{"product_id":"allen-bradley-1785-lt3-plc-5-12-processor-module","title":"Allen Bradley 1785-LT3 PLC-5\/12 Processor Module","description":"\u003ch3\u003eProduct Overview\u003c\/h3\u003e\n\u003cp\u003eThe\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003eAllen Bradley 1785-LT3\u003c\/strong\u003e, also known as the PLC-5\/12 processor, functions as the central intelligence unit for 1771 Universal I\/O systems. It manages complex control logic, executes high-speed data processing, and coordinates communication across multiple industrial networks. We provide this unit as\u003cspan\u003e \u003c\/span\u003e\u003cstrong\u003e100% Brand New\u003c\/strong\u003e, original factory stock, ensuring the highest level of performance for legacy system maintenance and critical infrastructure upgrades.\u003c\/p\u003e\n\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\n\u003cp\u003eThe 1785-LT3 delivers high-density I\/O management within a ruggedized single-slot module.\u003c\/p\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr class=\"firstRow\"\u003e\n\u003ctd\u003e\u003cstrong\u003eFeature\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cstrong\u003eSpecification\u003c\/strong\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003e\u003cstrong\u003eManufacturer\u003c\/strong\u003e\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eAllen Bradley (Rockwell Automation)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003e\u003cstrong\u003eUser Memory\u003c\/strong\u003e\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e6 Kilowords SRAM\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003e\u003cstrong\u003eTotal I\/O (Max)\u003c\/strong\u003e\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e512 (Any mix of Input\/Output)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003e\u003cstrong\u003eMax Analog I\/O\u003c\/strong\u003e\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e3072\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003e\u003cstrong\u003eCommunication Channels\u003c\/strong\u003e\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eData Highway Plus (DH+), Remote I\/O (Scanner or Adapter)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003e\u003cstrong\u003eSerial Ports\u003c\/strong\u003e\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e1 (RS-232-C \/ 422-A \/ 423-A)\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003e\u003cstrong\u003eBackplane Current\u003c\/strong\u003e\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e2.5 Amps @ 5V DC\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003e\u003cstrong\u003eMax Remote I\/O Racks\u003c\/strong\u003e\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e32 Per Link\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003e\u003cstrong\u003eScan Time (RIO)\u003c\/strong\u003e\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003e3 ms @ 230.4 kbits\/s\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cspan\u003e\u003cstrong\u003eExpansion Port\u003c\/strong\u003e\u003c\/span\u003e\u003c\/td\u003e\n\u003ctd\u003e\u003cspan\u003eControl Coprocessor Expansion Port included\u003c\/span\u003e\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003eEngineering Advantages\u003c\/h3\u003e\n\u003cul class=\"list-paddingleft-2\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eOptimized I\/O Throughput:\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eThe 1785-LT3 offers variable baud rates for Remote I\/O scanning. By utilizing the 230.4 kbits\/s setting, engineers reduce rack scan times to just 3 ms, significantly improving the responsiveness of time-critical PID loops and high-speed motion triggers.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eVersatile Network Bridging:\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eIntegrated DH+ and Remote I\/O channels allow the processor to operate as both a network master and a peer-to-peer node. This eliminates the need for external bridging hardware when connecting the processor to HMIs or other PLC-5 controllers.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eRugged Memory Protection:\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eThe 6 Kiloword SRAM utilizes battery-backed protection to prevent data loss during power outages. This ensures that recipe parameters, counter values, and system states remains intact without requiring constant EEPROM burns.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eExpanded Serial Compatibility:\u003c\/strong\u003e\u003cspan\u003e \u003c\/span\u003eThe multi-protocol serial port (RS-232\/422\/423) facilitates direct connection to legacy SCADA systems, barcode readers, and serial printers. This onboard flexibility removes the cost and complexity of dedicated ASCII modules.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eFAQs\u003c\/h3\u003e\n\u003cul class=\"list-paddingleft-2\"\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eCan the 1785-LT3 handle analog-heavy applications?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYes. While the total I\/O limit is 512, the processor supports up to 3072 max analog I\/O points through block transfer programming. This makes it highly effective for water treatment and chemical processing plants requiring extensive sensor monitoring.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eWhat is the primary difference between the 1785-LT3 and other PLC-5 processors?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 1785-LT3 (PLC-5\/12) targets small-to-medium applications. It offers 6KW of memory, whereas higher-tier models like the 1785-L40 provide larger memory capacities. However, it retains the full instruction set and communication flexibility of the more expensive units.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eDoes this processor require a specific chassis?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 1785-LT3 installs into the left-most slot (Slot 0) of any 1771 Universal I\/O Chassis. Ensure your power supply (e.g., 1771-P4 or P7) can provide the 2.5A current required specifically by this processor.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003e\u003cstrong\u003eHow do I configure the communication baud rates?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eYou set the DH+ and Remote I\/O baud rates via physical DIP switches located on the side of the module. Ensure you configure these switches while the power is off to prevent communication errors during startup.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":52788026573109,"sku":"1785-LT3","price":66.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0973\/7630\/5461\/files\/1785-LT3.png?v=1777259601","url":"https:\/\/www.5gplc.com\/products\/allen-bradley-1785-lt3-plc-5-12-processor-module","provider":"High Five PLC Solution Limited","version":"1.0","type":"link"}