The Allen-Bradley 1771-OFE2K is a Conformal-Coated PLC 5 Analog Output Module. Conformal Coating protects the module from humidity and contamination. It is a current version with 4 – 20mA output range which converts 12-bit binary and 4-digit BCD (binary-coded decimal) values to analog signals with its 4 outputs. Peripheral devices such as motor speed controllers, valve positioners, recorders, or signal converters can be connected as output devices. It uses block transfer programming for data transfer. The Write Block Transfer moves data up to 13 words away from the processor to the module for DA conversion in one scan and the Read Block Transfer moves 5 words of data from the module to the processor for debugging.

The 1771-OFE2K module has 4 1000V individually-isolated differential outputs. It requires a power of 1.4A at 5V which is supplied from the I/O backplane, thus no external power supply is needed. It has a channel update time of 8ms per 4 channels for BCD and 1.6ms per 4 channels for Natural Binary. It has a maximum power dissipation of 7.9W and maximum thermal dissipation of 26.9 BTU/hr. It includes a wiring arm to replace the module without disconnecting the wires. It can be installed in any slot in a 1771 I/O chassis and keying bands must be snapped between pins 10-12 and 26-28 for fixing that slot.

The 1771-OFE2K module can convert raw data to measurement units such as °C, °F, gallons/minute, and pounds/square inch. For diagnostics, it performs a self-check at start-up. If a fault occurs, the red fault indicator LED lights up and the green power status indicator LED remains off. It has 1500V of optoelectrical isolation which protects the system from overvoltage.