The Allen-Bradley 1771-OFE1 is an analog output module from the PLC series. This module delivers voltage signals which can be used to drive modulating devices such as control valves, adjustable frequency AC drives, Dampers, louvers, and positioners. It may also be used as a signal source of data loggers, splitters, panel meters, totalizers, and single loop controllers. The 1771-OFE1 output voltage ranges include +1 to +5 VDC; -10 to +10 VDC and 0 to +10 VDC. It has a digital resolution of 12 bits with a Digital to Analog (DAC)converter maximum settling time of 0.8 ms for a resistive load. The module’s internal scan rate is 8.0 ms for every channel utilizing Binary Coded Decimal (BCD) data and scaling and 1.6 ms for all channels using binary data and no scaling. The 1771-OFE1 analog output module accuracy is +0.1% of full scale; +1/2 Least Significant Digit (LSD) when operating in BCD mode and +1/2 Least Significant Bit (LSB) when configured in Binary mode. This module is a single slot module that directly installs to a Bulletin 1771 I/O chassis. It has a power dissipation of 7.9 Watts and backplane power consumption of 1.50 Amperes while the thermal dissipation is 26.9 BTU / hr. The 1771-OFE1 operating temperature is 32 to 140 Degrees Celsius; Operating shock of 30 g and operating vibration of 2g at 10-500 Hz. For module storage, it must be kept in an environment with temperatures -40 to 185 Degrees Celsius. Each output of this module has built-in overload protection against short circuit load conditions.

The Allen-Bradley 1771-OFE1 is a PLC 5 analog output module. It is a voltage version which converts 12-bit binary or 4-digit BCD (binary-coded decimal) values to analog signals using its 4 outputs. It has three selectable voltage ranges of 1 & - 5V DC, 0 -10V DC, and +/-10V DC. Peripheral devices such as motor speed controllers, valve positioners, recorders, or signal converters can be connected to the output. The 1771-OFE1 uses block transfer programming for data transfer. Write Block Transfer instructions move data up to 13 words away from the processor to the module for DA conversion in one scan and Read Block Transfer moves 5 words of data from the module to the processor as part of the debugging process.

The 1771-OFE1 module has 4 1000V individually-isolated differential outputs. It requires a power of 1.4A at 5V which is supplied from the I/O chassis 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. The 1771-OFE1 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 10-12 and 26-28 for fixing that slot.

The 1771-OFE1 module can convert raw data to engineering and measurement units such as deg. C, deg. F, gallons/minute, and pounds/square inch. For diagnostics, it performs a self-check at start-up. If a fault occurs, a red fault indicator LED and the green power status indicator LED remains OFF. The 1771-OFE1 has a 1500V optoelectrical isolation and this protects the system from overvoltage situation.

1. How many output channels does the 1771-OFE1 have?

The 1771-OFE1 has Four (4) individually isolated output channels.

2. What is the output signal voltage of the 1771-OFE1?

The 1771-OFE1 has output signal voltages of +1 to +5 VDC; -10 to +10 VDC and 0 to +10 VDC.

3. What is the resolution of this module?

The +1 to +5 VDC; -10 to +10 VDC and 0 to +10 VDC has output resolution of 12 bits.