The primary cause of F7490 is the removal of the enable signals while the drive is active. This typically places the drive in a "switching on inhibited" state. Common triggers include: Withdrawal of Enable Signals : Loss of signals such as OFF1, OFF2, OFF3 Enable Operation during a move. Secondary Fault Triggering
To prevent the F7490 Siemens drive fault from occurring, follow these best practices:
This fault essentially signals that the drive's signal was suddenly withdrawn while the motor was still in motion (traversing). What Causes the F7490 Fault?
The drive enters a "switching on inhibited" state because it was forced to stop unexpectedly during a positioning task. The most frequent triggers include: f7490 siemens drive fault
Activating safety features (like STO or SS1) during a positioning task will immediately withdraw EPOS enables, triggering the fault. Common Remedies
In the world of industrial automation, Siemens drives (particularly the Sinamics S120, G130, G150, and S150 series) are renowned for their reliability and precision. However, like any sophisticated piece of equipment, they occasionally encounter faults. One of the more common yet often misunderstood alarms is the .
A specific bit in the telegram toggles (0,1,0,1) with every cycle. If the Control Unit fails to see this bit toggling for a defined period (typically a few milliseconds), it assumes the connection is dead. The drive then triggers the F7490 fault and, depending on your parameterization, performs a emergency stop (OFF3) or a pulse disable. The primary cause of F7490 is the removal
To effectively fix the F7490 fault, you must understand its root causes. They generally fall into three categories: electrical noise, parameter misconfiguration, or hardware degradation.
: Ensure the PLC is not unintentionally dropping the control word signals (e.g., bit 0 for OFF1) while the motor is commanded to move. Verify Hardware Connections Check for intermittent encoder signal loss , as this can trigger a sequence that leads to F7490.
Siemens drive fault (often seen as F7490) signifies that an EPOS enable signal was withdrawn while traversing . This occurs within the Basic Positioner (EPOS) function when a command to stop or inhibit operation is received before the drive has finished its positioning task. Primary Causes Secondary Fault Triggering To prevent the F7490 Siemens
Confirm the assignment of binector inputs for the basic positioning function, specifically checking that the "no intermediate stop" (BI: p2640) signal is set to "1" during motion.
: Activating a safety function (like STO or SS1) during motion will immediately withdraw the EPOS enable signal, resulting in this fault.