Upgrading Boiler Controls with YS1700


The power plant for a small town has a single, coal fired boiler controlled by Bailey SLC controllers. Concerned about support issues for the aging controllers, the power plant initiated a control upgrade project.

Control board with new YS1700 YS1700 dual loop display
Control board with new YS1700 YS1700 dual loop display


New YS1700 Controllers in Panel
New YS1700 Controllers in Panel

The initial phase of the project involved replacing the following controllers:

  • Main steam desuperheater
  • Header pressure
    Auxiliary feed water heater
  • Steam temperature
  • Utility steam pressure


Graphic Programming Sample
Graphic Programming Sample

The customer evaluated a number of ½ DIN PID controller products. The new YS1700 dual loop controller from Yokogawa was the final selection. Reasons for the selection of the YS1700 included:

  •  YS1700 is a new product designed for extended product life.
  •  High impact, color LCD display
  •  Drag and drop graphic programming software
  •  Extensive communication options including
  • Peer to peer.
  • Complete backwards compatibility with previous generation Yokogawa controllers ( YS100 and YS80)

Using the graphic programming software for the YS1700, the system integrator working on the project recreated the existing Bailey control logic as new programs for the YS1700. The reduced panel depth of the YS1700 controllers allowed for easy rewiring.

The power plant is up and running with the new YS1700 controllers. Phase II of the upgrade which will replace all the remaining Bailey controllers is planned for 2008.



YS1700 vs Bailey SLC: panel depth 

YS1700 vs Bailey SLC: panel depth


Related Products & Solutions


The YS1700 Programmable Indicating Controller can be tailored for various applications by running a user program, and offers high reliability thanks to Yokogawa's proprietary technology, user friendliness, and expandability.

Single Loop Controllers

Single loop controllers receive temperature, flow rate, pressure, and other types of measurement readings from sensors and send corresponding instructions to control elements such as valves in order to maintain these values within a desired range.


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