Emerson Control Techniques EN Series Installation Manual page 56

Encoder State
Certain encoder states and state transitions are invalid and will cause the drive to report an
encoder state fault. This is usually the result of noisy encoder feedback caused by poor
shielding. For some types of custom motors it may be necessary to disable this fault. Refer to
the Advanced Tab section of Setting Up Parameters for more information.
Encoder Hardware
If any pair of complementary encoder lines are in the same state, an encoder line fault is
generated. The most likely cause is a missing or bad encoder connection.
Motor Overtemp
This fault is generated when the motor thermal switch is open due to motor over-temperature
or incorrect wiring.
RMS Shunt Power
This fault is generated when RMS shunt power dissipation is greater than the design rating of
the internal shunt.
Overspeed
This fault occurs in one of two circumstances:
1. When the actual motor speed exceeds the Overspeed Velocity Limit parameter or 150%
of motor maximum operating speed. This parameter can be accessed with PowerTools
software.
2. If the combination of command pulse frequency and Pulse Ratio can generate a motor
command speed in excess of the fixed limit of 13000 RPM, an Overspeed Fault will be
activated. In Pulse mode operation and any Summation mode which uses Pulse mode,
the input pulse command frequency is monitored and this calculation is made. For
example, with a Pulse Ratio of 10 pulses per motor revolution, the first pulse received
will cause an Overspeed fault even before there is any motor motion.
Following Error
This fault is generated when the following error exceeds the following error limit (default
following error limit is .2 revs). With PowerTools you can change the Following Error Limit
value or disable in the Position tab. The Following Error Limit is functional in Pulse mode
only.
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Diagnostics and Troubleshooting
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