What are the points to check in case of SLF1 fault on Altivar71/61 drive?


22 October 2021

SLF1 fault causes on Altivar71/61 drive

Product Line:
All ATV61 ATV71


Fault condition drive will not run.

A modbus communication fault indicates that the communication has worked properly between the drive and the server.  But during the time set in [Modbus time out] (ttO) parameter, a loss of communication has been detected.

On configuration:
- Check the server state (RUN, stop…).
- Check if there is no network overload.
- Check the time out value (try to increase the value).
- Check the time between the sending of 2 Modbus requests (if the time is higher than the time out value, the drive can trip in fault).
On environment:
- Use the Telemecanique cable with 2 pairs of shielded twisted conductors (catalog number: TSXCSA100, TSXCSA200 or TSXCSA500).
- Keep the Modbus cable away from the power cables (30 cm minimum).
- If it is necessary for the Modbus cable and the power cables to cross each other, be sure they cross at right angles.
- A reflection in a transmission line is the result of an impedance discontinuity that a traveling wave sees as it propagates down the line. To minimize the reflections from the end of the RS485-cable, it is required to place a line termination near each of the 2 ends of the bus.
- Whenever possible, connect the cable shielding to the protective ground, e.g., to the ground of each device if this ground is connected to the protective ground.