The Allen-Bradley 1771-IJ module is an encoder or counter module for PLC-5 controllers. The number of counters available on the 1771-IJ module is one. The counter input is single-channel while the encoder input is dual-channel. The maximum pulse rate for the input is 50 kilohertz. The supported data transfer modes include a single transfer mode and a block transfer mode. The 1771-IJ module requires a 5 Volts DC power supply with a maximum tolerance of ±0.25 Volts. The typical current consumption rating is 1.2 Amps, which can go up to 1.4 Amps. The range of input voltage is from 0 to 5 Volts DC. The device driving the input must be able to sink a minimum of 16 Amps of current. The output ratings are a maximum voltage output of 5 Volts DC and a maximum current output per module output of 500 milliamps. The module has 2 open collector outputs without internal pull-up resistors. The peak power dissipation for the 1771-IJ module is 6.7 Watts and the thermal dissipation is 22.9 BTU per hour.

The Allen-Bradley 1771-IJ module can be installed in an Allen-Bradley 1771 I/O chassis. The I/O isolation voltage has been tested at 1500 Volts AC for 1 second. The limit switch input voltage range is 12 to 48 Volts DC. The module current consumption rating from an external power supply is 150 milliamps at 12 Volts DC and it is 75 milliamps at 24 Volts DC. The environmental specifications for the 1771-IJ module include a 5 to 95% relative humidity range, a 32 to 140 degrees Fahrenheit operating temperature range, and a –40 to 185 degrees Fahrenheit storage temperature range. The enclosure of the module is open.