Rexroth Diagnostic Messages


Rexroth electric motion control units won’t remind you of the movie Her, but they do their best to communicate with you. The messages they send are called “diagnostic messages.” These messages consist of a string of numerals followed by a string of text. If there are multiple messages, one will be shown at a time, in order of priority. Once one message is resolved, the next will show.

The first item in the string

The first place shows the type of message you’re getting:

  • Error diagnostic messages begin with F.
  • Warning diagnostic messages begin with E.
  • Command diagnostic messages begin with C.
  • Drive mode diagnostic messages and Operation status messages may also be seen, and they will begin with other letters.

Right away we can see that the process of understanding diagnostic messages will not be as easy as we might have expected, because “C” stands for “command,” but “E” does not stand for “error.”

“F” typically stands for “fatal,” actually, and F messages will fall into four broad categories:

  • Fatal errors, shown by strings beginning with F8, will be met by the drive with torque free switching.
  • Travel range, beginning with F6, will bring on speed command value-zero switch from the drive.
  • Interface, starting with F4xx, and non-fatal starting with F2, will both lead to “Best possible
    deceleration” responses from the drive.

Once the error is resolved, the drive must be reset with the S-1 button or by initializing through the control.

The rest of the string

The rest of the error code number gives more detail. For example, an invalid cam shaft will show the code F205 — a non-fatal interface error, since it starts with F2. 05 tells you the specific problem: an invalid cam shaft.

Rexroth components rarely break down, so chances are good that you won’t recognize the diagnostic message you see, but the numerals are followed by text in the language chosen when the parameters were set. So you might see “cam shaft invalid,” “undervoltage in power section,” or “excessive deviation.” The object of these codes is to make the problem clear. However, since the space available is less than for a Twitter message, you may need to go to your manual for more detail.

For example, a specific error might be caused by overheating, which could result from excessive ambient temperature, dirt or debris in the cabinet, or a defective blower in the drive. Only the third issue requires you to buy a new drive.

That means that it’s worth getting out your manual and following the instructions before you do anything rash… like buying a new unit. Make sure you’re checking the manual for the part you have.

If you need a manual, expert support, or a new unit, call us.

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