I have just joined a boiler making company and I am required to write plc code for the boiler water level regulation. The new instrument I added is a differential pressure cell between the boiler pressure and the pump pressure. The differential pressure cell produces a 4-20mA signal. We aim to increase the pump pressure to be always above the boiler pressure. I am supposed to write the code using concept. Any heads up

 

Pump pressure or the circulation rate (gpm)? Match the 4-20 signal to the range of the designed pump curve. Then output a digital signal to the VFD/motor controller with the same scaling.

 

What make PLC?
Presumably you have the 4-20ma extension unit for the PLC?
Max.

 

I have just joined a boiler making company and I am required to write plc code for the boiler water level regulation. The new instrument I added is a differential pressure cell between the boiler pressure and the pump pressure. The differential pressure cell produces a 4-20mA signal. We aim to increase the pump pressure to be always above the boiler pressure. I am supposed to write the code using concept. Any heads up

I assume that the zero is @ 12mA + or - 8 indicating direction.
What I do not understand:
When do you stop the pump (detected from this differential measurement) ?
Is this an open boiler?
The temperature is very important in a closed system boiling steam could go up to 400++ degree @ 100Bar or more so pump must be able to handle.
This call for the question: how to measure the water level pressure is not enough?

Picbuster