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ControlByWeb Case Study: Water Treatment Process Control System

How To Make Water Treatment More Accessible To Rural Communities

When the town of Denison, TX decided to replace their aging SCADA system at the Randell Water Treatment Plant, they gave themselves a budget of $100K. For a growing town of just over 20,000 residents, that money was highly sought after for many municipal needs, from roads to employees.

But a new SCADA system was also badly needed. Not only was their system out of date, it was overly complex for their city employees to manage. When programming needed to be altered in any way, they were forced to pay a specialist, who understood ladder logic programming, to come in from out of town. This was both time consuming and expensive. Angus Evans, Water Plant Superintendent in Denison, knew they needed a system they could operate and program themselves.

Water Treatment System Stats:

  • 12.8 MGD Capacity
  • 4.6 MGD Daily Average
  • 2 Clarifiers
  • 6 Mixed Media Filters
  • 5 Ground Storage Tanks
  • 5 Elevated Tanks

The Right Fit

After doing some research, Evans found ControlByWeb’s X-600M Expandable I/O system that not only was easy to program in-house, but one that also worked with their existing equipment. The cost of the system would also come in significantly under budget.

The platform was a perfect fit. The X-600M’s no-code programming, open communications, and small price tag was exactly what they needed. Evans currently uses seven X-600M controllers and various expansion modules to monitor and control Denison’s sedimentation-filtration treatment system, rated to treat up to 12.8 million gallons per day.

The total price tag for their new control system came in around $10K; about 90% under budget.

“We use the X-600 from ControlByWeb as both our process controllers and SCADA in our municipal water supply treatment facility. They’re easier to set up and program than a Ladder Logic PLC and their graphing feature gives us what we need to monitor every parameter at our water plant. We created our control system using the X-600 for around $10k as opposed to the $100k that our city had budgeted, and we no longer need to call in a ladder logic programmer to adjust our controls,” explains Evans.

The new control system was installed in the fall of 2017. Several years later, Evans is still happy. The controllers have proven reliable and easy to program. With the X-600M, his crew is able to monitor and control a variety of I/O points such as:

  • Pressure
  • pH
  • Turbidity
  • Level
  • Flow
  • Chlorine residual
  • Pump speed
  • Motor speed
  • Motor temperature
  • Motor run status
  • Valve position
  • Pressure switches
  • Limit switches

“The controllers have been reliable, the support from ControlByWeb has been awesome, and there is nothing proprietary about their software or communications that limits what we can do. We’re able to monitor any 4-20mA or digital signal so we can do all the pump, motor, and valve control we need for our entire water treatment and storage process.”

X-600M as a SCADA

The X-600M’s dashboard is used as the SCADA software. Plant operators monitor graphs and other visual metrics for each process, and can determine action items based on the charted results. More expensive systems have an illustrated schematic of the water treatment system. However, Evans says, ”We know what it looks like. The most important part is the graphing function. That’s what we like to see.” For Evans and the city of Denison, the savings are worth not having illustrated schematics.

For those who have or want traditional SCADA software, all ControlByWeb I/O modules, including the X-600M, can easily send data to any SCADA over Ethernet via Modbus TCP/IP. This inherent flexibility is a tremendous benefit, especially for smaller water districts, or whenever budgetary constraints require concessions.

Water Treatment Process Control Kits

Water treatment process control systems need many I/O points, programmable logic, and a graphic interface for viewing the process performance. The X-600M is a great process controller for small to medium-sized water plants. The analog inputs on the X-22s and the variety of relay control provided, through the X-19s, give you the I/O points needed. Finally, the VEGA level sensor and display units round out a great foundation for a water plant control system from which to build.

Items in Kit:

Continuous level data must be accurate for proper water plant operation. With the increasing affordability of non-guided radar, the VEGAPULS C 11 is an ideal level transmitter for nearly any water level measurement task. VFD pump control maintains a continuous process via the X-420 programmable controller and the X-317 analog output module.

Items in Kit:

Frequently Asked Questions

There are many technologies for water treatment solutions on the market. However, the basic operating principle is to remove suspended solids from the water and then disinfect it. This is done through a variety of screens, tanks, filters and chemical additives. Each stage of the water treatment process removes finer particulates until the water is ready for human use.

Conventional systems usually follow the same steps: collection, screening, coagulation and flocculation, sedimentation and clarification, filtration, and finally, disinfection. Collection simply refers to your water source and how you pipe it into your water plant. Screening filters out large debris. Coagulation and flocculation happens by adding chemicals that cause suspended solids, like dirt, to bind together and fall to the bottom. Sedimentation and clarification allows those solids to separate and skims the clear water off the top. Filtration uses fine filters to remove any remaining solids and prepare it for disinfection. Finally, disinfection kills any micro-organisms, which makes the water safe for human consumption. The clean water is then stored for delivery to businesses and homes.

Sensors for liquid monitoring and control are used in water plants to control their flow through the mechanical and chemical processes which ultimately prepares the water for residential, commercial, and industrial use. Common sensors found in any water treatment facility include:

  • Level
  • Flow
  • Turbidity
  • Temperature
  • Pressure
  • pH

ControlByWeb I/O modules gather all this data and provide the programmable logic and output signals which, in turn, controls each process. Our programmable controllers have RS-485 Modbus and analog inputs such as 4-20 mA and 0-10 VDC to monitor data continuously, and they also have digital inputs to monitor dry contacts. Our relays, analog outputs, and digital outputs allow you to convert that sensor signal into nearly any process control.

Nearly any water treatment process can be automated. So which ones should you prioritize, and which ones are best left to manual intervention? Like all things in life, it depends on the situation. If you have access to and can afford to hire very technical, well-trained operators, then you could automate the whole process and feed data to your operators who can understand the nuances and intervene only when necessary. That requires the right maintenance crew and industrial programmers to alter the process as necessary and optimize for the health of your community. If you don’t have this kind of workforce, for whatever reason, then you’ll need varying degrees of simplification to suite the skill set and resources available to you.

With ControlByWeb, the control programming and monitoring is not only more affordable, but simpler as well. This gives smaller communities more access to automation which increases productivity, enhances quality control, and improves response time to and proper diagnosis of problems.

ControlByWeb programmable I/O controllers use a built-in web server that allows you to monitor and control pumps using a standard web browser. The logic is stored on the device which offers a few advantages:

  • Your control reliability is independent of network connections.
  • Cloud server stability does not affect reliability or the ability to program the controller.
  • Cloud data storage is optional, so you don’t have to pay monthly fees.

Each controller has a variety of inputs and outputs. For basic pump control with continuous level sensors, we often recommend our X-420 which has 4 analog inputs and two digital outputs. For float level switches, we typically recommend our X-410 which has 4 digital inputs and 4 relays. Both modules use our Task Builder software which lets you easily create set points and program relays using drop-down menus in a no-code environment.

Three of the most common continuous level sensors for water plants are ultrasonic, radar, and hydrostatic pressure. There are also point-level switches of various types. Here’s a quick synopsis for each:

  • Ultrasonic Level Sensors
    These are great sensors for clean water tanks, flumes, and weirs. They’ve been around a long time, are reliable in controlled environments, cost effective, and have good accuracy. However, they aren’t always suitable for tanks with interior features, obstructions, or process variables like foam, vapor, or high temperatures.
  • Non-guided Radar Level Sensors
    The clear competitor to ultrasonic is the more recent non-guided radar level sensor. They can be more accurate and handle process variables like foam, vapor, etc better than ultrasonic. The price has come down fairly dramatically over the last several years and some non-guided radar sensors are price competitive with ultrasonic. The main disadvantages are their higher cost and they are a bit more complex to tune.
  • Hydrostatic Pressure Transmitter
    Also known as a submersible pressure sensor, these pressure transmitters are housed in a waterproof case that can be lowered to the bottom of a tank and convert water column pressure, or head pressure, into a tank level in your preferred unit of measure. These are ideal for deep wells and water towers where the distance is too great for a non-contact type of measurement.
  • Point-Level Switches
    Float switches, capacitive level switches, and others are staples in the basic level control world. They work great for alarms, valves, redundant level control, and emergency on and off switches. They’re still widely used for pump control because they work. They’re inexpensive and reliable, but don’t provide the data or the fine-tuned control possible with continuous measurements, PID loops, VFDs, etc.

ControlByWeb – Etäohjaus ja etämonitorointi

ControlByWeb verkkopohjaiset I/O ohjaimet ja kontrollerit ovat erittäin luotettavia ”drop-in” ratkaisuja etäohjaukseen ja -monitorointiin. Ensimmäinen tuote on jo vuodelta 2005 eli WebRelay™, joka on verkko-ohjattu rele sisältäen myös digitaalisen tulon. ControlByWeb on sittemmin valmistanut laajan valikoiman tuotteita teollisuuden automaatioon, tiedonkeruuseen ja seurantaan.

Monet heidän tuotteistaan ​​sisältävät erilaisia ​​tuloja ja lähtöjä (relelähtöjä, digitaalisia ja analogisia tuloja, 1-johdinväylän (1-Wire) lämpötilan ja kosteuden seurantaan jne.), joita voidaan käyttää elektronisten laitteiden kaukoohjaukseen ja -valvontaan. Suurin osa heidän I/O-tuotteistaan ​​tukee sähköposti-ilmoituksia, toimintojen ajoituksia, tallennusta, useita protokollia (Modbus, SMNP, SMTP …) ja monia muita ominaisuuksia.

Kaikissa ControlByWeb-tuotteissa on sisäänrakennetut verkkopalvelimet, jolloin niitä voidaan konfiguroida, monitoroida ja hallita verkkoselaimella tai CBW-mobiilisovelluksella. Ne toimivat kuten standardi RTU (Remote Terminal Unit), joten ne on myös helppo integroida olemassa olevaan prosessiohjaus-järjestelmään. Kummassakaan tapauksessa ei tarvita erityistä ohjelmistoa, ei ajureita asennettavaksi eikä muita ylimääräisiä veloituksellisia palveluita.

ControlByWeb-pilvipalvelu helpottaa tietojen käyttöä ja laitteiden hallintaa.

Helmikuussa 2021 julkaistu ControlByWeb-pilvipalvelu tekee etävalvonnasta ja usean sijainnin hallinnasta helpompaa kuin koskaan. ControlByWeb-pilviyhteensopivien laitteiden avulla voit seurata ja ohjata melkein mitä tahansa, kuten ravintolan kylmälaitteita, etäreleitä tai generaattorin polttoainesäiliöitä.

ControlByWeb-pilvipalvelu tekee luonnostaan joustavasta I/O-alustasta entistäkin helpomman käytettävän ja hyödyllisemmän kuin koskaan ennen. Pilvipalvelun käytön veloitus pohjautuu palvelun piirissä olevien laitteiden määristä, ei I/O-pisteiden (endpoint) määristä.

Tutustu tuotteisiin oheisen linkin kautta: ControlByWeb – Etäohjaus ja etämonitorointi
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