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 CIPR-CR70A Series Technical Manual

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Drive Frequency Reference Differs from the Controller Frequency Reference

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.
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Large Inconsistency in Stopping Position Due to the Load Rate

Causes
The deceleration is inconsistent because of the Stall
Prevention during Deceleration function.
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Deceleration Takes Longer Than Expected When Dynamic Braking Is Enabled

Causes
The stall prevention during deceleration setting is incorrect. • Examine the setting for L3-04 [Decel Stall Prevention Selection].
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.
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The Motor Rotates after the Drive Output Is Shut Off

Causes
DC Injection Braking is too low and the drive cannot
decelerate correctly.
The stopping method makes the drive coast to stop.
YASKAWA ELECTRIC SIEP C710617 19A YASKAWA AC Drive CR700 Technical Manual
3 Startup Procedure and Test Run
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 setting value of 0, and change the settings if necessary.
• Check if the analog input values set to terminals A1, A2, and A3 are
appropriate using U1-13 to U1-15 [Terminal A1, A2, A3 Level].
Decrease the value set in n4-70 [Speed Command Comp @ Low Freq].
Possible Solutions
Extend deceleration up until the Stall Prevention function no longer
operates.
Possible Solutions
• 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.
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].
• Examine the values set in L7-01 to L7-04 [Torque Limit] and increase
them if necessary.
Note:
If the torque limit is enabled, deceleration time can increase because the
drive cannot output more torque than the limit.
• If H3-02, H3-10, H3-06 = 10, 11, 12, 15 [MFAI Function Select =
Torque Limit] has been set, 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.
Replace the drive with a larger capacity model.
Possible Solutions
• 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].
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