The Allen-Bradley 1771-DS is a latching module with an input of 10-27V DC. It latches and detects pulses with a duration of 0.1-5.0 ms. Using an input terminal, the module discovers pulses and puts a bit within a corresponding image address table during the next I/O scan. 

The 1771-DS module responds to pulses by using an optical sensor which has an isolated gate output and an isolated pulse output. This module’s input has two ways to operate. Unless paired, this module operates independently, and when this module is paired, it either responds to a certain pulse or it responds to the gate signal.

The pulse that this module can capture is the minimum pulse width. With a pulse capture time of 0.1ms, 0.5ms, 1.0ms, 2.5ms, or 5.0ms, you can select the pulses by measuring the duration of some typical pulses. It is recommended that the usable capture time you select is the shortest in terms of using the paired input. And in each pulse, the 1771-DS requires time to recover and this depends on the time that you selected.

In this module, there are two ways to reset the latched inputs. If you choose “master,” it resets all inputs and if you choose “individual,” it resets the individual inputs. The 1771-DS operates at a temperature range of 0-60°C and a storage temperature of -40-85°C with 5 - 95% relative humidity without condensation. 

When selecting module functions, place plugs or jumper pins that are appropriate pairs together. 240V DC is the maximum reverse voltage that is used to protect the module’s input. The 1771-DS module is protected by keying. Prevent installation in the wrong module slot by using or inserting keying bands in the following positions; between pins 2 and 4 and between pins 18 and 20. These keying bands have an I/O chassis on the upper back place connector.