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Logging Data from Logix Controllers

Wayne Welk1/3/2019

Logging data from a controller is a useful feature to see trends in a machine, or process, or for monitoring remote skids. Having historical data available can help you troubleshoot problems or optimize your process.

Version 12 of Connected Components Workbench (CCW) software includes a new feature, the Micro800 Simulator. The Micro800 Simulator provides a software application to emulate the behavior of a Micro850 48-point controller. It allows experimentation and debugging of application code in a controlled environment. Micro800 Simulator supports project version 12 and later. 

Logix controllers don’t log data natively, so to speak (meaning simple check a box to log a tag). But there are several options available to log data, both on-board the controller or externally. 

Below are just some of the solutions available from Rockwell Automation and their Encompass Partners to help you log data. We’ve listed them from the most simplistic to the most advanced. 

Log to a Secure Digital (SD) card 

If you’re using a newer Logix controller (version 16 and above), you can take advantage of the Compact Flash (CF) or Secure Digital (SD) card slot to log tags in the application. All you need is a memory card, and some programming to write to the card. It’s fairly easy to do and comes with little to no cost. Rockwell Automation provides sample code to help you with the programming steps needed to write to the removable memory card. 

Reference (C:\RSLogix 5000\Projects\Samples\ENU\v16\Rockwell Automation) for the following files (note sample code will be in the folder that matches the version installed on your PC – v16 is shown in the path above): 

  • CF_Read_Write.ACD (routines to reuse in your project) 
  • CF_Read_Write_Example.ACD (working example with 4 Recipes) 

Why it’s a good solution: 

Writing data to the on-board SD card is the least expensive option for data logging – all you need is the SD card. But you will need to write code in the controller to initiate the log file on the SD card, and write data to the card. Fortunately, Rockwell Automation has some sample code to help with that. Gathering the logged data can also require some work. You will need to extract the SD card from the controller and bring it back to a PC to review the data. 

Learn more about using a SD card with a Logix Controller 

ProSoft PLX51 Data Logger 

The PLX51-DL-232, is a relatively new product from ProSoft, that can read and store data from EtherNet/IP PLCs, DF1 Serial PLCs and devices, or Modbus PLCs and devices. The PLX51-DL-232 has the capacity to store over 16 million records in its solid-state non-volatile memory. Each stored record includes a Date Time stamp, Tag Name, Data Type, and Value. 

Why it’s a good solution: 

The PLX51 data logger is small, DIN-rail mounted, rather inexpensive (under $1000), and very easy to configure. It can communicate using EtherNet/IP to Logix controllers (ControlLogix and CompactLogix), and can also communicate with DF1 and Modbus serial to legacy controllers. Accessing the logged data is fairly easy, and exports to a CSV file for easy manipulation. And with storage of over 16,000,000 timestamp points, it can keep a rather large buffer of data. 

Learn more about the ProSoft PLX51 Data Logger 

eWON Flexy 205 

The eWON Flexy 205 is an advanced internet data gateway that allows Machine Builders to monitor and collect vital KPIs for analysis and predictive maintenance. With data logging, alarming, built-in web interface, scripting and enhanced internet connectivity, the Flexy 205 is a modular Internet Gateway for your IoT deployment. It also supports VPN Remote Access for easy troubleshooting of your distant industrial equipment. 

Why it’s a good solution: 

The eWON Flexy 205 is a “Swiss Army Knife” of sorts for industrial automation applications. The Flexy 205 can combine several products into one device – industrial Ethernet switch, data logger, remote access gateway, alarm management, web-based HMI, plus a lot more, and all for under $1000. The data logger can store up to 1,000,000 timestamp points. Although the storage buffer is not as large as the ProSoft PLX51, the Flexy 205 can still make for a good data logger, in addition to providing many other useful features. 

Learn more about the eWON Flexy 205. 

Historian ME Module (ControlLogix® only) 

FactoryTalk® Historian Machine Edition (ME) module installs in a ControlLogix chassis, and provides high-speed, reliable data capture. It achieves its superior reliability through a solid state design hardened for on-machine use and with no moving parts. A limited software footprint requires no server or PC, significantly reducing the risk of data loss due to network or other system interruption and making the unit ideal for remote or hard to service locations. 

Why it’s a good solution: 

The FactoryTalk Historian ME module can work as either a stand-alone historian/data logger, or can roll up into a larger plant-wide historian like FactoryTalk Historian SE. This provides for greater flexibility, and long term storage beyond the 2 GB on-board storage. The Historian ME module can also perform high-speed data capturing by leveraging backplane communication to achieve 10 millisecond scan rates. The Historian ME module comes in at a higher price-point that the ProSoft PLX51 and eWON Flexy 205, but has it’s advantages if you need high-speed data capturing, or need to easily move your data to a larger plant-wide historian. 

Learn more about the Historian ME Module 

Historian SE 

The most complex, but yet the most powerful data logging option, would be to use FactoryTalk Machine Edition SE for logging and archiving data. Whereas Historian ME is an in-chassis solution with limited storage, Historian SE runs on a PC or server, and and not only log data from the Logix controller, but can also aggregate data from multiple sources and devices. Data storage is only limited to the resources available on your PC or server (hard drive size), so you can capture and store a very large amount of data. 

Why it’s a good solution: 

Historian SE is built on OSIsoft’s PI historian and has a robust set of features. Reporting features include Excel add-in components to easily get data from the Historian archive. Data can also be easily viewed in dashboard form, and shared with key stake holders using FactoryTalk VantagePoint. Historian SE is a scalable solution, starting as small as 250 tags for roughly $5000 in cost (software only). There is more overhead and infrastructure required for Historian SE, but this is also the most powerful data archiving option available from Rockwell Automation. 

Learn more about FactoryTalk Historian SE