Another question for you guys to mull over.
I have a process that I want to setup, Cascade control. I have two hot water tanks, one above the other, only one heating. I have a drive controlling a pump, that pumps the water from the bottom tank out through some piping and into the top tank where it eventually goes to the bottom tank again. There is heat tracing wired to a thermon controller and placed on the piping so temp. loss should be at a minimum.
I also have a turbine flow transmitter in line with the pipe so i can determine the flow.
This is what i was thinking: One flow loop, One temp loop of the water in the piping (RTD sensor).
The tank element is 240V. I need to control the water temp in the tank. regulate at "what ever temp." Is there a way that i could do this? One controller controlling the temp the other controlling the flow based on the required temp.
I was thinking i need something that could take 4-20ma input and vary 0-208V and handle max 20 amps.
Do such a thing exist? Any suggestions as to another way i could do this? One person that i've asked suggested to me that i could use a plc and have two timers setup so that i could adjust the amount of time my output is on. and use a PUC or SCR Relay to swith the 240V. Almost like Pulse width modulation idea. Not to sure about doing this. Any sugestions??
Thanks for the help.
Terry
I have a process that I want to setup, Cascade control. I have two hot water tanks, one above the other, only one heating. I have a drive controlling a pump, that pumps the water from the bottom tank out through some piping and into the top tank where it eventually goes to the bottom tank again. There is heat tracing wired to a thermon controller and placed on the piping so temp. loss should be at a minimum.
I also have a turbine flow transmitter in line with the pipe so i can determine the flow.
This is what i was thinking: One flow loop, One temp loop of the water in the piping (RTD sensor).
The tank element is 240V. I need to control the water temp in the tank. regulate at "what ever temp." Is there a way that i could do this? One controller controlling the temp the other controlling the flow based on the required temp.
I was thinking i need something that could take 4-20ma input and vary 0-208V and handle max 20 amps.
Do such a thing exist? Any suggestions as to another way i could do this? One person that i've asked suggested to me that i could use a plc and have two timers setup so that i could adjust the amount of time my output is on. and use a PUC or SCR Relay to swith the 240V. Almost like Pulse width modulation idea. Not to sure about doing this. Any sugestions??
Thanks for the help.
Terry