{"product_id":"allen-bradley-1756-rmc3-3-m-rm-fiber-optic-cable-controllogix-redundancy-system","title":"Allen-Bradley 1756-RMC3 3 m RM Fiber Optic Cable ControlLogix Redundancy System","description":"\u003cp\u003eConfigured for peer-to-peer chassis synchronization in ControlLogix redundant systems, the \u003cstrong\u003eAllen-Bradley 1756-RMC3\/A\u003c\/strong\u003e (\u003cstrong\u003e1756-RMC3\u003c\/strong\u003e RM Fiber Optic Cable) transports the duplex optical redundancy link between paired 1756-RM-class modules .\u003c\/p\u003e\n\u003ch3\u003eCatalog Marking and Length Family\u003c\/h3\u003e\n\u003cfigure\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eMarking\u003c\/th\u003e\n\u003cth\u003eDefinition\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e1756-RMC3\u003c\/td\u003e\n\u003ctd\u003eBase catalog number, 3 m (9.84 ft) prefabricated RM fiber optic cable\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e1756-RMC3\/A\u003c\/td\u003e\n\u003ctd\u003eRevision A hardware\/build of the cable assembly\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e1756-RMC1\u003c\/td\u003e\n\u003ctd\u003e1 m sibling in same RM cable family\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e1756-RMC10\u003c\/td\u003e\n\u003ctd\u003e10 m sibling in same RM cable family\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e1756RMC3\u003c\/td\u003e\n\u003ctd\u003eNon-hyphenated BOM \/ shipping label string\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/figure\u003e\n\u003ch3\u003eHardware Specifications\u003c\/h3\u003e\n\u003cfigure\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eParameter\u003c\/th\u003e\n\u003cth\u003eSpecification\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eModel\u003c\/td\u003e\n\u003ctd\u003e1756-RMC3\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBrand\u003c\/td\u003e\n\u003ctd\u003eAllen-Bradley \/ Rockwell Automation\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOrigin\u003c\/td\u003e\n\u003ctd\u003eUnited States\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e0.15 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eShipping Dimensions\u003c\/td\u003e\n\u003ctd\u003e19.5 x 16.3 x 4.3 cm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAssembly Type\u003c\/td\u003e\n\u003ctd\u003ePassive prefabricated duplex LC-to-LC RM synchronization cable\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLength\u003c\/td\u003e\n\u003ctd\u003e3 m (9.84 ft)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTypical Connector\u003c\/td\u003e\n\u003ctd\u003eDuplex LC, keyed for 1756-RM \/ 1756-RM2 \/ 1756-RMXT \/ 1756-RM2XT ports\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eFiber Class\u003c\/td\u003e\n\u003ctd\u003eMatched to RM module port: 62.5\/125 um or 50\/125 um multimode, or 8.5\/125 um singlemode per RM generation\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eLink Topology\u003c\/td\u003e\n\u003ctd\u003ePoint-to-point only; no couplers, media converters or switches in line\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower Consumption\u003c\/td\u003e\n\u003ctd\u003eNot applicable; passive optical link, no backplane current draw\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOperating Temp\u003c\/td\u003e\n\u003ctd\u003e-25 to 70 deg C (-13 to 158 deg F) per supplied nameplate data\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eStorage Temp\u003c\/td\u003e\n\u003ctd\u003e-40 to 85 deg C typical for industrial-grade prepatch cord\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMinimum Bend Radius\u003c\/td\u003e\n\u003ctd\u003e30 mm floor for OM1\/OM2 multimode service; observe larger singlemode cable rating where G.652 singlemode is used\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eUsed With\u003c\/td\u003e\n\u003ctd\u003e1756-RM, 1756-RM2, 1756-RMXT, 1756-RM2XT redundant modules\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eStatus\u003c\/td\u003e\n\u003ctd\u003eDiscontinued as standalone cable assembly in legacy RM families\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/figure\u003e\n\u003ch3\u003eControlLogix Redundant Link Throughput and Firmware Pairing\u003c\/h3\u003e\n\u003cp\u003eThe 1756-RMC3 is the physical media carrying the ControlLogix redundant chassis synchronization traffic between two 1756-RM-class modules mounted in separate 1756 racks. On 1756-RM \/ 1756-RMXT the optical link runs at 100 Mbps; on 1756-RM2 \/ 1756-RM2XT the same duplex LC path runs at 1000 Mbps, mirroring program, I\/O image, tag, timer, alarm and communication buffer state between primary and secondary controllers . There is no backplane bus communication velocity licence field on the cable itself; the effective synchronization rate is fixed by the slower of the two terminated RM modules and the fiber grade. Firmware flash compatibility is enforced at the 1756-RM pair, not at the cable: a primary 1756-RM2 and secondary 1756-RMXT, or 1756-RM mixed with 1756-RM2, are rejected by the redundancy manager regardless of a clean 1756-RMC3 optical link . I\/O density scaling of the overall system is unaffected by the 3 m cable length, but 3 m only closes adjacent or neighboring-cabinet rack pairs; longer RM cable assemblies (1756-RMC10 or field-terminated singlemode spans) are required before the 100 m multimode or 10 km singlemode limits are reached.\u003c\/p\u003e\n\u003ch3\u003eOrdering Information\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e1 x 1756-RMC3 3 m duplex LC-to-LC RM fiber optic cable (base assembly)\u003c\/li\u003e\n\u003cli\u003e2 x LC dust caps pre-fitted on both ends on sealed NOS stock\u003c\/li\u003e\n\u003cli\u003e1 x Cable label set for PRIMARY \/ SECONDARY rack identification\u003c\/li\u003e\n\u003cli\u003e1 x Printed cleaning instruction card for LC ferrule wipe before insertion\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eRack-to-Rack Optical Laydown Rules\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eDe-energize both redundant chassis or rely on RM module RIUP only when the exact RM generation and firmware match is already confirmed; never insert a suspected-damaged cord into a live SYNC port\u003c\/li\u003e\n\u003cli\u003eConnect 1756-RMC3 directly between the two RM module optical ports of the same generation; no patch panel, media converter or Ethernet switch is permitted in the path\u003c\/li\u003e\n\u003cli\u003eKeep the 3 m service loop away from 480 VAC tray cable, VFD output duct and welding return conductors; route through separate grounded steel conduit where cabinet separation is not achievable\u003c\/li\u003e\n\u003cli\u003eWipe each LC ferrule with lint-free IPA swab before mating; a contaminated ferrule is the dominant cause of intermittent SYNC LED loss on a previously commissioned redundancy link\u003c\/li\u003e\n\u003cli\u003eDo not kink, staple or zip-tie the jacket below the 30 mm bend radius; a crushed jacket section raises return loss and collapses the redundant channel even when the OK LED is still lit on one side\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eTechnical Questions and Answers\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs 1756-RMC3 a standard LC-LC patch cord usable on a switch?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo. It is a prepopulated RM synchronization cord sized, labeled and validated for the 1756-RM family optical budget. Connecting it to a non-RM port or through a coupler\/switch breaks the ControlLogix redundancy handshake and leaves both chassis non-synchronized.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan 1756-RMC3 link a 1756-RM to a 1756-RM2 across the two racks?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo. 1756-RM and 1756-RM2 are not cross-pairable; the redundancy manager faults on dissimilar module type even with a clean 1756-RMC3 optical link. Primary and secondary must be the same RM generation and firmware major revision .\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes the 3 m length limit system availability?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eOnly mechanically. Electrically the multimode RM link supports up to 100 m on 1756-RM \/ RMXT, and singlemode spans support longer distances on RM2 \/ RM2XT. A 3 m cord simply means the two redundant racks must sit in adjacent or near-adjacent enclosures.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWho carries the switchover delay, the cable or the RM module?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 1756-RMC3 is passive; it adds only propagation delay over 3 m, which is negligible. Primary-to-secondary bumpless takeover is governed by the 1756-RM2 \/ RM2XT synchronization engine, commonly sub-20 ms to sub-50 ms depending on program size and I\/O map .\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan two 1756-RMC3 cords be spliced to make 6 m?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNot recommended. Every added splice, barrel or inline adapter inserts insertion loss and reflectance into a link that has no margin headroom reporting at the cable level. Use a factory 1756-RMC10 or a qualified field-terminated singlemode span instead.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhy does SYNC stay off although both LC ends click home?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eMost often the far-end RM module is not in redundancy mode, the primary\/secondary role is unassigned in Studio 5000, or one LC face is dirty \/ partially seated. The 1756-RMC3 itself has no diagnostics; verify with RM OK \/ SYNC \/ COM LEDs and the redundancy diagnostics object.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDoes XT and non-XT mix work if both use 1756-RMC3?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e1756-RMXT pairs with 1756-RMXT, and 1756-RM2XT pairs with 1756-RM2XT; a wide-temp module does not form a redundant pair with its non-XT sibling merely because the optical cord is inserted. The 1756-RMC3 only closes the physical layer, not the firmware compatibility gate .\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan the cord survive cabinet door flexing over years?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eOnly if the service loop is not loaded by the door hinge. Repeated bending at one point, or trapping the jacket in the door gasket, microfractures the cladding and produces gradual attenuation increase that first appears as periodic COM LED flicker before hard SYNC loss.\u003c\/p\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":46066422087853,"sku":"1756-RMC3","price":88.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0733\/1613\/9181\/files\/allen-bradley_1756-rmc3_1.jpg?v=1786892880","url":"https:\/\/www.maxwellplc.com\/ru\/products\/allen-bradley-1756-rmc3-3-m-rm-fiber-optic-cable-controllogix-redundancy-system","provider":"Maxwell PLC Ltd","version":"1.0","type":"link"}