Fieldbus control 299
Diagnostics – EFB
Fault queue for drive diagnostics
For general ACS320 diagnostics information, see section LEDs. The three most
recent ACS320 faults are reported to the fieldbus as defined below.
Serial communication diagnostics
Network problems can be caused by multiple sources. Some of these sources are:
• Loose connections
• Incorrect wiring (including swapped wires)
• Bad grounding
• Duplicate station numbers
• Incorrect setup of drives or other devices on the network
The major diagnostic features for fault tracing on an EFB network include Group 53:
EFB protocol parameters 5306…5309. Section Parameter listing describes these
parameters in detail.
Diagnostic situations
The sub-sections below describe various diagnostic situations – the problem
symptoms and corrective actions.
Normal operation
During normal network operation, 5306…5309 parameter values act as follows at
each drive:
• 5306 EFB OK MESSAGES advances (advances for each application message
properly received and addressed to this drive).
• 5307 EFB CRC ERRORS does not advance at all (advances when an invalid
message CRC is received).
• 5308 EFB UART ERRORS does not advance at all (advances when character
format errors are detected, such as parity or framing errors).
• 5309 EFB STATUS value varies depending on network traffic.
• BACnet protocol: 5316 EFB PAR 16 (MS/TP token counter) advances for each
token passed to this drive. (Does not apply for other protocols.)
Drive Parameter
Protocol Reference
Modbus N2 FLN BACnet
0401 Last Fault 40401 17 90 AV18
0412 Previous Fault 1 40402 18 91 AV19
0413 Previous Fault 2 40403 19 92 AV20