March 15, 2017, 03:01 PM
UPC Code to Control a Pump Pumping from a Small Tank to a Large Tank
I have a problem where I need to write the UPC code for a pump that fills a large tank from a very small tank. The large tank
suppies water to the reticulation system of a small tourist town.
When the small tank is empty, it calls water from a water treatment plant that produces water at a rate of 5 l/s. Once the small
tank is full the water treatment plant pauses. The pump from the small tank to the large tank pumps at a rate of 8 l/s.
Consequently, the small tank goes through a number of fill-empty cycles before the large tank can be filled.
The graph of the filling and emptying of the large tank should have a rising limb that resembles a staircase, with horizontal
step-treads and sloping risers, as the filling of the large tank pauses every time the small tank is emptied. Once the large
tank is filled to its pump-off level it should then drain down to its pump-on level without the pump coming on.
The graph of the filling and empting of the small tank should resemble a horizontal saw-tooth.
I suspect the UPC code for this scenario will involve nested do-loops with the loop for the operation of the small tank being
contained within the loop for the operation of the large tank.
This scenario must be fairly common.
March 16, 2017, 03:40 PM
I'll leave this post open in case someone has any suggested code for you, but this forum is mostly for hydraulic modeling type questions and your audience with experience for Universal Pump Control programming may be limited.
This type of condition can also be a little challenging to complete within a hydraulic model as well as it can be difficult to write controls such that the larger pump will stay off the entire time while the smaller tank fills. While making a quick example model of this it can also take a long time for the large tank to fill if the system demand that drains the large tank approaches the fill rate of the small pump or if the small tank is so small that the cycling limits the fill time the pump filling the large tank has to fill.
But perhaps there may be a few users that can provide suggestions for the code you need, but you may also want to post this on other boards that have more PLC type programming users who might be able to provide better suggestions for you.