The Allen-Bradley 1794-IJ2XT module is a digital 2-point 24 Volts DC input frequency module with extended temperature support for 1794 FLEX I/O systems. The FLEX I/O system is a modular I/O system and it contains 3 components which are the adapter, terminal base, and I/O module. The 1794-IJ2XT module is basically a tachometer that is capable of reporting direction, acceleration, and frequency. It supports 2 frequency inputs, 2 gate inputs, and 2 outputs. The input devices can be magnetic pickups, flowmeters, incremental encoders, and proximity detectors. The module outputs are activated by alarms. The 1794-IJ2XT module supports 2 input channels with a frequency and gate input per channel. The maximum input frequency supported is 32 kilohertz. The input pulse width is 20 microseconds. The nominal on-state voltage for magnetic pickup is 500 millivolts. For switch input, it is 24 Volts DC, for the vortex flowmeter (low range), it is less than 3 Volts, and for the vortex flowmeter (high range), it is greater than 6 Volts.

The minimum on-state voltage of the 1794-IJ2XT module is 10 Volts. The maximum on-state voltage is limited to an isolated 24 Volts DC power supply. The minimum, nominal, and maximum on-state current values are 2 milliamps, 9 milliamps, and 10 milliamps. The frequency input impedance for magnetic pickup is greater than 5 kiloohms and for both the low-range vortex flowmeter and the high-range vortex flowmeter is greater than 10 kiloohms. The dimensions of the 1794-IJ2XT module are 94 x 94 x 69 millimeters. The nominal power supply voltage is 24 Volts and the range of input voltage is from 21.6 to 26.4 Volts DC. The maximum supply current range is 0 to 60 milliamps at 24 Volts DC.