The 1746-IB8 SLC 500 Digital DC Input Module by Allen-Bradley is a DC input module in the SLC 500 I/O module series with eight 24V DC current sinking inputs. The 1746-IB8 has an operational voltage range between 10 and 30V DC with its nominal voltage at 24V DC and it has a backplane current of 50mA at 5V DC and of 0.0mA at 24V DC. The maximum signal delay time on each input point of the module is about 8ms for ON mode and 8ms for OFF mode, and the maximum OFF state voltage in the circuit is 5.0V DC. The 1746-IB8 has a maximum OFF-state current of 1mA, and when operational, its nominal input current is 8mA at 24V DC. 

The 1746-IB8 module has a maximum of 0.27W power dissipation on each output point and the total heat dissipation of the module is 1.3W with 4.4 BTU per hour of thermal dissipation. It has a Dielectric withstand of 1500V AC and an isolation between the communication circuits tested at 500V and between backplane-and-inputs at 1500V AC. The 1746-IB8 module has an operating temperature range between 0 and 60 °C (32 and 140 °F) at 5-95% non-condensing humidity. It has an operational vibration of 2.5G at 57-500Hz and a shock rating of 30G. The 1746-IB8 is UL and CE-certified and has a NEMA standard ICS 2-230-tested Noise Immunity.