High-speed programmable logic controller (PLC) signal processing is accomplished using a programmable signal processing arrangement that is capable of altering characteristics of signal processing in response to one or more signal processing coefficients. According to an example embodiment of the present invention, a PLC-based arrangement includes a PLC controller and a signal processing arrangement that oversamples and processes a signal at a frequency that is greater than a maximum input-process-output scan rate of the PLC controller. In one implementation, the signal processing arrangement is programmable with complex high-speed signal processing parameters that can be downloaded, for example, via the Internet in response to an end-user request. With these approaches, signal sampling and processing is achieved with a PLC-based system at a rate that can be much higher than previously-available signal processing rates with PLC controllers.