BRX Do-More Communication Do-More Do-More Designer HMI Modbus TCP PLC PLC Basics PLC Learning

Now You Can Have Robust Data Logging for Free – Part 1

Robust PLC Data Logger
With traditional loggers, the software will read the memory of the PLC and store in a local computer. If the network stops or the PLC communication fails then the logging will stop.
Creating a robust PLC data logger allows the communication to be stopped for a period of time without losing any of the data for collection. This is accomplished by storing the data locally on the PLC until communication is restored. All of the data is then read without loss. The amount of time that the connection can be lost will be dependent on the memory size of the PLC and the frequency of the data collected.
This series will walk you through the steps to create and implement a robust PLC data logger using the following equipment and hardware.

  • Automation Direct – Do-More – H2-DM1E PLC (Ethernet Modbus TCP)
  • Do-more Designer 1.3 (Simulator instead of PLC mentioned above)
  • Windows-based computer running IIS
  • Visual Basic 6

The following steps will be explained in details and sample programming.

Now You Can Have Robust Data Loggin...
Now You Can Have Robust Data Logging For Free

PLC program
The programmable logic controller PLC will log the data in the PLC memory using indirect addressing for the data log. Information will be collected based upon shifts.
We will use the following shift schedule. Midnight, Afternoon and Days for the weekday and have two-weekend shifts. Each shift will show the amount of product made, utilization of the machine and rate of product made.
Also, we will log a minute by minute account of the machine. This will log the amount of product made and the rate at which it is made. We can then graph the machine performance to determine if it is running correctly.

Data Collection
Visual Basic 6 will be used to log the data into a database. The information will be collected using Modbus TCP communication to the Do-More PLC and/or Simulator of the Do-more Designer. This will use an Ethernet communication cable to the PLC. The program will read the indirect address pointers in the PLC. It will then read the information collected and store the information into an Access Database. The indirect address pointers will then be reset by the program.

Data Distribution
We will set up a web server (IIS). This will allow the access database containing the information from the PLC to be available to all of the computers on the local network. (Intranet)
We will use Active Server Pages (ASP) and HTML to create programs to access this database information. Web browsers will call our ASP and HTML program so the information can be displayed on the device. This will be universal when we look at it with computers, tablets, and phones.

Advanced Data Distribution
Using Raphael and SVG programming, we will graph using line graphs. We will also see how we can use dials to create dashboards on our web server.

This may sound like a lot of work to do, but it is not. What we are doing is breaking down the fundamentals to display information. Using a robust logging system from the PLC ensures the reliability and your confidence in the data collected. Once the basic principles are applied, your system can expand rapidly.

Are you ready?

If you have any questions or need further information please contact me.
Thank you,

If you’re like most of my readers, you’re committed to learning about technology. Numbering systems used in PLC’s are not difficult to learn and understand. We will walk through the numbering systems used in PLCs. This includes Bits, Decimal, Hexadecimal, ASCII and Floating Point.

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The ‘Robust Data Logging for Free’ eBook is also available as a free download. The link is included when you subscribe to ACC Automation.

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