Describe analog modules of PLC.

These modules have A/D & D/A converters signals in the form of voltage and current are converted in the form binary data and depends upon the resolution of the module. As all cpu needs digital signal to process so it the best method to convert analog signal into digital or vise versa.

Hi Bilal,

    Analog Modules are just a convertor which converts analog signal to digital and vice versa. As the controller accepts discrete commands and also generates discrete commands.

Thanks

Analog modules are used to convert the input or the output analog signals to digital as the PLC  is  a digital system could not deal with the analog inputs or outputs without conversion.

The Analog modules are only inputs/outputs of PLC; PLC itself is Digital controllers, so Analog modules are only there with Analog to Digital Converters or vice-versa. They will produce/take signal of4~20mAdc or0~5Vdc,0~10 or higher ratings. but they communicate with PLC in digital signal form. They are

Analog I/O modules perform the required A/D and D/A conversions to directly interface analog signals to PLC data table values using up to16-bit resolution. Analog I/O can be user-configured for the desired fault-response state in the event that I/O communication is disrupted. This feature provides a safe reaction/response in case of a fault, limits the extent of faults, and provides a predictable fault response.

 

Source: Rockwell Automation site