AB 1794-IR8 Flex 8 Point RTD Input Module

The Allen-Bradley 1794-IR8 is a Flex I/O analog input module, Specifically, this module is a Resistance Temperature Detector (RTD) that is particularly used in temperature applications.

The 1794-IR8 has an RTD excitation current of 718.36?A.It has a resolution of 16 bits across 435 ohms and accuracy of 0.05% full scale in normal mode and 0.01% full scale in enhanced mode. The module converts the analog data into digital format and stores it to a 16-bit register with data format of 16-bit 2’s complement or offset binary (unipolar). The module has system throughput of 325ms (1 channel scanned), programmable to 28ms 2.6s (8 channels scanned), programmable to 224ms under normal mode and programmable from 56 to 650ms/channel - 650ms (1 channel scanned), 2.925s (8 channels scanned) in enhanced mode.

The 1794-IR8’s RTD excitation current is 718.36 µAmps. It comes with an accuracy of 0.05% full scale, which is the maximum in the normal mode, and 0.01% full scale, which is typical in the enhanced mode at low humidity without calibration. It has 0 Volts common mode input range and a common mode rejection of -120 dB at 60 Hertz and -100 dB at 50 Hertz with A/D filter cutoff at 10 Hertz. The normal mode rejection ratio of the terminal is -60 dB at 60 Hertz for A/D filter cutoff at 10 Hertz. The 1794-IR8 module also has a channel bandwidth of 0 to 2.62 Hertz or -3 dB, a maximum power dissipation of 3 Watts at 31.2 Volts DC, and a thermal dissipation of 10.2 BTU/hour, also at 31.2 Volts DC. The 1794-IR8’s cold junction compensation range is from -20 to 100 degrees Celsius. The 1794-IR8 has a signal input range of 1 to 433 Ohms and an overvoltage capacity of 35 Volts DC and 25 Volts AC, which is continuous at 25 degrees Celsius. Its isolation voltage has been tested for 60 seconds at 707 Volts DC from the inputs and user power to the logic side. The 1794-IR8 module has a current certification of 140 mA, a current specification of 150 mA at 24 Volts DC, and voltage specifications of 24 Volts DC nominal, 19.2 to 31.2 Volts DC that includes the 5% AC ripple and for ambient temperatures of less than 40 degrees Celsius, and 24 Volts DC maximum for ambient temperatures that are equal to 55 degrees Celsius.