t the fiber receive (Rx) f the next device. That secnd device s fiber transmit cnnects t the next device s fiber receive, until a cmpleted ring is frmed. Bth Antaira s STF-401C and STF-501C series cmpletely perates at Layer 1. Hwever, the lgic cntrl will ensure that any transmitted data will flw t each device in the ring but it will nt lp. The prtcl layer is required t handle prper cmmunicatin flw cntrl. Receptin f data at any receive shuld nly be allwed frm ne device at a time. That received data will then be bradcast (transmitted) t all units and interfaces. In the example t the right, ne RS-232 interface receives data and it is bradcast t all ther interfaces. WP-P_STF Phne: sales@antaira.cm Page 4

6 Self-Healing Dual Fiber Ring Cnnectin Mde with Full Duplex Sme critical applicatins require a zer data lss slutin within the serial netwrk because the single ring fiber mde with half duplex prvides n redundancy. In the event f a fiber link lss, r a pwered ff device, 2-way transmissin between the devices will nt be pssible. Depending n where the link is brken, there still may be transmit r receive paths between sme devices. Antaira s STF-502C series prvides a dual fiber prt slutin, in rder t allw users t perfrm a self-healing redundant ring serial fiber netwrk t ensure zer data lst prtectin. The figure t the right demnstrates hw t setup a dual ring serial fiber netwrk with Antaira s STF-502C series. Serial Fiber Cnnectin Mde Cmparisn Pint-t-pint cnnectin mde is a simple bus tplgy setup, but may require mre media cnverter units when there are multiple serial lines that require cnnectin with the system. - Available Antaira mdels include: STF-401C series- Cmpact industrial RS232/422/485 serial fiber cnverters STF-501C series- Industrial RS232/422/485 serial fiber cnverter with islatin prtectin. Single ring cnnectin mde is recmmended when multiple serial lines require cnnectin t a system and it requires fewer media cnverter units and reduces the ttal length f required fiber cable. *** When using a ring structure, the maximum length f the fiber cable is up t 100 km - Available Antaira mdels include: STF-401C series- Cmpact industrial RS232/422/485 serial-t-fiber cnverters STF-501C series- Industrial RS232/422/485 serial fiber cnverter with islatin prtectin. Dual ring cnnectin mde is recmmended whenever there are applicatins with extreme envirnmental cncerns. Antaira s STF-501C series prvides dual fiber prts t perfrm a self-healing redundant serial fiber netwrk slutin. It als has a built-in high surge and ptical islatin prtectin t secure serial data signals. WP-P_STF Phne: sales@antaira.cm Page 5

7 Prduct Cmparisn Chart Abut Antaira Technlgies, LLC Antaira Technlgies is a leading develper and supplier f industrial device netwrking and industrial cmmunicatin prducts. Antaira s turnkey netwrk cnnectivity slutins include: industrial Ethernet switches, industrial Ethernet media cnverters, industrial wireless , industrial serial cmmunicatins, and industrial embedded cmputing. WP-P_STF Phne: sales@antaira.cm Page 6