Station Design Philosophy

Having been involved with the service, repair and maintenance of water and waste water station controls for many years, a licensed operator said one day "There has to be something better than this".

-------Challenge #1------

This was the start of the engineering development of our line of station controllers. First, we knew we needed to get away from this!

In order to accomplish that one benefit, the only viable solution was to utilize PLC's. Knowing their reliability had become excellent, placing the equivalent of hundreds of relays in one package carried great attraction provided the package had been properly designed, reliable and error free. Reliability was enhanced by the addition of extensive surge/lightning/MOV protection. Our field experience has been shown to be outstanding. We have not had to replace any of our controllers due to lightning or surge damage.

------Challenge #2------

The second action was to make this reliable package in such a manner that all the existing station operators in the field would not have to be trained in PLC's or Lap top communication interface protocols, or for that matter in ladder logic design software. This brought about the 4 button(yes ,I said four button) operator access and control panel. We determined a 20+ button control panel with associated room for operator entry error was too much and would make a difficult situation even worse. We have proven by our many field installations that 4 buttons have been more than adequate and warmly received by the station operators.

------Challenge #3------

The next challenge was to design the controller and interface such that the operator had total control of all operating parameters for the station and did not have to hire or call in a "field engineer" to make set point or other adjustments. The operator interface has a simple up/down digital display where all settings are digital, with 1/10 unit (PSI or feet) increments for the tightly controlled applications should they be necessary. Once these points are set, the digital accuracy allows for excellent repeatability without the detrimental exposure of mercury or other traditional control schemes. All settings are prompted by plain English, field usage terminology already familiar to most station operators. The operator can readily read what the set points are and enjoys not having to adjust mercury tilt switches to some unknown value subject to change the next day due to mechanical corrosion or lack of lubrication.

------Challenge #4------

The next challenge was to design a controller that performed it's control function equal to or better than the typical installed controllers that have been available. Ensuring no short cycling or hidden faults could occur from "within" the PLC was of utmost importance. Extensive bench testing, simulation etc, were performed followed by real life installation applications. Real life applications tend to separate the men from the mice and slamming check valves or oscillating flow switches can wreck havoc on many of a control scheme. Extensive use of internal time delay relays handled this problem nicely. Once accomplished, problems with external devices that had an effect on the controls were recognized and assigned specific fault indications for the operator to recognize any external source of problems. All of the major ones are listed here: Water Alarms Lift Alarms

------Challenge #5------

The next thing we wanted was a controller that would "talk to the operator" and notify him/her of any pending problems with any of the devices attached to the controller. This resulted in displays showing alarms such as "starter fail", "transducer fail","flow fail", "lead level float fail", "flow fail","low level alarm", "high level alarm", "low psi alarm", "probe fail alarm", minute run time as well as cycle time meters. High cycle count on a particular pump warns of a loose starter coil wire or other problem immediately. See the appropriate controller of interest to see the alarms generated for that particular application.

------Challenge #6------

The next thing of great importance was to design ,as close as possible, a universal controller that could be applied to most typical unmanned water and waste water pumping stations. This resulted in the incorporating the operator capability for easily selecting how many pumps to be installed in the particular application. We designed alternation capabilities for up to four pumps should field upgrade ever be needed. This eliminates the tremendous expense of buying a new control scheme should you add an additional pump. An operator just selects 3 pumps and alternation automatically occurs. It can't get any simpler than that.

------Challenge #7------

We were intimately familiar with field conditions where some pumps were smaller than others. This left the operator to deal with significant run time differences between pumps or select the larger pump as always the lead pump. To simplify this problem we incorporated a function we call "tracking". In these situations, the operator can easily select one pump to "track" another. e.g. Pump#1 comes on as lead, 5 seconds later, Pump#2 comes on. When alternation occurs and Pump#2 comes on as lead, Pump#1 comes on 5 seconds later. This, as you can see, will allow for equal run time between different size pumps and proves very effective when the system gets to the point where the small pump cannot keep up with system demand.

------Challenge #8------

We wanted a controller that could be installed easily by an electrician or experienced station operator. This involved a simple diagram and I/O connection points with immediate display indicators that they are working properly. Once you know how to install one, the rest is a piece a cake. Turn it on and let her go to witness our "Plug & Pump Technology". One thing we found was different jurisdictions utilized or preferred specific starters or electrical equipment. Rather than dealing with the additional expense of "custom panels" fabricated to individual taste, we decided to just build a 120VAC controller panel that would easily interface into your existing starters for after market applications. It could also be interfaced to a straight forward "Combination Starter" that are also readily available. We can supply Furnas ESP100 Combination starters for this purpose, wired and tagged for our panel, if desired. Yes , you can place a handle on this control panel and carry it around different stations for emergency control requirements. All you need is a 120VAC outlet. Warning! You might like it so well that it would become a permanent installation.

------Challenge #9------

An easily repairable controller was a necessity should a major equipment failure occur. This is facilitated by the fact the PLC is rail mounted with a simple plug in terminal strip for operator change out should it be necessary. Again, no need for PLC computer geeks out in the field.

------Challenge #10------

A tremendous amount of engineering and field testing time has gone into the design of these panels and our goal was to ensure competitive pricing once completed. We feel we have achieved this goal once the capabilities are known compared to any competitors. As sales volume increases, we anticipate a reduction in pricing due to quantity ordering of parts.

------THE RESULT ------

Now we have a simple, straightforward controller with all the complicated wiring contained within a fully tested module, totally void of all loose connections or operator modifications that can have an adverse effect on operations.

Now it contains one compact module w/display, two pump control relays plus one alarm relay, a surge protector and terminal strip for field wiring.

Since the module is a simple DIN railmount plug in, operators love this design when in the field at 3 A.M. on a service call. If needed, plug in a new module and you now have a brand new control panel.

Well, that pretty well sums it up. We are always looking for feedback to make our panel even better and encourage you to give us feedback on your applications or desires for future designs. Best regards from the engineering staff at U-Tap Controls!