Process Control Interface

I am trying to think of ways to present a generic, ideally graphical interface to the user that will allow them to implement their own control logic with a particular system that incorporates a given number and types of input/ouput. For example, if the system has 3 inputs for speed, temperature and pressure and 3 outputs for controlling a switch/alarm, motor and gauge, what kind of user interface could/should I present that will allow them to select any combination of the inputs and set conditions on them in order to trigger and drive any combination of the outputs. A set of control instructions might look like:

1 -( SPEED >10 AND SPEED <20 AND [ TEMP <50 OR PRESSURE <200 ] ) DO ( MOTORSPEED=10; GAUGE=2.5 )

2 -( SPEED >100 AND [ TEMP >=50 OR PRESSURE >=200 ] ) DO ( ALARM; MOTORSPEED=1; GAUGE=5 )

3 - …

I could have the user input the above as text in a line by line set of control commands and parse them to generate the necessary code, but this would not be a very user friendly way to do things. I’m looking for a generic/graphical/systematic way of doing this and wondered if anyone has any ideas as to how I might go about achieving this or ideally whether there is some industry standard interface for Programmable Logic Controllers that I might be able to base my design on.


Google for Ladder Logic Language. It's the defacto standard, and one of the first things a process control tech learns.

Thanks, never heard of this before but does look similar to the area of boolean switching functions... I shall read further..! ;)