{"product_id":"1746-a4-allen-bradley-slc-4-slots-chassis","title":"1746-A4 | Allen Bradley  | SLC 4 Slots Chassis","description":"\u003cp\u003e\u003cstrong\u003eAllen Bradley 1746-A4 SLC 4 Slots Chassis\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe \u003cstrong\u003eAllen Bradley 1746-A4\u003c\/strong\u003e, also cataloged as the \u003cstrong\u003e1746-A4\u003c\/strong\u003e chassis module, operates as a dedicated 4‑slot frame for housing SLC 500 PLC and I\/O modules within 1746\/1747 system architectures.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eHardware Specifications\u003c\/strong\u003e\u003c\/p\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\u003cth\u003e\u003cstrong\u003eModel\u003c\/strong\u003e\u003c\/th\u003e\n\u003ctd\u003e1746-A4\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003e\u003cstrong\u003eBrand\u003c\/strong\u003e\u003c\/th\u003e\n\u003ctd\u003eAllen Bradley\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003e\u003cstrong\u003eOrigin\u003c\/strong\u003e\u003c\/th\u003e\n\u003ctd\u003eNot specified\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003e\u003cstrong\u003eWeight\u003c\/strong\u003e\u003c\/th\u003e\n\u003ctd\u003eNot specified\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003e\u003cstrong\u003eDimensions\u003c\/strong\u003e\u003c\/th\u003e\n\u003ctd\u003eNot specified\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003e\u003cstrong\u003eOperating Temp\u003c\/strong\u003e\u003c\/th\u003e\n\u003ctd\u003e0 deg C to 60 deg C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003e\u003cstrong\u003ePower Consumption\u003c\/strong\u003e\u003c\/th\u003e\n\u003ctd\u003eNot applicable (passive chassis)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003e\u003cstrong\u003eCore Performance Indicators\u003c\/strong\u003e\u003c\/th\u003e\n\u003ctd\u003e4-slot chassis for SLC 500 PLC \u0026amp; I\/O modules\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cstrong\u003eBackplane Bus Communication Velocity \u0026amp; I\/O Density Scaling\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003eThe 1746-A4 chassis provides the mechanical and electrical backplane required for SLC 500 module communication. Its 4-slot configuration supports deterministic scan cycles by maintaining stable backplane impedance and ensuring predictable module arbitration. When paired with Allen Bradley processors, the chassis enables scalable I\/O density without compromising communication timing. Firmware flash compatibility is determined by the installed CPU, as the chassis itself contains no programmable logic.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eFrequently Asked Questions\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Can modules be hot-swapped in the 1746-A4 chassis\u003c\/strong\u003e A: SLC 500 modules generally require the chassis to be de‑energized before removal or insertion to avoid backplane faults.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Does the chassis impose current limits on installed modules\u003c\/strong\u003e A: Current limits are defined by the power supply, not the chassis. The 1746-A4 provides only the mechanical and electrical backplane.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Are Series B and Series C modules compatible with this chassis\u003c\/strong\u003e A: Yes. The 1746-A4 supports standard SLC 500 module families across multiple series revisions.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eField Installation Guidelines\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cp\u003eEnsure proper seating of modules to avoid bent backplane pins or intermittent communication.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eMaintain adequate ventilation around the chassis to support module thermal dissipation.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eRoute high-voltage wiring separately from low-level signal conductors to reduce noise coupling.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eVerify power supply alignment and secure mounting before energizing the system.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp\u003eKeep humidity within 5–95% non-condensing to prevent terminal oxidation.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Allen-Bradley","offers":[{"title":"Default Title","offer_id":43822895431754,"sku":"1746-A4","price":230.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0587\/8569\/3770\/files\/1771-A1B_3.png?v=1784540985","url":"https:\/\/www.topbrandsplc.com\/products\/1746-a4-allen-bradley-slc-4-slots-chassis","provider":"Topbrands PLC Limited","version":"1.0","type":"link"}