1794-OF4I

The Allen-Bradley 1794-OF4I is a FLEX I/O analog module. It has 4 isolated analog outputs that is compatible with several terminal base units, namely the 1794-TBT, 1794-TB3, 1794-TB3TS, 1794-TB3S, 1794-TBNF, and the 1794-TBN. It can be mounted using a DIN rail or a panel, it has an open enclosure, and it measures 3.7 x 2.6 x 3.7 inches.

The external DC voltage range of the 1794-OF4I module is 19.2 to 31.2 Volts DC, including the 5% AC ripple. It also has an external DC power supply current of 210 mA at 24 Volts DC. Its maximum overload is 30 Volts or 32 mA continuous in one channel at a time. This module has a maximum 3 mA current load on voltage output and a 0 to 750 resistive load on voltage output. Its output current ranges are 4 to 20 mA and 0 to 20 mA. Both of these ranges are user-configurable. The module's output voltage varies from +/-10 Volts, +/-5 Volts, 0 to 10 Volts, and 0 to 5 Volts, all of which are also user-configurable. Both the voltage and current terminals have 0 output until the module is configured.

The 1794-OF4I has a maximum power dissipation of 4.7 W at 31.2 Volts DC and a maximum thermal dissipation of 16 BTU/hour at 31.2 Volts DC. The module's isolation voltage is dependent on the terminal base unit it is connected to. It has an isolation rating of 250 Volts continuous when using a 1794-TBN base unit and 120 Volts continuous when using other compatible base units. The FlexBus voltage of the module is 5 Volts DC, while the FlexBus current is 50 mA. It has a resolution of 15 bits + sign, 0.320 mV/cnt (voltage), and 0.656 mA/cnt (current). It also has an update rate of 2.5 or 5 milliseconds for all channels and a <25 µs step response at 63% of full scale. Both the voltage and current terminals have an absolute accuracy of 0.1% full scale at 25 degrees Celsius but they have different accuracy drifts with temperature, since it is 0.0012% full scale per degree Celsius for the voltage terminal and 0.0025% full scale per degree Celsius for the current terminal. The conversion type for the 1794-OF4I is digital-to-analog.

This module has digital to analog (DAC) conversion resolution of 15 bits plus sign or 0.320 mV/cnt for Voltage signal and for Current signal 0.656 mA/cnt. This module has output signal update rate of 2.5 ms or 5.0 ms on all channels which may be configured to all channels. The module’s step response to 63% full scale is < 25 s with current load on voltage output of 3 mA.

The module’s absolute accuracy is 0.1% full scale @ 25 °C for both voltage and current terminal with accuracy drift of 0.0012% full scale/°C for voltage and 0.0025% full scale/°C for current. This module is factory calibrated and provides an option to manually calibrated if necessary. It has a maximum overload of 30V continuous or 32 mA continuous, one channel at a time.

The 1794-OF4I is compatible for use with terminal base units such as 1794-TB2, 1794-TB3, 1794-TB3S, 1794-TB3T, 1794-TB3TS, 1794-TBN. It requires a FlexBus voltage of 5VDC and FlexBus current of 50 mA. For external power supply, nominal supply voltage is 24VDC with applicable voltage range of 19.2-31.2 VDC.

The 1794-OF4I is mounted to a DIN rail or directly to the enclosure sub-panel. It may be used with any available Flex I/O communication adapter and approved for use in hazardous locations.