Overview

This document describes the installation, usage, and functionality of a TOPDOC Loadable Module (TLM) for version 4.x SoftPLC that is used in process control applications, with particular focus on hydro electric turbine governors. The TLM provides working code for a number of common control algorithms in ladder block form. Under license agreement the C source code is available and can be used as a starting point for extensions by integrators and end users.

SoftPLC can load one or more TLMs. TLMs may contain application specific extensions in the form of custom ladder instructions. The custom ladder instructions are called TLI's (TOPDOC Loadable Instructions). They appear as block type functions within the ladder program.

This TLM and build kit includes the following instructions. If you need one not listed, please ask.

• Lead Lag - and doubles as a 1st order filter if the Lead time constant is set to zero.
• Ramp - used to ramp up or down a float value or to integrate or accumulate a signal over time. It can be used to ramp up or ramp down a setpoint, or to integrate a signal over time. It can also be used as part of a feedback loop or to simulate a process component.
• PID Super - is an example of a supervisory/adaptive/auto-tuning agent that sits on top of a standard PID block and manages its operation. The standard PID block is the built-in ladder instruction that is standard with SoftPLC. This TLI is intended mostly as an example to show how to wrap your own logic around the standard PID block to create a governor type state driven controller. It is fully useful only when you have access to its C source code, which give structure definitions for the standard PID block and define new ones for the PID Super parameter data. It is a framework to allow you to extend these PID Super structures to your liking.
• PID Super Load - will read the parameters for the PID Super instruction in from a text based configuration disk file. This technique can be used to parameterize the PID Super instruction after you have copied the configuration text to disk. It is complementary to the PID Super Save instruction, but you can also use either a text editor or an FTP download to create the configuration parameter file.
• PID Super Save - will write the parameters for the PID Super instruction to a disk file. It can be used to save known working parameters.
• Any Others - that you write with the source code, or ask us to add.