ABB AC 800M Hardware And Operation page 132

FOUNDATION Fieldbus – CI852
One or more field
devices appear to
be slow to
respond or
completely dead
The network
problem is
proving very
difficult to solve
132
Table 25. FOUNDATION Fieldbus CI852 – Fault-Finding (Continued)
Fault
1.A device may be:
• Incorrectly addressed.
• Connected with incorrect polarity.
• Faulty and causing breakdown or heavy loading of the
network.
2. The fieldbus cable may:
• Be damaged causing a short-circuit, breaks or grounding
of the data wires, (possibly intermittent).
• Be incorrectly terminated.
• Contain sections having reversed polarity due to incorrect
connections.
• Cause supply voltage drops due to damage or bad
connections.
3. The network power supply may be faulty.
• Rectify the network power supply.
Give consideration to possible activities within the plant, such
as maintenance or repair work, which may be causing the
problem. Having totally ruled this out, then proceed as follows:
Check the DC supply voltage in powered networks by means of
a digital voltmeter having an input capacitance of less than
1000 pF.
Possible Cause and Corrective Action
Section 5 Maintenance
3BSE 027 941 R301