ABB DO820 3BSE008514R1 Digital Output Relay
Description:
DO820 is an 8 channel 230 V a.c./d.c. relay (NO) output module for the S800 I/O. The maximum output voltage is 250 V a.c./d.c. and the maximum continuous output current is 3 A. All outputs are individually isolated. 

Each output channel consists of optical isolation barrier, output state indication LED, relay driver, relay and EMC protection components. 

The relay supply voltage supervision, derived from the 24 V distributed on the ModuleBus, gives an error signal if the voltage disappears, and the Warning LED turns on. The error signal can be read through the ModuleBus. This supervision can be enabled/disabled with a parameter.

Six different types of MTUs can be used. The TU831/TU851 Extended MTU, TU811 Compact MTU, and TU813 Compact MTU enable two wire connection to the devices without additional terminals. The extended MTUs, TU836, provides an individual fuse (3 A max.) per channel on the load outlet terminals. The extended MTUs, TU837, provides an individual fuse (3 A max.) per channel. Outputs can be individually isolated or grouped by bridging. Signal return terminals are provided in two groups of four terminals. 

Features:
8 channels for 230 V a.c./d.c. relay Normal Open (NO) outputs
8 isolated channels
Output status indicators
OSP sets outputs to predetermined state upon error detection