Allen Bradley 1746-NT4 SLC 500 Thermocouple/mV Analog Input Module

The Allen Bradley 1746-NT4 is a Thermocouple/mV Input Module for an SLC 500 system. It provides all SLC 500 processors with a digitally converted thermocouple or millivolt (mV) analog data, received and stored in its image table. It does not require any external power supply as it receives 5 Volts DC and 24 Volts DC power from the SLC 500 power supply through its backplane. It has two cold-junction compensation (CJC) sensors instead of offset voltages to retain thermocouple input signal accuracy. Block transfers are required by this module in a remote I/O configuration. It interfaces to thermocouple types J, K, T, E, R, S, B, and N, and accepts direct +/-50 mV and +/-100 mV analog input signals. The 1746-NT4 module auto calibrates at power-up and whenever a channel is enabled. It has 5 green LED status indicators, one for module status and one for each of the four channels.

The 1746-NT4 module has 4 backplane isolated input channels. It has a backplane current consumption of 60 mA at 5 Volts DC and 40 mA at 24 Volts DC. It has a backplane power consumption of 0.3 Watts at 5 Volts DC and 0.5 Watts at 2 Volts DC, a 16-bit converter resolution, and a 12 to 300 millisecond Step response at 95%. It has a bandwidth of 2.62 - 65.5 Hertz and a 26 millisecond - 1.2 second update period and uses sigma-delta modulation for A/D conversion. It can be installed in any slot except slot 0 of the SLC 500 chassis. It uses two wires per terminal with a maximum wire size of 2.5 millimeters (14 AWG) and 25 ohms maximum cable impedance. For Thermocouple inputs, use shielded twisted thermocouple extension wire; for mV inputs, Belden 8761 or equivalent wire must be used.