{"product_id":"1771-nbsc-allen-bradley-plc-5-high-resolution-isolated-analog-combination-module","title":"1771-NBSC Allen-Bradley PLC-5 High Resolution Isolated Analog Combination Module","description":"\u003cp\u003eThe \u003cstrong\u003eAllen-Bradley 1771-NBSC\/A\u003c\/strong\u003e, also cataloged as the \u003cstrong\u003e1771-NBSC\u003c\/strong\u003e High Resolution Isolated Analog Combination Module, executes 6-channel 4-20 mA input acquisition and 2-channel 0-25 mA output drive across PLC-5 1771 backplane I\/O image tables .\u003c\/p\u003e\n\u003ch3\u003eCatalog Number and Spare Cross-Reference\u003c\/h3\u003e\n\u003cfigure class=\"table\"\u003e\n\u003ctable\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth\u003eMarking\u003c\/th\u003e\n\u003cth\u003eMeaning\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e1771-NBSC\u003c\/td\u003e\n\u003ctd\u003eBase catalog number, N-series high-resolution isolated analog combo module\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e1771-NBSC\/A\u003c\/td\u003e\n\u003ctd\u003eRevision A hardware\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e1771NBSC\u003c\/td\u003e\n\u003ctd\u003eNon-hyphenated nameplate \/ BOM string\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e1771-NBSC listed as discontinued\u003c\/td\u003e\n\u003ctd\u003eManufacturer end-of-life, no new production\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/figure\u003e\n\u003ch3\u003eElectrical and Mechanical Data\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\u003e1771-NBSC\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\u003e0.66 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eShipping Dimensions\u003c\/td\u003e\n\u003ctd\u003e3.2 x 15.5 x 25.5 cm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eModule Class\u003c\/td\u003e\n\u003ctd\u003e1771 N-Series High Resolution Isolated Analog Combination Module\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAnalog Inputs\u003c\/td\u003e\n\u003ctd\u003e6 x 4-20 mA sourced \/ sinking current loops\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eAnalog Outputs\u003c\/td\u003e\n\u003ctd\u003e2 x 0-25 mA current outputs (some older catalogs list 4-20 mA; verify by module legend \/ jumper)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eResolution\u003c\/td\u003e\n\u003ctd\u003e12 bit (per N-series analog conversion class)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eIsolation\u003c\/td\u003e\n\u003ctd\u003eChannel-to-backplane and input\/output galvanic isolation, N-series barrier topology\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBackplane 5 VDC Load\u003c\/td\u003e\n\u003ctd\u003e3.0 A max from 1771 chassis backplane\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOperating Temp\u003c\/td\u003e\n\u003ctd\u003e0 to 55 deg C ambient, chassis mounted\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eMounting\u003c\/td\u003e\n\u003ctd\u003eSingle-slot 1771 I\/O rack, keyed slot\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eStatus\u003c\/td\u003e\n\u003ctd\u003eDiscontinued by manufacturer\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eTariff Code\u003c\/td\u003e\n\u003ctd\u003e8538907080\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/figure\u003e\n\u003ch3\u003eBackplane Bus Transfer and I\/O Density Scaling\u003c\/h3\u003e\n\u003cp\u003eThe 1771-NBSC transfers converted analog words into the PLC-5 processor data table through the 1771 parallel backplane I\/O scan, not through EtherNet\/IP or DeviceNet. Backplane bus communication velocity licences are absent on 1771 N-series hardware; scan update is governed by the local chassis adapter and the processor sweep time. I\/O density scaling is limited by the 3.0 A 5 VDC backplane draw of this module plus the sum of all co-installed 1771 modules against the rack power supply. No field-flashable firmware resides in 1771-NBSC; electronic keying is resolved by the processor I\/O configuration file and the module hardware ID pins, so revision A replacement is accepted only when keying is set to compatible or disabled. Remote termination is performed via 1771-NC6 (1.82 m) or 1771-NC15 (4.56 m) cable to a 1771-RTP4 panel, which physically separates field wiring from the rack slot .\u003c\/p\u003e\n\u003ch3\u003eOrdering Information\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e1 x 1771-NBSC module (base unit, revision A or B subject to available NOS stock)\u003c\/li\u003e\n\u003cli\u003e1 x 1771-NC6 6 ft \/ 1.82 m N-series analog remote termination cable, where remote panel is used\u003c\/li\u003e\n\u003cli\u003e1 x 1771-RTP4 remote termination panel, where panel-mount field wiring is required\u003c\/li\u003e\n\u003cli\u003e1 x Module-to-chassis keying strip, pre-seated on new-old-stock units\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eRack and Field-Wiring Practice\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eInsert module only after 1771 chassis 5 VDC backplane power and AC\/dc auxiliary supply are removed\u003c\/li\u003e\n\u003cli\u003eRun 4-20 mA input twisted pair inside shielded cable; drain shield to 1771-RTP4 ground stud, not to both ends\u003c\/li\u003e\n\u003cli\u003eFeed two-wire transmitters from the N-series loop power terminals; do not parallel external 24 VDC onto sourced inputs\u003c\/li\u003e\n\u003cli\u003eKeep 0-25 mA output lines separated from input loops to preserve galvanic isolation boundary\u003c\/li\u003e\n\u003cli\u003eConfirm chassis frame ground impedance to panel before applying process-loop power\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eIs 1771-NBSC hot-swappable in a live PLC-5 rack?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo. 1771 analog modules are not RIUP-capable. Extracting or inserting the module with backplane power applied can arc the 5 VDC logic connector and force a chassis major fault. Remove rack power first.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhy do some catalogs show 2 x 4-20 mA while the nameplate shows 0-25 mA?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eN-series combo modules support multiple output ranges through internal scaling and termination. Where the physical module legend reads 0-25 mA, honor that. Older Rockwell selection tables sometimes compressed the N-family into a generic 4-20 mA column .\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat backs up the 12-bit input conversion claim?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e12-bit conversion aligns with the N-series high-resolution analog class for 4-20 mA current inputs . Final scaling into engineering units is done in the PLC-5 data-table words via the application program, not inside the module.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHow much backplane current does one 1771-NBSC consume?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe module draws up to 3.0 A from the 1771 chassis 5 VDC backplane rail . In an 8-slot or 16-slot rack, total installed-module backplane load must remain under the 1771 power supply rating before adding digital I\/O.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eAre input channels individually isolated from each other?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNo. The N-series provides galvanic isolation between the field side and the 5 VDC backplane logic, and between analog field power and processor bus; intra-channel input grouping follows the 1771-NBSC internal barrier map, not full point-to-point isolation.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCan a 1771-NBSC\/A replace a failed 1771-NBSC without program change?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eIf the PLC-5 I\/O configuration keying is set to compatible, yes. If exact keying is enforced, the processor compares the returned module ID and faults on mismatch until the configuration is edited or keying relaxed.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat happens to outputs on loss of field 24 VDC but intact backplane 5 VDC?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eOutput drive amplifiers lose loop compliance voltage and both 0-25 mA outputs go to 0 mA. The module remains logically addressed on the backplane, but no current sinks or sources to the actuator until field power returns.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eIs external surge protection required on 4-20 mA inputs?\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eNot internally provided beyond the N-series isolation barrier. In environments with long field runs past VFD panels or switchgear, fit external current-loop suppressors on the 1771-RTP4 entry terminals to limit transient coupling into the analog front end.\u003c\/p\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":46066443649197,"sku":"1771-NBSC","price":88.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0733\/1613\/9181\/files\/allen-bradley_1771-nbsc_1.jpg?v=1786890912","url":"https:\/\/www.maxwellplc.com\/ru\/products\/1771-nbsc-allen-bradley-plc-5-high-resolution-isolated-analog-combination-module","provider":"Maxwell PLC Ltd","version":"1.0","type":"link"}