Eaton D77A Installation And User Manual

Contents

Intelligent Technologies (IT.) D77A I/O Module ProductsMN05002001E For more information visit: www.EatonElectrical.com 23I/O FunctionDiscrete Input ModulesFigure 17 illustrates the basic signal processing operation. When a signal is present at the input point, the module responds with thefollowing sequence:1. Optical Isolation — Optical isolation protects the I/O circuits and communication circuits from possible damage due totransients and over-voltage.2. Debounce Logic/Control — A debounce circuit and software limits the effects of transients and electrical noise by requiring theinput to be true for a certain period of time before the logic acknowledges a true signal. Once a true signal is achieved, the logicturns on the LED.3. QCPort Com./Logic — The logic updates the QCPort communication on a regular, scheduled basis as to the status of the inputpoint.Figure 17: Discrete Input Module OperationDiscrete Output ModulesFigure 18 illustrates the basic logic processing operation. When the processor activates an output point, the module responds withthe following sequence:1. QCPort Com./Logic — QCPort communication updates the logic circuit on a regular, scheduled basis as to the status of theoutput points.2. Optical Isolation — Optical isolation protects the I/O circuits and communication circuits from possible damage due totransients and over-voltage. Once an active signal is transmitted to the optical isolation circuit, the LED is forward-biased.3. Output Drivers — The driver activates the output point.Figure 18: Discrete Output Module OperationD77A-004OpticalIsolationInp ut DebounceLogic/ControlQCPortCom.LEDIndicationD77A-005QCPortCom.OpticalIsolationOutputDri versLEDIndicationOutput