Intelligent Valve Monitor
January 18, 2006
We run several IVM600 Intelligant Valve monitors on a test pumping setup outside the back of our shop. It's interesting to see how some common problems are picked up, and how the errors that are reported should be interpreted. In this example we'll see how two consecutive errors (and assumptions about the weather) show the valve almost freezing up.
NOTE:
- It's January in Canada
- This valve monitor has a seat time set to 5 seconds.
- We're pumping a 50% windshield washer antifreeze solution.
- The system is not insulated or heated.
This morning we checked an IVM6000 for errors.
The valve reported:
5:36:12 Outlet Stuck # 6
5:36:08 Inlet no Outlet
So what does this mean?
At 5:36:02 the pump panel started pumping.
The Inlet no Outlet occurred when the seat time was violated. This means the valve's internal disk only made it part of the way down, and didn't seat on the outlet.
The pump ran for another 4 seconds before reporting Outlet Stuck.
It (must have) reported Outlet Stuck because the previous dosing didn't cause the cam to rotate the plunger.
This is plausible since the operating conditions are very cold, it was 5:30 in the AM (likely the coldest point) and internal icing could occur.
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January 17, 2006
We were recently asked:
> I do have one question: Does the timer reset itself, the reason I ask
> is if the valve was operating normally for say two years and then
> suddenly started to malfunction It would take some time for the
> percents to vary, delaying the alarm, or are the percents calculated
> after each rotation forcing an alarm immediately?
Answer: Certain types of alarm conditions would cause it to alarm more or less "right away". For example if it detects the valve is dosing the same zone/outlet over and over (several times in one day or in a row) or if it detects the valve is skipping one or more outlets every time it would alarm right away.
To capture an "uneven distribution" type of alarm condition, the percentages are calculated over a *sliding* operator set "period". So for a high cycling system you might want the monitor to calculate the average on a daily basis. For certain types of facilities where the wastewater flow rate will vary a lot throughout the week (ie. schools, restaurants) you might want to set the averaging period to 7 days, one month or more. The actual alarm condition is checked at regular intervals within the sliding period.
So a sliding period of 7 days means "the last 7 days" as opposed to "every 7 days". So if the percentages go out of whack within the last seven days it will pick that up.
The IVM will alarm whenever the % variation of the data within that last period goes outside the user-configurable parameter "percent variation". So for some systems a 15% variation might be acceptable but for others a 5% variation might be desired. There will be a balance between avoiding unnecessary alarms for minor "glitches" or variations that are not important and ensuring that if there is a serious problem the operator is notified.
We include some suggestions for how to best set these user configurable parameters in the user manual, or the default settings can be used to start off.
January 01, 2006
Inlet no outlet occurs when the valve monitor detects that there is flow coming into the valve, but after waiting the length of time specified by the seat time parameter it did not detect the internal mechanism seating at an outlet. This could be caused my a sticking stem and plunger assembly, debris, or partial freezing conditions.
NOTE: This error will commonly occur if the monitor is removed or lifted off the valve without entering shutdown mode.
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Outlet stuck means that the valve did not sequence to the next outlet, rather the same outlet was detected two times in a row. this could be caused my a sticking cam, debris, or partial freezing conditions.
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October 06, 2005
The Intelligent Valve Monitor (IVM) has three mdoes of operation: Run/On mode, Sleep mode, and Shutdown mode. While the unit is On or in Sleep mode, the IVM is constantly collecting and analyzing data. In the micropower shutdown mode, the unit is effectively disabled. This provides maximum shelf life during storage.
Run Mode
In Run mode, the unit is considered to be fully on. The IVM is collecting, logging and analyzing data, and the LCD screen is on. The user is presented with real time graphical indicators of the valve's current state of operation, as well the opportunity to review past data and set various options.
The IVM will automatically enter Run mode upon power-up, or upon receiving any keypress during Sleep mode. Through the admin menu, the user also has the option to have the IVM "wake on event", which means that the device will enter Run mode upon sensing any activity from the valve.
Sleep Mode
In Sleep mode, the unit is still collecting and logging data, but the LCD is turned off to conserve battery power. This is the most common mode of operation; when everything is working the way that it should, the IVM will sit silently and watch the valve.
The IVM automatically enters sleep mode when the Sleep timer runs out. A value for this timer can be set in the admin menu; a common value is around 60 seconds. The timer begins as soon as the last key is pressed on the keypad, and resets with every keypress. Pressing a key while the unit is in Sleep mode will still reset the timer, thus waking the unit.
Shutdown Mode
Shutdown mode was introduced in order to conserve battery life during periods of non-use. This can be useful for a contractor who uses a single unit to monitor several different sites temporarily. When the contractor is finished with a particular site, the unit can be shut down and the contractor will not have to worry about removing the batteries. While in Shutdown mode, the unit is completely off; the IVM will not collect any data and will not perform any calculations.
To enter Shutdown mode, enter the Version Info screen from the Admin menu. Pressing UP while viewing the Version information will Shutdown the IVM. To wake from Shutdown, press and hold the OK button for approximately three seconds, until the display turns on.
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September 28, 2005
Our Intelligent Valve Monitor (IVM) prototypes are seeing more use each day. We've had a number of inquiries about the device, and would like to take a moment to answer some of the most common questions. Please feel free to contact us with any additional questions. We will update this article with new questions as we receive them.
How do I install the IVM?
To install the IVM, line up the opening on the side of the mounting pipe with the inlet of your valve, and lower the IVM on top of the valve until it lies flush with the base. There should be very little side-to-side play; if there is, the IVM should be turned gently clockwise until resistance is encountered.
What do I need to do to retrofit an existing system?
Inside the valve, there is a disc/stem assembly. This assembly needs to be replaced with one of ETC's IVM disc/stem assemblies, included with the IVM. To do so, simply remove the 8 screws on the top of the valve, lift off the cover, and swap the assemblies. Once you've replaced the cover, your valve is ready for our IVM.
What kind of valve can the IVM be used with?
The IVM can be used with K-Rain's 6000 series valves, either the 4-outlet or 6-outlet versions. Both models can be configured mechanically to use less than their maximum outlets (ie, 3 outlets active on a 4-outlet valve), and the IVM can be set up to recognize this.
Will I need a different unit for 4-outlet and 6-outlet valves?
No. Our current IVM can be used on either model; there is an option on the admin page of the unit which allows you to select which valve you are monitoring.
What kind of battery does the IVM use?
Our current model uses a single CR123A, commonly used as a camera battery. This should be readily available in most stores. In the future, a AA or AAA version may be available.
How many events/errors does the IVM store?
In addition to storing the total count and time spent on each outlet, we save the 16 most recent events. Also, if an event occurs more than once in a row, we store the number of times that that event occurred, rather than creating a new entry.
The "Reset" function only clears the period counts. How can I clear the totals?
Currently, the only way to clear the totals is to perform a complete memory erase on the board. Do not do this unless you are absolutely sure that you want to erase everything. When powering on the unit (when you first insert the battery, or when waking from Shutdown mode), hold down the ! button. When the display turns on, release the button and press UP and DOWN together.
How do I wake the IVM from Shutdown mode?
The IVM has a Shutdown mdoe that is intended to conserve battery life during storage, accessible from the Version screen. While in Shutdown, the unit is completely non-functional, and keypresses will not wake the unit up. The unit can be powered up again by holding the OK button for approximately three seconds, until the display turns on.