RsLogix 500 - Allen Bradley Micrologix Data Logging
The Allen Bradley Micrologix 1100, 1400, and 1500 all have a built in data logging feature that allows acquired data from these units using the free Micrologix DataLog Extract Utility.
To be free, this is one of the most straight forward methods I have seen for acquiring data from a Programmable Logic Controller. Below is a step by step rundown on how to do it.
1. First we will create a new project with the processor type of a “Micrologix 1100 Series A”.
2. Then on the left pane, scroll down to Data Logging and double click "Configuration".
3. Right click “Data Log Configuration” and click “New”.
4. For this example we will record 10 records. This is a first in, last out system, so if we continue to write data then the oldest records will be overwritten.
5. For the Separator Character that will delimit our data we will use “Comma”.
6. For most applications, time stamping is desired, so let’s check the “Date Stamp” and “Time Stamp” fields.
7. Now we will enter the addresses we wish to log. Note: The data must be in form of a word or double word. If you wish to log B3:0/5 then you must log the entire word, B3:0. We’ll get into how to extract the bit later. Also floating point data is not supported.
So let’s enter B3:0 and press the select key. You will now see it added to the “Current Address List”.
8. Let’s also add “T4:0.ACC”, “C5:0.ACC”, “R6:0.POS”, and “N7:0”.
9. Now go ahead and click “OK”. We have successfully completed our Data Logging Configuration. We can trigger our logging based off of practically anything. So let’s throw some code in there to vary our data and trigger the logging. Below is mine. There is no logic to it and you don’t have to copy it. The main thing is that you vary your data and trigger the DLG instruction for this example. Download your program and let it run long enough to trigger the Data Logging several times.
10. Open up the Micrologix DataLog Extract Utility.
11. Go to the Configuration menu and click “Select Devices…”.
12. Select your Micrologix. The path will vary depending on your network configuration.
13. Press the right arrow button to send it over to the “Selected Devices” and press OK.
14. Now we are ready to read our data. Go to the File menu and select “Read DataLog”.
15. You will now see your data in the right pane.
16. Now we may save this data to Excel and manipulate it as we need or import it into our data system as we need to.
While this is a manual method of data logging, it doesn’t take much to modify the GetDataLog.exe file to make it fairly automated. You can already schedule automatic polls of the data under the Configuration menu. With a few modifications to the exe file you can customize the column descriptions and add your paths of your PLCs permanently into the file.
Go to the Allen Bradley RsLogix 500 PLC Training PLC Training Getting Started Lesson series to select your next lesson. There are also many other Lesson Series on PLC Programming and Industrial Automation.