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General PLC Implementation to Boiler Information
Looking for some simple answers for some general questions about connecting a PLC to a boiler

Hello,

I'm a current technology student doing a project for my school. Because of the thousands of sources out there, I just wondered if anyone here can help me since people here are from industry.

My objective is to implement a PLC to a hypothetical boiler.

The PLC I've chosen is Allen Bradley and the the program is RSLogix.

I just have some general questions for my research.

1. Can all boilers be implemented with PLC?

2. How does a PLC control a boiler? What is the process? I have worked with PLC before, but I just can't wrap my head around it. Do boilers have input and output terminals like a motor connected to a plc?

3. Do all boilers work the same? I need to select a boiler and I've researched that there are different pressures they operate on. Will these affect the PLC implementation? I've narrowed down a manufacturer though, Hurst.

If possible, you may also include your name and occupation so I may use you as a reference. (Citation is a big thing for me)

Thank you

Hello Student1,

Here are my answers

> The PLC I've chosen is Allen Bradley and the the program is RSLogix.
I'm familiar with RSLogix implementation to Boiler/steam generator application

> 1. Can all boilers be implemented with PLC?
Definitely, PLC can be implemented for control to all types of Boiler

> 2. How does a PLC control a boiler? What is the process? I have
> worked with PLC before, but I just can't wrap my head around it. Do
> boilers have input and output terminals like a motor connected to a plc?

In my opinion, basically there are 4 major section on the boiler control system:

- Combustion control: control air-fuel ration for boiler firing

- Buner Mangament Control: Boiler safety system for startup, shutdown and monitoring of combustion process

- Boiler Drum level control: provide control to maintain drum level under operating conditions

- BOP (Balance of plants) Control : to provide control to auxiliary process such as feed water flow, fuel storage and pre-processing, condenser control, water treatment, etc.

> Do boilers have input and output terminals like a motor connected
> to a plc?
Yes, boiler will have motor to control blower, control valve to control fuel flow, pump motor and recirculation control valve to control feed water, etc and all should be connected to PLC for automatic control.

> 3. Do all boilers work the same? I need to select a boiler and I've
> researched that there are different pressures they operate on. Will
> these affect the PLC implementation? I've narrowed down a
> manufacturer though, Hurst.

basically all of boiler will have the same working philosophy but the control system will depend on several factors, you may want to start your research by read below documents and back to us for more discussion:
http://www.slideshare.net/nosuhaila/introduction-to-boiler-control-systems

> If possible, you may also include your name and occupation.
I'm working for Rockwell Automation

Hope this helps, if you need more information please be more details.

Thanks and best regards
Ikhtiander

By Bob Peterson on 3 February, 2017 - 10:22 am

I would suggest this.

PLCs are very good general purpose controllers. There are no control functions in a boiler that are especially complex or would require some unusual capability within the control system so there is no reason a general purpose PLC could not control a boiler (and it is not unusual for them to be used that way).

Having said that, boilers require some safety controls that not all PLCs would be able to accommodate. Sometimes safety functions are handled separately.

Specialty controllers often bundle in normal functionality such as might be required for boiler control so it is easier to implement.