{"product_id":"relay-output-module-abb-do821-3bse013250r1-s800","title":"Relay Output Module | ABB DO821 3BSE013250R1 S800","description":"\u003ch2\u003eABB DO821 3BSE013250R1 Digital Output Module\u003c\/h2\u003e\n\u003cp\u003eThe \u003cstrong\u003eABB DO821\u003c\/strong\u003e, also cataloged as the \u003cstrong\u003eDO821\u003c\/strong\u003e Digital Output Module, operates as a dedicated hardware component for relay-isolated actuator and contactor control within S800 I\/O platforms. It provides direct physical switching of external AC and DC circuits while maintaining total electrical separation from the logical controller.\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\u003e\u003cstrong\u003eParameter\u003c\/strong\u003e\u003c\/th\u003e\n\u003cth\u003e\u003cstrong\u003eSpecification\u003c\/strong\u003e\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\u003eDO821\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eBrand\u003c\/td\u003e\n\u003ctd\u003eABB\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOrigin\u003c\/td\u003e\n\u003ctd\u003eSweden\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eWeight\u003c\/td\u003e\n\u003ctd\u003e0.32 kg\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDimensions\u003c\/td\u003e\n\u003ctd\u003e119 x 45 x 102 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOperating Temp\u003c\/td\u003e\n\u003ctd\u003e0 to +55 deg C\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003ePower Consumption\u003c\/td\u003e\n\u003ctd\u003e2.9 W typical (derived from backplane bus)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOutput Channels\u003c\/td\u003e\n\u003ctd\u003e8 individually isolated channels\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOutput Contact Type\u003c\/td\u003e\n\u003ctd\u003eRelay, normally closed (NC)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOutput Voltage Range\u003c\/td\u003e\n\u003ctd\u003e24 - 230 V AC\/DC\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eOutput Current Rating\u003c\/td\u003e\n\u003ctd\u003eUp to 3 A per channel\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eDC Load Capacity\u003c\/td\u003e\n\u003ctd\u003e42 W per channel\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRequired MTUs\u003c\/td\u003e\n\u003ctd\u003eTU811, TU813, TU831, TU836, TU837, TU851\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/figure\u003e\n\u003ch3\u003eS800 Backplane Bus Communication and Output Mapping\u003c\/h3\u003e\n\u003cp\u003eThe DO821 maps its 8 discrete output bits directly over the S800 I\/O backplane bus to control internal relay coils. The module features localized I\/O density scaling, enabling dense terminal grouping on a single rack without sacrificing heat dissipation margins. Power consumption on the backplane is monitored continuously, while onboard firmware controls the synchronization of relay transitions to reduce peak bus current draw during simultaneous block switching.\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003eQ: Are there diagnostic indicators on the face of the DO821 module?\u003c\/p\u003e\n\u003cp\u003eA: Yes. The front panel features LED indicators for module status (Fault, Run, Warning) alongside eight dedicated yellow channel status LEDs that reflect the real-time physical state of each relay output contact.\u003c\/p\u003e\n\u003cp\u003eQ: Can different voltage potentials be applied to adjacent output channels?\u003c\/p\u003e\n\u003cp\u003eA: Yes. Each of the eight relay channels is individually galvanically isolated, allowing the mixing of diverse external control voltages (such as 24 VDC and 230 VAC) across different channels on the same module.\u003c\/p\u003e\n\u003cp\u003eQ: How is backplane bus noise prevented during high-inductive switching?\u003c\/p\u003e\n\u003cp\u003eA: Physical galvanic isolation barriers block any voltage spikes, flyback EMF, or surge transients from crossing back into the low-voltage logic side of the S800 backplane.\u003c\/p\u003e\n\u003ch3\u003eField Installation Guidelines\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eConfirm the S800 rack and associated Module Termination Unit (MTU) are securely mounted to the grounded DIN rail before sliding the DO821 module onto its mate.\u003c\/li\u003e\n\u003cli\u003eVerify the field supply breaker is switched off before terminating wiring on the MTU terminal blocks.\u003c\/li\u003e\n\u003cli\u003eInstall external arc-suppression components (such as RC snubbers for AC loads or freewheeling diodes for DC loads) across highly inductive external actuator coils to protect the internal relay contacts from premature erosion.\u003c\/li\u003e\n\u003cli\u003eRoute high-current field AC\/DC output lines through separate cable trunking away from low-voltage communication buses to prevent capacitive signal coupling.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"ABB","offers":[{"title":"Default Title","offer_id":43865700106339,"sku":"DO821 3BSE013250R1","price":676.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0583\/5246\/8067\/files\/154_93b9d88e-df07-47e2-84b3-6dd7c36e8589.jpg?v=1764582043","url":"https:\/\/www.autocontrolglobal.com\/products\/relay-output-module-abb-do821-3bse013250r1-s800","provider":"AutoControl Global","version":"1.0","type":"link"}