The INFO-Scan Graphical Programming Language (GPL) provides a convenient way to control chilled-water systems in such a way that they provide the warmest water that still satisfies the worst case load. Each load's cooling needs are determined and the chilled-water system is controlled to minimally meet the requirements of the most demanding load.

When the individual loads using chilled-water are not monitored, the GPL is used to provide a control scheme which maintains a constant chilled-water return temperature.

GPL PBID blocks are used to calculate the chilled-water temperature that would be required to satisfy each load. The ASEL block then selects the lowest of the chilled-water temperatures calculated and provides this as a set point. From here, either a local hardware controller can take the set point as an input and maintain chilled-water temperature, or a PEPOS block may be used to accomplish the same function. 

To implement chilled-water reset the GPL uses a library of blocks which perform specific functions. By assembling different control schemes from these blocks, almost any system configuration can be controlled. Control schemes can be used for Direct Digital Control or Control Point Adjust. The only difference is the final PEPOS block is deleted for Control Point Adjust and its function is handled by a hardware controller.