The DI821 is a 8 channel, 230 V a.c./d.c, digital input module for the S800 I/O. This module has 8 digital inputs. The ac input voltage range is 164 to 264 V and the input current is 11 mA at 230 V a.c. The d.c. input voltage range is 175 to 275 volt and the input current is 1.6 mA at 220 V d.c. The inputs are individually isolated.
Every input channel consists of current limiting components, EMC protection components, input state indication LED, optical isolation barrier and an analog filter (6 ms).
Channel 1 can be used as voltage supervision input for channels 2 – 4, and channel 8 can be used as voltage supervision input for channels 5 – 7. If the voltage connected to channel 1 or 8 disappears, the error inputs are activated and the Warning LED turns on. The error signal can be read from the ModuleBus.