Drive Frequency Reference Differs From The Controller Frequency Reference; Command; Large Inconsistency In Stopping Position Due To The Load Rate; Deceleration Takes Longer Than Expected When Dynamic Braking Is Enabled - YASKAWA CR700 Technical Manual

Drive Frequency Reference Differs from the Controller Frequency Reference

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Command

Causes
The analog input gain and bias for the frequency reference input are set to
incorrect values.
Frequency bias signals are being entered via analog input terminals A1 to A3
and the sum of all signals builds the frequency reference.
During low speed operation the motor rotates faster than the frequency
reference.

Large Inconsistency in Stopping Position Due to the Load Rate

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Causes
The deceleration is inconsistent because of the Stall Prevention during
Deceleration function.

Deceleration Takes Longer Than Expected When Dynamic Braking Is Enabled

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Causes
The stall prevention during deceleration setting is incorrect.
The deceleration time setting is too long.
The motor torque is not sufficient.
The drive and motor system reached the torque limit.
The load is more than the internal torque limit as specified by the drive rated
current.

The Motor Rotates after the Drive Output Is Shut Off

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Causes
DC Injection Braking is too low and the drive cannot decelerate correctly.
The stopping method makes the drive coast to stop.

Suspension Drops (Falls)

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Causes
The V/f setting is too low.
Motor parameters are not adjusted while using Open Loop Vector Control,
Closed Loop Vector Control, or Advanced Open Loop Vector Control.
The torque limit setting is too low while using Open Loop Vector Control,
Closed Loop Vector Control, or Advanced Open Loop Vector Control.
YASKAWA SIEPC71061723A YASKAWA AC Drive CR700 Technical Manual
3.11 Problems that Can Frequently Occur during Setup and Possible Solutions
Check the gain and bias settings for the analog inputs that are used to set the frequency reference.
• Terminal A1: H3-03 [Terminal A1 Gain Setting], H3-04 [Terminal A1 Bias Setting]
• Terminal A2: H3-11 [Terminal A2 Gain Setting], H3-12 [Terminal A2 Bias Setting]
• Terminal A3: H3-07 [Terminal A3 Gain Setting], H3-08 [Terminal A3 Bias Setting]
• Check whether two or more of H3-02, H3-10, H3-06 [MFAI Function Selection] have a
• Check if the analog input values set to terminals A1, A2, and A3 are appropriate using U1-13
Decrease the value set in n4-70 [Speed Command Comp @ Low Freq].
Extend deceleration up until the Stall Prevention function no longer operates.
• Examine the setting for L3-04 [Decel Stall Prevention Selection].
• When the drive has a dynamic braking option installed, set L3-04 = 0 [Disabled].
• If the drive detects ov [Overvoltage], set L3-04 = 3 [General Purpose w/ DB resistor].
Set C1-02, C1-04, C1-06, or C1-08 [Deceleration Times] to applicable values.
Use a larger motor.
• Examine the values set in L7-01 to L7-04 [Torque Limit] and increase them if necessary.
• If H3-02, H3-10, H3-06 = 10, 11, 12, 15 [MFAI Function Select = Torque Limit] has been set,
Replace the drive with a larger capacity model.
• Increase the value set in b2-02 [DC Injection Braking Current].
• Increase the value set in b2-04 [DC Inject Braking Time at Stop].
Set b1-03 = 0 or 2 [Stopping Method Selection = Ramp to Stop, DC Injection Braking to Stop].
Increase the V/f setting.
Do the motor Auto-Tuning process.
Increase the setting values of L7-xx [Torque Limit].
Possible Solutions
setting value of 0, and change the settings if necessary.
to U1-15 [Terminal A1, A2, A3 Level].
Possible Solutions
Possible Solutions
Note:
If these items are correct, the demand on the motor is more than the motor capacity:
• Parameter settings are correct.
• The drive does not detect ov [Overvoltage].
Note:
If the torque limit is enabled, deceleration time can increase because the drive cannot output
more torque than the limit.
examine the settings for the MFAIs.
• Examine the values set in H3-02, H3-10, and H3-06.
• Use U1-13 to U1-15 [Terminal A1, A2, A3 Input Voltage] to make sure that the analog
input values set to terminals A1, A2, and A3 are applicable.
Possible Solutions
Possible Solutions
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