YS170 Single-loop Programmable Controller (DISCONTINUED)

YS100 series instruments are stand alone devices that control or indicate process variables throughout a manufacturing plant. RS485 communications cards can be optionally provided to transfer data from each instrument digitally to a PC-based operators station. Below is a typical system configuration to transfer data bi-directionally through this communications bus.

The boiler combustion control system is designed to maintain a proper air/fuel mixture under varying load conditions and within safe limits. The system should provide nearly complete fuel combustion as efficiently as possible. Discussions here are limited to oil and/or natural gas fired industrial boilers. 

Automated control of industrial boilers is an excellent application for YS1700 microprocessor-based loop controllers. These instruments can be programmed to perform the operations of plant master, boiler master, fuel and air control with oxygen trim and drum level/feedwater control.

Steam drum level control is necessary to add makeup water as steam is delivered into the header and to the associated process equipment. The system should control the drum level at a specific set point while compensating for varying steam demands and drum pressures. For a given volume of steam and blowdown leaving the steam drum, an equal amount of water should replace that inventory.

In process control it is not uncommon for systems to be affected by dead times, due to material transfer times. This is evident typically in pipelines. A fluid of density ρ and flow rate w in a section of pipe A the length of d takes the amount of time τ = ρAd/w to cover the whole distance (see Figure 1).