AI3281 module supports 32-point two-wire and four-wire 4~20mA AI signal inputs, and the module uses TMR architecture, the redundant three channels are designed on the same module. AI3281 is connected to PM01 and FTA via connectors fixed on the backplane. Each AI3281 has two FTAs, where there are 16 points in each FTA. When AI3281 is configured in dual redundant, two redundant modules share the FTA. AI3281 Model has extensive diagnostics on each channel, module, and functional circuit immediately detect and report operational faults by means of indicators or alarms. AI3281 module supports HART communication with the instruments which has HART function.