Volume 1, Issue 3

APPLICATION ARTICLE

This months application article focuses on a long standing customer of ours. McConkey Co. is a leader in the field of greenhouse irrigation. They currently use the SK1600-RIC ePLC in their systems. more >

If you have an application that you would like to submit for consideration, email us at plcs@entertron.com and in the subject area type in "application article"

TECH TIPS

GROUNDING

Entertron's ePLCs should be located in a well grounded metal enclosure. The metal mounting plate supplied with some of our controllers is not grounded. The necessary precautions must be taken to meet any local codes that apply to the application. ( Note: UL Versions of the SK1600-RIC provide grounding of the mounting plate).

The Elite-2000 controller has a third terminal on the 12VAC power connection that is for grounding the controller.

The Elite-2000 Analog controller has a third terminal for ground on the incoming 115VAC power. In order make a complete the earth ground connection, Jumper JP5 needs to be connected. Please refer to the Elite-2000 analog expansion board wiring diagram supplied with the controller for the proper location of JP5.

The Smart Pak Plus controller also has a jumper that must be connected in order to connect the board ground to earth ground. Please refer to the Smart Pak Plus wiring diagram for the proper placement of the earth ground jumper A to B.

The SK1600-RIC controller does not have an earth ground connection, but you can ground the mounting plate that the controller is mounted to. If the controller is ordered with UL recognition it has a terminal block that is connected to the mounting plate for earth grounding.

IMPORTANT- please be aware, that when you are connecting all earth grounds together, make certain there is no difference in potential between the different power supplies. It is possible to create a ground current loop, that could cause problems within your system.

Also please be aware that grounding a PLC can get rid of noise in the system or it can induce noise into the system. If noise is a problem you might want to try it both ways.

If there are any questions you would like answered, email us at plcs@entertron.com and in the subject area type "tech tips question"

THE PROGRAMMERS CORNER

PID Control

PID loops are popular control algorithms used in various applications. Some of the more common applications include controlling position and temperature. PID loops control a process by watching the error signal of the process and adjusting the control signal accordingly. There are six main sections of PID programming:

1. SET POINT - Is the value or reference you are trying to reach in a closed loop application .

2. ERROR - Is the difference between the set point and the actual value (Set point - Actual = ERROR)

3. FEEDBACK - Is the actual value or signal relating to the process (Actual measured signal)

4. PROPORTIONAL GAIN - Proportional gain is multiplied by the error to create an adjusted output signal. The larger the gain the larger the output change. If proportional gain is the only one used then the output can get relatively close to set point but there will always be an error.

5. INTEGRAL GAIN - Is based on a history of error. The lower the Integral number the more frequently it will check the error and the greater its influence on the output. With both P and I gain used, they help each other out by eliminating the steady error associated with proportional only control.

6. DIFFERENTIAL GAIN - Is based on the rate of change of the error. Its used to limit overshoot and hunting. The greater the derivative time the greater the influence

Please refer to Application Note 1 for more information and an example that provides the foundation for programming a PID loop using Entertron's ePLCs.

Eware32 Tips and Tricks

When Programming in Eware32 you must place your contacts as close to the left as possible. You should always start by selecting and replacing the short at the beginning of each rung. By doing this you avoid problems with compile errors.

If there are any questions you would like answered, email us at plcs@entertron.com and in the subject area type "programmer's corner question"

THE ENTERTRON ADVANTAGE

This month, being the half way point of the year, I thought I would do something a little different for the Entertron Advantage. Rather than do what we did with the first two news letters in offering useful information on how Entertron and it's products can best work for you, the OEM and your company, I thought I would provide you with some results from our web site.

Entertron is located on many search engines and is continually improving its rank in the web listings (non-sponsorship listings). It is amazing at what has happened in the first six months of 2003. Every time I look at the numbers, I am completely amazed. People are finding Entertron via the Internet. They are reading our content and are tired of what they have to put up with from our competitors. Here are some numbers for you:

* Total Visits = First time visitors + recurring visitors.

** Unique IP Address = First time visitors to Entertron's web site.

Some of these numbers may not seem like much, if you were working for Allen Bradley or Automation Direct that have enormous advertising budgets to specifically direct customers (current and potential) to their web site, but when you look at the size of Entertron in relation to our much larger competitors, we are starting to achieve acceptance with our unique approach to the PLC market. We have increased our total visitors by 33% since the beginning of the year and nearly 100% growth in both Total Visits and Total Page Views for the same six month period last year.

Where does Entertron rank on the world wide web? Of the entire world wide web - we rank 924,000. We are in the top million!!! That may not seem like much, but in the last three months, we have increased our position by over 200,000 spots. In terms of page views, we are 832,414 (again, in the top million!!!) and have improved our position there by over 224,000. Every day, more and more people are being introduced to Entertron's unique manner in how we do business.

The result of our web presence has produced many new applications currently under development. Even though our sales have been flat, mainly due to the current economic environment where engineering dollars are extremely tight, the future looks bright. More companies are reevaluating their existing application needs and looking for alternatives. Some are looking only for cost reductions, while others are frustrated with how they are being treated by the large companies. Entertron clearly offers an alternative to the larger PLC manufacturers by doing the following:

• Offering Free Programming Software

• Providing a longer warranty that no other PLC manufacturer comes close to.

• Repairing our own controllers for up to 10 years

• Some companies consider it a privilege, but Entertron considers it a right to talk with a live person when you first dial the phone. There is no automated attendant. During our regular business hours (8 am - 5 pm Eastern) you will always speak to a live person.

• Superior output ratings

Feel free to contact us any time to discuss your application needs.

PRODUCT NEWS

We at Entertron are extremely excited about the introduction of ePalm - Entertron's new interface for Personal Data Assistants (PDAs) also know as Palm Pilots.

ePalm installs into your PDA and through a cable attachment to Entertron's ePLCs, you have an inexpensive hand held interface. Entertron will not be selling the PDAs, but only the interface software and cable.

You will now be able to equip your entire team of field service technicians with a PDA loaded with ePalm and they can trouble shoot our ePLCs with ease. You can offer it to your customers as an inexpensive operator interface option in addition to, or in place of our panel mount options. As an OEM, you could save cost on your application when using ePalm. The PDA is your customer's operator interface.

Unlike other software where you have to renew a service contract, in order to obtain support, or the license is only for one year...the ePalm is good for the PDA it is installed on. Bug fixes are included. When Entertron comes out with a new version, offering new features, then if you wanted to upgrade, you would be required to purchase the new version....that is your option.

The ePalm interface requires a ModBus driver to communicate to our ePLCs.

Click for more information regarding ePalm. You can also view the press release.

SPECIAL OFFERS

With the Introduction of ePalm, we are providing a Free Download. The download will run without a license for up to 30 days. Once the 30 days have expired, you will require a license to operate ePalm.

To the many students that are currently learning about the incredible world of PLCs and programming, we are offering you a special student discount - Any controller, any configuration - 20% off (includes computer cable and programming software). Compare this to other offers and you will see the benefits.

We continue with great success our OEM introductory offer. Any OEM that has never purchased from Entertron in the past can take advantage of this offer - 50% off any controller, in any configuration. For more information, click for details.

CLOSING NOTES

If you have missed an issue of Entertron Intelligence, not to fear, you can view past issues on our web site.

Any general questions, not related to one of our subjects can be emailed to us at plcs@entertron.com and in the subject area type in "entertron intelligence question"

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