I have a Float Valve in my MLT. This is a DIN named “Float MLT”.
I have an Element in my MLT that is controlled by an Out name “MLTe”.
I have a valve for water flow that is a Out name “Fill MLT”
Process Start Water
State 0 => “Fill MLT”
Out “Fill MLT” asserted.
Exit Condition “Float MLT” asserted go to State 1 “Heat MLT”.
State 1 => “Heat MLT”
Out “ MLTe” under PID Control to 168 degrees.
Exit Condition none as I hold the MLT at 168 until I manually go to my next state.
State 2 => “Add Grain” …..
What I want is to have the following Logic in the Ladder Logic (or another method):
“Float MLT” must be asserted for Out “ MLTe” to work. I would want the “MLTe” to be PID controlled.
I put the “Float MLT” in the first Contact and the “ MLTe” in the Coil. This as expected causes the “MLTe” to assert as soon as the “Float MLT” is asserted.
What I am trying to do is shut the “ MLTe” off if the “Float MLT” is not made.
I have “destroyed” an Element when I got it out of water (adjusting water Temp manually by adding and draining water) and hope to find a method so that it will shut off when the Float is not made.
Can I do this? If so, how?
DIN, Ladder Logic
Re: DIN, Ladder Logic
I had read that thread, just did not click as I honed in one the "issue" rather than using a DIN as a safety switch in Ladder Logic. I see when it is "fixed" I will need to put my "MLTe" on BEFORE the "Float MLT" as a contact. The float valves I have have two floats so I could wire the lower one in series with the Out Control Circuit to the "MLTe" Out. I wanted to use the Float to cut off a fill valve and be a Safety Switch for the element but I will use the higher one to cut off the fill valve instead of double duty for the lower one.
These are the ones I have:
http://www.amazon.com/gp/product/B005NF ... ge_o02_s00
The are "normally closed" as sent so you have to turn them upside down to close when they float. The little "C" rings are easy to move or take off as long as you have the correct snap ring pliers (the kind that expand when you close the handles). Just remove the two bottom "C" rings and remove and replace the floats "upside down" and relace the "C" rings. You can also adjust the "C" rings up or down for a micro adjustment.
These are the ones I have:
http://www.amazon.com/gp/product/B005NF ... ge_o02_s00
The are "normally closed" as sent so you have to turn them upside down to close when they float. The little "C" rings are easy to move or take off as long as you have the correct snap ring pliers (the kind that expand when you close the handles). Just remove the two bottom "C" rings and remove and replace the floats "upside down" and relace the "C" rings. You can also adjust the "C" rings up or down for a micro adjustment.