Service Mode - What is it and how to collect diagnostics

What is Service Mode?

Service mode means that no task classes are running on the PLC. The application program is not running; the PLC is halted. There are three reasons why a PLC goes into service mode:

  1. The Reset button is pressed on the PLC
  2. The “Stop Target” command is sent from Automation Studio
  3. A critical error occurred at runtime

Points 1 & 2 are intentional actions by the user, so the reason for service mode is known. If a critical error occurs on the PLC which sends it into service mode (point 3), then the error will be entered in the logbook. The purpose of this document is to show you how to obtain the log file so that the reason for unexpected service mode can be determined.

Steps to Obtain the Log File

There are three options to obtain the log file which do not require the B&R Automation Studio software:
B&R Service Utility
This method should be used if your only option is to establish a serial connection (RS232) to the PLC. This utility is only supported in Windows XP and Windows 7. This is the preferred method if the PLC was programmed around or before roughly the year 2010.

System Diagnostics Manager
This method should be used if you are able to establish an Ethernet connection to the PLC. You must know the IP address of the PLC in order to access the System Diagnostics Manager. The PLC must be SG4 (CPU with an Intel processor) and it must be running Automation Runtime 3.0 or higher.

CF / CFast card
If your PLC has a CF or CFast card and it is running ARembedded, then you can obtain the logbook directly from the card. This method requires a CF or CFast card reader, which can be purchased at any general electronics store. This method is useful if you are having trouble establishing a serial or Ethernet connection to the PLC.

B&R Service Utility

Here are the steps to obtain the log file via an RS232 connection and the B&R Service Utility:

  1. Download the B&R Service Utility from the following link:
    BR Service Utility | B&R Industrial Automation

  2. Install the Visual Studio 2008 (VC++ 9.0) SP1 Redistributable Package X86 Architecture from
    Microsoft from the following link. Make sure to restart your laptop after installing this package.
    Latest supported Visual C++ Redistributable downloads | Microsoft Learn

  3. Make or acquire an RS232 serial cable (null-modem). The required pinout is shown below.

  4. Run the B&R Service Utility (brServiceUtility_v14.exe).

  5. Click OK to the initial pop-up:

  6. Set the connection type to “Serial” (this is the default value) and click OK:

  7. Select the COM port of your serial port or USB-to-serial adaptor. The COM port in use can be foundin the Device Manager.

  8. Select “Save Error Logbook” (this is the default value) and click OK.

  9. Choose a download location. Note that the folder that you save the logbook to must already exist (you cannot create a new folder with this window). Also be sure to include the trailing backslash.

  10. Choose a file format for the log file and click OK.

  11. Send the resulting log file to your local B&R Support Team.

System Diagnostics Manager

The System Diagnostics Manager (SDM) is an integrated web server which contains a plethora of diagnostic information about the PLC. There is a feature called the System Dump which collects all of the data (including the log file) into one file. The System Dump is available starting with AR V3.08. Here are the steps to access the SDM and get the System Dump:

  1. Identify the IP address of the PLC. If you don’t already know this information, contact the OEM or see Determining a PLC's IP Address using Wireshark.

  2. Set the IP address of the Ethernet port on your laptop to be unique and on the same subnet as the PLC. For example:

    To check and/or change the IP address of the Ethernet port on your laptop, refer to the following article from Microsoft: Change TCP/IP settings - Microsoft Support
    For example, in Windows 10:

  3. Open a web browser (e.g. Google Chrome) and type the IP address of the PLC /sdm. For example ifthe IP address of the PLC is, then you would navigate in a browser to:
    If you are unable to access the SDM in this step, then that either means that your Automation
    Runtime version is too old or the SDM has been disabled on your PLC. In this case, obtain the log using one of the other methods described here.

  4. Click the System Dump icon in the middle:

  5. Choose “Parameters + Data-Files” and click OK

  6. Click OK on the subsequent pop-up.

  7. Click “Upload from target”.

  8. Send the resulting .tar.gz file to your local B&R Support Team.

Note: If your PLC is running a version of Automation Runtime greater than or equal to V3.0 but less than V3.8, then you can access the System Diagnostics Manager but the System Dump will not be available. In this case, select the Logger tab and then click the “Upload from target” button to upload the arlogsys log file separately.

CF / CFast card

Here are the steps to get the log files directly from the CF / Cfast card:

  1. If you don’t already have the Runtime Utility Center, download the PVI Development Center off of the B&R website from the following link:
    PVI Development Setup | B&R Industrial Automation
    Otherwise, skip to step 2.

  2. Open the Runtime Utility Center. You can find this on your Start menu under B&R Automation.

  3. Select “Create, modify and execute projects (.pil)”

  4. Go to “Tools” → “Back up files from Compact Flash / Image file…”

  5. Select the CF card:

  6. Wait for Runtime Utility Center to finish reading disk information:

  7. Expand the contents of the disk as follows: DATA1 Partition → RPSHD → SYSROM

  8. Within the SYSROM folder, select all entries which begin with a $. These correspond to the log files. (Note that you may not have all of the entries shown in the screenshot below.) Checking these boxes will automatically check the boxes of the parent folders DATA1 Partition, RPSHD, and SYSROM.

  9. Browse for a location to save the files (for example, C:\LogFiles):

  10. Click Start:

  11. Once the files are saved, you will receive this pop-up:

  12. Send the saved log files to your local B&R Support Team.


Can you use the B&R service utility via ethernet instead of serial? I tried to ping the unit unsuccessfully, but I was not sure when it assigns an IP address.

Yes, you can! But you have to know the IP address of the PLC.

I know the IP, but I was unable to ping it. When does a panel get assign the IP when booting up? I had another panel not too long ago that booted in Diagnostic mode and I was unable to connect VIA SDM because the IP was established.