Yaskawa Z1000U HVAC Matrix Bypass - Manual (Page 272)

n Oscillation or Hunting
Cause Possible Solutions
Gain is too low when using PI control. Refer to b5: PID Control on page 142 for details.
The frequency reference is assigned to an external
source and the signal is noisy.
• Ensure that noise is not affecting the signal lines.
• Separate main circuit wiring and control circuit wiring.
• Use twisted-pair cables or shielded wiring for the control circuit.
• Increase the analog input time filter constant (H3-13).
The cable between the drive and motor is too long.
• Perform Auto-Tuning for line-to-line resistance.
• Reduce the length of the cable.
u PID Output Fault
Cause Possible Solutions
No PID feedback input.
• Check the multi-function analog input terminal settings.
• Set multi-function analog input terminal A1, A2, or A3 for PID feedback (H3-02, H3-10, or
H3-06 = B).
• A signal input to the terminal selection for PID feedback is needed.
• Check the connection of the feedback signal.
• Check the various PID-related parameter settings.
• No PID feedback input to the terminal causes the value detected to be 0, causing a PID fault
and the drive to operate at max frequency.
The level of detection and the target value do not
correspond with each other.
• PID control keeps the difference between target and detection values at 0. Set the input level
for the values relative to one another.
• Use analog input gains H3-03, H3-07, and H3-11 to adjust PID target and feedback signal
scaling.
Reverse drive output frequency and speed detection.
When output frequency rises, the sensor detects a
speed decrease.
Set PID output for reverse characteristics (b5-09 = 1).
Adjustment made to PID parameter settings are
insufficient.
Refer to b5: PID Control on page 142 for details.
u Motor Rotates after the Drive Output is Shut Off (Motor Rotates During DC Injection
Braking)
Cause Possible Solutions
DC Injection Braking is set too low and the drive
cannot decelerate properly.
• Adjust the DC Injection braking settings.
• Increase the current level for DC Injection Braking Current (b2-02).
• Increase the DC Injection Braking time at stop (b2-04).
The stopping method is set so that the drive coasts to
stop.
Set b1-03 (Stopping Method Selection) to 0 or 2.
u Output Frequency is Not as High as Frequency Reference
Cause Possible Solutions
Frequency reference is set within the range of the Jump
frequency.
• Adjust the parameters used for the Jump frequency function (d3-01, d3-02, d3-03).
• Enabling the Jump frequency prevents the drive from outputting the frequencies specified in
the Jump range.
Upper limit for the frequency reference has been
exceeded.
• Set the maximum output frequency and the upper limit for the frequency reference to more
appropriate values (E1-04, d2-01).
• The following calculation yields the upper value for the output frequency:
E1-04 x d2-01 / 100
Large load triggered Stall Prevention function during
acceleration.
• Reduce the load.
• Adjust the Stall Prevention level during acceleration (L3-02).
6.9 Troubleshooting without Fault Display
272 YASKAWA SIEP YAIZ1D 01A Z1000U HVAC MATRIX Drive Bypass Technical Manual