{"product_id":"allen-bradley-1785-bcm-c-backup-communication-module","title":"Allen-Bradley 1785-BCM\/C Backup Communication Module","description":"\u003ch2\u003eAllen-Bradley 1785-BCM\/C Backup Communication Module\u003c\/h2\u003e\n\u003cp\u003eThe \u003cstrong\u003eAllen-Bradley 1785-BCM\/C\u003c\/strong\u003e, also cataloged as the \u003cstrong\u003e1785-BCM\/C\u003c\/strong\u003e Backup Communication Module, operates as a dedicated hardware component for redundant PLC-5 processor coordination within 1771 I\/O chassis control platforms.\u003c\/p\u003e\n\u003ch3\u003eHardware Specifications\u003c\/h3\u003e\n\u003cfigure class=\"table\"\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\u003e1785-BCM\/C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBrand\u003c\/td\u003e\n\u003ctd\u003eAllen-Bradley\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\u003e0.6 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOperating Temp\u003c\/td\u003e\n\u003ctd\u003e0 to 60 deg C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower Consumption\u003c\/td\u003e\n\u003ctd\u003e5 VDC backplane current draw: 1.0 A\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eProduct Type\u003c\/td\u003e\n\u003ctd\u003eBackup Communication Modules\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCompatible Processors\u003c\/td\u003e\n\u003ctd\u003ePLC-5\/15 Series B, PLC-5\/20, PLC-5\/25, PLC-5\/30, PLC-5\/40, PLC-5\/60\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eInstallation Location\u003c\/td\u003e\n\u003ctd\u003e1771 I\/O chassis local installation\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCommunication Interface\u003c\/td\u003e\n\u003ctd\u003eHigh-Speed Serial Link (HSSL)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCommunication Speed\u003c\/td\u003e\n\u003ctd\u003e1.2 Megabaud\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCustomer Relay Output\u003c\/td\u003e\n\u003ctd\u003e0.25 A at 24 VDC resistive load\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eKeying Positions\u003c\/td\u003e\n\u003ctd\u003eBetween 8-10\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWiring Arm Compatibility\u003c\/td\u003e\n\u003ctd\u003e1771-WG\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eStorage Temperature\u003c\/td\u003e\n\u003ctd\u003e-40 to 85 deg C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRelative Humidity\u003c\/td\u003e\n\u003ctd\u003e5-95% non-condensing\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eCertifications\u003c\/td\u003e\n\u003ctd\u003eUL Listed, CSA Class 1 Division 2\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDiagnostics\u003c\/td\u003e\n\u003ctd\u003eStatus indicators and system status word bits\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/figure\u003e\n\u003ch3\u003eIndustrial Control Network Interface Characteristics\u003c\/h3\u003e\n\u003cp\u003eThe 1785-BCM\/C provides PLC-5 redundancy communication through a dedicated High-Speed Serial Link (HSSL) interface. The module exchanges synchronization data between primary and backup PLC-5 processors to support automatic controller transfer functions.\u003c\/p\u003e\n\u003cp\u003eThe module operates through the 1771 chassis backplane interface and maintains processor status monitoring through hardware diagnostics. The design supports bumpless switchover behavior by transferring control coordination between paired PLC-5 processors without requiring additional I\/O capacity or processor execution resources.\u003c\/p\u003e\n\u003cp\u003eThe 1785-BCM\/C integrates with PLC-5 automation architectures using defined backplane communication paths and controller health monitoring. The module supports fault detection through status indicators and system status word information.\u003c\/p\u003e\n\u003ch3\u003eFirmware and PLC-5 Redundancy Interface Characteristics\u003c\/h3\u003e\n\u003cp\u003eThe 1785-BCM\/C is configured for PLC-5 Series redundant control systems and uses HSSL communication at 1.2 Megabaud for processor-to-processor data exchange. Firmware compatibility must match the installed PLC-5 processor configuration and redundancy system requirements.\u003c\/p\u003e\n\u003cp\u003eThe module provides communication coordination only and does not increase controller memory, processor performance, or local I\/O capacity. Correct chassis keying and wiring arm installation are required for proper hardware integration.\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003eQ: What PLC-5 processors are compatible with the 1785-BCM\/C?\u003cbr\u003eA: The module supports PLC-5\/15 Series B, PLC-5\/20, PLC-5\/25, PLC-5\/30, PLC-5\/40, and PLC-5\/60 processors.\u003c\/p\u003e\n\u003cp\u003eQ: What is the backplane current requirement of the 1785-BCM\/C?\u003cbr\u003eA: The module requires 1.0 A from the 5 VDC 1771 chassis backplane supply.\u003c\/p\u003e\n\u003cp\u003eQ: Does the 1785-BCM\/C add PLC processing or I\/O functions?\u003cbr\u003eA: No. The module provides backup communication and redundancy management functions only.\u003c\/p\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003cp\u003eInstall the 1785-BCM\/C in an appropriate 1771 I\/O chassis slot using the specified keying position and compatible 1771-WG wiring arm. Confirm chassis power availability before module installation.\u003c\/p\u003e\n\u003cp\u003eConnect redundancy communication wiring according to the PLC-5 backup configuration. Separate communication wiring from high-voltage conductors, motor cables, and switching equipment to reduce electrical interference.\u003c\/p\u003e\n\u003cp\u003eVerify front-panel status indicators and PLC-5 system status information after startup. Maintain installation conditions within the specified operating temperature and humidity limits. Ensure processor firmware and redundancy configuration compatibility before placing the system into operation.\u003c\/p\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":43738643759194,"sku":"1785-BCM\/C","price":123.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0612\/4601\/3530\/files\/1785-BCMB1.jpg?v=1785133410","url":"https:\/\/www.plcmasters.com\/products\/allen-bradley-1785-bcm-c-backup-communication-module","provider":"PLC Masters Ltd.","version":"1.0","type":"link"}