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Fuses vs. Circuit Breakers

The recommendations in this article are admittedly biased towards fuses, but for what EPG believes to be valid reasons. Fuses are not always the correct choice for motor protection. However, it has been our experience that fuses are the best choice for the products we are manufacturing. When designing our products we strive to provide a product that will be safe, reliable, and cost effective.

Safety

EPG uses current limiting fuses which have a 200,000 Amp interrupting capacity. The typical fuse size used on our applications is smaller than 30 amps, with 200,000 Amps of prospective short circuit current. The current limiting fuses that we use limit the RMS let-thru current to less than 4,000 Amps and the peak let-thru current to less than 8,000 Amps, greatly decreasing the risk to personnel and equipment.

NOTE: When evaluating prospective short circuit current in multiple motor applications you must consider the contribution of all operating motors to the short circuit current in addition to the utility.

Overcurrent protective devices that trip are often reset without first investigating to find the cause of the fault. Electromechanical devices that have opened high level faults may not have the reserve capacity to open at a 2nd or 3rd fault safely. (When a fuse opens it is replaced with a new fuse, the protection is not degraded by previous faults.)

Arc Flash

The use of fuses can reduce the dangers of Arc Flash. Arc Flash can be described as an explosion of energy with the potential to cause severe injury and damage to equipment. The costs of medical treatment and equipment repair or replacement due to these incidents can be great. It is more important than ever that employers be diligent in their effort to provide a safe working environment.

Reliability

A fuse has no moving parts to wear or become contaminated by dust, oil, or corrosion. The speed of response of a fuse will not slow down as the fuse ages. In other words, the fuse’s ability to provide protection is not adversely effected by the passage of time.

Selectivity

Fuses may be coordinated to provide selectivity without compromising short circuit protection; something that is very difficult to do with circuit breakers.

Cost Effective

You do not pay a premium for high-interrupting capacity. The fuses we use are rated 200,000 A.I.C. or greater. Devices with lower interrupting ratings are often rendered obsolete by increases in available fault current. Costly system upgrades may be required to maintain system safety.

EPG designs are Type 2 coordinated protection. If a fault should occur, only the zone containing the fault will be effected. The rest of the system will continue to function. Type 2 protection, as a result of the use of current limiting fuses, assures that system components are not subjected to damaging fault currents, minimizing repair costs.

The use of current limiting fuses with high interrupting capacities often allows the use of smaller, lower ampacity disconnects. This also allows the use of the smaller IEC motor starters. Both in turn result in lower initial costs as well as repair costs.

 

The video clips below help illustrate the power of Arc Flash and the benefits of using Fuses vs. Circuit Breakers.

NEMA Starter Test

IEC Starter Test

*Video clips courtesy of Cooper-Bussmann.

Learn more about the anatomy of Arc Flash and NEC Article 409 regarding industrial control panels in EPG's Summer 2006 newsletter.

For more information regarding the dangers of Arc Flash, prevention of incidents and compliance visit the following websites:
www.osha.gov (OSHA code 29)
www.nfpa.org (NFPA 70)

EPG or equivalent?

A photo may not tell the whole story...

...but it's a great way to begin.

Choosing the right equipment for the job seems like a fairly obvious notion to adhere to. A recent trip to a landfill revealed some all too familiar results when disregarding this idea. A competitor seemed to have over-sold the capabilities of their equipment, leaving the customer in a position to replace it sooner than might be expected. All too often false claims and misleading price comparisons influence the decision to, unknowingly, acquire products unsuitable for the application. As shown in these photos, using components intended for less harsh environments can save money but will most likely lead to serious corrosion and premature pump & controls failure. In fact, many components including the touch screens (which can be susceptible to exposure to the sun and elements if not installed properly), starters and circuit breakers in those panels required replacing.

EPG's stainless steel pumps, controls and breakout boxes have been operating at the same site successfully, providing a clear indication that they are up to the task in the very same environment that literally "ate" the competitors equipment.

It's no accident that a majority of projects today call for "EPG or equivalent" in the specifications. We take pride in having a good reputation within the industry and being recognized in this manner. We also caution against the notion there is an equivalent to EPG's equipment.

The quality, reliability and longevity of EPG products is proven and not only stand on their own merits, but in comparison to numerous imitators, inferior designs, and empty promises.

EPG understands that our customer's ultimate goal is to get maximum value without compromising performance. This is a philosophy we believe in as well and drives us to provide the best equipment and service in the industry.

s-pump002

s-pump001

s-panel001

 

EPG or Equivalent

 - Is it Really Equal?

From the November 2013 Connection Newsletter

It's no accident that a large number of landfill projects today call for "EPG or equivalent" in the specifications.

We've worked diligently for many years to establish "best practices" with research, development, experience, and innovation. We take pride in our good reputation within the industry and being recognized in this manner.

We also caution against the notion that there is an equivalent to EPG's equipment. The quality, reliability and longevity of EPG products is proven and not only stand on their own merits, but in comparison to numerous imitators and inferior designs.

The photos to the right are a great example of an imitator failing to deliver "or equal" quality and performance. The pump discharge adapter at the top of the first photo and shown closeup in the second leaked when put into service. This occurred due to the poor welds, inferior design, and lack of testing. Did this customer get what they paid for? What do you think? The second adapter is part of EPG's NW Series and performs as advertised.

EPG understands that our customer's ultimate goal is to get maximum value without compromising performance. This is a philosophy we believe in as well, and it drives us to provide the best equipment and service in the industry.

nwss

 

EPG NW Series Discharge Adapter

Features:

  • Solid 316 or 304 Stainless Steel construction.
  • 1.5″, 2″, 3″, and 4″ NPT sized fittings for pump, lift-out, and discharge pipes.

Download the NW Series Flyer Here

 

 

EPG U.S. Patents

EPG holds 4 patents relating to the SurePump™ Sump Drainer product line.
March 10, 2009

256px-us-patenttrademarkoffice-seal-svg

 

 

 

 

SUMP DRAINING APPARATUS
Patent Number:  4,966,534
Date of Patent: Oct. 30, 1990

SUMP DRAINING APPARATUS
Patent Number:  4,992,030
Date of Patent: Feb. 12, 1991

SENSOR MOUNT FOR SUMP DRAINING APPARATUS
Patent Number:  6,729,848 B1
Date of Patent: May 4, 2004

SUMP DRAINING APPARATUS HAVING EASILY REPLACEABLE SENSOR AND MOUNT THEREFOR
Patent Number:  7,500,835 B2
Date of Patent: Mar. 10, 2009

EPG Pumps – Suitable for Class I, Div 1 & 2

EPG Pumps – Suitable for Class I, Division 1 & 2 Locations

Before a pump can be considered suitable to be used in Class I, Division 1 hazardous (classified) locations, it must first meet at least  one of the four criteria established in paragraph (a) of the National  Electric Code (NEC), Article 501-8 Motors and Generators. Condition (4) states:

“Of a type designed to be submerged in a liquid that is flammable  only when vaporized and mixed with air, or in a gas or vapor at a pressure greater than atmospheric and that is flammable only when mixed with air; and the machine is arranged so to prevent energizing it until it has been purged with the liquid or gas to exclude air, and also arranged to automatically de-energize the equipment when the supply of liquid or gas or vapor fails or the pressure is reduced to atmospheric.”

EPG pumps meet the intent of NEC 501-8, condition 4 in the following way:

The motors used in EPG pumps are filled with a mixture of glycol and water. During normal operation, this fluid lubricates the internal sleeve bearings. If motor temperature increases beyond normal operating temperature, the internal fluid boils out and the motor temperature starts to rise. At 225° F, internal insulation of the motor fails causing a winding-to-winding internal short, (sealed between inter and outer stainless steel shells surrounded by non-hydroscopic insulation). When this phase-to-phase short occurs, the motor will be automatically de-energized. Without an ignition source, there can be no explosion.

Paragraph (b) Class I, Division 2 of the National Electric Code (NEC), Article 501-8 Motors and Generators, states:

“The installation of open or non-explosion proof enclosed motors, such as squirrel-cage induction motors without brushes, switching mechanisms, or similar arc-producing devices, shall be permitted.”

EPG pumps also meet this criteria since they contain no arc-producing devices. In fact, the same motor design of EPG pumps is used in almost every underground gasoline storage tank pump application throughout the US.

EPG pumps have been time-tested (over 35 years) and field-proven (over 12,000 installations) to be suitable for service in over 1,500 landfills worldwide. EPG pump motors have also been tested under a dozen or more failure modes and found to have a maximum surface temperature at failure of 225° F. In addition, the power cable used with EPG pumps are made from the same material used in off-shore drilling rig applications. This material was selected when designing the power cables because it is extremely chemical resistant, waterproof, and more cut/abrasive resistant than extra heavy-duty service cable and it does not sustain combustion.

Based on meeting NEC criteria, manufacturing design and service/performance record, EPG pumps have been proven to be suitable for Class I, Division 1 & 2 locations.

EPG Pumps

  • Meet NEC criteria for Class I, Division 1 & 2 locations
  • Field proven with over 12,000 installations in more than 1,500 landfills
  • Time tested with over 35 years of dependable service
  • Motors contain no arc-producing device
  • All internal parts are dissimilar and not a source of energy release
  • Extremely chemical resistant, waterproof and abrasive resistant
  • Maximum surface temperature of 225° F – can not sustain combustion
  • Power cable used is more abrasive resistant than extra heavy-duty service cable
  • Motor stator windings are hermetically sealed
Get The Bulletin

SCADA System Assessment

Inquire About SCADA Systems

This article offers a basic overview of SCADA telemetry network system information. It is intended to help educate and equip you for future SCADA and/or telemetry system decisions.

See also our E-WaveTM Wireless Switches and if you are interested in telemetry hardware, please give us a call or visit NBT, our telemetry hardware division. See also the PEMEX – SCADA Case History.

INTRODUCTION

Supervisory Control and Data Acquisition (SCADA) is a system that allows an operator at a master facility to monitor and control processes that are distributed among various remote sites.

A properly designed SCADA system saves time and money by eliminating the need for service personnel to visit each site for inspection, data collection/logging or make adjustments. Real-time monitoring, system modifications, troubleshooting, increased equipment life, automatic report generating . . . these are just a few of the benefits that come with today’s SCADA system.

Other benefits SCADA Systems provide:

  • Reduces operational costs
  • Provides immediate knowledge of system performance
  • Improves system efficiency and performance
  • Increases equipment life
  • Reduces costly repairs
  • Reduces number of man-hours (labor costs) required for troubleshooting or service
  • Frees up personnel for other important tasks
  • Facilitates compliance with regulatory agencies through automated report generating
  • And more . . .

As technology continues to advance, SCADA systems will become recognized as a standard for any processing site. But from the hundreds of system providers available today, which one will you listen to? What system will be right for your application? Who will you choose to partner with and why?

Choosing a SCADA system provider that will design a system applicable to your needs can be an overwhelming and confusing task. With little or no knowledge of SCADA and Data Acquisition systems and an incomplete pre-system assessment, the decisions made can be costly mistakes. Too often the decisions are based on . . .

Price:

The quality of the work and components suffer when vendors are eager to get to the bottom to win the low bid. Vendors will then indiscriminately find ways to still make a profit. You get what you pay for!

Proprietary Equipment:

Do not eliminate your options. After proprietary equipment has been installed as “standard” for the system, the customer can be held hostage and be forced to pay an inflated price. In addition, a closed protocol leaves the end-user with fewer options for integrating future equipment from vendors as well as being vulnerable to lack of support and inability to replace failed components due to obsolescence and/or company shutdown.

Excessively Complex or Customized Equipment:

Many operators are “wowed” by system specialists demonstrating all the capabilities of their SCADA system. After installation, the system is too complex for them to understand, operate and support. What you will have is a very expensive system running at minimum while the operator continues to work the old habits. The only recourse is to purchase expensive training and/or service contracts, which do not always guarantee prompt and professional service. Some SCADA systems have been shut down for months while waiting for a single source of technical support to arrive. Keep it simple wherever possible.

Years of Experience:

Be careful. There are a host of reputable SCADA providers with years of experience and knowledgeable expertise that have designed systems that are too broad, expensive and/or do not work. Many companies use this line as if it sets them apart from all the rest. Experience and knowledge is important but only as a starting point when determining what vendor is right for you.

Sales People and/or Flashy Marketing:

Good sales and marketing strategies are meant to produce “top-of-mind”, “foot-in-the-door” results. They may lure you or pressure you rather than equip you in making a sound decision based on all factors that affect optimum system performance.

These and other costly mistakes can be avoided through knowing, understanding, and carefully assessing your particular needs. For some, that may mean skimming through this article and then focusing on Table A and B below. For others, with little or no SCADA knowledge, you should read and become familiar with the background information provided below.We at EPG Companies Inc. have prepared this Pre SCADA System Assessment to help equip you in determining what SCADA or Data Acquisition system is right for you. If you have any questions or comments after reviewing this assessment, please call us at 800-443-7426 and ask for a SCADA or Data Acquisition specialist. We have served the industry for over 20 years manufacturing systems that save time and money, are easy to use, and give years of dependable process control.

A BRIEF HISTORY

The development of SCADA can be traced back to the early 1900’s with the advent of telemetry. Telemetry involves the transmission and collection of data obtained by sensing real-time conditions. The monitoring of remote conditions became possible with the convergence of electricity, telegraph, telephone, and wireless communication technology. Throughout the last century, more industries, such as gas, electric, and water utilities, used telemetry systems to monitor processes at remote sites.

SCADA began in the early sixties as an electronic system operating as Input/Output (I/O) signal transmissions between a master station and a Remote Terminal Unit (RTU) station. The master station would receive the I/O transmissions from the RTU through a telemetry network and then store the data on mainframe computers.

In the early seventies, DCS (Distributed Control Systems) were developed. The ISAS5.1 standard defines a distributed control system as a system that while being functionally integrated consists of subsystems, which may be physically separate and remotely located from one another. Large manufacturers and process facilities utilized DCS primarily because they required large amounts of analog control.

Further development enabled Distributed Control Systems to use Programmable Logic Controllers (PLC), which being more intelligent than RTUs, have the ability to control sites without taking direction from a master.

In the late nineties, the differences between SCADA and DCS blurred. SCADA systems had DCS capabilities. DCS had SCADA capabilities. Systems were customized based on certain control features built in by designers. Now with the Internet being utilized more as a communication tool, control functions that were once old telemetry systems are becoming more advanced, interconnected and accessible. Automated software products are being developed to exploit the inter-connectivity of the Internet and certain portals can connect to a SCADA system and download information or control a process.

Good SCADA systems today not only control processes but are also used for measuring, forecasting, billing, analyzing and planning. Today’s SCADA system must meet a whole new level of control automation, interfacing with yesterday’s obsolete equipment yet flexible enough to adapt to tomorrow’s changes.

Whether you need a new system or are upgrading an older one, it is important to know the system components before you decide on who to talk with and what equipment you will need for your particular application.

SYSTEM COMPONENTS

SCADA systems typically have four major elements:

  1. Master Terminal Unit (MTU)
  2. Remote Terminal Unit (RTU)
  3. Communication Equipment
  4. SCADA Software

 

 

 

1. Master Terminal Unit (MTU)

The Master Terminal Unit is usually defined as the master or heart of a SCADA system and is located at the operator’s central control facility. The MTU initiates virtually all communication with remote sites and interfaces with an operator. Data from remote field devices (pumps, valves, alarms, etc.) is sent to the MTU to be processed, stored and/or sent to other systems. For example, the MTU may send the data to the operator’s display console, store the information, and then send an operator’s initiate command to a field pump’s RTU.

2. Remote Terminal Unit (RTU)

The Remote Terminal Unit is usually defined as a communication satellite within the SCADA system and is located at the remote site. The RTU gathers data from field devices (pumps, valves, alarms, etc.) in memory until the MTU initiates a send command. Some RTUs are designed with microcomputers and programmable logic controllers (PLCs) that can perform functions at the remote site without any direction from the MTU. In addition, PLCs can be modular and expandable for the purpose of monitoring and controlling additional field devices. Within the RTU is the central processing unit (CPU) that receives a data stream from the protocol that the communication equipment uses. The protocol can be open like Modbus, Transmission Control Protocol and Internet Protocol (TCP/IP) or a proprietary closed protocol. When the RTU sees its node address embedded in the protocol, data is interpreted and the CPU directs the specified action to take.

During the sixties, many manufacturers developed RTUs with communicative functions that performed a few specific tasks such as monitor and control digital and analog field devices. These “all-in-one” RTUs needed constant communication with the MTU in order to operate. A wide variety of programming languages were used that were not well known or supported. In the eighties the first “micro” PLCs were introduced as the first “Open Architecture” technology which has evolved and gained acceptance as today’s preferred alternative to closed, proprietary systems.

Some manufacturers, like EPG’s SCADA division NBT, now make Remote Access PLCs (RAPLC) specifically designed for SCADA and Data Acquisition applications. With NBT’s PLC system, you can:

  • Perform control
  • Check site conditions
  • Re-program anytime from anywhere
  • Have any alarm or event trigger a call to your personal computer

This can all be done from a single, master site and the system can control one or multiple sites. Both industry representatives and customers welcome these “smart” PLCs because they provide remote programmable functionality while retaining the communications capability of an RTU.

3. Communication Equipment

The way the SCADA system network (topology) is set up can vary with each system but there must be uninterrupted, bidirectional communication between the MTU and the RTU for a SCADA or Data Acquisition system to function properly. This can be accomplished in various ways, i.e. private wire lines, buried cable, telephone, radios, modems, microwave dishes, satellites, or other atmospheric means, and many times, systems employ more than one means of communicating to the remote site. This may include dial-up or dedicated voice grade telephone lines, DSL (Digital Subscriber Line), Integrated Service Digital Network (ISDN), cable, fiber optics, WiFi, or other broadband services.

There are many options to consider when selecting the appropriate communication equipment and can include either a public and/or private medium. Public medium is a communication service that the customer pays for on a monthly or per time or volume use. Private mediums are owned, licensed, operated and serviced by the user. If you choose to use a private medium, consider the staffing requirements necessary to support the technical and maintenance aspects of the system.

Private Media Types:

Private Wire

Sometimes it makes sense to string or bury your own cable between sites to provide continuous communication. This type of media usually is limited to low bandwidth modems.

Wireless

(Spread Spectrum Radio)

This media type is license-free and available to the public in the 900 MHz and 5.8GHz bands. The higher the frequency used in the system, the more “line of sight” it becomes. Some Spread Spectrum radio units have the ability to span distances by re-strengthening signals for the next radio in line, acting like a repeater for other units in the network. Spread Spectrum radio modems generally have built in error correction, encryption and other features that make them a reliable, secure and long-lasting solution for network communication.

(Microwave Radio)

Microwave radio transmits at high frequencies through parabolic dishes mounted on towers or on top of buildings. This media uses point-to-point, line-of-sight technology and communications may become interrupted at times due to misalignment and/or atmospheric conditions.

(VHF/UHF Radio)

Good for up to 30 miles, VHF/UHF radio is an electromagnetic transmission with frequencies of 175MHz-450MGz-900MHz received by special antennas. A license from the FCC must be obtained and coverage is limited to special geographical boundaries.

Public Media Types:

(Telephone Company)

There are different services that your local telephone company can provide including: Switched Lines, Private Leased Lines, Digital Data Service, Cellular and PCS/CDPD.

  • Switched Lines: Public Switch Telephone Network (PSTN) and Generally Switched Telephone network (GSTN) are dial-up voice and data transmission networks furnished by your local telephone company.
  • Private Leased Lines: Private Leased Lines (PLL) are permanently connected 24 hours a day between two or more locations and used for analog (continuously varying signal) data transmission.
  • Digital Data Service: Digital Data Service (DDS) is a private leased line with a special bandwidth used to transfer data at a higher speed and lower error rate. This service is applicable for computer-to-computer links.
  • Cellular: This service is equivalent to Switched Line services over landlines.
  • PCS/CDPD: This service is provided by cellular companies on a monthly fee or traffic volume basis and is used when continuous communication is needed.

Other Media Types:

(WiFi-SMR)

Sometimes it makes sense to use the infrastructure of another company. WiFi equipment utilizes broadband with high data rates and is used in a “time-share” basis to communicate between sites of the system. This media type generally requires advanced protocols like TCP/IP and network type connections.

(Satellite-Geosychronous/LEO)

Geosynchronous satellite’s orbits are synchronous with the earth’s orbit and remain in the same position with respect to the earth. These satellites use high frequency transmissions received by parabolic dish antennas. Low Earth Orbit (LEO) satellites hand off signals to other satellites for continuous coverage and latency times are less than geosynchronous satellites due to the lower orbit.

4. SCADA Software

A typical SCADA system provides a Human Machine Interface (HMI) allowing the operator to visualize all the functions as the system is operating. The operator can also use the HMI to change set points, view critical condition alerts and warnings, and analyze, archive or present data trends. Since the advent of Windows NT, the HMI software can be installed on PC hardware as a reliable representation of the real system at work.

Common HMI software packages include Cimplicity (GE-Fanuc), RSView (Rockwell Automation), IFIX (Intellution) and InTouch (Wonderware). Most of these software packages use standard data manipulation/presentation tools for reporting and archiving data and integrate well with Microsoft Excel, Access and Word.

Web-based technology is widely being accepted as well. Data collected by the SCADA system is sent to web servers that dynamically generate HTML pages. These pages are then sent to a LAN system at the operator’s site or published to the Internet.

THE MICROPROCESSOR OPTION

 

Now that you have a basic understanding of the SCADA system components, you may want to consider utilizing a microprocessor (MP) and/or a PLC-based SCADA system over a basic RTU or a proprietary system for the following reasons:

MCH1000 Level MeterPs, like MTUs, can continuously collect, process and store data, operating independently from the MTU through “intelligent” programming. In addition, by utilizing an EPG microprocessor-based level meter (pictured), you can have a robust SCADA system with both a master and a local display that automatically gathers, processes, and reports data necessary to comply with local, state and federal regulations in formats that integrate well will Microsoft Excel, Access and Word.

MPs can provide security and monitoring of door switches, heat and motion detectors. Managers/operators can be informed 24 hours a day through automatic email, paging and dial-up call features. Multiple users can easily be added and if open architecture protocol is used, future equipment can easily be integrated. Since MPs have no moving parts, they are extremely reliable and can be designed to be repairable with components that any local electrical distributor supplies.

MP-based SCADA system can reduce the number of man-hours needed for on-site visual inspections, adjustments, data collection and logging. Continually monitoring and troubleshooting potential problems increases equipment life, reduces service calls, reduces customer complaints and increases system efficiency. Simply put, open-architecture, MP-based SCADA systems are an excellent means for process control facilities to save time and money.

FEATURES & BENEFITS

Now lets look at some of the features and benefits you’ll receive from a properly engineered PLC-based SCADA system.

 

 

Features:

  • PLCs have no moving parts. They are extremely robust and reliable.
  • If communication with the MTU is lost, a PLC-based RTU can operate alone through “intelligent” programming.
  • PLC programs are easy to understand and easy to use and can be completely documented with simple and extensive descriptions, technical programming and support manuals.
  • PLCs are modular and can provide room for future expansion and growth.
  • Programming for security sensors can be integrated into PLCs providing security and monitoring of door switches, heat and motion detectors. The SCADA system can then automatically notify as prescribed.
  • No waiting period to replace electrical components. The SCADA system can be designed to use components that any local or national electrical distributor supplies.
  • Standard built in diagnostics can continuously monitor and display all status and fault information in easy to understand text.
  • The HMI (Human Machine Interface) software can provide extensive, on-screen documentation including operators manual, wiring diagrams, programs, etc.
  • PLC-based SCADA systems can automatically gather and report data necessary to comply with local, state and federal regulations in formats that integrate well will Microsoft Excel, Access and Word.
  • Data collected can be stored in the PLC and also in the MTU’s database providing a more robust reporting system.
  • The SCADA system can keep managers and operators informed 24 hours a day through automatic email, paging and dial-up call features.
  • Future upgrades and/or new installations of pumps, monitoring systems, level and flow sensors etc., can be easily integrated into the system.
  • Multiple user features can easily be integrated into the SCADA system through web-based technology.

Benefits:

  • PLC-based equipment is usually more reliable and can run without direction from the master control.
  • Operators can see real-time system trouble.
  • The number of customer complaints/inquiries can be drastically reduced, for example: incoming calls concerning low pressure or poor water quality in water systems.
  • PLC SCADA systems save time and money.
  • Wear and tear on equipment can be reduced by continuously monitoring levels.
  • The number of man-hours for troubleshooting and/or maintenance can be drastically reduced.
  • Labor costs can be reduced through automatic report generating.
  • Operating costs can be reduced and greater ROI (return on investment) can be achieved by using a PLC-based SCADA system compared to a proprietary system.
  • Compliance with local, state & federal agencies is met easier.
  • Expensive service calls by repair technicians can be eliminated.
  • Local system integrators and electrical distributors can provide the needed support.
  • NBT PLC-based SCADA systems use open architecture, non-proprietary products and protocol. Price lists are published to eliminate “hostage”, discriminatory price fixing.

You may be able to think of some additional benefits that would be applicable to your own site. Begin by answering the following questions:

  1. What could a PLC SCADA system do for your site?
  2. What type of operation would it perform at the master/remote site?
  3. What are some benefits you would like to receive by having a PLC SCADA system installed at your site?
  4. What aspect of SCADA systems do you need more information on? Organize your thoughts for future reference and then give us a call if you need more help.

IN REVIEW

SCADA systems of today are an excellent means for operators of process control sites to save time and money. But from the hundreds of SCADA system providers to choose from, one poor decision may lead you down the path to countless frustrations, inefficiencies and unnecessary expenses. We at EPG Companies Inc. have prepared this pre-system assessment to help prepare the way for you to purchase a SCADA system that will give you years of cost-effective and dependable process control while leaving you open for tomorrows expansions and options. In closing consider the following:

QUESTIONS TO CONSIDER

The ROI (return on investment) and benefits produced by a properly engineered PLC SCADA system will far outweigh your initial investment if the right equipment is chosen and installed correctly. To help facilitate a suitable and beneficial choice, consider answering the following:

Existing Equipment

  1. How many sites do you have in operation?
  2. What type of equipment is presently in place at all sites? (pumps, valves, monitors, etc.)
  3. What type of equipment will be installed in the future? (upgrades, additions, new sites, etc.)
  4. What type of telemetry, data acquisition or SCADA system is presently installed? (proprietary, outdated, basic telemetry, etc.)
  5. What type of telemetry network or communication path is presently in place?
    Topology: Point-to-Point, Point-to-Multipoint, Multipoint-to-Multipoint
    Transmission Mode: Hardwire, Telephone, Fiber Optics, Radio/Microwave
  6. What type of protocol is being used and will it integrate well with future equipment?
  7. What type of software is being used with the present system? Does it come with complete documentation and support? Is it likely to be supported in the future?
  8. How many data-dependent users are on the present system?
  9. How well would you rate the performance standards of your present system? Is it reliable?
  10. What equipment can/will continue to be used? (field equipment, present SCADA components, software, etc.)
  11. Can the present equipment and/or upgrades integrate well and communicate with the new equipment?
  12. What type of maintenance or service arrangement is presently in place? How will it change with new equipment?
  13. What are your present costs for inspection, maintenance and repair? How can it be changed to be cost-effective? How will it change with a new SCADA or data acquisition system?
  14. If changes are made to the present system, will outside vendors (telephone company, satellite links, etc.) service change and what are those changes? (new transmission modes, service charges, etc.)

Future System Needs

(Telemetry/Communication Path)

  1. Where will the control center be located?
  2. What is the distance you need to span between sites?
  3. Will additional sites be added in the future?
  4. What obstacles are between the control center and each present and future site, if known?
  5. What topology and transmission mode is best suited for your application?
  6. What transmission media is available? (May be different for each site.)
  7. What are your maintenance/service needs? Will you assign your own maintenance personnel or contract out?
  8. How much is in the budget to spend?

(Protocol-Encoding/Decoding)

  1. Will the future system use existing protocol? (If new purchase, do not use proprietary protocol! You will reduce your options for integrating future equipment. If possible, use the Modbus protocol.)
  2. Is there complete documentation?
  3. What existing equipment do you need to connect to?
  4. Do you need a multi-vendor software application to communicate with a variety of manufacturer’s equipment?
  5. Consider the security issues: What type of protection/safeguards will be needed and used to keep out hacking, tampering, sabotage and other unauthorized use.

(Master Control Station)

  1. Do you need the master station to control local input/output and back up operations?
  2. How many sites and stations does your application require?
  3. Will the remote station collect data independent from the master station?

Purchasing Principles

  1. Use open standards architecture, i.e. Modbus protocol.
  2. Purchase from a reputable, established manufacturer.
  3. Equipment must integrate well with existing and future equipment.
  4. Equipment must be supportable and well documented.
  5. Equipment and system overall must be reliable.
  6. Equipment must be easy to use and not cause disruptions to the every day business operation.
  7. Equipment must be non-proprietary, proven technology.

EPG equipment uses the open architecture Modbus protocol, is well documented, and will integrate into any existing system. For over 20 years we have been manufacturing dependable, cost-effective process control solutions for thousands of industry professionals. If you have any questions or would like to talk to a Data Acquisition, SCADA or Telemetry hardware specialist, please give us a call at 800-443-7426. We look forward to partnering with you.

SCADA System Case History

See NBT’s web site (EPG’s Telemetry Division)

SCADA and Data Acquisition:

Pemex System
Natural Gas Production

Objective: Automate 24 sites in Rural Villahermosa, Mexico using Radio Telemetry

This particular project involved using Radio Telemetry to monitor remote gas production sites. The operators needed a central PC to retrieve the production data, view site status, and perform shut downs. Data included AGA-3 calculations from the flow computer (SM805-AGA-3).

Picture of Remote Monitoring using Radio Telemetry to monitor natural gas production

Pemex Case History Flyer

NBT, the Telemetry/SCADA division of EPG, designed, documented, assembled, programmed, and tested the complete system in the factory. Just 5 weeks after receipt of the order, NBT shipped a complete, turn key SCADA system that matched the customer’s specifications. Once received, the mostly Spanish speaking engineers, used our documentation to install and startup the entire system. The SCADA PC was also setup and started without on-site factory support.

The PEMEX system has been in and running without a glitch. There have been NO system problems related to the telemetry equipment. Additional stations and systems have also been added since the original system. Other gas production monitoring systems are in varying stages of completion. The scope of these additional systems has increased, now including automatic report generation and increased point counts.

Most systems integrate bits and pieces of hardware and software from different sources. This is normally required to meet the varying specifications between systems. NBT equipment has the built-in flexibility and functionality to fulfill the requirements of virtually any system. From gas and electric applications to landfill, municipal utilities and industrial applications, we have a solution. Additionally, all NBT products feature an industry standard MODBUS protocol which ensures open connectivity to any existing or new systems.

If you want quality and functionality backed by a company with over 20 years experience supplying systems that work, contact EPG today and talk with an NBT specialist.

For more SCADA information, please see our White Paper:

 Choosing Your SCADA System – A Pre-System Assessment.

E-Wave™ Wireless Switch

Wireless Switches, Modems and RTUs NBT (EPG’s telemetry division) directly designs, manufactures and supports a full range of telemetry products, from RTUs, PLCs, Wireless Switches, Modems to Software. NBT supplied products are engineered and tested to work together long before you get them and are backed by unequaled support. NBT automation systems have been designed to provide complete control over any field operation, from monitoring vital signals, levels, and temperatures, to performing control functions and complex calculations.

EPG Systems At Work

In Mississippi, a landfill had seven leachate sumps, serving forty acres. A sideslope riser design was being utilized with a variety of pumps and control systems spread over a large footprint requiring thousands of feet of conduit and wire. Over time, as pumps failed, a variety of types and brands of pumps were used including water well-type submersibles and grinder pumps. Electrical control panels had been patched together by various contractors with no uniformity. A recent permit modification included a requirement to monitor leachate head daily. This was not possible with the installed equipment. So EPG was invited to visit the site and make recommendations. Why? Because of EPG’s reputation of good performance, technical support, the system approach to leachate management (all components sourced through a single supplier), and the value-added services including EPG’s Pump, Control Panel and Telemetry Schools. Today, after installing EPG pumps, control panels, flow meters, transducers, transmitters, repeaters, receivers, and easy-to-use software, this landfill is experiencing, the EPG difference; optimum performance, uniformity, centralized control and documentation of leachate level.

A 373-acre disposal site in Virginia was having difficulty obtaining field data on a consistent and reliable basis. Personnel had the time consuming task of driving out to each location to make manual adjustments or collect data, and then translate it into a useful spreadsheet format. Needless to say, data gaps and compliance issues occurred due to scheduling, vacation conflicts and time/personnel restraints. EPG had the solution: full site monitoring and control including alarm functions and report writing capabilities from one location. The system includes wireless remote RTUs installed at tanks and lift stations which report to the master station’s computer back at the office. Data to be reported is from nineteen flow meters, seven sump levels and four tank levels. All monitoring information is displayed on the computer and placed in a spreadsheet format.

Now that the EPG system is in place, operating and maintenance costs are down, breakdown and pollution incidents are prevented and system monitoring/reporting help to meet compliance issues.

Does your site need upgrading? Are you facing compliance issues? Do you need centralized control and documentation? Is expansion in the near future? Yes? Then make a difference at your site. Call EPG Companies today and ask for a telemetry control systems specialist.

 

NBT Inc.

EPG Aquires NBT
March 18, 2003

In December 2002, EPG Companies Inc. completed a significant expansion of its control systems integration and SCADA telemetry operations through the purchase of NBT, Nota Bene Technologies of St. Louis Park, MN. This expansion augments EPG’s systems engineering and design manufacturing capacity to continually meet the needs of the landfill, remediation, water & wastewater, mining and industrial markets.

NBT has been involved in the design and manufacturing of a variety of control and communication related products for over 29 years. NBT will operate as a division of EPG serving primarily the US, Canada and Mexico markets providing controllers, remote telemetry units (RTU’s), modems, switches and other communication products.

NBT’s web site is located at www.nbtinc.com

Leachate Collection Sump Design

From The Pumps Point of View - by John Hasslen

GOALS:
Effective Collection of Leachate
Long Life
Leave Trash in the Landfill
Minimum Head on Liner

  • Designing deep sumps allows pumps to run longer without increasing head on liner. The goal is to keep infiltration gallery as wet as possible.
  • Design sump inlet area for velocity of 0.1 foot per second. Slots are more effective in retaining small particles then round holes.
  • Design larger infiltration area around sump. Decrease velocity to one (1) foot per minute in the infiltration gallery.
  • Design guidelines should be taken from good water well design practices.
  • It has been proven in water well design that extended pump run cycles and low velocity reduce or delay incrustation and infiltration of fine solids.
  • Design using coarse filter pack around sump and then finer gravel around this to reduce infiltration.
  • Small sumps and infiltration gallery create greater changes in pressure (velocity) which increase precipitation.
  • The more often gallery is exposed, the more progressive the reduction of open area.

 

STEPS TO TAKE TO DELAY INCRUSTATION AND FOULING

  • Maximize possible inlet area to reduce velocity of flow through infiltration gallery and sump openings.
  • Reduce pumping rates to extend pumping period.
  • Use more then one sump to increase infiltration area and reduce velocity.
  • Periodic maintenance and cleaning.
  • Strictly enforce good construction practices. Use clean infiltration material of controlled size.

 

SOURCES
“Water Well Handbook”, Keith E. Anderson Published by Missouri Water Well and Pump Contractors Association, Inc.
“Ground Water & Wells”
Published by Johnson Division, UOP Inc.
“Ground Water & Wells” 2nd Edition, Fletcher G. Driscoll
Published by Johnson Division

Leachate Collection Sump Pumps

Some Ideas - by John Hasslen

Over sizing pumps tends to be the most common cause of premature failure.

A centrifugal pump and motor are happiest if they run all the time.

  • Less heat is generated
  • Less precipitation and build-up of scale
  • Fewer solids will settle out

One obstacle in sizing leachate pumps close to generation rate is the 100-year storm event requirement of many regulators.

This very often leads to over sized pumps.

I would like to offer these suggestions as possible solutions to this sizing dilemma:

  1. Use 100-year generation to size pump with pump running 24 hours per day (with no service factor).
  2. Design in more than one sump with lower flow rate pumps.
  3. Design sump with two or more pumps installed in one or two risers into a common sump area. These pumps could alternate running at low generation and both run at high generation. The control scheme would be lead, lag, alternating.
  4. Design system using variable frequency drive to change flow rate of pump. If you double the pump's speed, you will get twice the flow rate and four times the discharge pressure. For example, a pump designed for 25 GPM at 50 TDH at 1,800 RPM will produce 83 GPM at 550 TDH at 6,000 RPM. This pump would require 1HP at 1,800 RPM and 25HP at 6,000 RPM.
  5. Design system with pump for 100-year generation flow capacity and a flow control valve on its discharge line. This pump is used when the cell is first opened and then replaced with a lower flow pump as the cell fills with trash and the generation rate falls. Large pumps can be moved to a new cell as the site expands.
  6. Design system at permitting time for recirculation; pumping leachate from new cell to old cell to help promote biodegradation.

The reality of sizing pumps based on 100-year storm generation rate quite possibly will not meet regulator intent of minimum head on liner if pump and/or sump are out of service caused by over sized pumps.

Over sized pumps (high flow rate) create problems.

  • High velocity
    • This pulls in fine particulate matter and increases incrustation and fouling.
  • Rapid start/stop cycles
    • Decreases motor and pump life and increases motor surface temperature, which increases plating out on motor surface.

 

The goal should be to size leachate collection pumps at just above average leachate generation rate. From the pumps point of view, the closer the better.

SOURCE

Company’s Experience – 25+ years and over 10,000 pumps in the field.
Personal Experience – More than 40 years in the pump business.