Several issues could be the cause of this. A few typical causes are listed below:
- Communication cable is unplugged/damaged.
- Drive is in a boot up state.
- Flash card is unplugged.
- Installed hardware revisions are not correct.
- Programming device has not been assigned in NetPro.
- Correct communication path, Device/S7ONLINE, has not been selected.
- Incorrect communication protocol has been set.
- IP address on the programming device is not set to the range of the drive or is the same address.
- Using an eWON connection.
- Baud rate is set incorrectly.
- Node address on the programming device is the same as the drive.
- PG/PC is the only master on the bus” is/is not set. This is specific for direct connection to a drive or via a routing method.