6.4 Fault Detection
YASKAWA ELECTRIC
SIEP C710606 44B YASKAWA AC Drive T1000V Technical Manual
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6.4 Fault Detection
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Fault Displays, Causes, and Possible Solutions
Table 6.9 Detailed Fault Displays, Causes, and Possible Solutions
LED Operator Display
Fault Name
bUS
Option Communication Error
• After establishing initial communication, the connection was lost.
• Only detected when the run command frequency reference is assigned to an option card.
Cause
Possible Solution
No signal received from the PLC.
• Check for faulty wiring.
• Correct the wiring.
• Check for loose wiring and short circuits. Repair as needed.
The communication cable is faulty or a
short circuit exists.
A communications data error occurred due
to noise.
• Check the various options available to minimize the effects of noise.
• Counteract noise in control circuit, main circuit, and ground wiring.
• Ensure that other equipment such as switches or relays do not cause noise and use surge
suppressors if required.
• Use cables recommended by Yaskawa or another type of shielded line. Ground the shield on the
controller side or on the drive input power side.
• Separate all wiring for communications devices from drive input power lines. Install an EMC noise
filter to the input side of the drive input power.
The option card is damaged.
• Replace the option card if there are no problems with the wiring and the error continues to occur.
The option card is not properly connected to
the drive.
• The connector pins on the option card are not properly lined up with the connector pins on the
drive.
• Reinstall the option card.
LED Operator Display
Fault Name
CE
MEMOBUS/Modbus Communication Error
Control data was not received for the CE detection time set to H5-09.
Cause
Possible Solution
Faulty communications wiring, or a short
circuit exists.
• Check for faulty wiring.
• Correct the wiring.
• Check for loose wiring and short circuits. Repair as needed.
A communications data error occurred due
to noise.
• Check the various options available to minimize the effects of noise.
• Counteract noise in control circuit, main circuit, and ground wiring.
• Use Yaskawa-recommended cables, or another type of shielded line. Ground the shield on the
controller side or on the drive input power side.
• Ensure that other equipment such as switches or relays do not cause noise and use surge
suppressors if required.
• Separate all wiring for communications devices from drive input power lines. Install an EMC noise
filter to the input side of the drive input power.
LED Operator Display
Fault Name
CF
Control Fault
A torque limit was reached continuously for three seconds or longer during a ramp to stop while in
Open Loop Vector Control.
Cause
Possible Solution
Motor parameters are not set properly.
Check the motor parameter settings and repeat Auto-Tuning.
Torque limit is too low.
Set the torque limit to the most appropriate setting (L7-01 through L7-04).
Load inertia is too big.
• Adjust the deceleration time (C1-02, C1-04, C1-06, C1-08).
• Set the frequency to the minimum value and interrupt the run command when the drive finishes
decelerating.
LED Operator Display
Fault Name
CoF
Current Offset Fault
The current detection circuit is damaged, or there was residual induction voltage in the motor (such
as during sudden deceleration or when coasting) when the drive attempted to start the motor.
Cause
Possible Solution
While the drive automatically adjusted the
current offset, the calculated value
exceeded the allowable setting range. This
problem may occur when attempting to
restart a coasting PM motor.
• Create a motor restart sequence that allows enough time for residual induction voltage to dissipate.
• Perform External Speed Search 1/2 (H1-
= 61, 62) using the external terminals.
• Enable Speed Search at start (b3-01 = 1).
Note:
When using a PM motor, both External Speed Search 1 and 2 perform the same operation.
