194 ACQ550-U1 User’s Manual
Embedded fieldbus
Faults 31…33 – EFB1…EFB3
Except as noted above, these three EFB fault codes (listed for the drive in
Diagnostics on page 251, fault codes 31…33) are not used.
Intermittent off-line occurrences
The problems described above are the most common problems encountered with
ACQ550 serial communication. Intermittent problems might also be caused by:
• Marginally loose connections,
• Wear on wires caused by equipment vibrations,
• Insufficient grounding and shielding on both the devices and on the
communication cables.
• Two conductor wire (plus shield) is in use instead of the recommended three
conductor wire (plus shield), see page 180.