Optimizing Motorola MDLC Over IP

Chris Phelps
Systems Software Engineer, Lord and Company, Inc.

This technical article for Motorola RTU networks using Ethernet links covers the messaging architecture of MDLC over Ethernet. How the MDLC is implemented within the IP structure, how the retry settings affect the messaging and what IP protocol is being used.
In order to document and validate some concepts of MDLC over Ethernet test in a lab environment have been performed. Two ACE 3640 processors with ID’s 1000 and 2000 communicate over Ethernet port (ETH1). An application was loaded into both units to send a message from site 1000 to 2000 using in some cases a TxFrm (transmit frame) and later a SndFrm (send frame) message type. (STS software version 15.50). In order to capture the network traffic between the units a port mirroring device in conjunction with a computer with running Wireshark software network diagnostics software has been used.
Motorola uses UDP (User Datagram Protocol) as opposed to TCP (Transmission Control Protocol). The difference is TCP guarantees the recipient will receive the packets in order by numbering them. The recipient sends messages back to the sender saying it received the messages. When using UDP, packets are just sent to the recipient. The sender won’t wait to make sure the recipient received the packet — it will just continue sending the next packets.
Test 1. The port configuration parameters of both units have default values. When a TxFrm type message is used between sites the following capture is observed on Wireshark:

Fig 1. Wireshark capture between site 1000 and 2000 using TxFrm. Successful communications between sites.

The 3 messages sent back and forth between sites are known as a three way hand shake. It is a three-step method that requires both the client and server to exchange SYN and ACK (acknowledgment) packets before actual data communication begins. The first message (denoted above as No. 1) is the “SYN”, the second message (denoted above as No. 2) is the “ACK” and the third message (denoted above as No. 3) is the actual Data Packet sent from the STS Application. Notice that when both sites are communicating the time delays between each event is the milliseconds order (as expected for a 10/100 communication link)
Test 2. The port configuration parameters of both units have default values. In this test the communication link between sites is failed or disconnected. When site 1000 use a TxFrm to site 2000 the following capture is observed:

Fig 2. Wireshark capture between site 1000 and 2000 using TxFrm.  Bad communication between sites

Site 1000 did three attempts of the “SYN” message to the destination site (Site 2000) with a 10 second delay between each try. These results are correlated back to the Advanced Port Settings of the unit:

 Fig 3. Partial view of ETH1 Ethernet advance port configuration parameters for sites 1000 and 2000.

The Poll interval parameter is the time delay between retries (10 seconds in this example) and the Maximum number of poll parameter is the number of retries to send a message (3 in this example).

The importance of this parameters is that it allows a programmer to adjust the time delay between retries and the number of “MDLC” retries, without any additional programming at the application level.  Configuring this parameter accordingly reduces the possibility of overruns when a message is transmitted.  Message overrun is a term we use to describe when the application attempts a retry prior to the MDLC retry attempts expiring, this could cause the transmission buffer of one site to become full and the potentially start dropping messages and affect the performance of the CPU.

Finding the optimum balance between time and number retries and listening time (RTU is not sending messages) can be key to fixing communication issues and streamlining communications. The optimization procedure can be extensive and have multiple iterations before finding the correct balance; considerations to the network structure, speed, data reliability and the particular application will have to be considered to make proper adjustments.

Another important feature of the test was to demonstrate the use of network capture tools such as Wireshark to do diagnostics and help on the parameter settings configuration using reliable data.

On the next article a similar test will be performed using a transmission type SndFrm (Send Frame) between sites.  We will show the parameters effect on the sites that communicate using this type of frame.

Giving Versus Taking

Give

I am proud to say that I have been working at Lord & Company for almost 20 years.  I started with the company in May of 1996.  One of the things that impressed me most about the company was their generosity.  Generosity is an area of my life that I have struggled with since I can remember as a small boy growing up in a rural area of Carroll County, Virginia.

 

We all like to exaggerate about how it was when we were kids.  You know the old stories of walking to school uphill in the snow both ways.  I always had food to eat, clothing and anything that I needed.  I did not grow up with very many items that I may have wanted.  I saw others with much more and I wanted to be like them.  At some point in my early childhood I made a decision that I was willing to work hard but I was going to get those things that I wanted.  Unfortunately, I decided to become a taker.

 

As the years have passed by I have begun to see that it is not about Taking as much as it is about Giving.  The little boy inside of me has finally realized that he wants to become a Giver and not a Taker.  This process started when I repented of my sins and ask Jesus Christ to come into my life on November 29, 1992.  That was the single Greatest day of my life and since that day it has been a process of change.

Helping Hands

I am impressed with so many of my co-workers that give their time, talent and resources outside of work each week.  Some of them coach Special Olympics, others teach or train youth, while some raise money for charities or food for the hungry.  They come together for special events like Operation Christmas Shoebox and go over our goal of 200 boxes.  There too many to mention in this short article.

 

Lord & Company is a generous company that cares about our community and those less fortunate.  I have been blessed to see giving in action firsthand over the past 20 years.  Yes we have the most talented professional staff that I have ever worked with in my career but they are so much more.  They have demonstrated to me how to become a Giver and not a Taker.

Helping

You can ask anyone that knows me and they will tell you that I appreciate a job well done.  Well done Lord & Company Team.  Thank you for demonstrating volunteer work and for helping me to start opening up my hand and become that giver that God has always wanted me to become.  Lord & Company is a generous company made up of generous talented people that care about others.

Keep on making a difference in my life and those around me!     

#GivernotaTaker    

 

Tom Carico – PMP

Lord & Company, Inc.

The Places You Will See; Gary Mintz

curve-2-final2-990As I drive around the southeast, (NC, SC, GA, TN, VA & Washington, DC), I can tell those who are traveling with me that Lord and Company, Inc. installed that antenna on that tower or water tank you see in the distance.  Or this is the place where we installed PLCs and wrote programs and created graphics to let the operators know the status is of their systems.  Or it might be that we are gathering data via radio to know when to turn on pumps to fill the water tanks we are passing by on the road.  It makes me feel good to know that I have friends in these places.  These are people who I feel I could call on if I needed assistance in that area.  There is some comfort in knowing wherever you go, you could be near someone you know.

 

I will never forget the experience on Tuesday morning, September 11, 2001.  I was in Lockhart, SC.  This was one of my first TLI projects – a small control panel with a large led display that could be turned on remotely to show the customer the amount of water in their tank.  Saves the customer time now that they no longer have to unlock the gate, go in to read a value from inside the location.  I was here when the World Trade Center Towers were destroyed.  My daughter called to ask if I was alright, and I told her that where I was, no one would waste time bombing here because I’m in the middle of a large field.  I am okay.  How about you?

 

The historic city of New Bern, NC has memories for me as well.  This project had several PLCs, SCADA and fiber optics.  My first time traveling to New Bern was with Tim, one of our programmers.  Tim and I were able to discuss the project and I knew he had a good grasp on what was to be done.  We met the folks at New Bern, discussed our plans and they worked with us during the installation.  We hired someone nearby to install the fiber optics and test the installation for us.  I learned valuable information about fiber optic installations.

 

I pass near Lumberton, NC on my way to the beach.  I did PLC work there before I worked for Lord and Company and when I was given the opportunity to replace the Square D PLCs with Modicon PLCs, I was delighted.  Upon my first trip there, I was taken aback when they said this ODS panel does not work.  I said if it is not working and we are going to replace it, let’s be sure we get it working like you want it to before I write the new program.  On my next trip I asked what did not work.  I found the outputs quickly and noted the logic when called to run the pumps was not turning on the output.  There was a timer in the program that had no entry for the amount of time delay.  I entered a value into the reserved location and voila.  The logic showed the output was energized.  But, wait, the pump still was not coming on.  Let’s check the output fuse.  Sure enough, it was blown.  A replacement fuse was installed and this time, the ODS pumps worked.  Now the fun part – reprogram what was done many years previously.  Any time I am passing nearby, I call and ask, “How are you?  Is there anything I can do for you?”  I know the folks there really don’t need me anymore because they have very capable people running the plant.  However, I still like to keep in touch.

 

Upon my traveling home, about half way, I pass through the small town of Salisbury, NC.  Years prior, I called on these folks in a sales role for an electrical manufacturer.  I was delighted when appointed to handle their account with Lord and Company.  Salisbury was adding a new filtration system furnished by another integrator.  The new system must run simultaneously with their existing system.  They needed to be able to switch from the old system to the new system without losing data in their SCADA system.  When the day of the changeover occurred, there was no clue that anything had ever changed.  It was a successful merger of the two systems.  I had some really smart programmers working on the SCADA portion.  All I had to do was figure out what the previous systems integrator had programmed and understand their logic so I could advise our people what to expect, where to look for important data and they were well on their way to making all items appear as desired.

 

My family had a small trailer across the Intercoastal Waterway from Oak Island, NC.  When I was assigned a project in Supply, NC within seven miles of that trailer, I felt like I was home.  Previously I did some PLC work for Brunswick County.  On this project Lord and Company supplied nine control panels networked via fiber optics all around their water plant.  My New Bern experience helped.  Our service technicians were now able to make the fiber optic terminations.  Lord and Company has grown into a successful systems integrator.  I have close friends in Brunswick County and when I travel to the beach, they are remembered.  When hurricanes cause them problems, I call and ask how they came through.  God has blessed them as so far no damage has been done to their homes or lives as a result of hurricanes.

 

One last place is Washington.  Did I say, NC or DC?  I could mention both because I have been to each with Lord and Company.  I am into my 8th year doing something with the AOC.  These folks are quietly demanding and understanding about the construction process.  They are constantly meeting to be sure all parties are on the same page.  They handle questions and provide specific answers to the questions.  From the control room operators to the board room, the folks are really good to work with.  The operators are willing to learn what the new controls will be doing.  They know they have to run the system after we are gone and they get involved to make things work right.  They don’t get in the way, mind you, they just help when asked.  From coal fired boiler additions to boiler feedwater pumps to 5,000 ton air conditioning chillers all networked via fiber optics and coming to a central DCS system, Lord and Company has been there since 2007 to provide them the controls to run the pumps and equipment.

 

Also, in the Washington, DC area is the DC Blue Plains Enhanced Wastewater Treatment Plant.  Lord and Company is working with Ulliman Schutte Construction, LLC to provide/modify control panels, add flow meters and various other instruments to provide a distributive control system at one of the largest wastewater treatment plants in the United States.

 

When I travel, I see places where I have had an opportunity to make a difference.  It is a treat to ride down the highway knowing that you were somewhat responsible for the way that equipment operates.  It gives me a warm fuzzy feeling that I was able to help someone have a better life.  I have friends in these towns and there is not enough space to write about what took place at each location but it brings back memories to me – these places you will see.

Photo by James Clear

Live2Lead 2015, by Rafael Balderrama

L2L Pic
On Friday October 9th Team L&C had the opportunity to attend the Live2Lead conference. The speakers presented and shared key leadership tools to the participants. This event was broadcast to more than 40,000 people in USA and around the world.

John Maxwell and others, delivered passionate messages on how to improve our lives and the lives of people we work with. The main theme was developing a positive attitude in all circumstances as leaders.

The presentation emphasized that consistency and passion for our work produces positive working environments.  Implementing new action plans to lead a team to succeed was also an emphasis.

I have been a recreational tennis players for many years. I had the opportunity to hear the word consistency in a coach program I attended this year.  The key to win a match is not only to hit the tennis ball hard but being able to hit it inside the court and over net every time. This is as many people refer, “to be consistent”.  In our work environment we need to develop a similar attitude to be the best in our trade and to set an example for our team members.

I also found interesting the concept of differences in “Front end thinking” and “Back end thinking”.  In front end thinking we plan, set goals and priorities for good outcomes instead of looking at the back end results of unplanned activities.

L&C team leaders were impressed with the quality and content of the message of the speakers.  As a team leader I look forward to using the concepts within the Lord & Company. This will lead us to have continual growth and we can become a better organization to our society.

We want to thank Keith Harris of Fellowship Management and Lord & Company for coordinating and promoting this event in Rock hill, SC.

OPERATION CHRISTMAS CHILD AT L&C,

OCC Big Logo

By Brooke Morris, Design Team Member

Operation Christmas Child is a project of Samaritans Purse that partners with Churches in foreign countries to spread the Gospel to boys and girls.  OCC presents a shoebox full of gifts and essentials to the children, and many disciple through a Bible study course.  Each year Churches and companies across the region collect and pack shoeboxes to expand and grow the spread the word of Jesus Christ.

The method of filling a shoebox is simple. You can use an adult size shoebox or get a preformed box from the ministry.  The shoebox, made up of a “Wow item”, a special gift for the child such as soccer ball with pump, stuffed animals, dolls, toy cars and trucks. Also the box should contain school supplies, non-liquid hygiene items, accessories, crafts and other fun toys or activity books.  There are 3 age levels and you can choose the gender of the child also. Girls 2-4, Girls 5-9, Girls 10-14 & Boys 2-4, Boys 5-9, Boys 10-14. There is a suggested donation of $7 to cover the shipping of the shoebox. You can even track your box online by completing the tracking label and submitting your $7 donation for shipping.

Lord & Company, Inc. started participating in Operation Christmas Child in 2013. Our first year we collected about 25 boxes. In 2014 we encouraged our company to take part more and set and met a goal of 60 boxes.

For 2015 we wanted to push further and get even more people involved in the project.  Our goal is 200 boxes. To help reach this goal we had a company meeting to explain exactly what Operation Christmas Child is all about and showed our teams how to pack a shoebox. We have planned a packing party for November 6th and have encouraged our employees to get their kids and family involved. I know personally that my 15 year old son and 4 year old grandson love to help shop for the boxes. They are learning to give to others. These are kids that don’t have the everyday necessities that are often taken for granted by children in the US.

By adding something new each year, we hope to gain more interest and thus collect more boxes. To maximize our collection for 2015 we are doing a Penny Drive. Each L&C team gets a collection pale and challenged to see who could bring in the most change by November 6th for our packing party. The change collection will buy extra items needed when we pack the boxes.

Our final collection day is November 13th. We will pray over the boxes for God’s will and the Love of Jesus to spread and shared through the children that receive this special gift. Our boxes will then shipped to Samaritan’s Purse and distributed during December.

Basic Time Management for Team Environments

time management

 

I have been working in the Engineering Field for about 30 years now and one thing has not changed.  We need to be able to do more work in less hours.  I have read books on time management and went to seminars to help me develop time management skills.  I also know that everyone is different but I wanted to share a few items that has worked for me and helped me with my time management.  I hope that you will find some items that will help you with your time management.

 

Be aware and on the outlook for the small things that distract you from your work each day.  You may want to check your emails 2 or 3 times a day but do not leave them up in front of you at all times.  If you stop what you are doing to read each email as it appears on your screen this will take up half of your workday.  Impromptu meetings can also be a leading cause of disruptions in your work day.  Request that meetings have a schedule with an agenda so that it minimizes everyone’s time involved.  I know that meetings are necessary to get work done in a team environment but planned and scheduled meeting are far more productive.  I enjoy attending and being part of productive meetings but I do not recall a productive meeting that I attended without an agenda.

 

Have a written plan for each day.  This helps me stay focused on the work that has you’ve decided to be a priority for the work day.  This helps me stay on track each day and helps me to see my daily goals.  I typically use my tablet for this purpose.

 

Keep a daily progress report.  How many times have I worked 9, 10 or more hours in one day and left work feeling like I was not productive?  The answer is way too many times.  Keeping a daily progress report helps me focus on each day’s successes even when I worked on items that were not planned.  Yes, no matter how much planning you do there will be days that outside factors force you to change your priority list for the day and you work on other items.  Keeping a daily progress report helps me remember to focus on the work items that I completed for the day and not the items that I did not get accomplished.

 

Answer Phone calls.  If you are not deep in the middle of a task you should go ahead and answer that phone call.  I know we all get too many phone calls that we may consider non-productive but it may take less time to take the call than to return the phone call later.  Remember that we all want someone to answer our phone calls so we should do the same.  If you have voice messages, set aside a couple of times a day to return phone calls.  I try to return calls at 10 AM and at 3 PM each day.

 

A Good night’s sleep.  Each day starts so much better if you get a good night’s sleep.  I have found that I work better with 7 hours sleep each night.  I can make it on less sleep but it catches up with me by the end of the week.  I know that coffee is my friend in the morning since I am not a morning person but coffee will not make me productive all day long.  Sleep prepares my mind and body for each work day.  Do not underestimate the importance of a good night’s sleep.

 

Multi-tasking.  I have tried to multi-task and I have found myself making too many costly mistakes.  I work on many projects and I wear many hats each day so this is a daily thorn in my side.  I have my work schedule, my home family schedule, my church schedule, my volunteer schedule, my reading schedule and so on … You get the picture. We are all busy and if we are not careful we try to focus on too many things at one time and we are not effective at any of them.  Concentrate on one item at a time and complete it.  I try to keep one schedule for work and home with alert reminders to help me remember all the items that I want to do and schedule.  I often hear people say that I wish I could remember this or that thing tomorrow.  I typically say if we could only have someone invent something that was small and easy to carry that we could schedule reminders to alert us tomorrow?   It is too bad that you do not have such a device like this that could help you.  Use your Smart Phone to help you and remind you of anything and everything that is important to you.

 

One of our greatest resources that we have is time.  No matter rich, poor, young, older God gave us all the same 24 hours each day.  Make a plan and use your time wisely.  I hope that some of the things that I have learned and shared on time management will help you focus and become more productive each day.  I continue to work on improving my time management skills each day.  Speaking of time management; the phone is ringing and it is time for me to get back to work.

Time Clock

Date: 11/1/15

Respectfully Submitted:

Tom Carico – PMP

Lord & Company, Inc.

Top 5 – Reasons I enjoy working with the LC Team

top 5

I have been blessed to work at Lord & Company for the past 20 years in multiple areas in the LC Team. I wanted to share just a few things that I enjoy about my day to day work at Lord & Company.

5. I enjoy the opportunity to work with different types of technology. Each new project provides new challenges; whether it is Radio (RF Technology), Fiber LAN, WAN, PLC Control Panels or some new instrument. I have the opportunity to work with new software and technology on a daily basis. This keeps me learning and enthusiastic about the next new project.

4. I enjoy doing quality work and being part of the LC Team that puts an emphasis on doing high quality work for our clients. Doing your best just makes everyone feel better at the end of the day. We strive to continue to improve our quality on each phase of each project.

3. I enjoy the teamwork and the people. We spend some long hours working together to meet deadlines on projects and it can get hectic at times but at the end of the day I really appreciate working as a team. I am an introvert; so working as a team helps me get out of my comfort zone. I have made some friendships at work with some great people that will last a lifetime.

2. Customer Service is another high priority and I enjoy being able to help clients when the opportunity comes knocking. I appreciate the fact that we will email the client their PLC code on a past project if they need it and help answer questions after the project is over. I have heard way too many horror stories about System Integrators that will not send their client the PLC programs in an effort to force them to continue doing business with them. I have been able to help our customers and competitors; that is truly customer service.

1. Integrity is our number one goal at Lord & Company. I enjoy seeing a company practice what they preach; integrity. I enjoy building relationships with vendors and treating them the way I would like to be treated. Integrity is our foundation and a benchmark for our success.

I did not have room to add in the lunch hour and I always joke about it being my favorite time of each work day. Everyone that knows me; they know that I like to eat. I enjoy eating in our lunch room with others to catch up with them and their family. I also like going out to lunch to some of the local restaurants nearby.

Thanks for taking time to read about some of the reasons that I enjoy working with and being a part of the Lord & Company Team.

integrity post

Respectfully Submitted:

Tom Carico – PMP

Lord & Company, Inc.

L&C Has Big News!!

IMG_0082[1]Lord & Company would like to announce some Big News.  Tom Carico has served as the Engineering Manager for Lord & Company for the past 20 years.  Tom has decided to step down as the Engineering Manager September 1st, 2016 and has announced that Rafael Balderrama will be taking the position.  Tom will be working with Rafael over the next year to ensure that the transition goes smooth.

 

Tom explained that “Rafael has worked very hard and done whatever has been requested of him without the first complaint over his tenure with Lord & Company.  Rafael is well qualified and I look forward to see him fulfill his vision for the L&C Engineering Team.  Rafael has been a Big part of the Lord & Company Engineering Team for the past 10 years.  I congratulate him and I look forward to working with him.”

 

Tom will continue to serve his role as the Project Manager Team Leader and Manage Projects.  We appreciate the leadership that Tom has brought to Lord & Company and the growth that we have experienced in his tenure.  Tom gave credit to God and the talented and gifted staff that he has been privileged to work with at Lord & Company.  Tom was eager to remind everyone that he is leaving the LC Engineering Team in good hands with Rafael.