The PLC 1756-OF4 module is a ControlLogix non-isolated output module. It has 4 voltage or current outputs available with a current resolution of 15 bits across 21 mA, 650 nA/bit for a voltage resolution of 16 bits across 10.5V, 320 µV/bit. It requires a 20 pin RTB, or Removable Terminal Block housing for connection to field devices. The compatible RTBs are the 1756-TBSH and the 1756-TBNH. It is important to ensure that the chassis and power supply have already been installed and grounded prior to installing the module to it with the RTB.
The 1756-OF4 module has voltage and current ratings of 5.1V DC for the backplane, a maximum of 150 milliamps for 24V DC. It has a current draw of 150 milliamps at 5.1V and 120 milliamps at 24V and a total backplane power of 5.8 W. Its power consumption is 3.7 W of backplane power and its overvoltage protection is 24V DC. The module’s open circuit detection is only for current output, but the output should be set to greater than 0.1 milliamps. It also has a short-circuit protection that is limited to 21 milliamps or less.
