1771-DW

The Allen-Bradley 1771-DW is a wire fault module with an input of 15-27V DC. The 1771-DW have seven on/off DC inputs that can be converted to compatible logic signals with a programmable Allen-Bradley controller. This module detects the wire circuit which connects to the input device of the module or to the power supply that has short-circuited to the ground or circuits that are open. To monitor the module from this wire condition, a shunt resistor must be connected across the terminals. In the input devices, there are 2 typical wires that are hard-contact and compatible with the module are included and there are DC pushbuttons and limit, float, and selector switches that are been included also. Your input device should not exceed 1mA during the off-state leakage current of your 2 wires. The input indicators of this module are positioned in front of the module which has seven status indicators. The status of the inputs is shown by the indicators or by a wiring fault. Below the last input indicator is a reset pushbutton switch. After detecting and correcting a wiring fault, you can reset the module manually by using the switch. It can be pressed using a ballpoint pen or any narrow object. To report a wire status or a contact status you need to program the module. It is a standard discrete I/O module when you program a wire fault module but with a certain exception. The power supply in the 1771-DW module’s common terminal and the input terminal has a constant voltage to be maintained. A voltage of 15-27V DC must be selected as the power supply of this module. The 1771-DW’s 24V DC is the normal supply voltage that is recommended. If your supply is 24V DC, use a shunt resistor that is 3.3k carbon film ½-watt supplied in your module. Use a different shunt resistor if the voltage of your power supply is greater than 25V DC or lower than 23V DC. The 1771-DW has a maximum backplane current of 300 mA and 1500V DC optoelectrical isolation. The operating temperature ranges from 0-60°C and the storage temperature ranges from -40-85° C. The relative humidity is 5 - 95% non-condensing. The proper keying positions are between pins 2 and 4 and pins 20 and 22 with a wiring of 14 gauge stranded with 3/64-inch insulation.